ZX Computings - OpenLibra

AN ARGUS SPECIALIST PUBLICATION 

Britain's Biggest Magazine For The Sinclair user 

oftware reviews 

ut of this world? 

* Tourist trap 

•a Spectrum voyage 

I! to the sun 

Education 

or Business 

plan it on your ZX micro 

icwu"*

NO HARDWARE REQUIRED 

Applications include: define your own space invaders, draw lowercase characters 

and fine line characters. 

a . 

The 

tool-box 

has 8 

hi-res 

commands 

C . R . L • Dept PCT 

140 WHITECHAPEL ROAD, LONDON E1 

or TELEPHONE 01-247 9004 DEALER ENQUIRIES WELCOME 

r 

i

Professional Software 

for ZX81 and Spectrum 

SPECTRUM 48K 

• Payroll: Weekly, monthly, hourly All tax codes, £.nd pay levels 

Guaranteed correct £25 00 • Statutory Sick Pay: Better than 

programs costing 10 times as much on other machines £.40 25 

• Stock Control: Over 1500 lines Find, add, delete, in 2 seconds' 

Sinclair or full-width plain paper printer (with interface) supports.'. 

£25 00 • Spectrum Demo Tape: Demonstration versions of payroll, 

stock control. SSP On one tape £3.95 • Critical Path Analysis: Enter 

network of over 500 activities. Program finds critical path Durations 

and costs can be modified, and the calculation repeated Pull width 

printer supported. £ 15.00 

SPECTRUM 16K (usable on 48KJ) 

a Mortgage: See how repayment amount affects duration and total 

amount paid While paying see how much interest and how much 

capital you are paying Month by month table printed. On the same 

tape • Loan: Calculates true interest when "paying instalments etc. 

£6 00 (both programs together) 

Parallel Printer Interface: 

Allows you to use a full width plain paper printer with your 16K or 48K 

Spectrum 1 Has too many features to list hure! COMPLETE with cable, 

connectors, and supporting software - nothing else to buy! £45.00 A 

runaway best seller so please contact us about delivery • Printers: 

We can help you to choose the best printer for YOU and get it to you fast 

at a sensible price FREE on request with orders for printer or interface 

simple word processing program for Spectrum! 

Tape Loading Problems With Your Computer? 

a The Microcomputer User's Book of Tape Recording: Is a 

practical guide to help you get program s in and out of your com pute r 

Written for the computer user but several audio and computer 

professionals have found it useful! ISBN 0 946476 00 4 ONI.Y £3 1S 

. net postage < £2 90 in shops) • Teat and Alignment Cassette: Tape 

loading problems are often due to a mis aligned tape head Align your 

tape head by ear with our tape no instruments required! £4 90 

a Loading Aid: Allows you to get tape playback level right first time 

Helps with dropouts and to ease tape quality too! Standard model £S9S, 

De luxe model £7 95 

ZX8116K 

BBeamscan: Computers bending moment and shear force diagrams for 

a simply supported beam with 1 -99 point, uniform and uniformly 

tapered loads £25.00 » Time Ledger: For up to 17 employees. 200 

clients £15.00 • Optimal: A powerful linear optimisation program up 

to 75 variables < ,= -.constraints £40 00 • Payroll: As above butonly 

up to 30 employees £25.00 • Stock Control: As above but 400 stock 

lines 16K or 2000 lines in 64K £25 00 • Critical Path Analysis: 

Up to 500 activities in 16K. Over 500 activities in 48K £15 00 

a Budget: Keeps track of expenses and compares with budget 50 

headings plus 12 months or 12 categories £15 00 • financial Pack: 

Contains three programs: Mortgage. Loan and VAT £6 00 

All items are post free and includo VAT Programs are supplied with 

comprehensive manuals. 

Remember We at Hilderbay pride ourselves in the development of 

high quality professional software that is fully functional and with full 

support. Not fancy packaging, fancy prices or fancy names 

COMING SOON 

a Word Processing Package will allow the use of a daisywheel 

typewriter, linked to Spectrum, as keyboard and printer 

Contact us now for further information on these products and our full 

range of Apple II and CP M Software 

TRADE EtJQUIRIES WELCOME ON ALL PRODUCTS 

Professional Software 

Hilderbay Ltd Dept. 8 10 Parkway 

Regents Park London NW1 7AA 

Telephone: 01-485 1059 Telex: 22870 ZX8 

OPPORTUNITY 

OF A 

LIFETIME 

FOR 

ZX81 

OWNERS! 

These are the real thing Official Timex/Smclair memory extensions 

made in the USA and specially screened to stop radio interference 

Don't miss out - order today! 

COMPUTER^ 

7-9 Thane Works, Thane Villas. London N7 7PH Tel 01-609 7919 

^>j(Ckl Rush me my ME 16 USA by return post ^^ 

Add 40p post and packaging to your order 

Herewith cheque/PO for £ 

made payable to Computer Add-Ons or if you would like to pay by Access or 

Bardaycard enter your ale number and signature 

Signature < 

Date 

Name 

Address 

d i rrm rrm rrm 

Occupation ZX3 

jômputer Add-Om 7-9 Thane Works. Thane Villas. London N7 

COMPUSOUND 

TELESOUND 84 

"THE ONLY ONE OF ITS KIND TO 

FIT INSIDE THE SPECTRUM" 

Probably the worlds smallest modulator! 

TELESOUND 84 is ready built and tested so get lull Spectrum 

sound through your unmodified television set. black/white or 

colour. The unit can be fitted in minutes without any previous 

experience. Telesound 84 has been developed using the very 

latest ultra miniature components so that the size is kept to an 

absolute minimum 

TELESOUND 84 FEATURES 

• Sound and vision together tor added realism • Beep volume 

controllable from a whisper to a roar • Keyboard prompt click 

clearly hard to assist program entry • Programs can be heard when 

loaded • Compatible with all other ZX add ons • No soldering or 

case cutting required • Additional amplitier not necessary • 

Separate power supply not required 

TELESOUND 84 comes complete with a tree sound ettects program 

and costs £9.95 inclusive ot post, packing etc Please slate 

your computer when ordering (allow 28 days delivery). 

COMPUSOUND 

32 Langley Close, Redditch, 

Worcs B98 OET 

1983 ZX COMPUTING AUGUST/SEPTEMBER 1983 3

ZX Computing 

Volume One 

Number Eight 

Aug/Sept 1983 

Letters 

Editor: Roger Munford 

Advertising Manager: Miriam Roberts 

Managing Editor: Ron Harris 

Managing Director: T J Connetl 

Origination and design by MM Design & Print, 

145 Charing Cross Road, London WC2H OEE. 

Published by Argus Specialist Publications Ltd, 

CONTENTS 

145 Charing Cross Road, London WC2H OEE. 

Check out other readers' views, 

programming hints and tips, and 

opinions on the micro scene in general. 

Write on! 

Muncher li 

Robert Turner presents a spectacular 

conversion of his Spectrum program 

featured in our issue — now for the 

ZX81. 

sHReconnaissance 

Alert 32 News 

You'll find yourself up in the air over this 

program from Stephen Smith. 

college 

Computing. . . 38 

Reviewer, Nick Pearce, takes a look at an 

educational series of software of the 

mathematical kind. 

Toolbox Trio 16 • Enemy Satellites . 40 

Three BASIC utility routines for the ZX 

Spectrum, courtesy of Richard Sargent. 

My Kind of Town .18 

Fresh from the Consumer Electronics 

Show in Chicago, Tim Hartnell 

scrutinises the new machines from 

Timex which have recently been 

introduced to the American market. 

Problem Page 

Having problems? Let Peter Shaw come 

to your rescue. 

Play Your cards 

Right 

Play pontoon on your Spectrum with this 

great program from C Taft. No cheating, 

mind. . . 

The 1K corral 26 

A new feature in which we round up a 

smashing collection of 1K games, etc, 

for your ZX81. 

PT 1983 

Stick to your guns and shoot down the 

enemy before they relay your secrets in 

this game from Martin Clayton. 

invincible 

Shoot down the spaceship before it 

shoots you — a great game from David 

Price. 

it's in The BOX 

Peter Shaw takes a long, hard look at the 

Fuller Box and reports back. 

Tourist Trap 

Blaze the tourist trail in this amazing 

adventure board game for your 48K 

Spectrum, courtesy of Colin Gooch. 

The 81 Soft 

Selection .... . .59 

Selecting software can be a difficult 

choice — see what Nick Pearce makes of 

some of the latest packages for the 


Find out what's new on the hardware 

and software scene, as well as a report 

on the seventh Microfair. 

Reader's Reviews . 71 

Find out what other readers of ZX 

Computing think of the commercially 

available software on the market. 

Reversi'80 74 

Combining machine code and BASIC, 

Kar Wing Wong presents a version of 

this popular game for the ZX80. 

Striking The Right 

Chord 76 

If you're learning to play the guitar, C 

Read helps you find the right chord with 

this program for your ZX81. 

Aliens 

Stop the alien force or you'll find yourself 

in a lot of trouble — more arcade action 

from Andrew Cole. 

ZX COMPUTING AUG/SEPT 1983 4

ZX Computing is published bi-monthly on the fourth Friday of the month. Distributed by: Argus Press Sales ft Distribution Ltd. 12-18 Paul Street. London EC2A 

4JS. 01-247 8233. Printed by: Henry Garnett Ltd., Rotherham. 

The contents of this publication including all articles, designs, plans, drawings and programs and all copyright and other intellectual property rights therein belong 

to Argus Specialist Publications Ltd All rights conferred by the Law of Copyright and other intellectual property rights and by virtue of international copyright conventions 

are specifically reserved to Argus Specialist Publications Ltd Any reproduction requires the prior written consent of Argus Specialist Publications Ltd. 

© Argus Specialist Publications Ltd 1983 

FRENZY -! >quest 

Mastering Machine H^Sf^ , > 

Code on Your MPr I 3 y r 

Spectrum 80 

Toni Baker looks at the art of machine 

code programming in general, and starts 

you off on a 'Grand Prix' type game for 

your Spectrum. 

Naught But A 

Came . .82 

The classic game of Naughts and 

Crosses — an '81 games program from 

S Stratford. 

Nick Pearce investigates two ways to 

produce high resolution graphics on your 


Competition 90 

Win yourself an AGF Hardware joystick 

package in our easy to enter 

competition! 

^ 4 \ THE 

* 2 black 

:RAZY 

The Soft Touch..106 

A wealth of Spectrum software comes 

under the critical eye of James Walsh. 

3D Mover .. 110 

An exercise in three dimensional 

graphics on your 2X81, courtesy of D 

Munro. 

Bats 112 

A 'batty' program for 

from Colin Gooch. 

Morse Trainer. .126 

Learn the intricacies of Morse code with 

expert tuition from R Gilbert and your 

Spectrum. 

KONG peeper 128 

your Spectrum 

Air Raiders 115 

H Davis' games program has you 

shooting down the enemy 'planes and 

missiles. Watch for your own 'planes 

though,. . 

Someone's watching you! Shoot the 

faces in the tower block before they 

disappear in this game from David 

Wilkins. 

An Apple A Day .13 'i 

Isaac Newton would have liked Russell 

Morgan's program. Ail you have to do is 

catch the apples as they fall off the tree. 

Sound's easy, but. . . 

House Of 

Horror 136 

Dare you enter Chris Cox's house — you 

do so at your own peril! 

Getting Fizzical .138 

Ever tried your hand at lemonade selling? 

Type in this listing from Michael Guy and 

find out how good you'd be. 

Equation solver 94HClub Corner .. . .usHMachine 

"Specifications .. 141 

If you're having problems with quadratic 

equations, maybe you should check out 

this program from John Norbury. 

Moon Rescue 

A classic lunar listing from John Miller 

which has you rescuing astronauts from 

the moon. Watch out for the alien 

spacecraft though . . . 

The Profit 

prophet .... . .100 

Michael Carroll's program will help you 

work out the profitability of your 

company. 

If you're interested in expanding your 

experience of computing, why not join 

the club? 

Motor Madness .120 

In the tradition of all good 'racing car' 

programs comes this great game from 

Keith Ditchburn. 

Spectrum 

Streams ...122 

Author, Mike Lord, shows you how to 

use some of the commands normally 

associated with the proposed 

Microdrives/RS232 network. 

A reference guide to the Sinclair range of 

computers. It's all here! 

ZX Computing is constantly on the look-out for 

well-written articles and programs. )f you think 

that your efforts meet our standards, please feel 

free to submit your work to us for consideration. 

All submitted material should be typed if possible: 

handwritten work will be considered, but 

please use your neatest handwriting. Any programs 

submitted should be listed, a cassette of 

your program alone will not be considered. All programs 

must come complete with a full explanation 

of the operation and. where relevant, the structure: 

Spectrum programs should be accompanied 

with a cassette of the program (which will be 

returned) as well as the listing. 

All submissions will be acknowledged and any 

published work will be paid for at competitive 

rates. AM work for consideration should be sent to 

the Editor ai our Charing Cross Road address. 

PT 1983 ZX COMPUTING AUG/SEPT 1983 5

Are your finances driving you mad? 

Do you find thai working out your 

finances makes your head buzz? 

Do you see red? 

Don't worry, now you can have 

Milton's Personal Banking 

System on your side, giving you 

a clear head start and 

(hopefully) putting you back 

into the black! 

Maintain permanent records 

and fully detailed statements of 

your finances including: 

* All cheque book transactions 

and bank receipts 

* All standing order payments 

Automatically Processed 

(monthly,quarterly, six-monthly 

or annually and for set number 

of payments) 

HILTON 

COMPUTER 

SERVICES 

ZUCKMAN 

ZX81 (16K) 

•ALL MACHINE CODE 

(10K) 

•FOUR INDEPENDENT 

GHOSTS 

•HIGH-SCORE 'HALL 

OF FAME' 

•AUTHENTIC 

ARCADE ACTION 

•TITLE/DISPLAY 

MODE 

ONLY £4.95 INC. P&P 

In addition the ability to 

search, locate, delete or 

correct previous entries. List 

by category facility is included. 

Additional Bank Reconciliation 

module available to 

automatically match your Bank 

Statement to your Personal 

Banking System account. 

Full instructions included and 

guaranteed after sales 

maintenance provided. 

* PBS ZXB1 £8.95 (16K) 

* ZX SPECTRUM £9.95 (48K) 

* DRAGON £9.95 (32K1 

Bank r*r«DrilUtioa (for nt urUkibmltS. 

^k lor Ihe PBS s machine code, so 

you get 32K per file. Comes with example file and 22 page manual 115.00 

SEW Masterfile46 for 16K Spectrum owners. 

We have produced a subset version of MASTERFILE called MASTERFILE 16 

It has most of the features of big MASTERFILE, with 7 predefined report 

formats and 6 pre defined fields e.g. name, address, etc., and we have found a 

useful 4500 bytes of file space. MASTERFILE and MASTERFILE 16 are fully 

''file-compatible' and will happily process each other's files, so that 16K owners 

who upgrade to 48K can use their old files immediately Complete with 12 page 

manual, priced at £8 95 

PLEASE REMEMBER TO STATE CLEARLY WHICH VERSION OF 

MASTERFILE YOU REQUIRE. 

as. GULPMAty 

LUwP^^J aame of the • man'variety 

with 15 mates. 4 chasers, laser defence. 9 grades, 9 speeds, demo mode, choice 

of loystick control. "An extraordinarily good program" raves Boris Allan for 

Popular Computing Weekly We think you will agree £5 95 

16KZX81 QULP2 almost identical spec to GULPMAN £4 75 

16 64K ZX81 THE FAST ONE is the predecessor to 

MASTERFILE and is in use all over the world now Specification is very similar 

to MASTERFILE £12 00 

Campbell Systems, Dept {zx), 

15, Rous Road, Buckhurst Hill, 

Essex, IG9 6BL, England. • ^ ^ 

Telephone: 01 504 0589 

••• fM ••• •• ••• •«••!••• 

DEPT ZX, 9 TWEEN CLOSE, SWINDON, WILTS SN2 3PU 

Tel: (0793) 724317 Trade enquiries welcome 

Export Orders: Please add £1.00 per tape airmail 

SPECTRUM 16K/48K 

VERSION OF Z/MAN 

£5.95 inc p&p 

FROGGY 

ZX81 (16K) 

•MOVING CARS, 

LOGS, TURTLES 

'ALLIGATORS, 

DIVING TURTLES 

•FOUR 'SCREENS' OF 

ACTION 

•ALL ARCADE 

FEATURES 

•ENTIRELY MACHINE 

CODE 

ONLY £4.95 INC. P&P 

• a* 

••••••• 

• • • 

• •• 

ZX Spectrum 

FROGGY 16K or 48K 

Spectrum vinion of 

Arcade Game with Full 

Arcade Features:- 

'Fabulous Hi Res 

Colour Graphics 

•Authentic Sound 

Effects + 3 Tunes 

'3 0 Logs. Swimming 

& Diving Turtles 

*3 Lanes of Multicoloured 

vehicles 

•On screen Score, Hi 

Score. Time-bar 

•Snake. Alligators and 

Baby F'og 

"'Top 5" High-Score 

initials table 

'Demonstration Game 

routine 

Your home-sick Dog 

must leap across a 

busy main road, then 

onto logs and turtles in 

the river to reach 

safetv ol the riverbank 

frog-homes 

THIS MACHINE CODE 

GAME MUST BE SEEN 

TO BE BELEIVEDI' 

ONLY £5 96 INC P&P 1+ ^ 



THE HOME DOCTOR SERIES 

Exciting Breakthrough in Home Heallh Advice 

Announcing the launch of a series ol computer programs designed 

to educate and advise on a comprehensive range o< medical 

topics whilst being FUN to use 

The text has been prepared by Or Vernon Coleman who writes 

Irom 10 years experience in a busy general practice, and who is 

widely acclaimed for his many books on medical topics 

The cassettes in the series cover the following topics: 

1 Basic Medicine 4 All About Children 

2 Mainly for Women 5 How Healthy Are Vou? 

3 Mamty tor Men 6 101 Home Nursing Tips 

The computer programs are not intended to replace professional 

medical advice but rather to complement this by educating users 

on preventive medicine and how to cope with medical problems 

when they arise. The programs woukf therefore be equally useful in 

schools, homes and in industrial applications as part ol health 

screening programs. 

Each cassette costs C6 75 plus 45p postage and packing although 

as a special offer to Micro Decision readers all 6 cassettes are 

available for £35 75 post free 

Users should indicate whether they require a 16K RAM pack to run 

all of the programs. Please allow 28 days lor delivery 

EASTMEAD COMPUTER SYSTEMS LTD 

Eastmead House, Lyon Way, Camberley, Surrey GU16 5E2 

TELEPHONE: 0276 682041/2 

f/exiwords 

computershop 

18 Otley Road\ Leeds LS62AD 

Telephone Leeds (0532) 758474 

IN 

YORKSHIRE? 

* Come and visit a proper computershop. 

* You're welcome to come in and browse. 

* We've a super selection of software, and some 

fascinating computers 

* Printers, joysticks, books, magazines. 

* Families welcome. 

Remember, you're better off 

at a proper computershop. 

personal computers for business and home 

1983 ZX COMPUTING AUGUST/SEPTEMBER 1983 

IT'S HERE! 

CAMOUFLAGE 

THE EXCITING NEW 

'COMPUTER'GAME POP SINGLE 

CHRIS 

SIEVEY 

EMI 5398 

LOAD THE'B' SIDE INTO A 

sincilaii— zx an (M) ® 

AND SEE THE LYRICS AND 

COMPUTER GRAPHICS 

ON YOUR TV SCREEN 

THEN PLAY'FLYING TRAIN' 

A NEW COMPUTER GAME ALSO 

ON THE'B'SIDE 

IKVfMONJUSOlNClUDfD 

I S-nci®' 4 J»m«* 

ALL FOR THE PRICE 

OF A SINGLE! 

AVAIlABlf AS A 7 DISC [Ml S398 OR AS A CASSFTTl TAPl SINGH

Nice to be here once again 

with another package of information, 

news, reviews and 

best of all, programs, all for 

your Sinclair computer. 

Over the past few issues, I 

have been introducing a 

number of features such as 

Reader's reviews. Club corner. 

Problem page and the newest 

of them all. The 1K corral. 

Well, what do you think of 

them? If you have any comments, 

or you'd like to see 

something new within these 

pages, write in and tell me — 

there's nowt so refreshing as 

feedback! 

Going down 

Everytime I shut up shop on 

my news pages, something big 

always happens — the problems 

of being a bi-monthly! 

So, as soon as I finished the 

news last issue, what do I hear 

but all the prices on the Spectrums 

are to be reduced. If you 

didn't catch the news in the 

computer press, the 1 6K and 

48K Spectrums have reduced 

in price to 99.95 and 

£1 29.95 respectively. And not 

only that but the ZX Printer has 

come down from £59.95 to 

£39.95. So, if you were 

waiting in the wings wondering 

whether to make a leap to 

the ZX Spectrum, now seems 

like a pretty good time! 

And talking of things 

Sinclair, did you all see the article 

in the Sunday Times 

Magazine concerning 'A life in 

the day of Clive Sinclair'. How 

about this for a morning 

routine 'I usually get up at 

about 6.30, make a cup of tea, 

read the papers, then go for an 

hour's run of seven or eight 

13 

miles'. And that's all before 

most of the country has even 

managed to get themselves 

out of bed! 

Clive also talked to Sunday 

Times Magazine's Jean Goodman 

about some of his future 

projects such as the flatscreen, 

portable, pocket-size 

TV which should hit the streets 

later this year for around £50. 

He also spoke about his electric 

car idea and a distant objective 

which is to produce an 

artifically intelligent robot. 

Coming up 

Lots of great software for you 

to RUN on your Spectrum, 

ZX81 and ZX80 this issue. 

For the ZX81 we have 

some smashing games as well 

as domestic, business and utility 

programs. Remember the 

Muncher program in the last 

issue of ZX Computing — well, 

if you were gnashing your 

teeth because you were a 

ZX81 owner and didn't really 

fancy doing the conversion 

from the Spectrum version, 

never fear, because Robert 

Turner has done the job for 

you. For all would-be rock 

guitarists, there's a program 

for you to draw guitar chords 

on-screen illustrating the finger 

positions you'll need to make 

those crashing chords. You'll 

also find a very comprehensive 

business program called The 

profit prophet, which should 

help you to put your business 

in the black! 

Spectrum users are in for a 

treat this issue with some 

great games, useful utilities 

and lots more. We present a 

massive program for the 48K 

Spectrum called Tourist trap. 

This is a full scale board game 

WELCOME 

for you to play with one of 

your friends which has you 

blazing the tourist trail. There 

are also the usual selection of 

i space games and other arcade 

diversions, as well as a couple 

of Spectrum utilities. Toolbox 

^trio, and an article from 

Timedata's Mike Lord, Spectrum 

streams. 

Of course, our reviewers 

have been busy sifting through 

the piles and piles of great 

software that has been 

brought out onto the market 

over the last months. James 

Walsh has been busily inspecting 

the Spectrum software 

scene whilst Nick Pearce has 

been looking at how to create 

high resolution graphics on 

your ZX81. 

If you want to check out 

what you, the reader, think of 

the various software packages 

available, then look no further 

than Reader's reviews. And if 

you don't like what you read 

there, or you disagree with one 

of our regular software 

reviewers on your favourite 

tape, then please get writing 

and tell the world — if it's 

published you'll get your software 

free! 

Moving along 

Another new feature is starting 

this month in the shape of The 

1K corral. In this area of the 

magazine 1 would like to attract 

users of the ZX81 to contribute 

1K programs which illustrate 

good programming 

techniques to make the best 

use of the limited memory 

space. Obviously, these programs 

can be games, simple 

business or domestic routines 

— the only critera set is that 

they should RUN in IK. 

It may have been a long 

time since you wrote a program 

within the confines of a 

1 K memory space or you may 

just be starting off your career 

in the hobby of computing — 

either way you may discover 

you can find out a great deal of 

economic programming techniques 

by studying these programs. 

If you feel you would 

like to contribute to The IK 

corral, why not send in your 

programs with an explanation 

of what makes them special. 

Contributions 

We are always on the lookout 

for good programs and articles 

for future issues of ZX Computing, 

and where better to 

look than to our own readers. 

If, when reading through the 

magazine, you think you can 

write programs as well, or better 

than, our present contributors, 

then let's hear from 

you. 

All contributions are, of 

course, paid for at very competitive 

rates. So if you've got 

your eye on a new ZX add-on 

or you'd just like to supplement 

your pocket money, get 

writing! It is vital, though, that 

all the programs you send us 

are totally original, and not 

'borrowed' or 'adapted' from 

other magazines or books. 

(When Tim Hartnell was sitting 

in the Editor's chair, he even 

received 'original' contributions 

he himself had written for 

his own books!) 

Any kind of program 

(business, domestic, educational, 

or just fun) will be 

welcomed, but particularly 

those which use ZX BASIC in 

clever and efficient ways, or 

those which employ certain 

routines which can be re-used 

on other programs. 

Program listings are vital, 

along with a clear explanation 

of how the program is constructed, 

what it does and 

what the user can expect to 

see once the program is RUN 

(a screen dump is particularly 

valuable in this respect). When 

submitting Spectrum programs, 

it is very important to 

remember to enclose a 

cassette of the program as 

well as the listing, as this will 

allow us to check the program 

before publication. 

Exit stage right.. . 

Well, the weather has finally 

broken and (touch wood!) it 

looks as though it might be a 

nice summer. Still, I hope this 

magazine does inspire you not 

to ignore your computer for the 

sun. So, have a nice summer 

and make the most of micro 

with ZX Computing. 

Roger Munford. 


Your number's up 

Dear ZX Computing, 

The investigation of prime 

numbers must be one of the 

least useful of applications for a 

computer and yet it appears to 

have a fatal fascination! Using a 

Spectrum it took me a little over 

eight hours to establish the fact 

that the 10,000th prime is 

104,723. We then put the 

problem to a TMS 9900 1 6-bit 

microprocessor. This came up 

with the same result — but 

took 2% minutes! 

It then went on and found 

the 100,000th prime to be 

1,308,383 in 62 minutes and 

the 350,000th prime to be 

5,299,493. This took 6% 

hours! I am now intensively 

learning machine code so that I 

can see how long the Spectrum 

will take to do similar calculations. 

Have any of your readers 

tried this task in machine code? 

Yours faithfully, 

D Gold, 

London N1 2. 

Fantasy, cont.. . 


I write with reference to your 

recent letters in the April/May 

issue of ZX Computing concerning-the 

'Fantasy Island' game 

from Psion Software's 

Sorcerer's Island package. I 

have discovered four things 

about the program which may 

cause some of your readers 

some problems. 

1) Never use the instruction 

'OPEN' as this is interpreted by 

the program as 'OUT' and will 

stop the game. Always use 

'ENTER'. 

2) Upon becoming Monster- 

Bone grade 10, you will find it 

necessary to type CONT as the 

line containing this information 

only allows for a single digit. 

31 Never try to 'ZAP', 'ZZZ' or 

'EXPL' any friendly animal as 

this will only cause the game 

to halt with an undefined 

variable. 

4) Never ask for 'MAP' once 

inside a castle or cave as this 

just puts the computer into 

Fast mode. The map can only 

be generated once outside the 

building or cave. 

Here are some more tips on 

playing the game. Try the command 

'L' or 'LOOK'. Also, a 

Robot Marked Fight can be used 

once only unless you are 

carrying the correct medal. 

I hope this information proves 

of interest to anyone 

attempting this game. Myself, 

I am currently Monster-Bone 

grade 24 and have escaped 

from the Island with 4,000 life 

points and 12,000 treasure 

points left. This feat was 

achieved after several hours of 

play! 


T McGowan, 

Regents Park, 

Southampton. 

/? 

To the bitter 

end... 


I read with interest the review 

on The Hobbit in the April/May 

issue of ZX Computing and 

feel that I must write. Even 

though I have at last managed 

to finish the game, I still enjoy 

playing it and find it well worth 

the money, 

I quote the last few 

sentences of the adventure to 

prove that I really did finish! 

"A cheering crowd of 

dwarves, hobbits and elves appear. 

Led by Gandalf they 

carry you off into the sunset, 

proclaiming you hero of heroes 

and master adventurer!!!" 

Also, please could you tell me 

which printer paper is the best 

value on the market for the ZX 

Printer as I intend to buy one. 

Thank you. 


Graham Walker, 

Horncastle, 

Lincoln. 

• Recommending the best 

printer paper is a little difficult, 

Graham, as to be quite honest, 

it is all pretty much of a 

muchness. The printer paper / 

myself have used in my involvement 

with Sinclair 

printers has all been of a 

uniform standard (and a high 

standard at that!). As for value 

for money, / think you'll just 

have to look around — often 

you can pick up some very 

good deals at the various ZX 

Microfairs and other similar 

events up and down the country. 

Ed. 

WELCOME 

Bridging the gap 


The bridge problem incurred by 

R Wheen in your April/May edition 

of ZX Computing can be 

solved without recourse to 

machine code in just ten lines 

of BASIC: 

10 LET A$ = " TJQKA" 

90 LET 1 = 0 

100 LET l$ = INKEY$ 

110 IF l$>"9" OR l$

9911 REM / M M M U W W m W 

BLOCK DELETE. C.N.GOOCH 

V W A W i W ^ W / A V A ' A S V A V 

9912 LET XsPEEK 23535t2S6*PEEK 2 

3636: INPUT "ENTER FIRST LINE FO 

R ERRSING"jfl: INPUT "ENTER LAST 

LINE FOR ERR5ING";B 

9913 LET YT =PEEK +256*PEEK 

(X+3J : IF PEEK X*2S6+PEEK IX + 1J = 

fl THEM LET STHRT=X 

9914- IF PttK X #2fc»6 +PEEK (X + 1J =B 

THEN LET STOP —X +YT+4.: GO TO 9916 

9915 LET X=X+YT+4: GO TO 9913 

9916 LET LENGTH =STOP-STRRT-4.: PO 

KE 5TRRT+2 ,LENGTH-256*INT (LENGT 

H/256): POKE STRRT+3.INT (LENGTH 

/256): CLS : PRINT RT 10,0; FLRS 

H 1;"NOW TYPE IN ;R; RNO E 

NTER" 

9917 STOP 

Mental block? 

DearZX Computing, 

I wonder if any of your readers 

would be interested in a block 

deletion program I have written 

for the 48K Spectrum. 

Merged with any listing this 

will enable you to choose and 

delete any block of program 

lines. As the final action of 

deleting is not accomplished 

until you edit out (in the usual 

way) the first line you have 

chosen, the program can 

delete itself when you are 

finished with it! 

The line numbering, of 

course, is arbitary but is best 

chosen well up into the 9900s 

to be clear of most ordinary 

listings. Only six lines are used 

so it can be fitted in between 

normal 10 line increments. 

When loaded, typing 'GO 

TO 9911' will cause an input 

request for the first line of the 

block that you wish to delete. 

After this a request is made for 

the last line to be deleted. The 

program will then RUN. Finally 

you will be asked to type in the 

first line number again to be 

followed by 'Enter'. Hey 

presto... they are gone 

forever (so if you might want 

them again make sure the 

whole listing is on tape or 

printer!). 

13 

The program works as 

follows. Line 9912 uses 

system variable 23635 (it's in 

'the book'l to find the start of 

the BASIC. This is a two byte 

number with the most significant 

byte second (23636). 

PEEKing the value of this-will 

give the first line number in the 

program. This is done in the second 

part of line 9013 and a 

check is made to see if this is 

the same as the starting line 

you have chosen. If it is, a 

variable 'start' is designated. 

Also in line 9913, we PEEK 

at the second pair of bytes in 

the line which will give us the 

number of program bytes in 

the rest of the line. We call this 

YT. 

Line 9914 checks to see if 

we have reached the last line 

requested. If we have, it adds 

YT 4 4 (remember the first four 

bytes were not in the length) 

to the value of x and gives this 

value to a variable 'stop'. If we 

have reached a stop then we 

are put on the last line of the 

program. 

If not, line 991 5 increments 

x (the value of the line number) 

by YT+4 and the program 

starts the loop again. 

Line 9916 works out the 

total number of bytes involved 

and POKEs this value into the 

second two bytes of the first 

WELCOME 

line to be deleted. The Spectrum 

now thinks that the first 

line is that long and when you 

edit out that line the whole lot 

will go! 

STOP is only really needed 

if there is likely to be some 

lines following. . .perhaps 

say, a renumber routine. . . 

because without it the program 

will run on into those 

lines. 

Your faithfully, 

Colin Gooch(ii 

llminster. 

Computer 

corruption? 


While developing a machine 

code routine on my issue II 

48K Spectrum, I believe I may 

have found a bug in the ROM. 

If you type CLEAR 32775 

or a smaller number, certain 

memory locations above 

32768 begin to corrupt, 

seemingly picking up I/O 

signals. 

For example, if you type: 

10 CLEAR 30000 

20 POKE 40069 

30 PRINT CHR$ 

40069 

40 GOTO 30 

you will find characters other 

than CHR$ 0 appear. 

However, I have found a 

way of correcting this problem. 

If you add 128 to the 

machine code I register before 

typing the CLEAR statement, 

then type RANDOMIZE USR 0 

to re-start the computer, you 

can then type: 

10 FOR n = 30000 TO 

30004 

20 READ x 

30 POKE n,x 

40 NEXT n 

50 RANDOMIZE USR 

30000 

60 DATA 62,191,237,71, 

201 

Delete the above program line 

by line (don't use NEW as it 

will reset the I register) and 

then type the first program in 

again. 

I would be grateful to know 

if anyone else has experienced 

this problem. 


P Bown, 

Blunsdon, 

Swindon. 

Authors 

correction 


It was great to see my program 

'User character set' in the 

April/May issue of ZX Computing. 

However, I noticed a 

small error in the program at 

line 270, 

This line causes the program 

to skip the routines for 

entering the character codes. 

Deleting this line will cure the 

i bug'. 

Many apologies for this error 

and 1 hope it didn't spoil 

your readers' enjoyment of the 

program. 

Yours faithfully. 

David Mold, 

Cheshunt, , 

Herts. 

PEEK sound's great 


One evening whilst fiddling 

about with my ZX81 I 

discovered sound! Yes, with 

just a ZX81 and a standard 

black and white portable TV. 

Try this for the highest clear 

note possible: 

10 SLOW 

20 FAST 

30 GOTO 10 

RUN it and set your TV channel 

to approximately 35 and turn 

the volume up. Great eh? 

I then tried to write a program 

which would allow you 

to select several different 

notes, but the more notes one 

makes available, the lower the 

notes become. So I tried different 

notes. Try this for a terribly 

high note in Fast mode: 

10C0NT 

20 GOTO 10 

After much experimentation I 

came to the conclusion that 

you could get clear but low 

notes from SLOW and FAST, 

and high but distorted notes 

from REM in Fast mode. ! 

chose REM for my final program 

which follows. 


As you can see by the 

uneven distribution of everything 

the tuning of the notes 

relies on many factors. RUN it 

and play with the keys '1' to 

'8' and you should find you 

have something 

standard octave. 


John Goldie, 

Dumfries, 

Scotland. 

5 FAST 

10 IF INKEY$ = "8" THEN GOTO 30 

20 GOTO 50 

30 REM 

35 REM 

40 GOTO 1 0 

50 IF INKEY$ = tt-Jtt THEN GOTO 70 

60 GOTO 120 

70 REM 

80 GOTO 50 

120 IF INKEY$ = "6" THEN GOTO 1 50 

130 GOTO 170 

1 50 REM 

160 GOTO 120 


180 GOTO 250 

200 REM 

210 GOTO 1 70 

220 IF INKEY$ = "4"THEN GOTO 240 

230 GOTO 270 

240 REM 

250 REM 

260 GOTO 220 


280 GOTO 310 

290 REM 

295 REM 

300 GOTO 270 

310 IF INKtYS * 12 " THEN GOTO 330 

320 GOTO 360 

330 REM 

335 REM 

340 REM 

350 GOTO 310 

360 IF INKEY$ = (i ^ r« THEN GOTO 380 

370 GOTO 10 

380 REM 

390 REM 

395 REM 

400 GOTO 360 

Third time lucky 


I am now on my third Spectrum 

— the first packed up due 

to overheating problems and 

the second gave appalling 

displays, with colour fringing, 

rippling verticals, etc. 

Out of despair, I invested 

£1.00 in the display instructions 

from Fountain Computers 

which were mentioned 

in your April/May issue. They 

really are quite excellent and I 

now have a fine display. I feel 

it's a shame that Sinclair 

couldn't manage to produce 

such a sheet as part of their 

own instructions. 

Also, in the April/May issue, 

a reader suggested using a 

CLEAR instruction to remove 

machine code from the 

memory. This is OK but it 

doesn't shift user-defined 

graphics and you also have to 

remember the different RAM- 

WELCOME 

fairly near a 

top addresses for the 1 6K and 

48K versions of the Spectrum. 

I suggest readers use the 

single instruction RANDOMIZE 

USR 0 which will clear the lot 

out — BASIC, machine code 

and UDGs all in one swoop. 


DC Oates, 

Tamworth, 

Staffs. 

Two of a kind 


I have written two subroutines 

for my ZX81 which your 

readers might be interested in. 

One is for drawing reasonably 

straight lines on the screen and 

the other can be used for 

calculating the amount of 

memory left unused. 

The first routine draws a 

line between two points, (X,Y1 

and (XI, Yl). There is a program 

for this in the Sinclair ZX81 

manual, but this one is shorter: 

10 LET A = XI-X 

20 LET B = Yl - Y 

30 LET H = SQR (ABS A * 

* 2 +ABS B* * 2) 

40 FOR C = I TO H 

50 PLOT X + (A/H) * C,Y + 

(B/H)* C 

60 NEXT C 

The second routine is in 

machine code. I have placed 

the code in a REM statement, 

but it could be placed 

elsewhere, One alternative 

place is above RAMtop. If it is 

placed above RAMtop, line 10 

can be changed to 17325 if 

using 1K or 30000 if using 

16K. 

This program takes account 

of memory used for all purposes 

so, if you are taking account 

of memory used by 

variables, use 'GOTO 1' instead 

of'RUN'. 

(a) Enter: 

1 REM 0123456789012 

3456789012345 

'10 LET A = 16514 

20 FOR B = A TO A + 13 

30 INPUT C 

40 POKE B,C 

50 NEXT C 

(b) RUN this and Enter (taking 

',' as Newline): 

30,0,237,122,237,75,28, 

64,237,66,68,77,201, 

(c) Delete lines 10-50 and 

add: 

2 PRINT "MEMORY LEFT: 

",'USR 16514;"BYTES" 

3 STOP 

Hope this may be of use to 

your readers. 


Alastair McKinstry, 

County Dublin, 

Eire. 

Byting bugs 


I'm afraid I have found a couple 

of minor errors in my Spec- 

tramon program. However, I 

have two solutions to these 

problems: 

1) When the Spectrum tries 

to disassemble close to the top 

limit of memory, because of 

the way in which the Z80 instruction 

set is constructed we 

may have to 'look ahead' by up 

to four bytes. If you are at location 

65533 and this 'look 

ahead' occurs it will try to PEEK 

beyond the range of memory. 

This causes an 'out of range' 

error. There is no true solution 

without major alteration of the 

program. However, a simple 

'fix' can be achieved by changing 

line 605 to read: 

605 IF LOC 65532 THEN 

PRINT "End of memory.": 

POKE 23560,32: GO TO 

6 1 0: REM Pretend SPACE was 

typed 

2) The other problem in the 

program is far more subtle and 

occurs when the Spectrum 

tries to wrap around its 

memory map going from 

65535 back to zero. This 

shows up as a subscript error 

when using the hexadecimal 

conversion routine. This can 

easily be cured with the addition 

of the line 3435: 

3435 IF C>65535 THEN LET 

C = C - 65536 

Hopefully these two solutions 

will end all your worries with 

my Spectramon program. 


Simon Goodwin, 

Hereford. 

Stop press 


Please could I announce within 

your pages that I am considering 

setting up a newsletter for 

all owners of the ZX Spectrum. 

If anyone would be interested 

in this project and requires further 

information, could they 

please send a stamped addressed 

envelope to the address 

below. 

John Grain, 

Wychwood, 

School Road, 

Finstock, 

Oxford 0X7 3DJ. 

13 ZX COMPUTING AUG/SEPT 1983 11

THE WIZARD'S WARRIORS. A irtst moving isame 

thai matches developments in \our .skill as a player Spectrum 

b\ betominc increasingly more devious. IU ofUrinu C4.95 

to \ou the full ran«e iif options you ran chtmse how 

lo control sour warrior through I hi' maze. A full 

implementation of this program enables surh features 

as a continuous series of sound effects, arcade c11•.< 1 ii> 

graphics. douhlc-poinl storing, and--for I ho wn 

artful "bonus lives. 

FORTH A full implementation Ideal for writing fusl 

moving arcade type Kami's. Allows the full colour and 

sound fai ilitiesol" Ihe S|iertrum to In- used. Kill tire 

Microdrive enhancements will la- made available. 

ADVENTURE 0NK: Features a saw game routine .is 

the game can take months to complete, 

ZX81 C5.95 

'a remarkahK good version., well wortli llie mono..' 

Sinclair t mv 

MA/KM AN: A fast action in < uamc that reproduces 

the spirit ot the original 

'..is very a

Spectrum 

14.95 

Spectrum 

C4.95 

ZX81 £4.45 

CIIESS I -I I' M levels of plav will) this in e program 

(iood uraplut screen rlisphiv 


'In a < lass of it's own.* y.-nr ( om/w/rr 

1 C5.95 

INVADERS Vi '..Si in I .H lion Includes mvsier\ ZX81 C4.45 

slop ami ini nasinirlv difficult s< rcens. 

7 MAES AFALLEN. BOW ST.. DYFED, SY24 5BA 

24hr Ansaphone 0970 &28851 II 

TRS80 (LEVEL 2) 

ZX SPECTRUM — ZX81 

SUPER SOFTWARE PACK 

dERIWRs 4 

* 

25 Great programme* on one pack: Star Wars, Gambling Machine Breakout. 

Trap II. Populalion Simulation, Corridors ol Doom. Housebreak. Towers of 

Hanoi. Butterfly Chase, The Vault, Yahtzee. Maths, Calendar. Amazing 3D 

Mazes, 30 Noughts & Crosses Jackpot. Banaii, Hangman - Musical. Bible, 

History and Sport, Mastermind. Spelling. Diary. Records File and Time Warrior 

Here are descriptions of just a lew ot the games 

HOUSEBREAK You enter a house at mght in an attempt lo rob it ol money 

and any gold and silver iiems you can tind. Your obiect is to clean out the 

house. In the dark you must avoid bumping into the furniture Atter an interval ol 

time an alarm will sound and a short while later Ihe lights will be turned on A 

vicious dog is then released and you have to use all your skill and cunning to 

avoid getting bitten as he chases youarourtd the house Any injuries caused by 

Ihe dog will slow down your escape The game is played in real time, has 

excellent graphics and is very exciting A new house is generated each time 

Ihe game is played 

CORRIDORS OF OOOM! A dungeons & dragons type game that is very 

addictive You can never win this game by chance. A lot depends on 

discovering the secrets of just how you have to deal with each individual 

monsler in the game There is a liquid which will destroy Ihe Werewolf — but 

which one' How can you tame the giant spider 7 Will you ever learn the secret 

Ol how to defeat Ihe Blood Devil? All of the monsters have treasures lor those 

wno are both brave and wise enough to overcome them, but to escape alive 

you must tirsl cross some very nasly pits Play it again and again 

AMAZING 3D MAZES Wander through the giant 16x18x18 mazes 

collecling treasures, you know where they are, but how do you get to Ihem? 

Extra points are awarded for finding the shortest routes Don I get too frustrated 

by apparent dead ends 

3D NOUGHTS A CROSSES Played inside a 4x4x4 cube, this is a game for 

the intellectual Great graphics it plays a mean game and wins about nine out 

ol every ten games it plays 

TOWERS OF HANOI You will welcome this classical puzzle which is a must 

lor anyone with a computer The problems difficulty depends on how many 

disks you use II might on|y take you a lew minutes with lour disks, but with all 

nine it could take ail day Two variations ol the game are included There is a 

constant display ol Hours Mms Sees,sothatyouknow how well or how badly 

you are doing at any particular stage if you find you cannot work the problem 

out 1 The computer will show you the shortest possible solution 

THE VAULT A high security vault in Oxford (The game can be changed lo 

centre around your own home town) has ten doors, each wtlh its own five ligure 

combmalion The combination ol the nine inner doors are known, bul only the 

manager knows Ihe combination ol the outer door Unfortunately the manager 

has got himseit locked in the Vault. M is your job to get htm out before all Ihe 

Oxygon is used up The computer will give you metaphorical clues lo how near 

you arc getting The lime switches which change the combination every so 

often can prove a problem This is a case wh »ch r eally puis your powers of logic 

lo the test 

POPULATION SIMULATION This

In the June/July issue of ZX 

Computing, we were able to 

publish the program Muncher — 

a Spectrum version of the 

popular arcade game of the doteating 

kind. For all those of you 

with 16K ZX81 s who have yet 

to convert this program for your 

machine, the original author, 

Robert Turner, has done the job 

for you! 

For those not familiar with 

this 'infamous' game, you control 

a small character, an arrow, 

which travels around a small 

maze eating dots as it goes. 

That's not quite the end of the 

story thought As in all good arcade 

games there should be the 

omnipresent monsters — and 

this game is no exception. You 

are chased around the maze by 

two monsters eager to halt your 

progress. 

However, all is not lost as 

there are power pills situated in 

the corners of the maze which, 

when consumed, give your 

character the ability to destroy 

the monsters. You'll know when 

the monsters are vulnerable as 

they develop 'eyes'. When you 

have eaten a power pill, don't 

hang around as the monsters try 

to escape. 

You score one point each 

time you eat a dot, and power 

pills and monsters are worth 10 

points. Every now and then a' £' 

sign will appear under the 

monster's den and this too is 

worth 10 points if consumed. 

ZX81 CAME 

Robert Turner of Gwent 

presents the 16K ZX81 

adaptation of his 

arcade action 

game,Muncher. 

variables 

The variables used in the program, 

Muncher II, are as 

follows: 

S — Score. 

HS — High score. 

T — The score when the screen 

has been cleared. 

8$ — The variable which stores 

the maze. 

COUNT — If this variable is less 

than 30 the monsters can be 

eaten. If it is more than 30 the 

monsters can eat your 

character. 

LIVES — The number of lives 

you have left. 

Y and X — The position of your 

character. 

A$ — The shape of your 

character. 

GX and GY — The position of 

the first monster. 

GX1 and GY1 - The position of 

the second monster. 

C — This variable controls the 

movement of the monster. If 

C = — 1 then the monster moves 

away from your character, if 

C = 1 then the monster chases 

you. 

D$ — The shape under the first 

monster, 

E$ — The shape under the second 

monster. 

A — The skill level, 

N — Allotted for general use. 

So, dont just sit there — type 

in the program and watch out for ^ 

the monstersl W 1 


3 

3 

9 

LET s=0 

LET HS=0 

LET T=13C 

DIM B$ (21,21) 

LET COUNT=30 

LET LIUE3=3 

GG5U3 7000 

LET CHECK = 1 

LET E=0 

10 LET R = 1 

11 LET a%£1)=" 

20 LET 5$ C2J =" 

•B" 

30 LET Bt (3) = ". 

B-S" 

4.0 LET B*(4->=" 

Hcfl" 

50 LET B$t5)=" 

60 -B" LET B$ B»C10)«' fll) = ' 

ET B«117>«' 

LET B*(18> 

200 LET B*t20J=* 

230 PRINT RT N,1;B»(N> 

24.0 NEXT N 


250 LET Y = 14- 

255 LET E$ = " '* 

260 LET X = 12 

265 LET D$~" " 

270 LET R$=">" 

275 LET C=1 

280 LET GX = 12 

285 LET GY = 12 

290 LET GX1=12 

295 LET GY1=11 

300 PRINT RT GX,GY;"3" 

310 PRINT RT GXl.GVi;"!*- 

320 PRINT RT V,X;H5 

325 PRINT RT 0,0; "LIUES: ; LIVES 

;RT 0,19;"HI-SCORE: "; HS 

330 IF INT (RND*50)=0 THEN GOSU 

B 1000 

335 PRINT RT Y,X;" " 

34-0 IF INKEY $ = " 8 " OR CB»(Y,X + 1) 

i"-" RND R = l) THEN GOTO 1500 

350 IF INKEY* = "5" OR (B>IY,X-1> 

="-" RND R»-l) THEN GOTO 1600 

355 IP INKEY $ < >"5" RND INKEY$ 

"6" RND INKEY $ < >"7" RND INKEY$< > 

"3" RND INKEYSO"" THEN GOTO 4-00 

0 360 IF INKEY$="7" THEN GOSUB 17 

00 

365 IF INKEY $ = "6 " THEN GOSUB 18 

00 

370 IF B*"•" AND B$(GX1,GY1+C) — " THEN 

GOTO 30S0 

4-78 IF RND < R THEN GOTO 4-86 

480 IF GX1'B" THEN GOTO 3100 

4-86 IF RND < R THEN GOTO 500 

4.90 IF GX1>Y RND B$ (GX1-C, GYli < 

>"•" THEN LET GX1=GX1-C 

. 500 LET COUNT=COUNT + l 

510 IF COUNT >-30 THEN LET C=1 

520 IF C=-l THEN PRINT RT GX,GY 

• it it ii •• 

525 IF C-l THEN PRINT RT GX , GY ; 

• yJ** 

530 IF C=-l THEN PRINT RT GX1,G 

vi; 

14 ZX COMPUTING AUG SEPT 1983

ZX81 GAME 

535 IF C=1 THEN PRINT RT GXl^GY 

3L " * * 11 

540 IF GX=Y AND GY=X THEN GOTO 

9000 

550 IF GX1-V RND GY 1 =X THEN GOT 

O 9000 

560 LET D*=B$(GX.GY) 

570 LET E$=BS(GX1,GY1J 

580 LET CHECK = 1 

600 GOTO 330 

1000 IF B$(14,11)="£" THEN RETUR 

N 

1010 PRINT RT 14.11;"£" 

1020 IF 8$ (14, 11) ="." THEN LET T 

—T -1 

1030 LET B$ ( 14,11) ="£" 

1040 RETURN 


1510 LET R $ = ">" 

1520 IF B$(Y,X + 1 ) a " T H E N LET C 

HECK=0 

1530 IF CHECK=0 THEN LET X=2 

1535 IF CHECK=© THEN GOTO 375 

1540 IF 6$ (Y , X + l) < > "•" THEN LET 

R = 1 

1545 IF B$(Y,X + 1) "B" THEN LET 

E =0 

1550 GOTO 370 


1610 LET (=)**'

I 

The ability of the Spectrum to 

MERGE one program into 

another makes it very easy to 

tack one or more utility programs 

onto a BASIC program 

under development. Each utility 

program included in this article is 

a little longer than it need be 

because sensible prompts are included 

— however, these could 

be taken out if space is at a 

premium. Each program has 

been compacted to a reasonable 

number of lines so that it may be 

deleted fairly quickly when it is 

no longer required. 

Hexadecimal/ 

decimal 

conversion 

Once you have entered the two 

routines which make up this program, 

you use the following 

inputs to access the utilities: 

RUN 9000 enters the Hex to 

decimal conversion routine. 

RUN 9011 entersthedecimalto 

Hex conversion routine. 

The program will prompt for the 

number to be converted. Should 

you wish to change the direction 

of conversion, you do not need 

to break and re-RUN the other 

program, you can simply input 

'T* and '123456'. If you input 

'0', you stop the program. 

PEEK and POKE 

RUN 9020 will PEEK a specified 

memory location. The program 

will ask you if you wish to read a 

single byte or a double byte, and 

then returns with a decimal 

number in the range 0 to 255 in 

the case of the former and 0 to 

65535 in the case of the latter. 

Three BASIC utility programs for 

your ZX spectrum, courtesy of 

Richard Sargent of wantage. 

RUN 9030 wilt POKE a 

decimal number in the range 0 to 

65535 into a specified memory 

location. Numbers greater than 

255 will automatically be 

entered correctly into two 

consecutive memory 

locations. 

Attribute 

finder 

This program will be of use to 

anyone investigating a BASIC 

program when they only have a 

black and white television 

available. It may also be useful 

to anyone who has colour blindness. 

The BASIC program under 

investigation is stopped with the 

Break key and then RUN 9040 is 

entered. 

Immediately the global attributes 

are displayed — the 

BORDER colour, the default 

PAPER colour, the default INK 

colour and BRIGHT/NORMAL 

mode — together with the attribute 

number that was set by the 

last PRINT statement before the 

break. 

Then the user is prompted for 

a row and column co-ordinates 

until '33' is entered, which will 

stop the program. 

The Attribute finder program 

itself obtains the global attributes 

by PEEKing three locations 

in the Spectrum 

workspace. This is done in 

line 9041. Local attributes 

are picked up using 

ATTR(R1,C1) 

in tine 9048. 

The attribute 

number, held in 

N, is broken up into its 

component parts by the 

subroutine starting at line 9050. 

Notice the use of the computed 

GOSUBs in lines 9052 and 

9053 which pick up the names 

of the colours. 

16 ZX COMPUTING AUG/SEPT 1983

1 I PROGRAM ONE 

I HEX-DEC and DEC-HEX conversions 

9000 REM Hex to Dec Conversion 

9001 PAPER 7: INK O: CLS : PRINT 

"CAPS LOCK ON PLEASE."*"O ABORT 

s. " *"T FOR DEC TO HEX." 

9002 INPUT "HEX";H$: LET T=0: LE 

T D-ls IF H*-"0" THEN GO TO 9019 

9003 IF H$="T" THEN GO TO 9011 

9004 FOR P=LEN -1 TO O STEP 

-1 

9005 LET C=CODE : LE 

t D=D+1: IF C>=48 AND C=65 AND C: LET R=Q 

-4096+D: LET E=I NT : LET 

R=R-256*E: LET H=INT : LET 

L=R-16*H 

9017 PRINT "DEC "?QS" = " 5 

9018 PRINT A*;A*;" HEX": GO TO 9013 

9019 STOP 

9020 PRINT 

9021 1 NF'UT 

D>"?A*: IF 

9022 INPUT 

PROGRAM TWO 

PEEK AND POKE WITH EASE 

=0 THEN STOP 

"PEEKER" 

"SINGLE OR DOUBLE 

A*="0" THEN STOP 

"DEC ADDR = ";N: IF N 

9023 PRINT "Address ";N;" contai 

ns IF A$="D" OR A$="d" THEN 

PRINT PEEK N+256*PEEK : GO 

TO 9021 

9024 PRINT PEEK N: GO TO 9021 

9030 PRINT "POKER" 

SPECTRUM UTILITY! 

9032 INPUT "DEC ADDR = ";N: IF N 

=0 THEN STOP 

9034 INPUT "DEC UALUE = "SUs IF U 

U—256* I NT : P 

OKE N+1, INT 

9038 PRINT "Address " SNS" cor.tai 

ns "SU: GO TO 9032 

PROGRAM THREE 

^ ^ ^ ATTRIBUTE FINDER 

9O40 REM ATTRIBUTE FINDER 

9041 

LET 

695: 

9042 

LET B=I NT s 

A-PEEK 23693: LET T=PEEK 23 

GO SUB 9063 

LET N=A: GO SUB 9050 

9043 GO SUB 9055+B 

9044 PRINT AT 19,O; INK O;"GLOBA 

L ="?A;" LOCAL="* T?" BORDER-"'B; 

" "SAT 20.01"PAPER-"J" INK-"S 

1$;" 21,O;"Press O to -=iu 

it, else continue.": PAUSE O: IF 

INKEV«="0" THEN STOP 

9045 30 SUB 9063 

9046 PRINT AT 19,0? INK O?"LOCAL 

ATTRIBUTE—"?AT 21,O?"Enter 33 t 

o =i u i t. " 

9047 INPUT "ROW NUMBER IS "sRls 

I NF'UT 'COLUMN NUMBER IS "SCl: IF 

R121 OR C131 

THEN STOP 

9048 

9O50 

LET N=ATTR : GO SUB 

9049 PRINT AT 19,16? INK O? N S AT 

20,05"PAPER-"5P*?" INK-"SI**" 

R$: GO TO 9047 

9050 LET R$=" NORMAL": IF N>=128 

THEN LET N-N-12S 

9051 IF N>=64 THEN LET N-N-64: L 

ET R$=" BRIGHT" 

9052 LET P=INT

EXHIBITION NEWS 

My kind of town 

Imagine an electronics show 

which is five times larger than 

the PCW show in London, a 

show so big the organiser provide 

buses to move visitors 

from section to section. That's 

the Consumer Electronics 

Show held in Chicago each 

year. 

Although it is just for the 

trade, that is for dealers who 

will sell to the public, this 

year's show attracted over 

80,000 visitors. The hit of the 

show, in the computer section, 

was Coleco's Adam. This product 

combines a keyboard, 

processor unit, two keypad/joysticks 

on separate cables, 

daisy wheel printer plus double 

stringy-floppies (similar, we 

believe, to Sinclair's 

Microdrives) and all for around 

£400. Coleco's stock rose 

1 5 '/i points on the New York 

stock exchange in a day as a 

result of the launch. 

However, t was more interested 

in what Timex were 

doing. After some 18 months 

with the Timex version of the 

ZX81 (a 2K ZX81 called the 

Timex Sinclair 1000, or T/S 

1000), Timex have managed 

to sell 600,000 of the 

machines in America. There 

are 750,000 VIC-20s in the 

States, with the T/S 1000 and 

Apple II taking equal second 

position. With a user base like 

that, Timex seem in a strong 

position to continue to hold 

their ground, Coleco notwithstanding. 

in good standing 

The Timex stand was enormous, 

about the area of fourroom 

flat, and it was 

dominated by giant pictures of 

the T/S 2000 and the T/S 

1 500. The T/S 1 500 is essentially 

a ZX81, with 1 6K builtin, 

plus a Spectrum-like 

keyboard. The whole unit is 

silver, and looks very good indeed. 

Timex will be introducing 

it at around £45. That is a 

great price, compared to the 

ZX81, when you remember it 

has a Spectrum-like keyboard, 

and 1 6K onboard. 

Daniel Ross, Vice President 

(they have such titles in 

business Over there) of the 

Timex Computer Corporation, 

says he believes the T/S 1 500 

will produce as much excitement 

as the T/S 1000. He also 

After a long delay, Timex in America 

have finally released their version of 

the Spectrum, known as the T/S 2000. 

Tim Hartnell was at the launch in 

Chicago for zx Computing. 

stated that "the T/S 1000, 

T/S 1 500 and T/S 2000 series 

colour computers, with the 

growing line of Timex 

peripherals and software, constitute 

the best price/value 

family of computing products 

available today." While some 

may argue with that, there 

seems little doubt that the 

Timex versions of Sinclair 

computers are pretty impressive. 

The T/S 1 500 is compatible 

with all of the peripherals and 

software available for the T/S 

1000

are a whole world apart. The 

story gets quite complicated 

here, so I'll try to explain it 

clearly. America will have two 

versions of the Spectrum. The 

1 6K version will sell for around 

£ 100 and is much like our 1 6K 

Spectrum, with the following 

extras: five new commands 

(ON ERROR GOTO, RESET, 

FREE — to tell how much 

memory is left, STICK — to 

work the joystick, and SOUND 

— to trigger a three-channel 

synthesiser), a hole in the side 

to take a joystick, an on/off 

switch, a slot (with flip-up 

cover) to take the plug-in cartridges, 

and a new paint job in 

shiny silver. 

The 48K version of this 

(called the T/S 2048) has all 

the above plus the ability to go 

into a second graphics mode 

which gives 64 characters 

across each line. This version 

sells for around £1 35. 

It seems as though there 

will be little chance of these 

machines being available on 

the UK market. A Timex 

spokesman who I won't name 

(so that Uncle Sir Clive won't 

belt him one next time they 

meet in the States) said that 

Sinclair in the UK have shown 

no interest whatsoever in bringing 

any developments of 

Sinclair products back into the 

UK. "We offered him our 

printer," that spokesman said, 

"and he just wasn't interested. 

I guess that's 

because he didn't build it 

himself. I predict the same 

thing may well happen with 

the plug-in cartridges and the 

extra commands." 

However, Timex themselves 

may not be as hot 

as they think. 1 managed to 

cause a couple of Timex 

executives a moment of 

embarassment by asking them 

to come with me to the T/S 

2000s on display, and told 

them to watch as I typed in the 

new commands. To their 

discomfort, the machines on 

display (or at least the ones I 

tested) were only dressed-up 

Spectrums fitted with 

modulators to drive American 

TV sets. None of the exciting 

new commands actually 

worked. Instead, the keys 

produced such things as the 

Spectrum's pretty (but 

useless) curly brackets. 

Sadly... 

Finally, a rather sad note. 

About 100 yards beyond the 

Timex razzle-dazzle of chrome 

and giant pictures of the new 

computers, was a smalt little 

booth marked 'Sinclair'. In it, 

three somewhat bewildered 

people sat. On display was a 

ZX81 (not a T/S 1000), a UK 

Spectrum (modified to drive a 

US television), a copy of The 

Hobbit and Scrabble. "We are 

here to demonstrate that 

Sinclair Research is a separate 

company" I was told. "We 

need to show that Sinclair 

have not been taken over by 

Timex. And we're maintaining 

a public stance so we'll be 

ready for the next product." 

"And what will that be?" I 

enquired politely. 

"The flat screen TV . , .we 

hope," I was told. 

Upstairs at the show, Casio 

were hammering nails into the 

coffin of that hope, with a 

crowd gathered around its 2'/* 

inch square TV which uses 

LCDs for a very clear screen. 

The highlights of the show 

for me were Casio's little TV, 

the Coleco Adam and the T/S 

2000 series of computers. It is 

strange that the three of them 

may well have more impact on 

Sinclair's fortunes in the 

coming year in the US than any 

other products. 

PT 1983 ZX COMPUTING AUG/SEPT 1983 19

Peter Shaw, author of 'Games for 

your Spectrum', will be 

endeavouring to answer a 

selection of your programming 

(and other) problems you 

encounter on your ZX 

computer. Should you have any 

problems, why not send in your 

queries to the following 

address: 

Problem page, 

ZX Computing, 

145 Charing Cross Road, 

London WC2H OEE. 

Please try and include as much 

information about your particular 

problem, including screen dumps, 

listings, etc. 

It must be appreciated that 

Peter will not be able to answer all 

of your queiries, but will choose a 

selection that reflect general problems 

that should affect you all. 

Dear Peter, 

After some months of studying 

the market of microcomputers 

for one that my spare capital 

would allow, I am now the 

owner of Sinclair ZX Spectrum 

(48K). An excellent unit, as is 

some of the software produced 

for it, but I have encountered 

an irritating problem. 

Many of the 'games' 

programs that I have obtained 

do not use the same keys for 

similar functions, ie I would 

have thought it obvious to use 

the cursor controls for movement. 

But no, programmers 

have other ideas, and the 

selection of games tapes that I 

have purchased offer differing 

control keys. 

The problem of getting used 

to the new control keys is easily 

overcome, but the real problem 

occurs when I would like 

to use a joystick on the games. 

Of the joysticks I have looked 

at, none are compatible with 

the games I already have. 

Surely the answer is to have a 

standard — programmers 

write the programs to work on 

PT 1983 

SINCLAIR SOLUTIONS 

Peter Shaw answers your 

questions and offers advice on 

your programming techniques. 

the cursor keys, and joystick 

manufacturers make their 

joysticks act on cursor inputs. 

Malcolm Jay, 

Chingford. 

Malcolm, 

The problem behind using the 

cursor keys is because they are 

so close together. You must 

admit that there is not a lot of 

room between the cursor keys, 

especially if you are using the 

standard Sinclair keyboard. If 

you are looking for a joystick 

which works with the cursor 

keys, then look no further than 

the AGF joystick, (AGF Hardware, 

26 Van Gogh Place, 

Bognor Regis, West Sussex 

P022 9BY I. But, as you will 

find, most of the new 'popular' 

games will work with some of 

the more popular joysticks, ie 

the Kempston joystick. Fuller 

interface and Mikro-Gen 

joysticks. All three work on IN 

commands, so the keyboard 

doesn't come into it. Sinclair's 

joysticks, when they arrive, 

will work on the block of keys 

from 6 0, disregarding the cursor 

keys altogether. You will 

probably find most games written 

by the larger software 

houses will incorporate the 

Sinclair joystick for INKEY$, 

and one other joystick via the 

IN command (the Kempston is 

the most likely choice). So, 

Malcolm, / advise you to either 

invest in a Kempston joystick 

(Kempston Micro Electronics, 

Dept ZXCP, 180a Bedford 

Road, Kempston, Bedford 

MK42 8BL) or wait for 

Sinclair's own joystick. You 

might also like to investigate 

the new programmable 

joystick interfaces emerging 

onto the market; / believe AGF 

Hardware are releasing one 

such interface as you are 

reading this. 

Dear Peter, 

I am encountering an increasingly 

irritating problem with my 

ZX81. The connection of the 

9V DC lead from the Power 

Pack into the computer has 

become very loose. This is 

causing programs to crash and 

the computer can not be used 

with any confidence. Can you 

suggest a solution to this annoying 

problem? 

Edward Parsons, 

Stourbridge, 

West Midlands. 

Edward, 

The problem you are having is 

not uncommon, through persistant 

unplugging and setting 

up; the 'spring' which holds 

the jack plug in place has 

become loose. The problem is 

easily cured, however, but it 

will involve opening your case, 

and if you would rather not 

open it yourself then take it to 

your nearest electrical store 

who would be able to do the 

job in a couple of minutes. 

Firstly, unplug all leads from 

your '81. Unscrew all the 

screws you can see in the 

base, then lift up the foam 

pads. Carefully open the case 

and locate the 9V DC plug, 

then using your screwdriver or 

similar gently push down the 

metal bars which run across 

the top until they are firmly 

down. While you are in the 

case, do the same to the other 

plugs, ie EAR and MIC, so that 

they are tight as well. Carefully 

put the computer back 

together and tighten all the 

screws, and the jack plugs 

should not wobble any more. 

Dear Peter, 

The articles in ZX Computing, 

on the development of the 

Checkers type game contain a 

line which has me completely 

baffled: 

6070 LET Y=-9*(Y = 

- 11J + 9 * (Y= -9) 

+ 11 * (Y = 9) + 

(Y= 100) 

I have never met this form of 

notation before, could you 

please explain what is happening? 

Hugh Neilson, 

Kettering, 

Northants. 

Hugh, 

This problem is difficult to explain 

but easy to understand. If 

the expression, ie Y= — 11, is 

true then the bracket takes the 

value of one, ie if Y does equal 

-11 then the line will read: 

6070LET Y = -9*1+9 

*0 + 11 *0 +0 

You will gather that if the contents 

of the bracket is false 

then it takes the value zero. 

For example try: 

PRINT (2 = 2) 

You should get the result one, 

because two does equal two, 

but if you try: 

PRINT (3 = 4) 

Then you will get zero, 

because three does not equal 

four. 

/ hope you are a little more 

enlightened. 


91 

onilse 

me, 

wo. 

iro, 

j ual 

tore 

983 

Spectrum 

16k-48K SINCLAIR 

£2 Z i ^ ^ ^ ^ ^ H 

« v n n - 

from 16k - 48k 

With our ME48 memory expansion add-ons 

your ZX Spectrum can Increase Its capacity 

by up to three times. 

ik No soldering * easy to fit * simply plug 

In • fully guaranteed • no loss of memory 

through wobble or white out. 

NB Before ordering your Spectrum add-on please check 

which Spectrum you have in your possession. 

At the back of the ZX Spectrum the metallic contact strips 

can be clearly viewed. In the series A the space separating 

the strips is the same width as the strips. In the series B 

the strips are twice as wide as the space between. 

SPECTRUM ZX81 

ME16-48 Series A £34.50 ME1-I6 £19.25 

Series B £22.00 ME 1-64 £44.25 

ME 16-80 Series B £46.00 

FITTING/TESTING SERVICE. While-you-wait, personal 

callers Monday-Friday 9.30-5.00, £3.00. 

By return registered post £7.00. 

ZX81 & SPECTRUM 

SSI SPEECH SYNTHESISER 

SIZE 3Vt"x SWx 1 

• Make amazing speech effects with your 

ZX Spectrum. 

• Specially designed for use with your 

Spectrum. Just plugs in, no dismantling or 

soldering. 

• No power pack, leads, batteries or other 

extras. 

• Ample volume for built in loudspeaker. 

Manual Volume Control on panel. Can be 

plugged In to Existing hl-fl system. 

• Uses no memory addresses. 

• free Dictionary of Sounds. 

SSI SPEECH SYNTHESISER £39.00 

[MEW LEVEL-VU PRISM 

Allows you to see your tape 

counter without moving from your seat! 

• attaches easily to recorder body or lid 

• fits most recorders including Radio Shack, 

Vlc-20, Atari 

• greatly magnifies counter 

numerals LVP £3.99 

• All Items are normally despatched within 24 hours 

COMPUTERSW 

7-9 Thane Works, Thane Villas. London N7 Tel: 01-609 7919 

ZX COMPUTING AUGUST/SEPTEMBER 1983 

TAPE LOAD ANXIETY? 

Vu-Load takes the frustration 

out of loading your ZX8I or Spectrum 

programmes. 

• helps to ensure programme load every time 

• monitors tape output level 

•k gives positive save Indication 

• detects blank tape without disconnecting 

cassette wires _ __ 

• ready to use - no wiring TL t iV.vv 

l M F W EXTERNAL MEMORY 

irvw-îr FOR THE SPECTRUM! 

Upgrade your Spectrum to 48K with 

the new ME16-48E suitable for series A and B 

* Plugs Into the back of your Spectrum 

* Specially designed to avoid loss of memory 

through wobble or white out 

* Has a piggy back' connector so you can add 

other peripherals like the Spectrum 

printeretc ME 16-48E £39.95 

« » j C \ A / 1 M,CRO TAPE Mve 11 -f,rst t,me 

l | \ | t on American microtape 

» specially designed for uit with 

•^^^^rntcro computers 

* Low drop out occurence * uniform coating » High saturation level 

* So good, we can quarantee them for 12 months 

AUDIO DIGITAL AD.CI 2 - 55p AD.CI 5 - 60p AD.C20 - 6Sp 

• Free 23 line memory test 

programme with every add-on. I 

Port and 

..ill tmlv *°P P** 

Please tick the appropriate box to order your Computer Add-on 

Memory Expansion Spectrum ME16-48 Series A U Series B • 

ME 16-80 Series B • ZX8J ME1-)6 • ME1-64 • 

Speech Synthesiser SSI Spectrum • ZX8I • Tape Load TL C 

Level VU LVP QME16-48E • Audio Digital AD.C12 • 

AD.C1S • AD.C20 • 

*NB. Add 40p Post & Packaging to the price of all items. 

I enclose a cheque or postal order f or _ made 

payable/Crossed to Computer Add-ons, or I would like to 

pay by Access ^ ^ or Barclay Card and I enter my 

number and signature accordingly -Aiiow?8djyiror

SPECTRUM GAME 

Play your cards right 

Twist and shout 

This program simulates the 

game of pontoon, in which you 

get to pit your wits against the 

computer. 

When RUN, you will be dealt 

a card and asked to place a bet; 

bets can only be made up to a 

certain amount — within 10% 

of your credit. You will then be 

dealt another card and given the 

option to 'stick', "twist' or 'buy'. 

This is done by pressing the 

appropriate key on the 

keyboard, ie the's' key to stick, 

the 't' key to twist and the 'b' 

key to buy. 

2 ^ 

Your deal. . . * w » 

h 

* i* ? ••• • 

4 

4 M ? 

If you've never played pontoon 

before, here is a brief resum6. 

You are dealt a single card, and 

on that you have to work out 

how good your hand might be 

and place a suitable bet accor- 

1983 

6 

dingly. You then receive your 

next card. The idea of the game 

is to make your cards up to a 

value of 21; Kings, Queens and 

Jacks are all worth 10 points 

each, and an Ace can be worth 

one or 11. With the two original 

cards you hold, you must decide 

either to 'stick' which means 

you pick up no more cards, 

'twist' which means you receive 

another card (you can receive up 

to three more cards!, or 'buy' 

which means you receive 

another card but you buy it from 

the dealer so that you effectively 

increase your bet. 

The winner of a hand of pontoon 

is the one who gets their 

cards to total 21 or the nearest 

to 21. If you get five cards to 

total 21 or under, then this is 

known as a 'five card trick' and 

this hand beats all. Should the 

computer and your hand equal 

the same, it will depend on who 

is dealing as to who will win — in 

the game of pontoon, this is 

known as Banker's privilege. 

When you have settled on your 

final hand and pressed the 's' 

key to stick, then the computer 

deals its own hand, decides 

whether to stick or not and finally 

checks its hand against your 

own. The computer then either 

takes your bet if it has won or 

returns your original bet plus 

your winnings if you managed to 

have the winning hand. 

One nice touch in the program 

is that the computer 

doesn't just keep dealing itself 

cards until it beats your own 

hand or 'goes bust' (which is 

pontoon-talk for holding cards 

which total more than 21) but 

actually makes a decision 

whether or not to draw another 

card. This decision is based on 

the value of the cards you have 

stuck on and the amount of cash 

you have placed as your bet. Only 

when the computer has stuck 

are the cards displayed and the 

winner announced. 

variations on a 

theme 

Although there are copius REM 

statements throughout the program 

to help you follow its intricacies, 

here is a list of the 

variables used. 

AMT — Amount of credit. 

ITME — The Spectrum or player 

dealing. 

ACEI — An ace has been dealt. 

ME — Value of the player's final 

hand. 

V — Current value of the cards. 

T — Number of cards dealt. 

ODDS - Calculation for the 

Spectrum to decide whether to 

stick or not. 

Bet — Amount bet on the initial 

card. 

Buy — Total amount for bought 

cards. 

Stake — The stake for each 

game. 

S$ — The suit of each card. 

R$ — The Jack, Queen or King, 


SPECTRUM GAME 

Play pontoon on your 

Spectrum with this 

game written for us 

by C Taft of Coventry. 

2« POKE 23609,38; GO TO 1350 

,30 LET arot=500 

4 0 LET Stake=10: DIM Z$(l,3): 

DIM S$t4): DIM C (52) : DIM h(5,2> 

DIM t (4-) : LET S$(l) LET S 

$ (2) ="D" : LET S$(3)="S": LET 

4* = "C" 

50 LET it«e=100. LET 3Cel=0: L 

ET w=0; LET K=l: LET 3=1: LET C = 

0: LET m e = 0: LET v=0: LET buy=0: 

LET be t =0 : LET a» t =an> t-s t a ke : L 

ET n =0 

60 FOR s=l TO 4- 

70 FOR r =2 TO 14 

80 LET n=n+l: LET cin)=10*r+s 

90 NEXT r: NEXT S 

100 FOR n =1 TO 52 

110 BEEP .003, -n +52: LET wi=INT 

fRND *52 > +1: LET t=c(m>: LET C(m> 

= c(n > : LET c in ) =t 

120 BEEP .003,n: NEXT n 

130 LET n =0 

14-iB PAPER 4-; BORDER 2; CL5 

ISO FOR n=0 TO 8 STEP 4-: PAPER 

7: INK 2 PRINT AT 0,0+n;"M"; IN 

K 0; "C"; INK 2; "D"; INK 0; "5", : 

NEXT n 

160 PAPER 1: INK 7: PRINT "PONT 

~170'FOR n=19 TO 27 5TEP 4: PAPE 

R 7: INK 2; PRINT AT 0,n;"H"; IN 

K 0; "C"; INK 2; "D"; INK 0; "5"; : 

NEXT n: PRINT INK 2; "H" 

180 PAPER 7: INK 1: PRINT AT 2, 

11;"Your hand";AT 15,2;"Your tot 

at ";v,AT 15,19; "Credit £"; a m t 

190 GO SUB 580 

200 IF ace 1=0 AND t>=2 THEN GO 

TO 310 

210 GO TO 510: GO TO 4-70 

220 REM S T B 

230 PAPER 4: PRINT AT 18,©;" 

"; PAPER 7; INK 2;AT 18,7;"E 

NTER "; INK I;"Your choice"; PAP 

ER 4.; " 

PAPER 7; "s - 

STICK,t - Twist.b -Buy." 

24-0 IF t =5 THEN LET roe =21: GO T 

O 1550 

250 INPUT a $ 

260 IF a $ < > "S ** AND a S < > " t " AND 

a $ < >"b" THEN GO TO 25© 

2 "70 IF a$ = "S" THEN PAUSE 50: GO 

TO 4- "70 

280 IF a$ = "b" THEN GO TO 34-0 

290 REM T 

300 LET t = t +1: GO SUB 600 

310 REM I BUST 

320 IF V >21 THEN GO TO 4-10 

330 GO TO 220 

340 REM I BUY 

350 PAPER 7: INK 2: PRINT AT 18 

,2;"ENTER"; INK 1;" fiaount lUhoL 

e £' s) . " 

360 PAPER 7: INK 2. PRINT AT 20 

,2;"UPTO "; INK 2;" £";INT (((am 

t-bet-buy) t.l) +.5) ; PAPER 4.;" 

•a 

370 INPUT buyl 

380 IF buy 1 > INT C (a® t-be t-buy ) * 

• 1) +.5 THEN GO TO 370 

390 LET buy=bu«fbuyl 

4-00 PAUSE 50: GO TO 290 

410 REM I BUST 

420 PAUSE 20: FOR Z =1 TO 4-0: BE 

EP .05/(2/7) ,-z/7: FLASH 1: PRIN 

T AT 13,6, PAPER 7; INK 2;"Sorfw 

you have bust": NEXT z: FLASM 0 

4-30 PAPER 4-: PRINT AT 13,6;" 

«t 

440 LET a»t=INT (ant t - ( buy+be t) + 

. 5) 


,27;amt; PAPER 4;" " 

460 GO TO 50 

470 REM S 

480 IF v >=15 THEN LET rae=v: GO 

TO 860 

490 BEEP .5,-5: PAPER 3: INK 7: 

PRINT AT 13,0;"You cannot Stic* 

on Less than 15": PAUSE 75 

500 PAPER 4: PRINT AT 13,0; 

GO TO 220 

510 REM Bet 


/ 2; ENTER"; INK 1," Your bet (U»tote 

£ ' s) . ";AT 20,2; INK 2; "UPTO 

"; INK 1; £" ; INT (a»t ».!)+.Si 

530 PAPER 4: PRINT " 

ta 

54-0 INPUT bet 

550 IF be t >INT

GO TO 1720 

570 LET tst+1: GO SUB 600: GO T 

O 220 

560 REH PICK CRRD 

590 LET t =1 

600 LET d=l; LET n =r> +1 : LET h(t 

,d) ac(n)*10ft: LET teapssc (ni : GO 

SUB 760 

S10 PfiUSE 70 

620 GO SUB 1780 

S30 IP r $ (1) =" J" OR r*(l)="q" O 

P rt (2Jr THEN BEEF* . 1 , r; GO T 

0 650 

64-0 BEEP . 1 ,r: GO SUB 1270+(r*P 

0) 

650 IF r*Cl)«"J" THEN GO SUB 14 

90 

660 IF r $ (1) = " q" THEN GO SUB 15 

1 0 

570 IF r$(l)="k" THEN GO SUB 15 

30 

660 IF itroe=100 THEN INK 1: PPI 

NT AT 15/13;V 

690 IF itroe100 THEN PAPER 7: 

INK 1: PRINT AT 15,2;"My total * 

i v ; AT 15, 19; "pay **; AT 19,2;"A«oU 

nt bet £"; be t + bu y;AT 19,19; "Crcd 

X I £ : 9 " d 01 ^ 

700 IF itme100 AND v > r 2 1 OR i 

• me 100 AND t = 5 THEN GO TO 74-0 

710 IF it me 100 AND v-20 THEN 

PRINT v +1; AT 17, 14-; "Five card tr 

icHs" 

720 IF i t m e < >100 THEN PRINT AT 

1S,23;v +1 

730 IF i t ® e < >100 THEN GO TO 75C 

74-0 IF i tine 100 THEN PAPER 4. : 

PRINT AT 15,19;" 

750 RETURN 

760 LET r = INT (tentp/10) : LET S - 

tsmp-fil0: LET r=r+l: LET f$=5TR 

* r 

770 IF r-15 THEN LET r$="RCE" 

780 IF r = 15 AND acel=0 THEN GO 

TO 1660 

790 IF r =15 AND ace 1 = 1 THEN GO 

SUB 600 

600 IF r =14- THEN LET r$(l)="k" 

510 IF r m13 THEN LET r$(l)="q" 

320 IF r=12 THEN LET r$tl)="J" 

630 IF r > =12 AND r -n e OR v=ne+l THEN GO 

TO 1030 

PT 1983 

1020 IF v < ib e +1 THEN GO TO 1100 

1030 REH I lose 

404-0 LET a m t = I NT Offi t - (be t+ buy ) + 

.5) 


,2;"You've Lost £";bet+buy 

1060 PAPER 7: INK X: PRINT AT 19 

t27;am t; PAPER 4;" 

1070 FOR X =20 TO -10 STEP -.7: B 

EEP .01 X' NEXT x 

1060"IF'amt"n" THEN 

GO TO 1230 

1270 REH Print cards 

1260 REH 1 

12A0 GO SUB 1760 

13O0 PAPER 7: PRINT AT k+3,a;"A 

"; AT k+4-,a;" ";AT k+S,a,' 

" ; AT k " ; CHR$ z; " 

,AT k+7,a;" ";AT k+6,a;" _ 

" ; AT k +9 , a; " " : LET a =a +t> 

RETURN 

1310 REH 2 

1320 PAPER 7: PRINT AT k+3,a;"2 

"; AT k +4-, a ; " ";CHR* z;" " ; A 

T k+5,a;" ";AT k +6,a; " 

;AT k+7,a;" ";AT k+6,a;" "; 

CMR$ z;" ";AT k+9,a;" LE 

T a=a+6: RETURN 

1330 REH 3 

134-0 PAPER 7: PRINT AT k+3,a;"3 

"; AT k+4-,a;" ";CHR$ z;" ";A 

T k +5 , a; " "; AT k+6,a;" ";CH 

R$ z;" "; AT k +7,a; "; AT k ^ 

e,a;" ";CHR$ z;" ";AT k+9,a;" 

": LET a =a +6: RETURN 

1350 REH 4 

1360 PAPER 7: PRINT AT k+3,a;"4- 

" ; AT k +4-, a ; " ",CHR$ z;" ";CHR 

5 z;" " ; AT k -»-5 , a ; " " ; AT K+6 , 

a;" ";AT k +7,a;" ";AT k + 

3, a; " ";CHR$ z;" ";CHR$ z;" " ; AT 

k+9,a;" ": LET a = a >6: RETUR 

N 

1370 REH 5 

1330 PAPER 7: PRINT AT k+3,a;"5 

"i AT k +4-, a ; " " ; CHR$ z;" " ; CHF 

£ z;" "; AT k+5,a;** "> AT k +6 , 

a;" ";CHR$ z;" ";AT K+7,a;" 

";AT k +6,a; " ";CHR$ z;" ";CHRs 

x;" ";AT k+9,a;" ": LET a=a 


1983 

+6; RETURN 

1390 REM 6 

14.0O PRPER 7: PRINT RT k+3,a;"6 

"; RT k+4,a;" ";CHRt z ; " "; CHf* 

$ r;" "; RT I;+5, a;" " ; RT k +6 > 

a;" ";CHR$ z; " ";CHR$ z; " ";RT X 

+ 7 , a ; " " ; RT k+8,a;" ";CHR$ z 

i" ";CHR* z; " ";RT k+9,a;" 

: LET a = a +6: RETURN 

141© REM 7 

14-20 PRPER 7: PRINT RT k+3,a;"7 

"; RT K + 4- , 3 j "; CHR$ z;" ";C-HF 

s z;" ";RT k+5,a;" ";CHR$ z;" 

;RT k+6,a;" ";CHR$ z;" ";CHR$ z 

;" "; RT k +7 , a; " " ; RT k +3 , a ; ' 

" i CHR $ z;" " ; CMR$ z;" " ; RT U9, 

a;" LET a =3 +6: RETURN 

14-30 REM 5 

14-4-0 PRPER 7: PRINT RT k+3,a;"8 

"; RT k +4,a; " ";CHR$ z;" ";CHF 

5 z ; " ";RT k +5/a; " ";CHR$ z;" 

SPECTRUM GAME 

m 9 m Ay 3 — 

• * 

: GO TO 1650 # A 

1640 LET r =1 y 

1650 LET v=v+r 

• • 

v 

1660 GO SUB 1780 

1670 BEEP .1,r: GO SUB 1290 GO 

SUB 630: GO TO 930 

1630 REM ZX/ME? 

1690 REM ME RCE 1/11 

1700 IF i tme=0 THEN GO TO 1530 

1710 IF r$(l)="R" RND t=l THEN L 

ET r=0: GO SUB 1290: LET 3C€l=l: 

GO TO 510 

1720 PRPER 7: INK 2; PRINT RT 16 

"flee dealt do you want 1 or l 

17"; PRPER 4;" 

1730 INPUT r 

1740 IF acel=1 THEN LET v=v+r: C 

O SUB 680 

"; RT K +6, a; " ";CHR$ z; " ";CHR$ z 

j •;RT k +7,a; ";CHR$ z;" ";R 1750 IF ace 1 = 1 THEN LET ace 1=0 

T k+8, a; " ";CHR$ z;" CHR$ z;" 

• • . 

LET a=a+6: 

. 1 , r : C- 

GO TO 220 

;RT k +9,a; " 

1760 IF ace1=0 THEN BEEP 

ETURN 

O SUB 1290 

14-50 REM 9 

1770 LET V=V+r: GO SUB 680: GO T 

3 460 PRPER 7 PRINT RT k +3, a ; "9 O 200 

";RT K+4,a;" ";CHR$ z; ";CHR 1780 REM SUIT COLOUR 

» z ;" ";RT k+5 , a; " CHR$ z; , 1790 IF S$(S) •H" THEN LET Z =151 

CHR* z;" "; RT k+6,a;" ";CHR$_z ; INK 2 

RT k +7, a ; " ";CHR* Z, " ";CHR 1800 IF s*(S)="C" THEN LET Z =146 

.

1K ZX81 GAMES 

The IK corral 

what can you do with an unexpanded ZX81? The 

possiblities are endless as you'll soon find out... 

In this new regular feature, 

we'll be including a galaxy of 

games and useful routines for 

you to type into your 1K 


Although sometimes 

frustrating to work within such 

a limited amount of memory, 

you may find it a worthwhile 

exercise to study pro- 

1983 

grammers have managed to 

use the memory space — 

something you may land 

should) find useful even when 

working within 1 6K or 48K. 

If you would like to contribute 

material to this feature, 

please try to explain the 

techniques you have employed 

to get your program into 1K. 

But enough of the introduction, 

get typing and have fun. 

Star swerver 

Paul Smith 

When you first play this game 

you must input your highest 

score. The computer then 

draws a star galaxy through 

which your ship {'< ') must 

avoid. 

As the game progresses 

and several crossings have 

been made across the screen, 

you will find the number of 

stars increases. In fact, the 

games gets very hard when 

the score goes over 400 — but 


if you manage to get that far, 

you'll no doubt be good 

enough to cope. 

At the end of the game, 

your score and the highest 

score are shown; there is also 

an option inviting you to have 

another game. 

As a brief note on the 

graphics, the following are on 

these lines: 

Lucky dice 

Colin James 

This program 'throws' five 

numbered dice on the screen 

and then allows you to rethrow 

from none to all of them 

again twice. In this way you 

could quite successfully play a 

game of Poker Dice with a 

friend on your ZX81. 

After RUNning the program, 

five dice are displayed on the 

screen and you have to choose 

which dice you require to 

change, if any. You enter the 

numbers of the dice you want 

to change as a string and then 

press Newline. For instance, if 

the display is as in Fig. 1 and 

you wish to change the '2', 'V 

and '4' (the second, fourth and 

fifth dice) you would press the 

'2', '4' and '5' keys followed 

by Newline. 

When your turn is over, a 

reminder message is displayed 

and pressing any key will rethrow 

all five dice for another 

turn. If you decide after your 

first or second throw that you 

wish to stick on your dice 

score, pressing Newline will 

finish your turn. 

I put the subroutine at line 3 

to allow GOSUB PI to be used 

as a memory saver. When I 

first started the program, I had 

line 10 as four quite long 

IF. . .THEN statements which 

caused the program to run out 

of memory. Using the 

subroutine at line 3 I managed 

to save enough memory to 

allow it to fit relatively easily 

into 1 K. 

Line 35 includes a Graphic 

shifted 2. 


shifted 1. 


shifted 1. 


shifted 1. 


shifted 2. 


1 

3 

4 

5 

6 

7 

8 

9 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

1 10 

120 

130 

140 

150 

160 

170 

180 

190 

1 INPUT H 

2 LET S = CODE " * 

G CLS 

35 FOR A = CODE " " TO CODE " 1 * + (CODE " • " 

* (S/CODE "1")) 

40 PRINT AT RND * CODE RND * CODE 

» J* ^ * 

50 NEXT A 

70 LET P= INTiRND * CODE":") 

80 FOR A = CODE " 1 " TO CODE " " STEP - CODE 

n w , 

90 PRINT AT P,A; " AT P,A - CODE ' • "; 

92 IF PEEK (PEEK 16398 + 256 * PEEK 

1 6399) = CODE " * " THEN GOTO CODE * COS" 

94 PRINT AT PA;"" 

95 LET P = P + (INKEY $ = " 6" AND P CODE ":") - 

(INKEY$ = " 7") 

100 LET S = S + CODE " • 

120 NEXT A 

160 GOTO CODE "0 0" 

200 PRINT AT P,A - CODE "•";"> X < " 

300 IF H< S THEN LET H = S 

350 PRINT AT CODE " *; CODE " "; " SCORE = " :S,, 

"HIGHEST = ";H„" AGAIN? (Y/N)" 

360 GOTO (VAL "360" AND INKEY$ = " ") + (CODE 

" •" AND INKEY$ = " Y") 

GOTO EXP PI 

LET T = N * 5 

PRINT AT 7,T - l;N 

PRINT AT 9,T-PI; " 

FOR S = l TO PI 

PRINT AT 9 + S, T - Pt; " 

NEXT S 

LET S = INT(RND * 6 + 1) 

PRINT AT 11.T-I; " "ANDS-2 

* INT (S/2);AT 10,T; " " AND S>l AT 12, T-2; " 

" AND S>I; AT 10, T-2;" " AND S>PI; AT 12, T; 

" " AND S>PI; AT 11, T-2; " "ANDS = 6 

RETURN 

RAND 

LET I = SGN PI 

FOR N = l TO 5 

GOSUB PI 

NEXT N 

FOR F «= SIN PI TO I 

INPUT R$ 

(F R$ = " ' THEN GOTO 160 

FOR V = I TO LEN R$ 

LET N = VAL R$(V) 

GOSUB PI 

NEXT V 

NEXT F 

PRINT AT 1 5, PI; " END OF YOUR GO" 

PAUSE 4E4 

CLS 

RUN 

or I 


Catch a star 

jan van den 

Broeck 

I have been experimenting 

with INKEY$ and worked out a 

small program for the 1K 

ZX81. It even has a cheat 

routine. 

You have to try and catch a 

falling star (' * ') in a black box 

('• '). To move the box, you 

must use the '5' and '8' keys 

to move left and right respectively. 

After ten turns, the 

score is displayed on the 

screen. 

When you have RUN the 

program, it'll wait for you to 

press any key. However, if you 

press the 'L' key the program 

switches over to auto-pilot so 

you can see what the game is 

all about. 

Shuffler 

Derek Sorensen 

This program simulates the 

shuffling of a standard pack of 

cards and then deals the pack 

out one after another. 

Line 10 sets up the string 

variable A$ for use as a data 

file, in this case representing a 

pack of 52 cards. Lines 20 to 

60 'shuffle' the pack, 

repeating the process 'N' 

times, using a FOR . . . NEXT N 

loop. We now have the pack of 

cards in its shuffled form. 

Lines 70 to 90 then print 

out the shuffled pack, this time 

using a FOR. , . NEXT M loop. 


1 RAND 0 

3 IF INKEY$ = " " THEN GOTO 3 

5 LET A$ = INKEY$ 

10 LET A = VAL "10" 

20 LET SCORE = PI-PI 

30 FOR L = 1 TO A 

40 LET X = INT (RND * 1 2)+1 

50 FOR Y = 0 to 21 

60 PRINT AT Y,X; " * " 

70 IF A$ = "L" THEN GOSUB 200 

75 LET A = A + (INKEY$ = " 8") - (INKEY$ - "5") 

80 PRINT AT 21, A; " • " 

90 IF X = A + 1 AND Y = 21 THEN LET SCORE = 

SCORE +1 

100 PRINT AT Y,X; " " 

110 NEXT Y 

120 NEXT L 

150 PRINT AT 10,10; "SCORE"; SCORE 

160 STOP 

200 IF (A + 1XX THEN LET A = A+1 

220 IF (A+1)>X THEN LET A = A-1 

230 RETURN 

10 

20 

30 

35 

40 

50 

60 

70 

80 

90 

Electronic fence 1 

Robert Saundby 

2 

LET A$ = "AH2H3H4H5H6H7H8H9HTHJHQHKH 

AC2C3C4C5C6C7C8C9CTCJCQCKCAD2D3D4D 

5D6D7D8D9DTDJDQDKDAS2S3S4S5S6S7S8S9S 

TSJSQSKS" 

FOR N= 1 TO 100 

LET X = INT(RND * 52) * 2 + 1 

LET Y = INT(RND* 52) * 2 + 1 

IF X> =Y THEN NEXT N 

LET A$ = A$(Y TO) + A$(X TO Y - 1) + A$(T0 X - 1) 

NEXT N 

FOR M = 1 TO 103 STEP 2 

PRINT A$(M TO M + 1); " 

NEXT M 

3 

LET X = VAL "9" 

LET Y = VAL "12" 

LET A = (RND * 9) + 5 

This program is a game in 

4 LET B = (RND * 8) + 4 

which you have to move a ' +' 

sign round the screen using the 

cursor keys to draw an elec- 

5 

6 

PRINT AT X,Y; "(inverse plus sign)" : AT A,B; 

" {graphic A)" ; AT X,Y; " + " 

LET X = X + (INKEY$ = "6")-(INKEY$ = "7") 

tronic fence around the inverse 

speech marks which are the 

'bugs' you have to catch. 

7 

8 

9 

LETY - Y + (INKEY$ = "8")-(INKEY$ = "5") 

PRINT AT X,Y; 

IF PEEK (PEEK 1 6398 + 256 * PEEK 1 6399) = 

These bugs appear whenever CODE " (inverse speech mark)" THEN GOTO 45 

the moving Queen bug lays an 10 PRINT AT A,B; " (inverse speech mark)" 

egg which, of course, immediately 

hatches into a baby 

15 

20 

LET A = A + (RND * 3)- 1.5 

LET B = B + {RND * 3)- 1.5 

bug. 

If the plus sign goes into a 

bug then you are bitten to 

death, but if the Queen bug 

(represented by a Graphic A) 

walks into the fence then she 

dies and you have won the 

game. 

After the game, pressing 

any key clears the screen and 

the game starts again. Watch 

out for the Queen bug as she 

will move about the screen at 

random and occasionally 

jumps to another part of the 

screen. 

25 

30 

35 

40 

45 

50 

55 

60 

65 

70 

75 

80 

85 

90 

IF RND > .9 THEN GOTO 3 

PRINT AT A,B; 

IF PEEK (PEEK 16398 + 256 * PEEK 16399) = 

CODE " +" THEN GOTO 55 

GOTO 5 

PRINT AT 4,2; " YOU ARE BITTEN BY A " " BUG" ' 

GOTO 75 

FOR N= 128 TO 182 

PRINT A,B; CHR$ N 

NEXT N 

PRINT "THE QUEEN BUG IS ELECTROCUTED." 

PAUSE 4E4 

CLEAR 

CLS 

RUN 


Manoeuvres 

David Clover 

This is a 1K version of the old 

schooldays game 'Battleships'. 

Player one inputs a string 

(unseen by player two) for a 

pre-agreed number of ships 

and/or submarines. For example, 

if the agreed forces are 

two submarines (S), two 

cruisers (C) occupying two 

squares each and one battleship 

(B) occupying three 

squares, then player one in- 

soccboss 

Graham Mitchell 

Soccboss is a simulation of 

managing a football club for 

puts 'S1AS9HC4BC5BC- 

7CC7DB2EB2FB2G' to place 

two submarines, one at 1A 

and one at 9H; two cruisers, 

one at 4B-5B and one at 

7C-7D; and one battleship at 

2E-2G. 

The second player tries to 

locate the position of the ships 

by inputting something like 

' 1B'. If the shot misses a ' +' is 

shown at the relevant position. 

If the player scores a hit the 

letter 'S\ 'C' or 'B' (or any 

other letters agreed by the 

players) is shown. Grid 

references must be shown 

number first, letter second. 

The program is entered first 

followed by the variables as 

direct commands without line 

numbers. Begin by GOTO 1 5. 

Do not use RUN. 

Variables 

LET A 

LET B 

LET C 

LET D 

LET E 

LET F 

LET G 

LET H 

1 

2 

3 

4 

5 

6 

7 

9 

LET I = 10 

LET J = 20 

LET K = J + G 

LET L = H + K 

the 1K ZX81. It features 

transfer markets, team 

strengths, money problems 

and as in real life, the ever present 

threat of being given the 

i) Enter the following as direct commands: 

LET A = 1, LET B = 2, LET C = 3, LET D = 4, LET E = 5, 

LET F= 10, LET G = 0, 

DIM A$(5,6), LET A$(1>= " WOLVES \ 

LET A$(2) = " Q-P.R. LET A$(3) = " VILLA 

LET A$(4) = " LEEDS " , LET A$(5) = " SPURS " . 

ii) The listing: 

(Note all items underlined are 

inverse characters.) 

3 LET T = E + F + INT(RND * C * F) 

6 LET M = F * F + INT(RND *C * F) 

10 LET P = G 

13 FOR I = A TO F 

16 PRINT " UNITED TS 

T;* £ " ;M;" PL";! - A;" PTS " ,P." BUY/SELL?" 

20 INPUT ZS 

23 IF Z$ = "B" OR Z$ = "S" THEN GOTO F*F 

30 PRINT "UNITED V ";A$(I/B) 

33 LET Q = INT(T/F - C + RND * D) 

36 IF Q

I 

I 

Printman 

Justin Perry 

The outline of this arcade-type 

game is that you are the person 

in charge of the letter 

store. When the printing press 

wants some letters, they send 

a requisition down to you. Letters 

always come to you in 

batches of six. Unfortunately, 

you only see the letters for two 

seconds, so you have to 

remember them. Your choice 

of letters are shown at the very 

top of the screen and you are 

the letter '0' flashing under 

them. The wanted letters appear 

at the bottom under the 

black line and stay there for 

two seconds after which they 

disappear. You must 

remember which letters were 

there and in what sequence 

they were in. 

Then, controlling your 

movement left and right with 

keys '5' and '8' respectively, 

you must manoeuvre yourself 

under the appropriate letter, 

pressing the 'Y' key to get 

your answer registered. You 

are allowed to have only five 

30 


wrong inputs after which you 

are sacked. All letter inputs 

must be in the sequence 

shown for the two seconds at 

the bottom or it will be rejected 

and you will lose one of your 

chances. An incorrect letter input 

leads to a 'w' being 

displayed at the bottom. Also 

displayed are your current 

score and the high score of the 

game so far. The scores for a 

correct letter are graduated 

from lowest to highest, from 

left to right at the top. 

The difficulty can be varied 

in two ways. The first is by 

altering the amount of times 

you can get your input wrong 

before stopping the game. This 

is done by changing the value 

Tl (a variable). To make this 

program harder, change the 

value in line 1020 to a smaller 

figure so that you are allowed 

less wrong goes. To make it 

easier do vice versa. 

The other way is to make 

the time longer that you see 

your letters. To do this, change 

the second value to either a 

larger value for an easier game 

or a smaller value for a harder 

game. At this level, my highest 

score is 40,850. 

1 REM "PRINTMAN" 

2 LET S = 0 

3 LET HS = 0 

4 LET Tl = 0 

10 FORF = 0T0 25 

20 PRINT AT 0, F;CHR$ (38 -I- F); AT 1 5, F;CHR$ 3 

30 NEXT F 

35 DIM A$ (6) 

40 FOR F = 1 TO 6 

50 LET A$

1983 

JULMîlLiL 

* t Addictive Games 

for SPECTRUM 48K 

AND ZX81 16K 

SI IN YOIJll If Mill 

stui:i

ACTION 

FROM 

THE A 

Z VERSION 

This superb game is now available from branches of 

W.H. SMITH * and BOOTS. 

Manage your own learn in this exciting game of skill which 

vividly captures the drama and excitement of real football. 

FEATURES INCLUDE 

* 4 DIVISIONS • F A CUP • PROMOTION & RELEGATION * 

* TRANSFER MARKET * TEAM SELECTION • 

* SAVE GAME FACILITY AND MUCH MORE! ** * 

+ 

WHAT THE PAtSS SAY ABOUT |T._ 

If YOU *W*H|I mantad to managa a footbaM tmam, FOOTBALL 

MANAGER, from Addpctiva Gamat. it for you — T ha gama ,nmr 

SINCLAIR USER FEBRUARY IN] 

4fl»wt*/ >iiwirMl/MlMI tad ! raatfy arôyodplaying (An (Wil 

— wl*rt o/cotew dafinad graphict Tha gama 

a rary logically put togothor, to that tha daralopmant of ttratagy and 

uccrci hat a rmaJ affact. for amampla. ona of my Mwni got through to 

tha fourth round of tha f .A Cup thara it wat baatan by a tacond 

dmition ttdo that uptat moral* and moant that our promotion bid 

fadad fat hap t I thould ha va giran up (A* f A Cup run and hatd toma 

good playart bach — tha ptudJMl art andfatt Unan C lough had 

battar aratch outI 

• irtCTtuw vintOM OMLY. ZX Computing Augusi September 1983 

«iW4f4f|i|[f MOM tut 'OllOW^ 

• uMll M«*0 tnor 

A«iaOGCOM»UT|it N«>t*y 

MClltttliVlCII 'Wr*H 

tH| COW»VlflHO' «M. HM 

MUSIC 

MAKER FOR 

io« tni tFicrauM u«ft H fmi im f* n 

)O0ltMi(t 0*1 » s |H'V 

t r ^ M & J .ikii ® 

V i V-^ 

• I'M' 

•" A 

BLACK CRYSTAL 

THE QUEST IS ABOUT TO BEGIN 

The utomate rote-playing adventure foi ihe SPECTRUM. ZX81 

You can become a warr or. atf or w>iard on a quest to find and uê 

the rings of creation, to destroy the Black Crystal and detest the 

Lords ol Chaos Held within sk program! lies a land ol labuious 

treasures and mythical monstees Journey through the land ol 

Berotti explore the castle of shadows, descend into the 

Shaggoths lair, search for diamonds in the sea ol sand but beware 

ol sand sharks I Confront the fne demon in his temple battle 

against the Lords of Chaos and win your way to the Black Crystal 

8y splitting Slack Crystal into m programs we can provide more 

variety and detail than any other adventure lor the Sinclair 

computers 

Real time monster battles Superb graphics Save game feature 

All x> parts are supplied together on cassette, boxed with 

instruction booklet 

SPECTRUM 48K: 180K OF PROGRAM 

IN SIX PARTS - ONLY £7.50 

ZX81 16K: OVER 100K OF PROGRAM 

IN SEVEN PARTS - ONLY £7.50 

WHY PAY MORE FOR LESS OF AN 

ADVENTURE 

X] 

t*n*lit " toir**i» 

To CARNELL SOFTWARE, DEPTI 4 STAUNTON RO. SLOUGH SL2 1NT 

Please send me: Black Crystal for my. 

O Spectrum «8K C7.50 

C ZX8t6K C7.S0 

I enclose a cheque/postal order i payable to Csmall Software) lor C 

NAME 

ADDRESS 

TRADE ENQUIRIES WELCOME 

31

it's action stations ail the 

way in Stephen Smith's 

program for your 

16K ZX81. 

The object of this game is to 

shoot down the enemy reconnaissance 

aircraft before they 

can relay your secrets back to 

their headquarters. The program 

requires 8K as it stands, 

but the PRINT statements after 

line 6 50 could easily be 

shortened to allow for a 

smaller memory capacity. 

in the air tonight 

Displayed on your control 

panel are the bearing (of the 

enemy from you), the distance 

{between you and the enemy), 

the air speed, the heading 

(degrees from 0° North), 

altitude (in metres above the 

ground), the flaps (which alter 

the heading of your 'plane) and 

the artificial horizon (which 

alters the altitude). 

When the flaps are set, up 

to a maximum of ±3, they will 

continue to change the 

heading until reset at zero. 

Likewise, the artificial horizon 

(A/H) will continue to change 

the altitude until reset at the 

centre. 

The first thing to master is 

the take-off — you need to get 

your speed to around 70mph, 

but if you go too fast before attempting 

to take off (arrow 

keys 'f and 'f will change your 

artificial horizon) you will inevitably 

crash into the control 

towers at the end of the runway! 

If this happens, the radio 

crackles and messages appear 

on the screen (this is my 

favourite routine — see lines 

700 to 800). 

Once the enemy is within 

distance 20 and bearing 10, 

the enemy aircraft will appear 

in your 'plane's window provided 

the craft is at your 

altitude or up to 10m higher. 

48-100 

1 10-220 

230-285 

300-490 

390 

400-460 

500 

535 

540 

600 

700 

800 

850 

900 

32 

Your firing range is within a 

distance of 10. 

in control? 

The controls you have at your 

disposal in your 'plane are: 

F - 

2 - 

3 - 

9 - 

0 - 

6 - 

7 - 

5 - 

8 - 

Fire. 

Slow down. 

Slow down fast. 

Speed up. 

Speed up fast. 

Decrease artificial 

horizon. 

Increase artificial 

horizon. 

Decrease flaps. 

Increase flaps. 

The '5', '6', *7' and '8' keys 

correspond to the arrow keys. 

The important variables in the 

program are: 

ES — Enemy speed. 

S — The speed of your 

'plane. 

H — The heading of your 

'plane. 

EA — Enemy altitude. 

A — The altitude of your 

'plane. 

F — Flaps. 

AH — Artificial horizon. 

AM— Ammunition left. 

D — Distance. 

B — Bearing. 

X — Your x-axis value. 

Y — Your y-axis value. 

These last two values are 

taken from the position of the 

enemy craft — your opponent 

is always at position (0,0) 

heading along the y-axis. 

Down the line 

Here is a breakdown of some 

of the more important lines in 

the program: 

Assign the 'calculating' variables. 

Print the control panel. 

Assign the 'displayed' variables. 

The main program loop. 

The heading conversion from plot to degrees. 

Calculate the new co-ordinates, bearing and 

distance. 

The routine for speed change. 

The routine for artificial horizon change. 

The routine for changing the flaps. 

The fire routine. 

The routine controlling a crash into the end of 

the runway. 

The routine for no enemy 'planes left. 

The routine for when your altitude is less 

than zero. 

Loading routine. 


20 5LOU 

25 GOTO 4.0 

30 SRUE "RECONNRIS5RNCE RLER§" 

4.0 RRND 

4.2 PRINT "YOUR CONTROLS ORE: " , 

FIRE",,,,"0 5LOU DOUN",,"HL 

SLOU DOUN FR5T" , "B SPEED U P " ^ 

^PFED UP QUICKLY",,, USE THE R 

9ROUS FOR DIRECTION","PRESS RNY 

KEY 

4-5 IF INKEYt="" THEN GOTO 4-5 

46 LET PLRNESs1 

55 LET ES=RNQ*1.57+1.67 

60 LET X=P.ND*10-5 

70 LET Y=RND*10-15 

30 LET H=RND*30-15 

SO LET Z=HfPI/15 

^FI Ef^Ss-XMT t.RWDH6>*M 

110 uL5 

15Q 

ZX COMPUTING AUG/SEPT 1983

K= R 

INY 

4-5 

PT 1983 

econnaissa 

alert 

170 PRINT "J TRB 30 ; " »« ^ 'M 

;TRB 3®.; MS"; "i8Ji ";TFiB 3S;. " Si" 

I80 PRINT «T &.. IS.; " + " 

21© PRINT 

; TO > .; ft 

220 priÎT 

230 LET 

2 4-Q LET F = 0 

250 PLOT 21+H„U 

260 LET RH = © 

270 LET R = 0 

28© LET RH=4 

ZX COMPUTING AUG/SEPT 1983 

RPI 

2 0 5 P R I N T RT 

S 9 Q G O T O 4-2© 

3 0 0 L E T I » = I W K E Y $ 

3 ® 5 I F I $ = " F " T H E N G O T O 

3 i e i f c o d e rt>a? h n d c o d e . r s c s 

8 T H E N G O S U B 5 * V « L 

•jaa l e t q = « 

3 2 5 L E T R = R + R H 

3 2 8 I F « < 0 T H E H G O T O © 5 ® 

3 3 © I F F =& T H E N G O T O 3 6 © 

34-0 U N P L O T a i f H . H 

^ = > 0 L E T H = H + F - 3 1 H H > 1 5 > + » (H < - 

3 5 5 P L O T 2 1 + H . U 

3 9 0 L E T Z = H * P I / 1 S 

403 LET X bX f-S t-SIN Z 

4-13 LET Y = Y + S * O O S Z - E 5 

4 1 5 I F O r 2 0 ftNC 1 R B 5 B E P 

> = Q ftND E R < = Q + 1 0 T H E N P R I N T RT & 

-iEft-Oi / 5 , 1 0 + B ; " *• 

^ X V L E T E R = E f t + 5 * I N T + 5 

0 I F X = 3 T H E N L E T B = 5 S H V * 9 d + 

~4-3© I F V = 0 T H E N L E T B = S & N • 

33

4.40 IF X=© Oft Y = © THEN GOTO 

L 5 T B - ! R T N ( X / Y ) - Z > X 

. 1 r 

J. 3C. f 

4.60 LET D=SOR (XfX+YiY) 

479 IF D < 20 AND OBS B < lw HND fc.H 

>=A AND EA1.3 AND A=0 THEN GOTO 

t>a© Xr -=,

JL 

EN 

• T 

UM 

o 

RT 

RT 

1983 

LIST . . LOAD . . RUN . . OR . . DIE . . 

VV^V^V 

/ EXTERMINATORY)* 

/ Robot intelligence has surpassed 

/ humans'. using homing mimics. move 

and fire in eight directions, avoiding 

indestructible robots with homing 

missiles, to save the last of the human 

•Joystick option available 

t ZX8I 

f f Ground Attack £3 9S 

f Super Wumpus £3 9S 

t Games Pack I £3 9S 

r Graphic Golf £3 95 

SPECTRUM 

Cyber Rats £5 9S 

SPECTRUM 

Slippery Sid £5 9S 

Starship Enterprise £S 9S 

Muncher £S 9S 

Ground Attack £S 9S 

Mission Impossible £S 9S 

Brain Damage £S 9S 

Armageddon £S 9S 

Send cheque or postal order to SILVERSOFT LIMITED 

London House 271.273 King Street. London W6 

or complete your 

Access or Visa No 

M 

TV 

I enclose cheque postal order for 

Address

ANOTHER QREAT 

ADVENTURE 

GAME FOR 

THE 1tK ^ 

zx»i 

AREALIVQREAT 

(ELECTION or 

ANOTHER GRSAT 

AOVINTURE 

C.AMt 

•mil** ^ 

IX»1 

A HtALLY GREAT 

CHESS GAVE 

fO« THI 

ANOTHtHGlUAt 

CHLSSt'.AVf 

rem thi 

IfiK /*!!! 

with Artie 

rifÂ CURSE 

(Adventure B) 

In a jungle clearing you come 

across an ancient Inca temple: 

Your mission to enter, collect the 

treasure and escape alive' 

But beware 1 

£5.95 for 16K ZX81 and £6 95 

for 48K Spec 

2. SHIP OF DOOM 

(Adventure C) 

You are unavoidably drawn to an 

alien cruiser. Can you reach the 

control room and free yourself 7 

Or will they get you first? 

Cassette £5.95 for 16K ZX81 

and £6.95 for 48K Spec 

3. PLANET OF DEATH 

(Adventure A) 

You find yourself stranded on an 

inhabited alien planet. Can you 

reach your ship and escape 7 

£5.95 for 16K ZX81 and £6 95 

g ghosts 

then 

High 

ith hi-res 

troy all the 

yand exit 

nto a new 

au have 

jr mission 

PUSH YOUR SINCLAIR TO THE LIMIT 

Artie supply the best selection of adventure, arcade and 

educational games available for the Sinclair home computers 

Artie also offer a wide range of utilities that will enable you 

t9 utilize your ZX81 /Spectrum to its full potential. 

These include: . M 

16K 2X81 Assembler £9.95 

48K Spectrum Assembler £9.95 

Toolkit £5.95 ^ ^ ^ 

Spec Bug £6.& 

ZX Bug . £6.95 M 

S.VS64 ,£6.95 M 

A'.OTHc* OÊi 

-BCJOE SAVE 

FCPT"? T6MK. 

S'ECTP.^r, j* 

StartreU

(SOFTWARE REVIEW! 

College computing 

Nick Pearce goes back to 

college and takes a look 

at the library of 

advanced mathematics 

software from 

university Software. 

University Software have produced 

five cassettes which 

comprise their library of advanced 

mathematics. They are 

designed to handle complex 

problems in various branches 

of mathematics. 

These are utility, rather 

than teaching, programs, 

although instructions printed 

on the cassettes covers are 'intended 

to introduce the nonspecialist 

to the theory'. In 

general, the instructions are 

adequate for this purpose. 

Matrix Operation This program 

is designed to handle the usual 

matrix operations of Inversion, 

Multiplications, Addition, Subtraction 

and Scalar Multiplications. 

The operation required is 

selected from a menu at the 

start of the program. The user 

dimensions the matrices and 

enters the values of the 

matrices row by row. The program 

will not accept invalid 

instructions at this stage. For 

example, if you select the inversion 

operation the program 

will not accept a matrix with 

an unequal number of rows 

and columns (which cannot be 

inverted) and prompts the user 

for new matrix dimensions. 

Whilst there seems no limit to 

the matrix dimensions this program 

will accept, a 20 by 20 

matrix is inverted in a little 

under seven minutes. 

The program works well 

and data input is logically 

organised. However, I would 

have liked the option to alter 

individual values within a 

matrix; as the program stands, 

a mis-type during data entry 

necessitates re typing of the 

complete matrix. On the 

reverse side of the cassette is 

Determinants, a program 

which computes the determinant 

by means of converting a 

matrix into a triangular matrix 

by the appropriate row 

transformations. 

Polynomials This program also 

severely tested my knowledge 

of such things. A polynomial is 

38 

an expression of the form: 

F(x) = C X" + C ,X" 1 + . . . 

n n 1 

+ C,X 2 + C.X + C 

I I o 

where C n ... C , are coefficients 

and n is the degree of 

the polynomial. The program 

calculates the roots of a 

polynomial expression, ie the 

values of x which satisfy Fix) 

= 0 (real roots only). 

The program employs three 

different methods. If the expression 

has two degrees the 

familiar formula for solving 

quadratic equations is used; 

for higher degree polynomials 

interactive methods are used, 

either the Newton-Raphson 

method (which I recall) or the 

Half-Interval Search method 

(which I don't). 

On the B side is Plot of 

Polynomials, a program which 

plots the polynomial equation 

between given limits. This 

works very well, you input the 

degree and coefficients of the 

polynomial as before, and the 

range over which it is to be 

plotted. The program scales 

the axes and plots the equation 

accordingly, and also labels 

the extreme values of the 

axes. If a root is found the 

value of the root is printed at 

the point of intersection. 

Integration On more familiar 

territory now, I can clearly 

recollect counting up squares 

to calculate the area under 

curves. This program 

evaluates the integral of functions 

between given limits by 

Simpson's and Trapezoidal 

rules. Two functions can be integrated 

simultaneously, 

allowing the area between two 

curves to be evaluated. 

Again, a program to plot the 

function is given on the B side. 

This plots two functions between 

given intervals and 

cross-hatches the area between 

them. To evaluate the integrals 

the A side has to be used. 

Regression On even more 

familiar ground, regression 

analysis is a technique I have 

had occasion to use recently. I 

devised for myself a short program 

for the ZX81; it worked 

adequately but could only handle 

one independent and one 

dependent variable. University 

Software's program is 

somewhat more elaborate and 

will solve a 'multivariate' linear 

regression problem. 

The user enters the number 

of observations and the 

number of independent 

variables. For each observation 

the values of the associated 

variables are entered. Data entry 

is a little tedious, and again 

there is no way to correct a 

mis-typed figure if you make 

a mistake you have to re-type 

from scratch. The program can 

deal, with both exponential and 

logarithmic regressions. 

The program calculates the 

equation coefficients, and 

gives the values of r 2. corrected 

r 2 (r 2 adjusted for the 

degrees of freedom), the 

F-statistic, standard error of 

regression, Durbin Watson 

statistic, and the t-statistic. 

Side B plots the regression line 

together with the numbered 

data points for a 'bivorate' 

regression — the sort of 

regression I understand. It 

gives the slope and intercept 

of the fitted line and the standard 

error and r 7 of the regression. 

Linear Programming This is 

where things started to get difficult 

again. The cassette is 

certainly no substitute for a 

good textbook on the subject, 

but having mastered the 

theory it can be of con- 

• 3 . 

l* x > >* > < x 

ti 

-x ;->-', 

o 

0 

xxxxx: 

xxxxxxx 

XXXXXXXX u % 

XXXXXXXXXX tCxxx 

xx xxxxx, 

I X X X X X X X X • 

•XXXXXXXX. 

• XXXXXX • 

•XXXXXX» 

•XXXXa 

n XXX r 

V V 

siderable assistance in the 

solution of linear programming 

problems. 

This optimization program 

is capable of handling any sort 

of linear programming problem 

with up to 20 variables and 20 

constraints. After data entry, 

the original form of the problem 

(the primal) is displayed 

together with the solution — or 

with a report that the problem 

is either unfeasible or unbounded. 

A second display 

gives the canonical equivalent 

of the primal, its solution and 

the variable relationships or 

the primal and canonical, A 

third displays the dual and its 

solution. 

Side B deals with 

simultaneous equations. 

All of these University Software 

programs run automatically 

once loaded, and pro 

mpts to guide the user are 

given on screen. The programs 

are all written in 8ASIC and 

can be listed, enabling the user 

to see how they work, or 

modify them. Output displays 

can be copied onto a printer. 

These are not teaching programs, 

but they take the 

tedium, and the human error, 

out of mathematical problem 

solving and will be a valuable 

aid to the serious user and student 

alike. They all perform 

well have obviously been 

carefully prepared. 

University Software also offer 

to prepare more specialised 

programs to order. 

University Software is at 45/c 

S/oane Street, London SW1X 

9LU. Matrix Operation, 

Polynomials and Integration 

cost €6.95 each; Regression 

and Linear Programming are 

priced at £7.95 each. 

'XXX 

"X XXX XX 

•xxxxxxxxx 

XXXXXXXXXXX 

XXXXX 

XXXX 

XX XX 

XXX 

• X X * 

m m XX 

«X X 

* X 

•X 

I F 

\ 

— * 

XG\ 

A sample semen dump showing the capabilities of the integration program 

{ 1 

ZX COMPUTING AUG. SEPT 1983

it 

/ a t>lc 

Ha V$ 

Afe, 

Vent 

a na 

f or 

'.A 

'ts 

Don't let the enemy get 

your secrets in this 

game written by 

fourteen year old Martin 

Clayton from 

Knavesborough. 

Written for the unexpanded 

ZX8 1, the object of the game is 

to shoot the satellites out of the 

sky before they can relay information 

on your military bases 

back to the enemy. 

As the satellites traverse 

across the top of the screen, it 

is your job to move the ground 

to air missile launcher until you 

can get a good shot at the 

enemy device. Movement of 

the missile launcher is achieved 

by pressing the '5' key to go 

left and the '8' key to move 

right. Key '0' is used to launch 

a missile at the satellite. 

Should a satellite reach the 

far left hand side of the screen. 


it is assumed the device has 1 REM "SATELLITE" 

escaped destruction and has 10 LET A = VAL" 10" 

thus relayed all of the secret 20 LET S = A - A 

data on your military establish- 30 LET B = VAL" 20" 

ments. This is achieved in line 40 GOSUB 500 

520 with the 'Q', and an error 50 LET A = A i (INKEYS - 

2 message denotes the end of " 8") - (INKEY$ = " 5" ) 

the game. go IF INKEY$ = "0" THEN 

To hit a satellite, you must GOTO 100 

aim for the '0' character of the 70 GOTO 40 

device. If you do manage to de- 100 FOR N = 10 TO 2 STEP 

stroy the satellite, line 160 

- 1 

causes an explosion to be dis 1 10 GOSUB 500 

played: this is followed by a 120 PRINT AT N.A + 2;" *"; 

PAUSE statement causing the AT N+ 1.A + 2;" " 

screen to blink (just to add a 1 30 NEXT N 

touch of realism). When the 140 IF A-INT B THEN 

game finishes, your score is dis- GOTO 160 

played. 1 50 GOTO 40 

160 

170 

180 

190 

200 

500 

510 

520 

530 

PRINT AT 2.8," > IX 

(

NOW AVAILABLE FROM W.H. SMITH 

SUPER IPV 48K Spectrum 

Locate the secret island hideaway of the mysterious 

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underground lair — but beware — even with your 

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^ win the day! 

Credit Card Hotline 

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Saving the world may 

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I 


shoot the alien spaceship five 

times before it gets to shoot 

you. You use the '1' key and 

the 'Q' key to move left and 

right respectively. You can fire 

at the spaceship using the '0' 

key. 

You must make sure your 

shots are aimed at the black 

squares of the spaceship — all 

1 PRINT 

other hits are counted as 

naught. The winner of the 

game is the first one to get five 

hits. The seemingly random firing 

of the spaceship is accomplished 

using the RND 

function. 

The game is great fun to 

play and beating the spaceship 

is no easy task! 

IINV IWC ISL E] 

2 P R I N T RT 5 , C ; " U S E 0 TO MOVE 

L E F T " . " U S E K T 0 MOUE R I G H T " , " U S 

E S T O F I R E - ' 

3 P R I N T RTT 16 . 0 . " Y O U R S H O T S 0 

PN P E N E T R f l T c T H E ' " / ' B L f t C K 53L'RRE 

5 O N L Y " 

4- P R I N T RT U , 0 . " F I R S T ONE T O 

SCORE 5 H I T S IJIN5" 

1 3 PRINT- 


1 2 

RT " 

20 

90 

l O O 

10 1 

102 

1 0 3 

1 0 4 

1 0 5 

1 10 

120 

1 3 © 

14-0 

I E 0 

1 6 0 

1 7 0 

3 0 0 

5 0 G 

54.0 

5 5 0 

5 5 s 

5 5 0 

5 6 1 

5 6 5 

5 6 6 

600 

1 

610 

1 

620 

00 

9 0 0 

1 0 0 5 

1006 

1010 

1020 

1 0 3 0 

P R I N T " P R E S S PkNY K E Y TO 5 T h 

P A U S E 4-E4 

C L S 

L E T m = 0 

L E T 5 H = 0 

LET zx=e 

L E T 5 K = 0 

L E T Z K = 0 

L E T 

L E T C 

L E T C' 

L e i E 

— O 

-» 

= i s 

in 

ia mi MMSm-M 

L E T H = I N T ( R N D * 2 5 ) 

L E T 

— 

F 

-* 

L E T G = I N T f R N D * 2 S ) 

L E T O = I N T ( R N D U ' i 

PR I N i-i T R " • • M ^ H 

I F 

I F 

'IT E , R, 

3 = 1 THEN L E T H = H - i 

Q = 2 T H E N L E T H =H + 1 

0 = 3 T H E N 5G5UB 1 5 0 0 

H ) = 2 5 T H E N L E T H = 2 6 

H < =0 T H E N L E T H = 0 

G > = 2 6 T H E N L E T G = 2 6 

G < - 0 T H E N L E T G = 0 

I N K E Y 1 " T H E M L E T 

I N K E Y $ = " Q " 

I N K E Y $ = " 0 " 

G = G - 

T H E M l e t g = g + 

T H E N G O S U B 10 

GOTO 3 0 0 

L E T S H = S H + 1 

FOR 1 = 14. T O I S T E P - 1 

P R I N T R T I ^ G + 2 ; 

P R I N T R T X . G + 2 ; " "; 

I F PEEK (PEEK 1 6 3 9 3 + 2 S 6 » P E f 

K 1 6 3 9 9 ) = 1 2 6 T H E N GOTO 

104-0 I F PEEK (PEEK 1 6 3 9 3 + 2 5 6 - + P E E 

K 1 6 3 9 9 ) = 1 2 9 T H E N GOTO 1 2 0 0 

1 0 6 0 N E X T I 

1 1 0 0 R E T U R N 

1 2 0 0 P D I N T RT B , H ; 

1 2 0 5 L E T S K = S K + 1 

1 2 1 0 I F S K = 5 T H E N GOTO 2 S 0 0 

1 2 2 0 GOTO 3 0 0 

1 5 0 0 FOR 1 = 2 T O 1 7 

1 6 0 1 P R I N T RT I , H + 2 ; 

1 5 0 5 P R I N T RT I , H + 2 ; 

1 5 1 0 N E X T I 

1 5 1 2 L E T 2 X = 2 X + 1 

1 5 2 0 I F H + 2 = G + 2 T H E N GOTO I 7 0 O 

1 S 0 0 R E T U R N 

1 7 0 0 P R I N T RT F . G ; 

1 7 0 5 L E T ZK = ZK + 1 

1 7 1 0 

1 7 2 0 

I F ZK =5 T H E M 

GOTO 300. 

GOTO ! 5 0 0 

2 0 0 0 P R I N T "S5" 

2 0 0 2 GOTO 3 0 0 

2 5 0 © C L S 

2 5 1 0 P R I N T RT 1 , 0 ; * * * * * * * * * *GRM 

E O U E R * * * * * * * * * * ' 

2 5 2 0 P R I N T RT 3 , 0 

" ; zx 

2 5 3 0 P R I N T 

2 5 — 0 P R I N T 

2 5 5 0 P R T N T 

ZXS1 S H O T S = 

2 5 6 0 P R I N T 

2 5 7 0 P R I N T * H U M A N SHOT: 

SH 

2 5 ©O P R I N T 

2 6 9C P R I N T UM6W" 

SK 

2 6 0 0 P R I N T 

2 6 10 P R I N T 

2 6 2 0 P R I N T ' P R E S S ANY KEY T O T R Y 

R G R I N 

2 6 3 0 P A U S E 4-E4- 

2 6 6 0 GOTO 9 0 

42 ZX COMPUTING AUG/SEPT 1983 

• bf

1983 

ncnoTccn 

The Complete Ban 

Fifteen months ago Memotech developed the first 64K Memopak, designed to maximise the capabilities of the Sinclair 

ZX81. Since then, using the ZX81 as a starting point, we've gone on to produce a comprehensive range of Memopaks, 

adding 16K and 32K memory expansions, utilities packages comprising a Word Processor, Z80 Assembler and 

Spreadsheet Analysis, plus Communication Interfaces, High Resolution Graphics and a professional quality Keyboard. 

To complete our range of ZX81 add-ons, we are now introducing the MEMOPAK RS232 Serial Interface. 

RS232 Interface 

The RS232 is an all-purpose interface 

which allows the ZX81 not only to 

output to suitable serial printers, but 

can link up with numerous types of 

peripheral or even other processors. 

The Interface has two main modes of 

operation: BASIC mode allows you to 

use the range of functions supplied in 

the RS232 I;PROM within an ordinary 

BASIC program, and TERMINAL 

mode allows you to use your ZX81 as a 

terminal to another processor. 

The I:PROM functions offered permit 

the user to send, receive and convert 

bytes between ZX81 code and ASCII, 

as well as check the status of numerous 

control flags. Received or transmitted 

data can appear simultaneously on the 

screen, and received data may be 

printed simultaneously. 

£39.95 inc. VAT 

Memopak Centronics 

I/F 

The BASIC commands l.PRIN'T, 

LLIST and COPY are used to print on 

any CENTRONICS type printer. All 

ASCII characters are generated and 

translation takes place automatically 

within the pack. Reverse capitals give 

lower case. Additional facilities allowhigh 

resolution printing. 

£24.95 inc. VAT 

Memopak HRG 

This pack breaks down the constraints 

imposed by operating at the ZX81 

character level and allows high 

definition displays to be generated. All 

248 x 192 individual pixels can be 

controlled using simple commands, and 

the built in software enables the user to 

work interactively at the dot, line, 

character, block and page levels. 

£29.95 inc. VAT 

Memocalc 

The screen display behaves as a 

'window' on a large sheet of paper on 

which a table of numbers is laid out. 

The maximum size of the table is 

determined by the memory capacity, 

and with a Memopak 64 K a table of up 

to 7000 numbers with up to 250 rows or 

99 columns can be specified. 

£29.90 inc. VAT 

Memotext 

Text is first arranged in 32 character 

lines for the scrccn with comprehensive 

editing facilities. On output the user 

simply chooses the line length required 

for printing and the system does the 

rest. Used with the Mcmopak 

Centronics Interface, the Word 

Processor makes available printout with 

80 character lines, upper and lower case 

and single and double size characters. 

£29.90 inc. VAT 

Memopak 

Memory 

Extensions 

For those just setting 

out on the road to real 

computing, these packs 

transform the ZX8I from 

a toy to a powerful computer 

Data storage, extended program 

ming and complex displays all bccome 

feasible. Further details available on request. 

16K Memopak £24.95 32K Memopak £34.95 

64 K Memopak £49.95 Prices inclusive of VAT 

MEMOPAKS ARE AVAILABLE AT MAIN 

BRANCHES OE WH SMITH and JOHN MENZIES 

Z80 Assembler 

The Assembler allows 

you first to code and 

edit a source program in 

the Z80 language, and 

then assemble it into 

machine code. You can 

now write flexible and 

economic programs. 

The Editor mode 

allows you to codc 

directly in the right 

format, manipulate 

individual lines and 

control the exact placing 

of source and machine 

codc. Routines may be 

merged or listed (even 

to a commercial printer 

using our Centronics 

Interface). The 

assembler mode handles 

all standard Z80 

mnemonics, numbers in 

hex or decimal, 

comments and uscrselectcd 

labels. 

£29.90 inc. VAT 

All Prices are inclusive of VAT, postage and packing. 

Memotech Keyboard 

The Memotech plug-in Keyboard plus buffer pack takes the 

effort out of data entry for ZX81 users. The Keyboard has a 

light professional touch and is housed in an elegant 

aluminium case. The simple plug-in system means that you 

are not obliged toopen->ip your ZX81, use a soldering iron or 

invalidate your ZX8I warranty. 

Keyboard Buffer Pak 

The Buffer Pak performs a "housekeeping" function for the 

Keyboard, interfacing directly with the port of your ZX81. 

£34.95 inc. VAT 

To Order: Send your Name, Address, Memopaks required, plus a Cheque/Postal Order 1 Access Barclavcard number (please state 

which) to: Memotech Limited, Station Lane Industrial Estate, Witney, Oxon. OX8 6BX. Telephone Witney 2977 

We want you to be completely satisfied with your Mcmopak - all our products carry a 14 day money back guarantee.

it's in 

the box 

Peter Shaw 

takes the lid off the 

Fuller Master Unit 

and tells us what 

he found there. 

Fuller, the Liverpool based 

company who have brought you 

add-ons for the ZX81 and 

Spectrum in great quantities in 

the past, have come up with the 

goods once again with a very 

useful peripheral for the ZX 

Spectrum. 

Does it measure 

up? 

The Master Unit itself is built into 

a tough black plastic box 

measuring 8cm by 24cm by 

3cm. The connector at the back 

of the Master Unit is strong and 

forms a good and healthy 

connection with the Spectrum. 

The unit also has a connector at 

the back allowing you to make 

the outputs you would from the 

Spectrum itself. 

The Master Unit can perform 

a wide range of fancy tricks 

although its main feature is 

speech. The unit is capable of 

forming a large number of 

phonemes, all of which are 

clear, easy to use and, more 

importantly, easy to understand. 

You use the Master Unit's 

speech facility by sending a 

chosen number in port 1 59, ie if 

you say 'OUT 1 59,x' where x 

would be phoneme you wish to 

be enunciated. The speech 

demo supplied with the unit was 

not amazing but was adequate 

to test the unit's prowess. There 

are also rumours to suggest that 

there might be software coming 

soon from Fuller themselves 

which could drive the speech 

unit as well as providing a well 

written arcade game. 

zap! pow!! boom!!! 

The next feature the Master Unit 

offers is three channel sound — 

a very useful addition to the 

limited voice of the Spectrum. 

Unfortunately, the demo tape to 

illustrate the capabilities of this 

facility is not that good, just 

providing some sample arcade 

zaps and explosions before 

giving you a do-it-yourself 

sound generator program. 

However, as I found, it is very 

worthwhile 'doing it yourself' as 

some of the noises you can 

come up with are fantastic. 

But the unit doesn't stop 

there! It also has a joystick port 

for Atari-type joysticks which 

works very well with a lot of the 

software I have. The Master 

Unit also has an on-board 

cassette interface which 

enhances all the signals from the 

Spectrum and allows you to 

keep both EAR and MIC plugs 

connected at the same time. 

we shall not be 

moved 

The Fuller Master Unit sounds 

amazing, doesn't it — and it is. 

I'm not going to take it off the 

back of my Spectrum for a long 

time. 

You can buy the Master Unit 

for £54.95, or if you would 

prefer a cheaper version which 

has all the features of the Master 

Unit except the speech, you can 

get one for £29.95. 

For more information on the 

Master Unit or any other Fuller 

products, get in contact with 

Fuller Micro Systems, The ZX 

Centre, Dale Street, Liverpool 2. 

Telephone enquiries can be 

made on 051-236 6109. 


irm 

cks 

i is 

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of 

are 

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Inside... 

Latest prices round-up... 

Latest software... 

Order form...

Introduction 

One thing's certain about the Sinclair 

world - there's never a dull moment. 

Every month sees new software 

and new hardware, produced by 

Sinclair enthusiasts, or produced by 

Sinclair itself. 

The magazines do a fantastic job 

of keeping you up to date with the 

input of enthusiasts We want to keep 

you in touch with Sinclair's own 

developments. 

Every month, there'll be a Sinclair 

Special in this magazine. 

Sometimes, inevitably, there won't 

be anything new to say - we want to 

break away from the breathless 

announcements of hardware and 

software you just can't buy. 

But when something new is available, 

we want you to have accurate 

information-fast. You'll find it here 

This month, we're giving you the 

latest information on the recommended 

retail prices of Sinclair 

equipment. They're our prices, and 

you may well find things cheaper (or 

dearer) in the shops. If they're 

cheaper-terrific! Snap them up. 

Note, however, that from us the 

ZX81 is down to £39.95. 

We're also announcing six superb 

new Sinclair cassettes for the Spectrum, 

and three more which make full use 

of the ZX81. There's an order form at 

the back of this Special. 

Next month... but there, next 

month is another story! Watch (as 

they say) this space. 

Nigel Sear/e. 

Managing Director, 

Sinclair Research Ltd. 

Spectrum-latest recommended 

retail prices. 

16Kwas £125.00 

16Know£99.95 

48Kwas £175.00 

48K now £129.95 

ZX Printer was £59.95 

ZX81 was £49.95 

ZX Printer now £39.95 

ZX81 now £39.95

Six new ways to make more 

of your Spectrum. 

Take a look at these brand-new titles. 

Each is an outstanding new program 

using the full potential of the Spectrum, 

for games with stunningly animated 

graphics, for strategies of fiendish 

cunning, for masterly applications of 

computing capability... 

Cyrus-IS-Chess Based on the Cyrus 

Program, which won the 2nd European 

Microcomputer Chess Championship 

and trounced the previously unbeaten 

Cray Blitz machine With 8 playing levels, 

cursor piece-movement, replay and 

'take-back' facilities, plus two-player 

option.The 48K version has many additional 

features including an extensive 

library of chess openings. For 16K or 

48KRAM Spectrum. 

Horace and the Spiders Make your way 

with Horace to the House of Spiders, 

armed only with a limited supply of antispider-bite 

serum. In the house, destroy 

the webs before the spiders can repair 

them Then destroy the spiders, before 

they destroy Horace! Undoubtedly the 

creepiest Horace program ever produced! 

For 16K or 48K RAM Spectrum. 

Computer Scrabble The famous board 

game, on-screen - with the whole board 

on view! A huge vocabulary of over 

11,000 words Full-size letter tiles, four 

skill levels - the highest of which is 

virtually unbeatable. For 1 to 4 players. 

For48K RAM Spectrum. 

(SCRABBLE trademark and copyright licensed by 

Scrabble Schutzrechte und Handels GmbH - a J W Spear 

and Sons PLC subsidiary.) 

Backgammon A fast, exciting program, 

with traditional board display, rolling dice 

and doubling cube Four skill levels. For 

experts - or beginners. (Rules are 

included - it's the quickest way to learn 

the game.) For 16K or 48K RAM Spectrum. 

FORTH Learn a new programming 

language, as simple as BASIC, but with 

the speed of machine code. Complete 

with Editor and User manual. For 48K 

RAM Spectrum. 

Small Business Accounts Speeds and 

simplifies accounting work, produces 

Balance Sheets, Profit and Loss information 

and VAT returns. Complete with 

User manual For 48K RAM Spectrum. 

Overleaf-your Sinclair order form.

Three new ways to get the 

best out of your ZX81. 

The range of Sinclair software for the 

ZX81 continues to grow. 

These three new cassettes offer two 

totally different challenges to you and 

your ZX81 The games-like so many 

ZX81 games today - really do use the 

ZX8Vs capability The FORTH program is 

a fascinating extension of your own 

computer understanding 

Sabotage Defender or attacker? The 

choice is yours in this exciting game 

Be the Guard and defend the randomly 

placed boxes of ammunition inside the 

compound-or be the Sabateurand 

attack the ammunition! 

Written by Macronics tor a ZX81 with 

16K RAM Cassette price: £4 95 

City Patrol You are the Commander of a 

laser-firing ship. Your task is to intercept 

and destroy alien suicide ships 

descending on your city. Judge your 

rating as Commander by how many aliens 

you destroyand how much of your city 

survives. 

Written by Macronics for a ZX81 with 

16K RAM Cassette price: £4.95. 

FORTH Discover a new programming 

language which combines the simplicity 

of BASIC with the speed of machine 

code. 

FORTH's compiled code occupies 

less than a quarter of the equivalent 

BASIC program and runs ten times as 

fast It is fully extendable by the addition 

of user-defined commands. 

Free User-Manual and Editor Manual 

with each cassette. 

Written by Artie for a ZX81 with 16K 

RAM. Cassette price: £14.95. 

How to order 

Simply fill in the relevant section(s) on 

the order form below. Note that there is 

no postage or packing payable on 

Section B. Please allow 28 days for 

delivery. Orders may be sent FREEPOST 

(no stamp required). Credit-card holders 

iinczlsir" 

Sinclair Research Ltd, 

Stanhope Road, Camberley, 

may order by phone, calling 01-200 0200 Surrey, GU15 3PS. 

24 hours a day 14-day money-back option Telephone: (0276) 685311. 

T To: Sinclair Research Ltd, FREEPOST. Camberley, Surrey. GU15 3BR. ORDER FORM 

Section A: hardware purchase Section B: software purchase 

Qty Item Code 

Item Price Total 

£ £ Oty Cassette Code 

Item Price 

£ 

ZX Spectrum -48K 3000 129 95 FOR SPECTRUM 

ZX Spectrum -16K 3002 99 95 G22/SBackgammon 4021 5.95 

ZX 81 (including 1 2 A Mams Adaptor) 1003 39 95 G23/S Cyrus-IS-Chess 4023 995 

16K RAM packtorZX81 1010 29 95 G24/S Horace & the Spiders 4022 5 95 

ZX Printer 1014 39 95 G25/S Scrabble 4024 15.95 

1 2A Mams Adaptor, for use with 

ZX81 computer/ZX Printer combination 

(only required il you have 

an early ZX81 with 0 7A Adaptor) 

1002 795 

L1 IS FORTH 4400 14 95 

B6 IS Small Business Accounts 4605 12 95 

FOR ZX81 

Printer paper (pack ot 5 rolls) 1008 11 95 G25 Sabotage 2124 495 

Postage and packing orders under £90 0028 295 G24 City Patrol 2123 495 

orders over £90 0029 495 LI: FORTH 2400 1495 

'1 enclose a cheque/postal order made payable to Sinclair Research Ltd for £ 

•Please charge to my Access/Barclaycard/Trustcard account no: 

TOTAL £ TOTAL £ 

•Delete/complete as applicable 1 1 1 1 1 1 1 1 1 I 1 (Please print) 

I Signature 

I 

Total 

£ 

j Mr/Mrs/Miss | | | | | | | | | I I I I I I I I I I 

Address, I I I I I I I 1 1 I I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I I I I 1 1 1 1 1 1 1 1 1 1 I I I I I I ZXC908

NOW. A ZX81 

PUSH-BUTTON 

KEYBOARD 

FOR UNDER £10. 

1 MM the original key hi ia

and ch« k (tut si the keys lunclion 

2 Ihf Butlonset is held m pl,Ke 

by serf adhesive pjds 

At last there's a really cheap but efficient way of 

ironing out the ZX81's only real bug: its keyboard. The 

Filesixty Buttonset offers: 

• A full-travel calculator-type moving keyboard for only 

£9.95.1 Installed in seconds. The peel-off adhesive backing 

means you just register into position and press. • No messy 

labels, dismantling or soldering. • 3 groups of colour keys 

to pick out shift, numerals and newline. • Precision moulded 

in ABS to match your ZX81, with contrasting legends for 

maximum legibility. 

Filesixty Ltd., 25 Chippenham Mews. London W9 2AN, England. 

Tel: 01-289 3059. Telex: 268 048 EXTLDN G 4087. 


3 So all you do is remove Ihe 

prolwtive bAckirg 

•i And ou;eit

SPECTRUM CAME 

Tourist trap 

Get the holiday horrors in this spectacular board 

game for your 48K Spectrum, written for 

us by Colin Gooch of llminster. 

This is a 'board game' program 

for two people to play against 

each other, rather than one person 

against the computer. It is a 

fairly large program using a major 

portion of the 48K RAM 

available on the larger Spectrum. 

This means that SAVEing 

and LOADing will take quite 

some time. The playing of one 

game usually takes something 

like 40 minutes. 

You can consider the program 

as operating in four main 

parts: 

11 The initialisation of values 

and graphics, the printing of the 

instructions and then the playing 

board display. 

2} The dice calling routine to 

decide your throw. 

3) The moving of your piece and 

the diversion if required at that 

new position onto a subroutine 

which will decide your score for 

that throw. 

4) The end game routine. 

After the first part has been 

executed, lines 120 and 130 

will keep the program looping 

through the second and third 

parts, automatically changing 

the players, until the end game 

condition is fulfilled to break out 

983 

into the fourth part. 

Going fourth 

The four sections operate as 

follows: 

Part One Lines up to 100 call all 

the initialisation routines. Line 

9000 allows the instructions to 

be displayed while the userdefined 

graphics are set up. 

These are the two playing 

pieces, plus a number of odd 

shaped 'blobs' used to create 

pictures in the course of play. 

The board printout begins at line 

8000. The PLOT DRAW facility 

draws out a playing track around 

the outside of the display area 

allowing the cenire to remain 

clear for the various graphics 

routines. The playing squares 

are numbered using different 

combinations of INK, PAPER 

and BRIGHTness, these being 

controlled by the DATA 

statements at line 8000. It is the 

attributes on these squares that 

will decide the 'fate' of a player 

landing on them. It is most important 

that these are not 

altered or you will not be sent to 

the correct subroutines. 

Part Two The dice routine is a 

straightforward affair. The 

variables for the pips' are in line 

8300 onward and it is printed 

out as required by GOSUB 

8425. To roll the dice you press 

Enter and keep it pressed until 

you think you have the number 

you want. Removing the 

pressure will stop the dice. 

Part Three Moving the pieces 

around the board is more complicated. 

It is done by a series of 

FOR. NEXT statements. 

These take the value of the dice 

thrown as the second control 

value in the statement and move 

the piece along that number of 

squares. If that line runs out of 

squares then the next 

FOR . . . NEXT loop will use up 

the surplus. (I'm usually fond of 

conditional statements, but in 

this case found this system 

operated in a speedier manner.) 

On arriving at a square, the 

attributes of the number of that 

square is read. If it is 104 then 

that turn ends, line 6660 

changes over the player and 

your opponent will have their 

turn. If it is anything other than 

104 then the value is converted 

to a GOSUB line and off you go 

to see what (ate has in store. 

The bulk of the program consists 

of these subroutines which 

I will let you discover for 

yourself. The operation of these 

routines is fairly straightfor- [ 

ward. There are nice things that 

will happen, not so nice things 

and, of course, some disasters 

all of which lose or gain you 

points, lose you money and use 

up your petrol. If you run out of 

petrol, you will have to pay for a 

rescue and if you are on the way 

to a location, you will lose the 

rest of that turn. The game ends 

when one person runs out of 

money. . . but the winner is the 

one with the most points, so 

towards the end of a game tactics 

can become important! 

Part Four Brief and simple. Once 

one person is out of money, line 

130 fails to maintain the loop 

and the 'game over' signal 

shows. The final scores are then 

displayed. The score display 

routine is at line 8600 and is used 

at intervals throughout the 

game. Line 8610 ensures that 

petrol and money are only 

displayed to two decimal places; 

without this line you'll find that 

as the game progresses you end 

up with petrol designated in 

scientific notation! 

Easy to enter? 

Debugging a program of this size 

can be a bit daunting and so I 

would suggest it is entered in 

sections. Enter the program as 

listed but omitting all the 

subroutines from line 1 000 to 

6490. This will allow you to get 

the board display and the piece 

moving routines all in working 

order. To do this enter a temporary 

line, 6480 RETURN. 

RUNning the program will then ; 

result in everything happening 

except any of the scoring 

subroutines. The subroutines 

can then be entered one at a 

time and tested out. There is no 

need to keep going round the 

board to test these, just let the 

Spectrum print out the board, 

then break into the program and 

type in GOTO (the appropriate 

routine) and all will be well. (The 

'Press enter to continue' uses 

the form 'INPUT:LINE Z$' which 

means that the usual Break and 

Stop keys will not work. Never 

fear. Use Caps Shift and '6' and 

you will get a 'stop in input' 

message.) The 'out of petrol' 

routine is the most difficult to 

test and may best be left until 

you are happy with the others. 

Most of the graphics are 

straight off the keyboard. The 

only user-defined graphics that 

are vital are those for the two 

playing pieces and the dots on 

the dice. The others are not so 

vital but if you enter and RUN 

50 

line 9000 to 9140 fairly early irly 

on, it is easy to see which keys iys 

are required. 


we're off... 

When all is entered and you are 

ready to play you will first of all 

see the instructions, then the 

Spectrum will choose at random 

someone to start. The board is 

then printed out; the player 

whose turn it is will be shown on 

the right-hand margin. If you 

throw the dice and land on a 

square that is not blue then 

some graphics and instructions 

will appear m the centre of the 

screen. To continue to play. 

simply follow all the prompts. To 

enter in the spirit of it all, you 

must imagine that you are on 

tour in a car, with a tent, and 

have the opportunity to visit 

various places. . . wild life 

parks. . . castles. . . the sea 

and so on. 

So off you go. Happy Holiday. 

variables 

The main variables used are: 

Some sample screen illustrations from the program. Tourist trap. 

0 

29 

£8 

27 

26 

25 

1 1 I 

26 

m 

125 

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IN THE 

RESERUE 

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THESE 

R N I M H L S 

SCORE £ 

FOR ERCH 

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LIONS 

ELEPHRNT3 

M O N K E Y S 

G I R R F F E S 

C H M E L S 

B U F F R L O S 

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23 52 21 

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SUB 

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Cash on hand. 

Value of dice throw. 

Horizontal position of 

playing piece. 

Total score. 

Flag indicating turn to be 

lost. 

Miles to travel. 

Petrol in gallons. 

Player. 

Subroutine in use. 

Flag to check the 

number of times the 

petrol is evaluated. 

Vertical position of play 

Z$ 

ing piece. 

Line input. 

(x> will be one or two according 

to value of PL. 

The subroutines use many more 

variables, but they are confined 

within those routines and are 

not difficult to trace through. 

There are also a number of 

DIMensioned strings and 

variables. These are used in 

several routines and are re- 

DIMensioned each time that 

routine is called. 

l o 1 2 3 4. I 5 6 7 Q 9 

I 2 9 

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Y O U R R E O U T O E P E T R O L 

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F O L L T R N K = 1 « 

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YOU N£ED PROVISIONS 1 3 

T i ; ' i • \ 

SPECTRUM CAME 

! 1 3 I E 

i j i i t : j 

j jgl ; 2£i j 19 { 1-5 j 17 j 15 j 15 (CJ 

210 IF INKEY $ =" D" OR INKEY 

THEN CLS : PRINT PIT 10,5; PHPEfi 

5;"START THE TRPE": LORD "" 

220 GO TO 190 

230 PRINT RT 10,7; "THRNKS FOR f 

L RY IND " ; RT 11,10;" BYE EE ' ( • C- 

2 3 0 

1000 REM CH^CK PETROL tfHtf 

1010 LET TI=T1*1: LET P(PL)-P 

) - ( TNT (MI/,3) ) y100. 

THEN RETURN 

.1020 LET DTU=D: LET 

PL) "O: GO CUB 85O0: 

0 , 32 : r. TRCL E 130.90, 

.30 f>RRU 30/ 

82: DRRIJ 

PRINT 

fuel";rtT 14-, ENK 2; 

9,16; INK 1;"B — 

1030 PRINT RT 4- j 

OF PETROL " 

3.04-0 PRINT RT 16 

Y f 10 

E FOR 

6 4 3 0 : 

IF P ( PL y (Pi 

> 0 

LO= 3 

GIRCl. 

30: P i o 

I PL. C O' 

m X3 

3 

Lf I 

.130 , 'i I 

A I s-: 

J '-* , 

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AT 

YOU flRt OUT 

YOU MUST PR 

* "/RT 17,4; "THROW OF D T v • 

R TOW" : PAUSE 2S0 CO 

1® REM ************ ********* 

11 REH *** TOURIST TRAP *** 

12 REM ********************* 

19 REM *** C.N.GOOCH *** 

21 REM ********************* 

22 REM *************** ft-*.**** 

SO CLS : PRINT AT 10,5; PAPER 

5; «5TOP TME TRPE ": GO SUB BSSt 

60 RRNDOMIZE : CLS . PAPER 

INK O: CLS : GO SUP 90O0 LET PL 

= I + INT (RNDtflJ : BORDER PL: CLS 

PRINT RT 12/6;"PLRYER "; INK PI 

; CHR$ (143+PL); INK 0," TO START 

": PEEP .7,20: GO SUB 8650. CUt 

: BORDER 0 

70 DIM U(2>: DIM H(2> : DIM JCi"' 

); DIM C ( 3 ) : DIM P(2) 

80 FOR N — 1 TO 2: LET JiN) s©: t 

FT C (N)=250: LET P(N)=?: NEXT N 

90 LET FUD=2: LET FSF-0. LET I 

I — 0 : LET D=1 

100 LET U(l)=l: LET U(2)»1. : L ET 

Hi n -1 LET H(2)=2 

; i o GO SUB 3000 

120 LET L.O-0: GO SUR 5430 . GO 5 

UB 6J-.00 

130 IF 

! HEN G 

O TO 

14-0 

RT 7 , 11 ; 

INK 

I , 6RH£ 

CRT UER";RT 

H O; "Pi.OVER 

f = 0 ) , c 

MR £> 1 1 4 h i C 

our 

OF lhsm" ; n 

F 

u h 5 w O P F . 6 " • 

ISO LET Js 

') =J (il * » P \ 

)=0. GO SUB 

160 IF k) ( 1 

PLflfVER 

) , C H R 

$ ( U 4 f (JtS) >J(1) ) J ; INK 

U JN 

•-J 

1B0 IF INKEY $ < 

190 PRINT RT 11 S ; 

TO PL RY " ; AT IS , 1 2, 

14- . £5; "PRE OR 

; "OR DIFFERENT FOR " ; A T I 7 , 8 ^ 

NEU GOME": IF INKEY$-"Y" OR 1W 

E;y $ = " y " THEN RUN £" 0 

200 IF INKE/$="H" OR INKEY*-"nw LET C (PL) ~C (PL) - < lO t[n 

3.050 LET JiPL) =J(PLi-5*(T,l=l ) -£>} 

C TI=2) : GO SUB 

1 0 6 0 g o s u e e e s o : g o s u e 8 S 0 0 

THEN GO SUB 8S00: GO TO 

7 

F TI=1 THEN PRINT RT 10,4;" DRY" 

RUINED "; RT 11/4, " LOSE 5 PO LTJTS 

";RT 12,4;" SCORE NOW ";J 

v > . o.« > ; INK I 

i U,-'^ "PRESS ENTfcR 

INPUT L II C Z% 

1 > = J i 1 j +P i A} L£T J (2 

L E T p { 1 > - 0 L E T p i2. 

8 D 0 0 : 

)=J(2> THEN GO SUB BS 

00: PRINT RT 10,7;" GRHH ORfiyN " 

GO SUB 86SO: GO TO 10& 

170 GO Sf.lB 8500: PRINT RT 

INK 1 * (U (2) >Lt;l) 

0 ; 

THEN GO TO 16 

' DO YOU U-4*JT 

' RGRJN? RT 

KJO ' , R-7 1 i* 6 

r' Ita Li a 

n Restaurant": GO SUB 8650 

2110 GO SUB 8500: PLOT 55,138: D 

RRW 81,0: DRRU 0,-100: DRRU -81, 

0: DRRU 0,100 

2120 LET SCM=0: DIH T$(B,10) 

2 130 DRTR "OYSTERS","PRRUNS","ME 

LON","SOUP" 

2140 DRTR "FISH","CHICKEN","STEft 

K","PIZZR" 

2150 DRTR "ICE CREAM","GATEAUX", 

"FRUIT PIE*,"PANCAKES" 

2160 DRTR "SOURSH","TEA","COFFEE 

","COKE" 

2170 FOR H=10 TO 40 STEP 10: LET 

NN = 1 + INT (RND*4) : RESTORE (2120 

fH). FOR N=1 TO NN; READ T$(H/1S 

>: NEXT N: LET SCM=SCM+NN: NEXT 

H 

2130 FOR N=5 TO 16: PRINT RT N,7 

;T$(S»: NEXT N: PRINT AT 5,9; PR 

PER 3; INK 7; BRIGHT 1;" MENU " 

2190 FOR N=7 TO 13 STEP 2: PRUSE 

25: BEEP .02,N; PRINT RT N,7;T$ 

: NEXT N 

2200 LET T$(6) ="YUK ! » " : LET T$ [• 

7)="NOT BAD": LET T$(8)="YUHHY 

2210 PRUSE 70: PRINT RT 12,17; P 

RPER 5;"HEAL UAS ";AT 13,17;T$i 

S* (SCH>8) * I5CH>11) ) : BEEP .4,1-2 

0* (SCM *20* (SCM>11) : PRINT RT 

14,17;"SCORE ";INT (SCM/2): LET 

U (PL.) =J (PL) +INT (SCH/2) 

4 

2220 GO SUB 8650 PRINT RT 12,17 

; PRPER 4," PRESS ";RT 13,17, fi 

ENTER ";RT 14,17;" TO FIND 

" ; RT 15,17;" C-Oir-T 

RT 16, 

7," £1+DICE " 

2230 IF INKEY® THEN GO TO 22 

30 

983 


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iTEH 

JX" , 

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LET 

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•XT 

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-IN£> 

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3 2 2 

SPECTRUM CAME 

2240 GO SUB 8650; GO SUB 8500: G 

0 SUB 34-30: LET C(PL) =C(PLJ -1-D: 

PRINT RT 14-,6;" MERL COST £";l- 

0 

2250 IF SCM>11 RND 10 THEN GO TO 

4.455 IF P (PL) +GR < =10 THEN LET P i 

PL) =P (PL) + GR : LET C (PL) =C (PL j -GR 

* (PR/100) 

4 465 GO SUB 8610: 

; "FUEL "; P (PL) ; '* 

" CRSH £ " ' C- (PL) 

PRINT RT 

GRL . " ; RT 

10 , 13 

14, 

4.4.70" GO 

4.490 IF 

SUB 8650 . GO 

LO OR PMD > . 5 

SUB 35G0 

THEN RETURN 

4-495 REM ttttBtttt SITE FEES ttiitttta 

•U9? 11= F5F = 1 THEN GO TO t550 

4500 FOR N=5 TO 7: PRINT PT N,6; 

": NEXT N; PR 

INT RT 6,7; PRPER 4-;" R CRMPINC- 

SITE " 

4S10 LET SF = 3 + INT (RNO*3^ * PR IN"* 

RT 8.4;"YOU MUST PRY ci r t u o 

;RT 9,4;" PRESS ENTER TO FIND 

";RT 10,13;" COST ";RT 13,4," 

COST UILL BE £";SF;" TIMES ";RT 

14,4;" THROW OF DICE 

4515 PRUSE 0: BEEP .2,20: FOR N~ 

1 TO 150: NEXT N: IF INKEY$:>"" 

THEN GO TO 4500 

4 520 GO SUB 8500: GO SUB 8430: P 

RINT RT 11,4;* COST IS £";SF*D 

; " ": LET C (PL) =C (PL) - (SF 

*D) 

4530 DIM N $(3,8) : LET N$(1)="TER 

RIBLE": LET N$(2)="GOOD": LET Nx* 

(3) =" PRETTY " : LET ST =1 +INT (RND if 

3) 

4540 PRUSE 100: LET J(PL)aJ(PL)+ 

( ST =3) + ( ST =2 OR ST =3) - ( ST =1) : PR 

INT RT 15,4-; " IT IS R "; N$ (5T) ; " 

SITE ";RT 16,4;"SCORE ";

_ 

GO 3650: GO TO 8600 

4.550 GO SUB 455f.: GO TO 4-590 

4-555 GO SUB 55(>G ; FDR N =3 TQ 11. 

PRINT AT INK 3; "KB3E«ffMa—^ 

Q T 

4-SStf P R I N T R T 

2, B R I G H T 1; 

A570 FOR N = 12 

NEXT N: FOR 

SPECTRUM CAME 

(v=Q TO 

N,7; INK 1, W 

NEXT N 

10,8; PAPER 7; 

5UIZUAY5 STORES 

TO 17; PRINT RT 

INr-. 

t • 

5 ; INK 3; ' » 

NEXT N 

4 5 S S PRINT AT 1 7 , 5 ; INK I; PRPER 

3 ' ' ^ y y ^ f r f f y r T T T r t i h ' ' r e t u r n 

4590 PRINT RT 5,5; "YOU NEED PROU 

ISIONS"; GO SUB 3650 

4300 PRINT RT 6,S; PRPER 4; "DICE 

WILL DECIDE UHftT";RT 7,5;"HPPPE 

MS. IN STORE": GO SUB 8650: GO 5U 

8 3500; GO SUB 843© 

4610 RESTORE 4-610: DRTR "OUTRRGE 

•US","EXPENSIVE","AUERAGE","FRIR 

_Y CHEAP","UERY CHERP","GIUE RUfi 

4-620 FOR N = 1 TO D; RERD NEXT 

N: LET DU=D: PRINT RT 12,4;"THE 

PRICES IN THE SHOP ";RT 13,4;"R 

RE ",G>$ 

4630 PRINT RT 15,5;" SCORE ";D: 

LET J(PL)=J(PL)+D: GO SUB 8650 

4640 GO SUB 8500: LET PR=12+INT 

i'PNOJ5) * PRINT RT 12,4; "YOU EXPE 

CT TO SPEND £";PR,RT 13,4;"DICE 

U' ILL TELL YOU RT 14- 4 ."SIZE OF 

SILL ": PRUSE 90: GO SUB 8430 

4 650 LET PP=5+D*3: PRINT RT 

; "YOU RC-TUALLY SPEND £";PP;AT 14 

,4; PRPER 6;" 

4 560 LET C(PL)=C(PL)-PP 

4670 IF PPU < 3 > : LET J(P 

L?= U(PL)+3>3*(DU GO TO 472C 

4.690 IF PP >PP+2 THEN IfxJT RT IS 

: 4; "YOU OUER SPEND IF DV>4. TH 

EN PRINT RT 16,19ALTHOUGH";AT 

1 7 , 4 ; " I T ' S " ; © $ ; " 

4^00 I F P P > P P + 2 THEN P R I N T RT 1~' 

, 20 ; , ,5COR£";-3-3*:-X ti4) : i-ET J( P 

L_) =JiPL) -3-3 * t DU >4 > GO TO 4720 

4 7 1 0 P R I N T RT 1 6 . 4 • " V O L R P E C L O t t 

£ T O Y O U R ' ; R T 1 7 , ^ ; " B U D G E T . S C O 

R E 2 " : L E T J ( P L J s J ( P L » + 2 

LET FSF=0: GO SUB 3650: GO 

TO 8600 

4740 REH tttznn LRZY DRY 

•i7t>i3 LET SC-D =0 : PLCT 39,-12®: DRR 

U 50 , 1 3 , — . 5*P I: T m =» - (>b 

AW -10,-2, .StPI; SEXT N. PLOT 64 

,125; DRAW 5,-40 * P L O T 39,64; DR 

RU 175,0: PLOT 10®,134: CRAW 30, 

30: DRAW 30,-33: PLOT 133,134: O 

RAW 50,8: DRRU 30,-30: DRAW -50. 

. r \ n m i c c nt 

— _ - O , t' 

47CCJ CIRCLE 90,80,7: DRAW 

DRRW 1 0 , 1 6 : D R R U 1 4 , - 1 6 . D R R U S - 

5: PLOT 1 0 0 , 7 7 : D R R U 2 2 , - 4 : PRIN 

T RT 1 4 , 4 ; " R LAZY DRY RT CAMP" 

4770 PRINT RT 15;4;"SUNBATHE RS 

LONG RS",RT 16,4;"YOU CRN T H R O W 

OUER 3";RT 1 7 , 4 ; PRPER 4 , " P R E S S 

ENTER TO G*j" : PAUSE ©; GO -SUB 84 

30: PRINT RT 10,20, FLRSH 1 , ; " R G 

RIN": LET U(PL)sj(PL)+D: LET SCO 

= SC-D+D: IF D > 3 THEN GO TO 4 7 7 0 

4780 PRINT RT 10,12; PRPER 5.; "SU 

N S GOME IN": FOR N=0 TO 

P -1; BEEP .05,N: NEXT N 

< =8 THEN GO SUB 2000 

4790 GO SUB 8650: GO SUB 

O TO 8600 

4795 REH Knntt GOLF' SiJtti* 

983 

-10 STE 

IF SCD 

8500: G 

4-800 GO SUB 4810. GO SUB 486©; R 

ETURN 

4-810 FOR N=4 TO 9: PRINT RT N,4 

PRPER 5;" 

": NEXT N 

4320 FOR N=13 TO 17: PRINT RT N, 

4; PRPER 4," 

": NEXT N 

4830 P RINT RT 12,6; PRPER 4; INK 

6;"DEG" 

4835 PRINT RT 13,6; PRPER 4; INK 

8;"HHI" 

4 840 PRINT RT 14,6; PRPER 4; INK 

6 ; " J K M " 

4850 PLOT 180,120: DRAW 0,-24: P 

PINT RT 7,23;"1": RETURN 

4-360 PRINT RT 6,6.-" A DRY RT "; fl 

T 7,6;" THE GOLF CLUB ": PRUSE 7 

5; PRINT RT 12,12," YOU PLRY YOU 

R ";RT 13,12;" OPPONENT IN ";RT 

14,12;" THIS GRME " 

A370 GO SUB 8650: GO SUB 4810: P 

PINT RT 6,6;"LOSER OF GAME";RT 7 

» 6 , 

PAYS FOR",AT 8,6 ,"THE GRME 

COST £10";RT 9,6;"WINNER GETS 

13 POINTS" 

4880 DIM 5 , IS > 

4S90 GO SUB 8650: GO SUB 8500 P 

PINT RT 10,5;"PLAYER INK 

"PLAYER "; INK 2,"B";RT 4,4,"H 

OLD ""S"" TO SPEED GRME " 

4900 DATA 2,3,4,3,4,2,3,3,4,4,- 

3,5,4,3,2,4,3 

4910 LET DR=0 LET GSA=0; LFT GS 

B=0 RESTORE 490O; LET HOL=l+IN T 

(RND*30): FOR N = 1 TO 18 

4920 RERD P: PRINT RT 6,6,"HOLE 

NUMBER ";N;RT 7,6;"PAR = ";P+l 

4930 LET S(1,N)=PfINT lRND+3) 

4940 LET 5(2,N)=P+INT (RND*3j 

4950 LET GSA=GSA+5 + 1 : L E T D R = 1 : P R I N T R T 1 7 , 4 

j p f l P ^ R 6 , "* 

4980 IF GSB =HOL RND DP=0 THEN PP 

INT RT 12,17; "1": FOR M = 1 TO 

STEP 4: BEEP , 4 , M: PRINT PT 17-4 

; FLRSH 1; "HOLE IN ONE PLRYER ",| 

INK 2;"B": NEXT H: LET GSB =G5B 

(2,N) +1: LE" 

PRPER 5; '* 

DR=2: PRINT AT 17, 

4990 PRUSE 150: BEEP .5,20: NEXT 

N: PRUSE 50: GO SUB 4810 

4995 IF GSA=GSB THEN PAUSE 100: 

PRINT RT 5,4;"GRME DRAWN. ";RT 6 

,4; "SHARE COST"AND POINTS": LET 

J(l) = J(1) +5: LET J(2) =J(2) +5: LE 

T C C 1) =C ( 1) — 5 : LET C(2)sC(2) -S 

5000 IF GSR >GSB THEN LET U(2) =J! 

2*+10: LET C(l)=C(1)-10: PRINT H 

T 5,4;"PLRYER "j INK 2;"B"; INK 

0; WINS" ; 

5010 IF GSAn'G&B THEN LET J(l) =JI 

1) +10: LET C(2) =C(2) -10: PRINT A 

T 5,4;"PLRYER "j INK 1;"A"; INK 

0 " * * y X N 5 " 

5015 IFDR=0 THEN GO TO 5060 

5020 IF DR = 1 THEN PRINT AT 7,4;" 

PLRYER ••; INK 1; "R"; INK 0, " HRD 

";RT 8,4;"R HOLE IN ONE" 

5030 IF DR =2 THEN PRINT AT 7,4," 

PLRYER "; INK 2;"8"; INK 0," HRD 

";AT 8,4,"A HOLE IN ONE" 

5040 GO SUB 8650: GO SUB 4810: I 

F DR > 0 THEN PRINT RT 10, 10, "B PC' 

UND RT 19th";RT, 11, 10; "TEE WILL 


COST : "j RT 12, 10; "£2xTHROU OF D I 

CE": PR USE 200: GO SUB 8430 

5050 IF DR>0 THEN LET C(DR) =C(DR 

}-2*D: PRINT RT 17 , 5; "COST £";2* 

D 

5060 GO SUB 6650 

5070 GO TO 8600 

5150 REM nntttt BERCH TRIP 

uutttt 

516© LET I? =6: GO SUB 5170: GO TO 

5230 

5170 LET SUB=5170: FOR N=4 TO IS 

: PRINT RT N , 4; PRPER 5;" . 

": NEXT N: FOR N 

= 11 TO 12: PRINT RT N,4; PRPER 1 

;" ": NEXT 

N 

518© IF D>=4 THEN FOR N = 1 TO 10 

INK 6: PRPER 5: CIRCLE 160,120, 

N: NE>£T N: INK O: PRPER 7 

51-90 IF D " J • — ^ 

; RT 14,15; INK 1, CRR PrtRK" , RT L 

5,17, " £ 1" ; RT 16 , 15; "R DRY"; GO S 

UB 6650 

5235 FOR N = 13 TO 17: PRINT RT N, 

14; PRPER 6;" ": NEXT N 

5240 LET M 1=20 f TNT (RND f 10 ) : PRX 

HT RT 13,5, "YOU MRY GO ON R UI5I 

14,5," TQ THE SER " ; RT IS, 

5; 11 IT IS "J MI; " MILES ": INPUT 

" ENTER "; FLRoH I;"Y"; FLRSH 0, 

'E5 CP "; FLRSH 1; "N"; FLRSH 0, " 

LINE Z$ IP Z$="N" THEN RETU 

"V 1 • 

v / 

RN 

IF LO=l THEN L 

GO SUB i 0 0 0 

ET T2=0: R E T U R N 

525© LET C (PL) =C ( PL > — 1 : LET LO=P 

: GO 5U3 350©: PRINT RT 10,5," T 

URDU DICE TO FIND " ; RT 11,5;" O 

•J' THE, UERTHER . " ; RT 12 , 5; " T 

HE HIGHER SCORE " ; RT 13,5;" T 

HE BETTER 

5260 GC SUB 8 4 3 0 : DIM H$I6,6) 

"5270 LET h $ ( 1 > = "STORMY" : LET H$ - 

= j ="RRIMY" : L E T H$ ( 3 ) ="CL0UDY" : 

ÊT H$(4i LET H*(5)="HOT 

11 LET H4i6) = "5UPER" 

5230 PRUSE 25: GO SUB 3500: GO S 

UB SUB: LET U(PL)=U(PL)+D: PRINT 

RT 10,5;" THE UERTHER IS '* : PRU 

SE 50: PRINT RT 1 1 , 5 ; H $ ( D ) ; " SCO 

RE " ; D ; 

5290 IF SUB < >5170 THEN RETURN 

5300 IF D > 2 RND RND < . 6 THEN GO S 

UB 8650: PRINT RT 5,4-; "YOU UIN R 

" ; RT 6, 4; "SRNDCRSTLE"; RT 7,4; "CO 

HPETITION": LET PRI=2 + INT (RND *4- 

): PRINT RT ©, 4, "SCORE ";PRI; " P 

OINTS": LET U (PL) =U (PL) +PRI 

5305 IF D > 2 THEN GO TO 5580 

5310 PfiUSE 70: PRINT RT 5,4;" GO 

ON THE ";RT 6,4;" PIER OUT OF"; 

,4;" THE RRIN' GO SUB 8S5*? 

5320 GO SUB 8500: FOR N=5 TO 17 

STEP 2: PRINT RT N , 4 + INT N/2; PR 

-EP 1 + INT : LET U$(6)=US(4): LET U$(7 

? =U$(2) : LET J$i8) =J$(2) : LET U$ 

(10) =J$(2) : LET J$ (il) =J$ (4-) 

5370 FOR N=1 TO 11: PRINT RT 6+N 

,6,; PRPER 7; J$ (N) : NEXT N: FOR N 

=10 TO 15: PRINT RT N,20; PRPER 

6;"I": NEXT N: PRINT RT 15,19; P 

RPER 6; 

5380 PRINT RT 6,21; PRPER 4;"POX 

NTS";RT S,23, PRPER 7," 2 ";RT 9 

.23; "--R" 

5390 PRINT RT 11,23;" 4 ";RT 12, 

23;"-BB";RT 14,23;" 8 ";RT 15,23 

; " C C C " 

LET UT=0: LET TU-1: LET GO= 

INT (RND*3): PRINT HT 17,8, PA 

PER 2; INK 7; BRIGHT 1, "lOp R G-'^ 

"SfTT 10,8; PRPER 1, "YOU HRUE" 

RT 11,8;" ";GO;" GOES ",RT 12 5 

D4 10 INPUT "PRESS ENTER TO PLRY 

LINE Z*. LET 

5420 PRINT RT 7,8, PRPER 3; INK 

7; BRIGHT 1; "GO ", RT 7,14;" *';T' 

it • a 

5430 LET NN = 20 + INT (RND-HO) : FO« 

N = 1 TO NN: LET FMR= t 144+ INT 

E>*3> ) : LET r MB = ( 144 * INT 

LET FMC = ( 144 + INT {RND-^Cl 

5440 FOR M = 10 TO 12 PP TNT PT M 

8; PRPER 5," N E X T M 

5450 PRINT RT 11 9; INK 3 / . ; H k $ * 

; RT 

! • 

11,12; INK 1;CHP3 

INK 2;CHP4 Ff^C 

RETURN 

5700 PRINT RT 

¥N ";RT 6,11;" 

8650: GO SUB 

•MS, HT 

— N 

j 

5460 IF FMC = 144 THEN 

5470 IF FMB=145 

M 

LET U=4 

5480 IF FMR = 146 RND ^MB = 146 R N D 

FMC = 146 THEN LET U = S 

5490 PRINT RT 15,12.U: LET TU=T\ 

+ 1 : L ET UT =UT + U : IF TU< >GO +1 "HE 

N BEEP ,5,TU: GO TO 54 10 

5500 GO SUB 8650: GO SUB 8S00• P 

RINT RT 6,5;" YOU SCORED ";UT;" . 

POINTS "; RT 8.5," IT COST YOU i 

; GO/10: LET U (PL) =PL) +UT : LET 

C(PL;=C(PL)-(GO/10) 

5590 GO SUB 8650- GO SUB 1O00: L 

ET TI=0; GO TO 3600 

5500 REM nnntitt RRILURY 

5510 LET DSL =0: GO SUB 5620 GO 

TO 5700 

5620 DIM U$ (6 , 1,7) 

5630 LET ( 1) ="" 

5535 LET U $ ( 2 ) ^ 

5540 LET US(3)= 

t-64 5 LET (4) = 

5650 LET U$(5)= 

5655 

U $ ( B ) = 

5680 FOR N = 1 TO 6 PRINT RT 8 +N 

5; PRPER 6,U$(N) : NEXT N 

5670 FOR N =5 TO 13: CIRCLE 30,54 

,N: CIRCLE 0,54,N: NEXT N. FOR 

N=50 TO 53: PLOT 75,N: DRRU 55. 

3: NEXT N 

5680 PRINT RT 

PRPEP 6, 

V *' 

1690 FOR N = • PRINT RT 

5; "S ' : NEXT N: PRINT RT 3,22; IN 

• * , 

K 2; ' S' ; INK 7 

INK 2; 

5,©;" THE FULL O T 

RRILURY ": GO SUBw 

5710: GO TO 5720 ^ 


SPECTRUM CAME 

571© FOR 

O PRINT RT N • 4- 8 5250 

PRPER 

5120 DATA "LIONS","TIGERS","ELEP 

": NEXT N: RETURN 

HANTS","HONKEYS","GIRAFFES","RHI 

, ni ii 

57?e LET hi =15 -fl NT ( RND flf) ; PRI NOS","CRMELS","BUFFRLOS","UOLUES IOLUES 

NT RT 5,5;"THE RAILWRY 15 ";MI;A ","ZEBRRS","GNUS" 

T 6,10;" MILES RURY";RT 16,13, P 6130 LET RN=0: RESTORE 6120 I: GO 1 

RPER 4, "COST £2" : INPUT "DO YCU SUB 8650: GO SUB 8500: FOR N = 1 T 

WANT TO GO BE5 OR fflJO", LINE Z* 0 11: READ Q*. IF RND . U SEE";AT 10,5, "THESE " ; AT 11,5 

6 THEN GO TO 5760 

;"ANIMALS " ; AT 13.5; "SCORE 2 " ; RT 

5750 GO SUB 57 10 PRINT RT 4,5;" 14,5 "FOR ERCH" 

NO STERM TRAINS TODAY";AT 5,5;"L 5150"IF N > 4 AND FUD.9 THEN 4: LET J(PL) = J(PL) +2: LET AN =RN* 

GO SUB 5710: PRINT AT 4,5;"NEXT 2: PRINT AT 15,22;"SCORE";AT 16, 

HER RNY": LET DSL=1 

25;AN: NEXT N: PAUSE 100 

5770 PRINT RT 5,5;"DIESELS 6170 LET FL = 1: GO SUB 8500: GO S 

R U N N I 

NG TODRY"; RT 6,5; "SCORE "; -3KDS 1 iR R « 7 « 

L = l) +4-J (DSL=0) : LET J(PL) =J(PL) - 6180 IF RND>.8 THEN GO SUB 8650 

3f ( DSL = 1 > +4 + ( DSL =0 ) : GO TO 579® PRINT AT 4,5, "YOU SL. IP IN SEAL 

5^30 GO SUB 5710: PRINT RT 4,5;" ON ",AT 5,5,"POOL LOSE 3 POINT5 

/CURE IN LUCK",RT 5,5;"STERM TR ": LET J (PL) srJ CPL ~3 : L.ET FLr.0 

AINS RUNNING";RT 6,5;"TODRY. SCO 6190 IF RND> .6 T MEN GO SUB 8650 

RE 5": LET JtPL>=U(PL)+5 

PRINT AT 4,5, 'HALE SUPER ICE Cfl 

5790 LET FL = 1: IF RND ; AT 7, 10; "YOUR RNKLE": L , PRPER 2; INK 7, BRIGHT 1 

LG=3+2f (Q-=2) +7* (©=3) 

hi 1; " 

;83© GO SUB 8650: GO SUB 5710: P EXT N 

' INT RT 5,5;"LOSE ";LG;" POINTS 6310 PRINT RT 

. AT 7,10, PAPER 6;" 

7;" D I S A S 

LET U (PL) =J (PL) -LG: LET FL =0 

St?50 

5850 IF RND>.5 THEN GO SUB 8650: 6320 PRINT 

GO SUB 5710: PRINT RT 5,5;" YOU WN IN THE 

SEE FAMOUS TRAIN ";AT 6,5;" SCO RsÊ 

RE 4 POINTS ": LET J(PL)~J(PL)+4 TEP TO SEE 

LET FL =0 

OINTS YOU 

5860 IF RND>.92 THEN GO SUB 8650 

: GO SUB 5710. PRINT RT 5,5;" YO 

U GET R RIDE ON ";AT 6,5;" THE F 

•JOTPLRTE "; AT 7., 5, "SCORE 8 POINT 

5 ": LET U (PL) -1} (PL) +8 : LET FL=0 

5870 IF FL THEN'-GO TO 5790 

5900 GO SUB 8650: GO SUB 1000: L 

FT T1=0: GO SUB 8600 RETURN 

5990 REM tttttttttt PARK tmtfltJt 

8000 LET HI =25+INT (RND*10) : GO 

SUB 6010: GO TO 6080 

6010 DIM J * ( 9 , 16 ) 

6020 LET U$(l) =1" 

6025 LET U$(2) 

5030 LET J$(3) 

5035 LET J$ 1 AND H (PL) =28+ (PL 

=2) THEN LET U (PL) =U (PL) +3 : IF U 

• PL) >19 THEN LET H (PL ) =H ( PL ) - (U ( 

PL)-19): LET U i PL ) =19 : LET D=D-N 

GO TO 6570 

5560 NEXT N 

6570 FOR N-1 TO D 

5580 IF y (PL) =19 AND M('PL)

B 

I 

r m 

> 2 

(H 

3 + 

PL 

U 

V ( 

—N 

fP 

^ 

U ( 

L * 

0 0 

SPECTRUM CAME 

6590 NEXT N 

660C FOR N — 1 TO D 

6610 IF U(PL) 104- THEN GO SUB 8500. 

GO SUB SUB *5 0: LET LO=0 

5660 LET PL=PL + (PL = 1) - (PL =2) : GO 

SUB 3500: GO SUB 3510: PRINT R^ 

2fl8n'PL=2) ,31; INK 1+(PL=2);CM 

Rt *»R : PLOT 4, A: DRRU 240,0 N 

EXT N 

3120 FOR Y=4 TO 172 STEP 24 

5130 PLOT 4,Y: DRRU 25,0: PLOT cL 

20, Y DRRU 24,0: NEXT Y 

6140, FOR N = 1 TO 4: PERD R: 

« , 4 : DRRU 0,163: NEXT N 

5150 FOR X =4 TO 248 STEP 24 

•3160 PLOT X,4: DRRU O,24: PLOT 

, 143 DRRU 0 , 24 : N E 

5170 

5180 

=39: 

5190 

STEP 

V tO";RT 7,12; THROW"" DICE "; M 

T 8,11;" RELEASE TO STOP"- TK»PM 

LINE Z$ 

3460 IF D =7 THEN LET D = 1 

8470 PRINT RT 6,6;A$(D);AT 7,6; 

* (D) ; RT 8 , 6 ; C $ (D ) 

8480 IF INKEY$="" THEN RETURN 

8490 LET D = D + 1 *. GO TO 8460 

8495 REM UUn BLRNK BORRD UUU 

8500 FOR Y=4 TO 17: PRINT RT Y , ; LET Ct(4)=R*(4) 

-3400 LET R $ f 5) =R$ (4) : LET B$ (5) -- 

8 $ (1> : LET C%(5)=A$(4> 

•5410 LET R$(6)-"CCC": LET B$i6)- 

Pf$ (1) : LET C$i628, 125,255,255,255,255, 0 , 0 , O , 0 J 

193,231,239,255,0,0,0,0,1 9 2'^ 

='24 , 240 , 15, 15,31,63, 127 , 63 , 63 , 15 

,240,224,252,252,243,240,224,240 

,15,15,3,1,0,0,0,0,255,255,255,2 

55,124,60,24,16,255,255,223,135 

6,4,0,0,240,224,224,128,0,0,0,0 

9130 RESTORE 9110: FOR N=0 TO IP 

FOR H=0 TO 7: BORDER H: BEEP ~ 

005 , N 

9140 RERD R: POKE USR CHR$ (

1983 

(BitiUersttp j§>ofttoare 

LIBRARY OF ADVANCED MATH/STAT/ECON 

TAPE 1: MATRIX OPERATIONS SPECTRUM £6.9S ZX81 £5.95 

State A: Inversion multiplication addition subtraction and scalar mulliplicalion ol 

"jt' jos arte vectors «ithm one smgltf piOfad Any output can in luin tw used as the 

!1 yiuare .tin.. 

TAPE 2: POLYNOMIALS SPECTRUM £6.95 2X81 £5.95 

Side A: :nadratic equations ias degree ? polynomials! and Newton Hapnson 

arvrtân- ntervai search methods tot higher degree polynomials Computes the roots «filh 

3 ftipits Ol piecuxin 

Stale B: You can plot polynomials handling all sorts ol linear 

programming problems (any combination ot . constraints and 

xi>.xi20 20x15 16K Spectrum 10x10 -SflKSpoctrum 10x501 25x40 50x30 

Side 8: Solutions ot simultaneous equations 

TAPE S(b): PROFESSIONAL LINEAR PROGRAMMING £14 95 

A'.ii sible tor I6K ZX8t and 48K Speclrum with above features plus save dala and 

farce-data facilities Any single data entry can be changed m order lo observe ils 

effect on the solution 

• All inclusive prices for the UK • 

• Tapes 1-5(a) Spectrum £35 ZX81 £30 

Cheques payable to: 

UNIVERSITY SOFTWARE 

29 St. Peter s Street, London N1 8JP. 

SPECTRUM 

UPGRADE 

ONLY 

(ISSUE 2 MACHINES ONLY) 

TANDEM 

Expandable Expansion system, 

gives 4 expansion slots for Vic 20 cartridges 

Custom designed case. Plugs directly into 

computer. Further expanded by using 

Taridern System ROM socket. No 

extra power supply needed £30.00 

SEND NOW TO 

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141 ABBEY ROAD BASINGSTOKE, 

HANTS TEL 0256 20671 

cAliens witcoMf APPOINT»tm 

FOX 

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incl VAT + P&P 

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FOR THE SPECTRUM OR 

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PLUGS IN (NO 

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Please allow 21 days delivery 

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Momentum is building last with the BLACK HOLE High 

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J 

ZX COMPUTING AUGUST/SEPTEMBER 1983 5

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SOFTWARE REVIEWS 

The #8l soft selection 

Nick Pearce casts his eyes over the 

latest software packages for 

the ZX81. 

Invaders — 

Odyssey 

Computing 

Invaders from Odyssey Computing 

is a high resolution 

yes, high resolution on your 

ZX61 - version of the popular 

arcade game. Unbelievable? 

Well, its true, and no ex pen 

sive hardware either, |ust the 

standard computer with 16K 

RAM. None of the usual ZX81 

characters to represent the 

alien fleet, in this game they 

are the genuine article. Action 

is fast and smooth too, and the 

explosion when your ship is hit 

really is shattering! 

Alter LOADing — which 

takes about five minutes — the 

program runs automatically. 

As well as the Hi res display 

the facilities offered are im 

pressive. The game required is 

first set up: a one or two player 

game can be selected (two 

players can either take turns or 

play simultaneously); the 

keyboard mode is selected; 

and the missile firing rate and 

bomb dropping rate are 

chosen. Selecting a high 

missile firing rate and a low 

bomb dropping rate gives a 

relatively easy game in which 

even the beginner can achieve 

a high score; increasing tha 

bomb rate and or reducing the 

missile firing rate makes the 

game more difficult for the ex 

perienced player. 

The game is robust but will 

crash if, for example, invalid 

entries are made in the setting 

up sequence A small price to 

pay for an excellent game. 

I am afraid your existing 

library of arcade games for the 

ZX81 is likely to lose much of 

this one. No sound or colour, 

of course, but the Hi-res 

display really does break new 

ground. An outstanding 

achievement. 

The use of high resolution 

graphics will almost certainly 

open up a whole new genera 

tion of ZX81 software as other 

software houses follow suit. 

An excellent game. 

Invaders costs €4.95 from 

Odyssey Comuting, 28 

Bingham Road, Sherwood, 

Notts NG5 2EP. 

Ocean Trader and 

Pioneer Trail — 

Ouicksilva 

Ocean Trader is a role playing 

adventure game set in the 

nineteenth century in which as 

captain and owner of a 1 30 

ton sailing barque, your aim is 

to make a profit of E'/im and 

retire. To do this you buy and 

sell coal, whisky and other 

cargos, sailing from port to 

port looking for a good price 

for them. Hazards abound and 

during the voyages you will en 

counter pirates, severe storms 

and overzealous insurance 

agents, to name a few. 

1 iuERPOOL 

LOMDON 

ueucnsTi-R 

JOUTnfMPTO" 

Some sample screen illustrations 

from the program, Ocean Trader. 

JER 1983 ZX COMPUTING AUG SEPT 1983 59

You make money by virtue 

of the varying prices in each of 

the five ports, but it is a slow 

and frustrating process just 

breaking even — never mind 

that elusive £500,000 profit 

you are after. You can lose half 

a valuable cargo in a severe 

storm, and if you cannot meet 

your insurance bills your ship 

can be impounded! 

Your home port is Swansea. 

A finance company here will 

loan you money if you require 

(you certainly will!) but 

beware, interest increases by 

1 2 Vi % each time you sail from 

port and there is a limit of 

£25,000. 

The game is in two parts. 

The first comprises comprehensive 

on screen instructions; 

the main game is loaded 

separately. This format 

enables the full 16K to be used 

for the game itself, but does 

have the penalty of extended 

LOADing times. The graphics 

accompanying the on-screen 

instructions are particularly impressive. 

Ocean Trader is a well 

thought out and enjoyable 

game. You will need to be a 

quick witted trader, and have 

luck on your side, to earn a rich 

retirement. 

Pioneer Trail is set in 1847 

when your family joins the trail 

to Oregon. You have 40 weeks 

to travel the 2,000 miles. 

Your assets consist of two 

tired old horses and $ 700 to 

spend on supplies; not a very 

auspicious beginning. You test 

your rifles before embarking on 

the trail, this is done by typing 

the changing letter or number 

on a moving target. You will 

need to be a good, and lucky, 

shot if you are to overcome the 

dangers of the trek. 

From then on you move 

along the trail towards your 

destination. You have the opportunity 

to stock up at forts 

along the way (finances permitting), 

and hunt for food. 

Dangers are encountered frequently 

and include hostile 

travellers, outlaws, rattlesnakes, 

severe weather and 

more. You can select one of 

20 levels of play from beginner 

to experienced pioneer. 

Limited use is made of 

graphics during the game. Instructions 

are displayed onscreen 

at the start. 

The incorporation of an in 

teractive element can add a 

touch of excitement to adventures, 

but I must admit that I 

found 'shooting' the target on 

Pioneer Trail rather uninspiring; 

success appeared to depend 

more on chance than reaction 

time or skill. Nevertheless, an 

entertaining game. 

Ocean Trader and Pioneer Trait 

cost £3.95 each from 

Quicksilva, Palmerston Park 

House, 13 Palmerston Road, 

Southampton SOI 1LL. 

Black crystal — 

Carnell Software 

Black Crystal is another role 

playing adventure in which you 

can become a warrior, wi2ard 

or elf in a quest to find and use 

the rings of creation to destroy 

the Lords of Chaos. Black 

Crystal is split into six parts 

which have to be played in the 

correct sequence in order to 

take the player through the 

Land of Beroth, the Castle of 

Shadows, Shaggoth's Lair and 

to the Black Crystal itself in the 

Dark Tower. 

SOFTWARE REVIEWS) 

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Comtmead 

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r 1983 

THE MOST EXCITING AND 

INNOVATIVE SOFTWARE EVER 

LAUNCHED FOR YOUR SPECTRUM 

BE SURE OF YOUR COPY 

SUBSCRIBE NOW! 

Cut out and SEND TO: 

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'OR AVAILABLE BY POST FOR £2.99 (POSTAGE FREE) FROM 

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7X81 . ZXSPECTHUMG fiMie tick FINAL TOTAL 

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THE WORLD'S GREATEST RANGE OF 

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PIONEERS IN 1981 — WAY AHEAD TODAY 

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SOUND with SINCLAIR 

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TIMEX Sinclair 1000 

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THE ZON X 

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• Tk? ZON SOUNO UNIT IS completely soil-containod and especially 

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• No powc pack naileries load* or oltaH e>tfas ' 

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SpaceinvaOers Explosions,Gun-srrots,D'ums Planes Lascs Organs, 

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FOR H8K SPECTRUH FOR iSX 2X81 

KNOT IN 30 -18* Spectrum Th, is an 

achon game, lhat needs nerve and quick 

reactions' Hurtling through a void, your 

task is to IrarviH as long as posubfe seeing 

po«ts along the way Be careful though 

as you will have to awwi your own trail 

and Ihose ol up to (our chasers As traits 

are let; you have to thread your way 

through, but don't toiget the mw trails 

Ihe lass space ID' manoeuvring You will 

be teimmated Mien you 'malty get caught 

in The Knot Compatible w

Facts 

from the 

Fair 

Our roving reporter checks out 

the microscene at the 7th zx 

Microfair. 

The day was June 4 — not a 

particularly inspiring date 

except for the fact that this 

was the day that the 7th ZX 

Microfair was to take place. 

Complementing the 1 30 

suppliers were over 8,000 

visitors to the exhibition in its 

new, and as it would seem, 

permanent home in the 

Alexandra Pavilion (or as we 

Londoners think of it, 'Ally 

Pally'). 

There were many new 

companies at the show, and it 

was very evident that the 

stands were put together very 

professionally. Vortex, an 

extremely new company, had 

one of the most prominent 

stands at the show. Vortex 

were selling two Spectrum 

games. Android One and Gun 

Law. They also had a great 

game for the ZX81 called 

Astral Convoy. 

Protek Computing, a new 

Scottish-based software 

company, were exhibiting a 

wide range of hardware and 

software, including a cursor 

compatible joystick interface 

for the ZX Spectrum. Another 

new company. Apocalypse 

Software had, what I thought, 

was the best software deal I've 

seen for a long time — they 

had two extremely good games 

on one tape for a mere £4.90. 

They also had some useful 

utilities for the Spectrum so 

they might be a name to bear in 

mind when you're looking 

around the software shelves. 

Old favourites, Quicksilva, 

had a stand at the show which 

looked more like a space-age 

house. They were exhibiting 

their latest titles to a large and 

interested crowd. As were 

Artie, who were showing five 

983 

of their new programs for the 

Spectrum. 

Hewson Consultants, 

famous for their 'Nightflight' 

flight simulation program, have 

now released a new software 

package called 'Heathrow — 

Air Traffic Control'. In this you 

must talk several aircraft down 

onto the runway, trying to 

keep their flight patterns 

regular and avoiding air 

collisions, etc. Hewson also 

gave away plans for a game 

called 'Quest' which they are 

soon to release. In this 

adventure/with 1 33 locations 

and sporting full graphics, you 

get to play one of five 

characters and fight various 

creatures — one of which is a 

Hobbit (some backstabbing 

here, maybe?). The idea behind 

the game is to accumulate 

points and eventually find the 

scroll which holds the clue to 

finishing the game. Hewson 

don't think anyone will finish 

the game in under six months 

— and I think they're probably 

right! 

Softek, who fronted an 

impressive six table stand, 

were displaying a wide range 

of Spectrum software of 

arcade quality. Automata also 

had an impressive display of 

software, with one particular 

package, Automonopoli, which 

was the best adaptation of that 

game that I have ever seen. 

They also added a fair amount 

of good cheer by serving up the 

champagne at just the right 

moment. 

The hardware company, 

Eprom Services, were 

displaying various new add-ons 

for the Spectrum and ZX81 

including an Auto Start board 

and A/D convertors. 

SINCLAIR NEWS 

But software was really the 

main attraction of the show for 

me, and Emsoft had a 3D 

graphics package which really 

quite amazed me. An 'X' was 

simulated on the screen in 

three dimensions, and was 

then made to spin round at 

speeds faster than I've ever 

seen before. The package also 

allowed you to enlarge the 'X' 

and even incorporate the 3D 

facility in your own programs. 

Procom, yet another new 

company, had tiwo Spectrum 

programs on display. 

Breakaway and Character 

Design, which were both 

worthy of praise. 

Of the clubs at the show, all 

had a range of software 

written by various club 

members. The Staines and 

Stanwell Computer Club had a 

Cesil interpreter, the Stevenage 

Club were selling graphics aids, 

and the people from the 

Aylesbury Computer Club were 

selling practically everything 

(as usual!). 

At the end of the day, I'm 

sure everyone would agree that 

the show was a definite 

success. I, for one, am really 

looking forward to the next 

one! 

ZX COMPUTING AUG/SEPT 1983 64 

s K 

s o 

h 

r< 

e 

F 

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r 

t 

t 

c 

a 

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Sinclair Advanced 

Research 

Sinclair Research are to invest 

over £2 million in establishing 

MetaLab, a new advanced 

research centre. At this new 

establishment, Sinclair 

Research will be exploring 

revolutionary and high risk 

ideas with a view to developing 

new products in high 

technology. 

Sir Clive Sinclair believes 

that MetaLab will provide a 

challenging 'think tank' 

atmosphere for a highly 

motivated multidisciplinary and 

Congratulations! 

As recognition of his 

achievements in the British 

micro industry, Clive Sinclair, 

Chairman and Chief Executive 

of Sinclair Research, is to be 

knighted as part of this year's 

Queen's Birthday Honours. 

Said Sir Clive on hearing the 

news "The award of a 

knighthood is a truly great 

honour and one I value very 

Safe AS Houses 

Computers For All have 

announced a complete 

warranty extension plan for 

home computers, printers, disc 

drives and monitors. 

Called the Computersafe 

Extended Guarantee Plan, you 

can extend your 

manufacturer's warranty for a 

further 12 months covering 

such items as complete cost of 

repair through mechanical or 

electrical breakdown, etc. The 

creative scientific team which 

it is now seeking to expand. 

"MetaLab will act as an 

incubator, fostering new 

products from initial idea to 

commercial launch" said Sir 

Clive , "Not only will MetaLab 

complement research work 

underway in existing computer 

and television divisions — it 

will also open up totally new 

fields ranging from battery 

technology to robotics". 

The MetaLab complex is 

planned to open in the 

Autumn. Watch these pages 

for future developments of Sir 

Clive's latest endeavour. 

highly. It was completely 

unexpected and a wonderful 

surprise. More than ever, I feel 

committed to achieving 

success here, in and for 

Britain." 

As readers of ZX Computing 

and faithful users of ZX micros, 

I'm sure you will not need us to 

tell you of his many successes 

over the past 20 years, so it 

only remains to wish Sir Clive 

all our congratulations. 

insurance has been organised 

by Computers For All in 

conjunction with Domestic and 

General Insurance Co Ltd. 

The extended guarantee is 

unique in as much as it will be 

serviced through all Computer 

For All dealers as well as most 

bone fide computer repair 

companies. 

Further information is 

obtainable from Computers For 

All, 72 North Street, Romford, 

Essex. Telephone enquiries can 

be made on 0708 752862. 

SINCLAIR NEWS 

The Return Of 

Horace 

Sinclair Research, in a further 

expansion of its software 

library, have released nine new 

cassette programs, including 

an additional language, 

FORTH, an advanced chess 

program and yet another 

adventure for the intrepid 

Horace. 

ForZX81 and Spectrum 

users with plans on increasing 

their programming interests 

comes a new FORTH program 

offering a language combining 

BASIC'S simplicity with the» 

speed of machine code. 

FORTH is extendable by userdefined 

commands, and its 

compiled code occupies less 

than a quarter of the equivalent 

BASIC program yet runs up to 

ten times as fast. Both versions 

for the ZX81 and Spectrum are 

available at £14.95. 

A major challenge for the 

games enthusiast is the new 

eight level chess program for 

the Spectrum called Cyrus-lS- 

Chess. Based on the original 

Cyrus program which won the 

second European 

Microcomputer Chess 

Championship, it features 

cursor movement of pieces, 

replay and take-back facilities, 

as well as the ability to 

function as a normal twoplayer 

game board. The CyrusiS-Chess 

program is priced at 

£9.95. 

In amongst the serious 

titles, there are, of course, five 

new software games packages 

fortheZX81 and Spectrum. 

And Horace rears his head 

once more in a program called 

Horace and the Spiders. In this, 

his third program, you have to 

help Horace survive the 

traumas of the mountain and 

the bridge before engaging the 

Spiders in a deadly duel in their 

web. Horace and the Spiders is 

available for £5.95. 

Other games for the 

Spectrum include a full feature 

Backgammon game and 

Scrabble which features over 

11,000 words in its memory 

and four levels of skill. 

Backgammon and Computer 

Scrabble are priced at £5.95 

and £1 5.95 respectively. 

For the ZX81 with 16K 

RAM, Sinclair Research have 

introduced two new adventure 

games. Sabotage and City 

Patrol. These two tapes are 

priced at £4.95 each. 

Finally, meeting the growing 

demand for business software, 

Sinclair Research have also 

released a program for the 48K 

Spectrum called Small 

Business Accounts. This 

program, priced at £1 2.95, 

provides balance sheet and 

profit and loss information 

together with VAT returns. 

All the new cassettes are 

available via mail order from 

Sinclair Research, Stanhope 

Road, Camberley, Surrey. They 

should shortly be on sale in 

major branches ol WH Smiths, 

Boots, Currys, John Lewis 

Partnership, House of Fraser, 

John Menzies and Greens, and 

other leading chains and 

computer stores. 


Hardware in Brief 

• AGF Hardware have introduced a Programmable 

Interface for the ZX Spectrum and ZX81. Accepting 

connection of one or two Atari-compatible joysticks, the 

new interface offers users compatibility with all games 

software through a unique programming design. 

Keyboard operation is not affected by the interface and 

expansion is accommodated through an extension edge 

connector. Full instructions are supplied with a 

demonstration program which allows high resolution 

drawing to be made under joystick control. The price of 

the programmable interface will be £32.95 plus £1.00 

postage and packing. For more information get in touch 

with AGF Hardware, 26 Van Gogh Place, Bognor Regis, 

West Sussex P022 9BY. 

• If you're having problems with a wobbly RAM Pack, 

Adapt Electronics may have come up with a solution to 

your worries. The RAMLOK kit consists of a gold-plated 

male connector which replaces the computer connector 

and, through an ingenious mechanical clamping device, 

clamps the RAM pack to computer. The RAMLOK kit is 

easily fitted and requires no cutting, drilling or special 

tools. Step by step instructions are included allowing for 

simple installation. Priced at £7.50 plus 50p postage and 

packing, you can find out more about RAMLOK from 

Adapt Electronics, 20 Starling Close, Buckhurst Hill, 

Essex IG9 5TN. 

• Cheetah Marketing Ltd have introduced a 32K RAM 

pack for the 1 6K ZX Spectrum allowing it to be 

upgraded to a fully fledged 48K machine. Its injection 

moulded case has been specifically designed to fit the 

contours of the ZX Spectrum thus hopefully eliminating 

the worries of the 'wobble'. The device is fully 

compatible with all Spectrum accessories. Now available 

on mail order, the RAM pack will soon be sold through 

selected retail outlets. All the devices are tried, tested 

and guaranteed, and are priced at £39.95. For further 

details contact Cheetah Marketing Ltd, 359 The Strand, 

London WC2R OHS or 'phone 01 -240 7939. 

• A speech synthesiser for the Spectrum or ZX81 is 

now available from Spirit Instruments. Housed in a sturdy 

case, the speech synthesiser plugs into the back of your 

computer, providing speech from its own built-in speaker 

or output to your hi-fi. Programming speech using the 

device is simple, and full instructions are provided with 

the package. For further details contact Spirit 

Instruments, Station Road, Maldon, Essex CM9 7LQ or 

'phone 0621 56969. 

• If you would like to get more sound out of your 

Spectrum then look no further than the new device from 

Compusound. Housed in a small box, the device has 

three leads which are attached inside the Spectrum via 

crocodile clips. Full details on how to connect up the unit 

are given with a comprehensive diagram for the nervous. 

Once connected you will get all the 'zaps, pows and 

booms' from your games through the speaker in the TV 

— so you can now drive everyone in the house mad with 

deafening explosions as you destroy the alien fleet! For 

more details have words with Compusound, 32 Langley 

Close, Redditch, Worcs B98 OET or 'phone 0527 

21439. 

HARDWARE NEWS 

Are You in Touch? 

Tactile have introduced a new 

concept in keyboard overlays 

for the Spectrum which is 

aimed at early education 

programmers, teachers and 

parents thus allowing the 

Spectrum to become a much 

simpler teaching aid. 

The Tactile keyframe, with 

its touch sensitive membrane, 

fits snugly over the computer 

and allows you to create your 

own easily changeable overkeys. 

The key surface can be 

configured as one large key or 

up to forty individual, userdefined 

keys using simple IN 

or INKEY$ instructions; 

prepared instructions are 

enclosed with the package to 

help you adapt your programs 

to suit the new key layout. 

The complete set includes 

a keyframe, coloured, white 

and clear backgrounds, 

symbols and shapes, allowing 

you to construct an infinite 

variety of over-key panels. A 

piano keyboard and a 

simplified children's 

typewriter layout are also 

included. 

The software company. 

Early Learning Opportunities, 

is to market software 

compatible with this keyframe 

and pictorial overlays. 

For further information on 

these products get in touch 

with Tactile on 0272 

678431 or write to Tactile, 

Wraith, 32 Elmfield, 

Kingswood, Bristol BS15 

2SS. 

Going Mobile 

If you ever wanted to 

combine the hobby of 

computing with robotics then 

you may be very interested to 

learn about the Zeaker Micro- 

Turtle. 

The Micro-Turtle is a twowheeled 

mobile robot whose 

66 ZX COMPUTING AUG,SEPT 1983

movements can be controlled 

by any microcomputer, 

including the Spectrum and 

ZX81, via a connecting 

umbilical ribbon cable. 

Suitable software is provided to 

permit the movements to be 

memorized and reproduced. 

Sensors indicate when the 

robot touches an obstacle and 

the computer instructs it to 

find an alternative route. An 

additional feature of the 

machine is that it has an inbuilt 

retractable pen which 

can be used to trace its path 

across a surface. The pen 

itself is controlled by the 

computer and is indicated by 

an LED on top of the robot; 

two other LEDs indicate 

which direction the Micro- 

Turtle is travelling in. 

The unit comes complete 

with interface, power supply 

and operation manual, as well 

as the necessary software to 

suit your particular computer. 

Aimed at the educational 

market, as well as anyone 

else interested in control 

systems, the unit has been 

priced very competitively. The 

Micro-Turtle is avilable as a 

kit priced at £52.00 + VAT 

or fully assembled at £69.50 

+ VAT, 


the Zeaker Micro-Turtle 

contact Colne Robotics Co 

Ltd, Beaufort Road, Off 

Richmond Road, East 

Twickenham, Middlesex TW1 

2PH or 'phone 01-892 

8197. 

Sounding Out 

Timedata, computer 

publishers, have now spread 

their business wings and are 

introducing a range of 

hardware add-ons for Sinclair 

computers. 

Their first product in the 

proposed new range is the 

ZXM Sound Box, Retailing at 

C29.95 inclusive, the Sound 

Box uses the 891 2 three 

channel sound generator chip 

to provide a wide range of 

programmable sound effects. 

The built-in amplifier and 

loudspeaker can also be used 

to boost the Spectrum's own 

BEEP. 

Not that the Sound Box 

can be used exclusively with 

the ZX Spectrum — it can be 

used with the ZX81 without 

the need for an adaptor. The 

ZXM also has a nine pin I/O 

socket which can be used 

with Atari/Commodore 

joysticks. Other Sinclair addons 

can be plugged into the 

back of the Sound Box. 


the ZXM Sound Box and 

details of their other products 

which should be forthcoming 

over the next few weeks, get 

in touch with Timedata Ltd, 

16 Hemmells, High Road, 

Laindon, Basildon, Essex 

SSI 5 6ED. Telephone 

enquiries can be made on 

0268 418121. 

HARDWARE NEWS 

Keyed up? 

Dk'Troniks have introduced a 

new keyboard which will 

function with both the ZX 

Spectrum and ZX81. 

Launched at the recent 

Midland Computer Fair, the 

new cased keyboard includes 

52 keys, 1 2 of which are 

used for the numeric keypad. 

The keypad is a repeat of the 

one to nine keys plus full stop 

and Shift keys. Measuring 1 5 

inches by 9 inches by 2 Vt 

inches, the cased keyboard is 

coloured black with grey and 

red keys. 

The computer, either the 

ZX81 or Spectrum, fits neatly 

inside the case; although the 

computer is removed from its 

original case, the base of the 

case has been customised to 

allow for easy fitting. Also 

The ZX Floppy 

Analogue Information 

Systems Ltd are introducing a 

floppy disc controller for the 

ZX81 which should prove 

invaluable to anyone 

contemplating using the 

ZX81 for business 

applications. 

The controller offers single 

or double density 

compatibility with all Shugart 

5% inch drives, the new 

Japanese 3 inch drives and 

the new Hungarian MCD1 3 

inch drives. It also allows the 

use of single or double sided 

drives up to any number of 

tracks. 

An important part of the 

fitted inside the case can be a 

motherboard (ZX81 model 

only) which allows 1 6K, 32K 

or 64K RAM packs to be 

fitted. There is also room 

inside the case for other addons 

to be included such as 

the Power Pack. 

All the connections usually 

found at the back of your 

computer are to found at the 

back of the keyboard case, ie 

Power, MIC, EAR, TV and the 

expansion port. 

Priced at £45 inclusive, 

you can find Out more about 

the keyboard case from 

Dk'Tronics, Unit 2, Shire Hill 

Industrial Estate, Saffron 

Walden, Essex CB11 3AX. 

You can always 'phone them 

on 0799 26350. 

controller board is the disc 

operating system which is 

supplied in ROM. This gives a 

simple disc interface to 

BASIC involving no USR calls, 

POKE, PEEK, etc. The DOS 

commands are many and are 

available directly from a 

BASIC program, from the 

BASIC command mode or 

from machine code. 

At the time of writing the 

controller board is set to enter 

the market at around £40.00 

inclusive, available by mail 

order only. For further details 

of the floppy disc controller 

board contact Analogue 

Information Systems Ltd, 43 

Gilmour Road, Edinburgh 1 6 

or 'phone 031-667 6862. 


Software in Brief 

• A tape which demonstrates three top-line Hilderbay 

programs for 48K Spectrum is now available priced at 

£3.95 (a fraction of the price of the software it 

demonstrates!. The demo program illustrates the three 

programs. Payroll, Stock Control and Statutory Sick Pay. 

This lets people get some idea of the content of the 

software before they take the plunge and part with their 

money. For more information on this tape get in touch with 

Hilderbay Ltd, 8/10 Parkway, Regents Park, London NW1 

7AA or 'phone 01-485 1059. 

• Following the success of Accounts ZX81 comes the 

launch of a similar piece of software for your 48K Spectrum 

called (of course! Accounts Spectrum. The programs 

featured on the tape are aimed at both practising 

accountants and businesspeople and can improve the 

efficiency of routine accounting. If you require any further 

information get in touch with Hestacrest Ltd, PO Box 1 9, 

Leighton Buzzard, Beds LU7 ODG or 'phone 052-523 785. 

• Collins have released the Spectrum Starter Packs 1 and 

2, which comprise a tape and booklet explaining the 

programs included on the tape. Providing a range of 

programs which have both sound educational content as 

well as being fun to play, these packs are designed for 

children and their parents to learn to handle the ZX 

Spectrum. Priced at £9.95 each, you can find out more 

from Collins Educational, 8 Grafton Street, London W1 or 

by 'phoning 01-493 7070. 

• Direct from Silicon Valley North comes a piece of 

software for the ZX81 called Gradebook. Aimed at teachers 

and professors, Gradebook is menu driven, allowing the user 

to manipulate data, such as exam marks, by different 

distribution methods. There are also built-in routines 

allowing you to print out displays. Supplied with full 

documentation, the price of the package is £6.25 plus 

£1.00 postage and packing. Orders can be made from 

Silicon Valley North, PO Box 2442, Hammond, Indiana 

46323, USA. 

• Virgin Games Ltd have produced a number of software 

packages for three of the most popular micros, including the 

ZX Spectrum. Of the four programs released, two packages, 

Starfire and Sheepwalk, are designed to run on the 48K 

machine. The other two packages. Golf and Yomp, are 

designed to run on either version of the Spectrum. All of the 

new programs are priced at £7.95 each. For more details 

contact Virgin Games Ltd, 61-63 Portobello Road, London 

W11 3DD or telephone 01-221 7535. 

• Micromega have announced their Spring collection of 

software for the Spectrum and ZX81. All priced at £4.95, 

for the Spectrum there is Monte Carlo, Roulette, Dominoes 

and Brainstorm. The final package is Gulpman, which also 

includes an advanced 1 6K ZX81 version on the same 

cassette. For further information on the new range of 

software contact Micromega, Personal Computer Division, 

Quantec Systems and Software Ltd, 230-236 Lavender 

Hill, London SW11 1 LE or 'phone 01-223 7672. 

• Hisoft have released two new packages for the 

Spectrum. The first is Pascal 4 and is a complete 

implementation of Pascal for the Spectrum and is priced at 

£25.00 inclusive. The second package is called DEVPAC 2 

and is an upgraded version of their current assembler, 

disassembler/debugging program. The DEVPAC 2 package 

is priced at £1 2.50 inclusive. Both packages come with 

comprehensive documentation from Hisoft, 60 Hallam 

Moor, Liden, Swindon, Wilts SN3 6LS. Telephone enquiries 

can be made on 0793 26616. 

SOFTWARE NEWS 

For The Record 

A computer game pop single 

was recently released by EMI 

Records (UK). The single, by 

Chris Sievey, features a selfpenned 

song, Camouflage, on 

the A-side, while the B-side 

contains three of his 

programs ior the ZX81. 

The programs, once played 

into the ZX81, will produce 

one demo program — 

illustrating the lyrics of the 

A-side with text and graphics 

— and two games programs, 

one for the 1 K and one for 

the 1 6K ZX81. These games 

are versions of an arcade-type 

game called Flying Train, 

Chris Sievey's single will 

be in your record store at the 

moment, but should you have 

any problems in obtaining 

your copy try contacting EMI 

Records (UK) at 20 

Manchester Square, London 

W1A 1ES. I haven't managed 

to see the programs yet, but 

anyone who could release a 

single entitled 'I'm in love 

with the girl on the 

Manchester Virgin Megastore 

checkout desk' must have 

something going for him! 

This is not, however, the 

record industry's first foray 

into the world of computing. 

Mainframe, a band comprising 

Murray Munro and John 

Molloy, released a single 

called 'Talk to me' in which 

they have included material 

for the Apple computer, 

ZX81, Spectrum and the BBC 

Computer. For more 

information on Mainframe, 

get in touch with MC 2 Music, 

24 Missden Drive, Hemel 

Hempstead, Herts. 

BASiCally, it's A Magazine 

68 ZX COMPUTING AUG,SEPT 1983 2

">9 

The Sound 

Of Music 

If you ever wanted to play 

and compose music on your 

48K Spectrum, Bellflower 

Software may have come to 

your rescue. 

As well as using the 

Spectrum's own BEEP 

command, the program has 

successfully managed to meet 

the challenge of representing 

each note on the screen in 

accurate musical notation. It 

will play and print melodies in 

11 different keys, each with 

a choice of 1 2 time signatures 

and ten playing speeds. 

Rests, accidentals and dotted 

notes can all be programmed 

into the tune and bar lines are 

drawn in their correct places 

automatically. 

A revolution in computer 

magazine publishing was 

witnessed last month with 

the launch of 'Spectrum 

Computing' — a bi-monthly 

magazine on tape! 

Edited by lolo Davidson, 

the new magazine, Spectrum 

Computing, is available for 

£2.99. Altogether there is 

some 80K of code which 

readers follow through a 

series of on-screen prompts. 

On the first issue, designed 

for both the 16K and 48K 

models, there were software 

reviews (including 'stills' from 

the programs under review), a 

Morse code trainer, chess 

graphics, a routine for turning 

text upside down and 

Don't worry if you don't 

rate yourself as an expert 

musician because all the 

musical knowledge you need 

is stored in the computer and 

tunes can be put into memory 

using single keys to make 

choices from the screen 

display. Starting off as a 

beginner, you can check that 

what you are doing is correct 

by comparing your efforts 

with the three tunes supplied 

with the program. Once you 

have input your tune, you can 

get the computer to print out 

the tune note by note as it 

plays it for you. 

Available at £5.75, you 

can find out more information 

by contacting Bellflower 

Software, 6 Rosewood 

Avenue, Greenford, 

Middlesex. Telephone 

enquiries can be made on 

01-903 1816. 

sideways, as well as a couple 

of arcade games thrown in for 

good measure. 

Said lolo "I've put in the 

sort of things that interested 

me. We don't want to go 

over the heads of some of the 

readers nor do we want to 

talk down to them. It's a 

difficult balance to strike and 

! hope I've achieved it". 

Perhaps this shows the 

shape of things to come — 

maybe soon the computer 

bookshelves in the newsagents 

will be filled with cassette 

magazines. 

Spectrum Computing is 

published by Argus Specialist 

Publications, owners of ZX 

Computing. 

SOFTWARE NEWS 

Fast Loader 

JRS Software have developed 

a unique system for their 

software for the 2X81 which 

will enable programs to be 

loaded at the maximum speed 

possible within the limits of 

the computer itself, ie 

without the need for 

additional hardware. 

Data is loaded at between 

300 and 500 bytes per 

second, or 10 to 15 times 

faster than the normal ZX81 

rate. This means that almost 

every program for the ZX81 

could be loaded in under a 

minute — a very effective 

cutting of the loading time. 

This breakthrough has 

been achieved by drastic 

modification of the I/O signals 

whilst limiting the maximum 

frequency to 4KHz to 

guarantee reliable operation 

even when using poor quality 

tapes or low-cost cassette 

recorders. 

JRS Software are based at 

1 9 Wayside Avenue, Worthing, 

West Sussex BN1 3 

3JU. 

The Artie Arrivals 

Artie Computing have 

released nine new titles to 

complement their growing 

range of software for the 

ZX81 and Spectrum. 

First up are two chess 

programs. Spectrum Chess II 

is for the 48K Spectrum and 

incorporates no skill levels — 

you just specify how long you 

want the Spectrum to think 

and it will come up with the 

most challenging move. The 

other chess program is called 

Chess Tutor and operates on 

the 16/48K Spectrum. This 

program not only plays chess 

on three different levels but 

also coaches the beginner to 

expert level. Spectrum Chess 

II and Chess Tutor are priced 

at £9.95 and £6.95 

respectively. 

There are also some games 

for the Spectrum including 

Cosmic Debris (48K), 3D 

Combat Zone (48K), 3D 

Quadracube (16/48K) and 

The Golden Apple (48K). 

These tapes are priced at 

£4.95, £5.95, £4.95 and 

£6.95 respectively. 

There is also a software 

package which enhances the 

power of the Spectrum so 

that you can produce 64 

column copy which can even 

by LISTed without any extra 

commands. This package, 

SYS 64, is suited to the 

1 6/48K Spectrum and is 

priced £6.95. 

The two packages released 

for the ZX81 are Reversi, 

incorporating four levels of 

play, and Raider, a version of 

the arcade game Scramble. 

Both tapes require 1 6K 

memory and are priced at 

£5.95 and £3.95 

respectively. 


these new releases contact 

Artie Computing Ltd, 396 

James Reckitt Avenue, Hull, 

North Humberside. 


1983 

YOUR MISSION 

To penetrate the witches defences, enter 

her cavern and destroy her wicked heart 

rm An Exciting range for 16K ZX81 rag 

« from SOFTWARE FARM 6iJ 

THE WITCHES DEFENCES 

Stalagmrtes and stalactrtes - which grow 

across your path 

Volcanoes - to get past alive - if you can 1 • Wntten entirely in machine 

code 

Vampire Bats - that cling to your ship and • Hall of Fame 

make controls sluggish 

• 1 or 2 players 

Cave-ins - should you hit the side of the • Mystery score positions to 

cave with your Laser Cannon or Bomb, part bomb 

of the roof will cave in on you 

• 5 skill levels 

Stay alive as long as possible in open space 

filled with ftying rocks Score by shooting • On screen scoring 

them -which also causes them to break into 

lots of little bits and makes life even worse! 

• Machine coded for fast action 

• High score with enter name 

facility 

• Up to 4 players 

• E xtra ship tor 1,000 points (riot 

as easy as it sounds!) 

• Ship moves iust like arcade 

version 

• Rotate left/rotate right/thrust 

• Fires in all 8 Erections 

• Increasing number of asteroids 

• Three asteroid sizes 

• alien spacesho (fires back!) 

• Machine coded for fast acton 

• Extra 'Gobbler' for 10,000 

points 

• On screen scoring 

• High score w*h onter name 

facility 

• Up to 4 players 

• 50 Skin levels' 

• Played against the dock - 

froggie only has a short white to 

live' 

Send your order to: 

Design Dept THE SOFTWARE FARM. Craigo Farm. Botany Bay. Tintem. Gwent 

Mk2 

Beat that high score! 

Gobble those dots before those meames 

gobble you! 

Your only aids are four "Power Pills' which 

make the meames edible But not for long 1 

'""ZZT* 

Jump your frog over the lanes in the road - 

preferably without being turned into jam by 

the approaching traffic 1 Then cross the river 

by hitching a few ndes on some passing logs 

and finally into the safety of your hole on the 

opposite bank Once all 'Frog Holes' have 

been filled you start again with a different 

pattern and a bonus frog. 

WIV ier you have an Or«. Spectrum

Reader's 

reviews 

Read what you, the 

reader, think of 

software commercially 

available for your micro. 

This feature provides you 

space to air your views on any 

1 software, be it for the ZX80, 

ZX81 or ZX Spectrum. If 

you've had a good or bad ex 

perience of any of the commerical 

software packages 

available for your micro, why 

oot write and tell us. 

Your reviews should contain 

your critical thoughts 

about the software and the 

relevant details concerning the 

availability of the package, its 

price, etc. If you can provide 

any screen dumps to illustrate 

the review, so much the better. 

Any reviews published in 

this section of the magazine 

will be rewarded with the price 

of the tape you review. So, if 

you buy a cassette and send in 

a review that gets published, 

you'll get your software for 

free! 

Spectrum Pascal 

Hl-SOft 

David Bolton 

I SOFTWARE REVIEWS! 

How would you like to write 

programs in a language very 

much like BASIC and then run 

them at machine code speeds? 

It is now a very practical suggestion 

with the release of a 

full Pascal compiler for the 

48K ZX Spectrum by the 

British company Hi-Soft. 

Before I look at the Spectrum 

version, let me give you a 

little history of Pascal. It is a 

very young language, born in 

1969 when a leading computer 

scientist called Wirth 

decided that ALGOL, the then 

leading academic language, 

was getting too complex. He 

designed Pascal specifically to 

teach good programming practices. 

It is now available in 

many forms on disc-based 

machines, but there are very 

few implementations on 

cassette driven micros. 

Pascal is very similar to 

BASIC in many ways, certainly 

much closer than languages 

like FORTH, LISP, assembly or 

PILOT. It is generally a much 

better language. 

This version of Pascal is a 

very high quality product comprising 

some 20K of machine 

code for the compiler, editor 

and run-time package. It completely 

compiles a Pascal program 

into Z80 machine code 

which runs very fast indeed. 

Try filling an array of 7,000 

elements in half a second, or 

summing up the numbers one 

to 20000 in seven! Obviously 

one could write faster programs 

using an assembler, but 

try assembling A- LOGfSIN 

IB/1 80 * 22 7) 10.45) 

- 8/2.2234! 

When the compiler package 

is loaded it starts in the editor, 

allowing the programs to be 

typed in, or loaded from tape. 

Hi-Soft have been very cunning 

with their editor as it completely 

bypasses the Spec 

trum's single-key entry 

system. Programs are entered 

line by line just like BASIC with 

a line number at the start of 

each line: 

10 PROGRAM DAVE; 

20 VAR l,J:INTEGER; 

30 BEGIN 

40 J: = 0 ; FOR I: = 

1 TO 100 DO 

50 J: = J + 1; 

60 WRITELN CJ = J:5) 

70 END. 

The line numbers are at the 

start of each line for purposes 

of the editor only, they have no 

bearing on the program. Com 

mands are included to do the 

equivalent (in BASIC) of 

AUTO, DELETE and 

RENUMBER as well as sear 

ching and moving. There is 

also quite comprehensive commands 

involved with line 

editing which can do find, insert, 

replace and delete on one 

line. 

Overall, the editor is not as 

good as a screen editor, but it 

is the next best thing and for 

anyone used to Sinclair editing 

it is a significant improvement. 

The editor only changes the 

'Source code', ie the program 

as it looks above. Once a program 

has been compiled into 

machine code lor object code 

as it is known) it can only be 

changed by changing the 

source code and re-compiling. 

Source code can be saved 

onto tape and it's quick to ao 

so because Hi-Soft uses 

tokens (just like BASIC) to 

represent reserved words, eg 

PROGRAM and INTEGER only 

occupy 1 byte each in internal 

storage. When source code is 

loaded into RAM it appends 

onto the end of any existing 

code; this makes the creation 

and use of libraries much more 

convenient. 

One problem with the editor 

is that there is no keyboard 

beeping. I tried unsuccessfully 

to get it to work, even writing 

a short program to POKE 

23609 with 255, but to no 

avail. As soon as I exited from 

Pascal to BASIC the beeping 

started working again. 

Compilation is the process 

which converts source code to 

object code. There are two 

ways of doing this in Hi-Soft 

Pascal: the first is for debugging 

purposes, and keeps both 

source code and object code in 

RAM at the same time to 

speed up the EDIT-COMPILE- 

TEST cycle. When testing is 

complete the specially compiled 

object code can be dumped 

out to tape so that it will 

automatically LOAD and RUN 

as a stand-alone program. 

If a syntax error is 

discovered during compilation 

then the choice is given of 

stopping and going into the 

editor at the faulty line, or 

listing other errors. Pascal is 

typical of compiled languages 

in that one error early on can 

generate lots later. 

Compiling is a very quick 

process, but it will be slowed 

down if the compiler provides 

a listing at the same time. The 

Spectrum 'write character' 

routines are not terribly fast, 

so if the compiler listing is 

disabled then the compilation 

takes place in a short period of 

time and instantaneously for 

small programs. 

There are seven compiler 

options which determine 

whether or not certain checks 

will be incorporated into the 

machine code. They check 

such things as overflow in integer 

addition/subtraction, or 

checking if array references go 

out of bounds. The idea of 

these checks is to include 

them while testing and debugging 

and then remove them in 

the finished program. Some of 

the other options are used to 

control compiler listing or printing. 

Tape and I/O facilities are 

included for the program to 

store variables on tape and 

read them back in. It is nonstandard 

for Pascal but is very 

powerful as just one statement 

can write out or read in any 

variable from one character up 

to a very large array. 

The I/O ports used on the 

Spectrum can be read and 

written to by use of the INP 

function and the OUT procedure. 

A statement similar to INP, i 

(OUT(X,C) is used to output a I 

» 1983 ZX COMPUTING AUG.'SEPT 1983 71

character byte C to port X. 

Statements and functions 

are included to allow reading 

from and writing to RAM. 

Again non-standard for Pascal, 

these are taken from BASIC 

and are PEEK and POKE. Both 

are much more versatile than 

their BASIC equivalents as 

they can work with single 

characters up to entire arrays. 

For example, POKE (CAOOO, 

'DAVID BOLTON') will deposit 

12 characters in RAM from 

A000 onwards. 

As well as the statements 

described above, there are a 

couple of features which are 

useful for the machine code 

programmer. 

INLINE is a statement which 

permits machine code to be 

directly embedded into the 

Pascal program. It is followed 

by a list of decimal or hexadecimal 

integers which represent 

the machine code. 

USER is a function which is 

similar to BASIC'S USR, and 

permits calls to machine code 

routines external to the program. 

For example with the 

Spectrum, there are lot of 

useful ROM calls which can be 

incorporated into programs. 

Note that addresses can be 

also given in hexadecimal 

form; this is a more useful 

representation than decimal 

for integers, because any in 

teger higher than 32767 must 

be given in negative form. 

This is a very impressive 

product, and certainly one that 

could be of benefit to any 

Speciurm programmer once 

he/she has mastered BASIC 

and wants to advance. 

The compiler is fast at its 

job and produces very quick 

machine code, and together 

with the ability to have 

machine code incorporated in 

the program should mean that 

there are not tasks which are 

better done in assembler than 

Pacal. 

Naturally there are some 

negative aspects, nothing's 

perfect, but I consider them 

fairly minor. 

Apart from machine code 

speed, integer and real 

arithmetic, better data structuring, 

recursive procedures 

and functions, there is also for 

matted output where you can 

specify how numbers are written 

out, with rounding. 

For the price of £25 you get 

the complete compiler/editor 

and a 60 page reference 

manual. This is not a teaching 

manual, so if you are unfamiliar 

with Pascal I would recommend 

purchase of a good 

book. The manual mentions a 

few at the back. 

13 

Ah Diddums 

Molar Maul 

imagine Software 

Peter Shaw 

As I make no secret of the fact 

that Arcadia is my favourite 

game, I was naturally pleased 

to recieve Imagine's latest 

Spectrum offerings. Ah Diddums 

and Molar Maul. Both 

cassettes are very attractively 

presented in very imaginative 

(no pun intended) cassette 

covers, and both packages 

come with a lifetime 

guarantee, something which 

few other software houses of 

fer. Instructions supplied with 

the tapes give detailed instructions 

on loading and playing. 

I loaded Ah Diddums first, 

mainly because the cover ap 

pealed to me, plugged in my 

joystick and prepared to fight 

off the other toys in the 

toybox. Ah Diddums, as you 

will have probably guessed, is 

rather an original idea, concerning 

a tubby teddy and his mission 

to comfort the baby. 

What Teddy must do is take 

some toys to Baby so she will 

stop crying, but it's not as simple 

as that — you see this 

game has many sub plots going 

on. If Teddy comforts Baby 

then the mother will quite sensibly 

put the lights out. 'What 

is wrong with that?' I hear you 

cry. The trouble is that the 

toys in the toy box can only 

play with the light on, so they 

will do all they can to stop Teddy 

comforting the baby. 

Sounds confusing — well, 

there's more! Teddy is in a set 

of 99 nested toyboxes, and to 

escape from any one of them 

he must pile building bricks up 

in a certain order. Also in the 

toybox (well most of them, 

I've yet to get out of the first) 

is a Jack-in-the-Box. This 

bouncy little fellow takes the 

pressure oii any sticky situations 

you might have got 

yourself into. Amongst the 

toys you can pick up is a 

peashooter, which I'm still trying 

to work out what to do 

with. I tried shooting the 

soldier who was in the box 

with me, but all I ended up in 

doing was making it turn more 

vicious. 

Ah Diddums uses amazing 

high resolution graphics and 

sound. It even uses colour, 

something I dearly missed 

when they brought out 

Schizoids. Also Teddy has one 

amazing walk! I think this program 

has the edge over Arcadia, 

but 1 will not definitely 

give this the accolade of 'My 


favourite program' until I have 

mastered it. 

Moving rapidly on, I then 

loaded Molar Maul. The way 

the title page was built up was 

quite fantastic. 

I pressed a key and a large 

set of teeth were displayed on 

the screen — they then opened 

and the play area, the inside of 

someone's mouth is, if not 

very convincingly, displayed in 

full gruesome colour. The idea 

of the game is to fight of the 

dreaded 'DK's (de-cays — get 

it?) with your trusty 

toothbrush and supply of Imagico 

toothpaste. The game is 

very fast, and no matter how 

quickly you can brush one 

tooth, another is being attacked. 

The teeth are colour coded 

so you have an idea of how 

long they will probably survive. 

You have three toothbrushes 

per game, and you can 

easily lose these every four 

cavities you get. You are not 

helped by the sweets which 

appear on the tongue, the 

'DK's rush over and their 

power is increased. 

Altogether, I think Molar Maul 

is the most original, addictive 

game for the Spectrum I have 

played in a very long while. 

Both Ah Diddums and Molar 

Maul are available for £5.50 

from Imagine Software, 

Masons Buildings. Exchange 

Street East, Liverpool L2 3PN. 

Spectrum Golf 

R & R Software 

Darren Norbury 

Like many other people, I enjoy 

a game of golf. Unfortunately, 

the Briitsh climate doesn't 

always allow me to go and play 

a few holes anytime I want. I 

don't mind though. If rain 

prevents play then I can stay 

indoors and load Spectrum 

Golf from R & R Software into 

my Spectrum. 

Having played quite a few 

different types of computerised 

golf before, I was pleasantly 

surprised at how close this program 

came to the real game. 

It is a game for one or two 

people over a nine or 1 8 hole 

course. Each hole is of a completely 

random construction 

and can be either a par three, a 

par four or a par five, with hole 

lengths ranging from about 

1 60 yards to over 500 yards. 

Although each hole looks the 

same length as the last on the 

screen they are all on different 

scales. 

For each shot, the player is 

asked for the direction of the 

shot, and the strength of hit. 

Direction is based on the 

numbers on a clockface, 

assuming that the ball is the 

centre of the clockface. 

Strength is gauged simply on a 

scale of one to 1 00. 

Between the tee and the 

green of each hole are varying 

amounts of water, sand and 

rough for the unwary player to 

get trapped in as well as the 

major hazard — trees. Once 

you've landed in one of these 

uncompromising positions 

then life is made very difficult 

indeed. 

This is an outstanding 

simulation which should appeal 

especially to the new 

Spectrum owner. I hope that it 

is as appealing to non golfers 

as it is to me. 

My best score? Nine under 

par, but then there was a very 

helpful wind behind me! 

Spectrum Golf, priced at 

£4.95, is produced by R & R 

Software, 34 Bourton Road. 

Tuffley, Gloucester, GL4 OLE. 

3D Defender 

JK Creye 

Enterprises 

Geoff Cheshire 

At the time when the software 

market for the ZX 81 was really 

beginning to take off, one of 

the tapes which gained the 

most critical acclaim (and is 

still a best seller) was the 3-D 

Monster Maze from J.K Greye 

software. It may be a differeni 

company this year but the 

author is the same. Escape, 

from New Generation Software, 

is based upon the 

aforementioned Monster 

Maze, but this time the required 

hardware is a ZX Spectrum 

(16K). 

Once again, there is a 

monster involved; once again, 

the player is trying to escape 

from the monster; once again, 

there is just one way out. This, 

however, is where the similarity 

with the former game ends. 

When the tape has loaded 

the instructions appear on the 

screen along with a preliminary 

warning about the dangers 

which the player is about to 

face. The computer then asks 

you to select a level of difficulty 

from the scale one to five. 

Upon pressing a number the 

game starts. 

Lo and behold, you are 

presented with a slightly 

angular aerial view of the maze 

with a high resolution version 

of your good self in the bottom 

right-hand corner, raring to be 

manoeuvered away by the 

usual cursor direction keys. In 

the top left-hand corner is the 


! a 

ain, 

ape 

ain, 

his, 

lari- 

is. 

ded 

the 

lary 

jers 

: to 

isks 

culive. 

the 

are 

illy 

aze 

sion 

torn 

• be 

the 

. In 

the 

maze exit. All you've got to do 

is get from the bottom righthand 

corner to the top left. 

Simple, isn't it? 

You're right - it isn't that 

simple. To get out of the exit 

you need the axe which is hidden 

somewhere within the 

maze. And then, of course, 

there is the added danger of 

thetyrannosaurus rex who can 

be aided, according to whether 

or not you attempt difficulty 

levels two to five, by either 

one, two, three or four of his 

beastly companions who include 

a flying pterodactyl in 

their ugly band. 

This is not, as it may sound, 

a jump on the Pacman' bandwagon 

but rather an original 

and absorbing game which can 

become extremely difficult and 

frustrating. 

Escape, priced at £5.95, 

is available from New Genera 

tion Software, Freepost, 

Oldland Common, Bristol 

BS15 6BR. 

Spectres 

Bug Byte 

Steven Meldrum 

The latest offering from Bug 

Byte for the 1 6K or 48K Spectrum 

is Spectres. For the price 

of £8 I was certainly expecting 

an excellent copy of a "certain 

arcade game', and I am pleased 

to say that although it is 

slightly different to the arcade 

game, in my opinion it is betier! 

Before I tell you some of the 

details of the game. I would 

like to comment on the 

packaging, which is first class. 

A colourful artworked cover 

(obviously to attract prospective 

buyers) and detailed instructions 

which blend a 

storyline in with the objectives 

of the game. 

As the game is being loaded 

into your computer, a message 

appears in the 'PAPER' area of 

the screen telling you to wait. 

From then on, the game is run 

automatically and the Break 

key is disabled. 

The objective of the game is 

to help your little man, Eddie 

the electrician, re wire the 

mansion (the maze) by fitting 

light bulbs. There are, 

however, four Spectres in the 

maze which have to be avoid 

ed. Eddie is aided in his task by 

four light generators which 

change the hunters into the 

hunted. The duration of how 

long the generators are kept on 

for is determined by how much 

fuel Eddie has collected. 

Spectres is fast, colourful 


and very addictive. When I first 

received Spectres, I spent 

nearly six hours trying to clear 

the first maze! Each Spectre 

had a different colour, name 

and character. The graphics 

are outstanding and obviously 

a lot of thought has gone into 

deciding the shape of the 

Spectres. 

Sound is used effectively 

throughout the program, but 

due to the internal speaker inside 

the Spectrum it is difficult 

to hear. (I especially like the 

'sparking' noise when a Spectre 

is ignited.) 

After the first maze has 

been cleared, a totally different 

structured maze has then to be 

cleared with your score and 

men left carried over. 

Altogether there are three different 

mazes. 

However, I do have a few 

quibbles. First up, on my copy 

a bonus 'man' is awarded 

every 3,000 points and not 

every 2,000 points as stated 

on the inlay card. Also, when 

you reach a certain level (either 

9,000 or 12,000 - I can't 

remember which as my Spectrum 

is with Uncle Clive at the 

moment) you get a full set of 

'men' and from then on, Eddie 

is invincible. 

But even with these quibbles, 

Spectres will become a 

standard by which other 

similar games will be judged. 

Froggy 

DJL 

Nick Breeds 

After loading the game for 

about five minutes, the game 

auto runs and thank goodness, 

the Break key is disabled which 

means that there's no way 

you're Suddenly going to lose 

your best score ever just 

through a misplaced finger. 

The title page is very impressive 

with a frog bringing 

on the title of 'FROGGY ' in 

large letters. Four more screenfulls 

of instructions revealed 

the scoring mechanism and 

which controls to use. DJL 

chose my favourite — the cursor 

keys ('5', '6', '7' and '8'). 

On playing the game, a full 

screen greets you with a busy 

road, a river full of turtles, logs 

and crocodiles, and five homes. 

The game is great fun to play 

with bonuses for picking up 

baby frogs, for finishing quickly 

and so on. Each completed 

screen brings a new, much 

harder one. The graphics are 

superb and very smooth. 

WARNING! This game is 

very addictive and will keep you 

on the keyboard for literally 

hours. 

However this is hardly a 

fault and, all in all, the game is 

superb. Oh, by the way, the 

price of the package is £ 5.9 5. 

For further information on the 

cassettes reviewed in this article. 

you can write to the following 

addresses: 

Hi-Soft, 60 Hallam Moor, 

Lidon, Swindon, Wiltshire. 

Imagine Software, Masons 

Building, Exchange Street East, 

Liverpool, Merseyside L2 3PN. 

R&R Software, 34 Bourton 

Road, Gloucester GL4 OLE. 

New Generation Software, 

Freepost, Oldland Common, 

Bristol BS1 5 6BR 

Bug Byte, 98-100 The Albany, 

Old Hall, Liverpool. 

DJL, 9 Tweed Close, Swindon, 

Wilts SN2 3PU. 

The authors of any of the 

reviews published within this 

section of the magazine will 

receive payment equal to the 

amount spent on the software 

reviewed unless another 

financial arrangement has 

already been settled on. All 

contributions should be typed, 

double spaced, and be accom 

panied with screen dumps 

where possible. Your reviews 

should be sent to the following 

address: 

Reader's reviews, 



London WC2H0EE. 


This program is designed for 

anyone who doesn't own the 

board game, but would like to 

play a game of Reversi with 

someone other than the computer. 

First up, you should type in 

the program shown in Listing 1. 

Once this is done, you should 

type, in the immediate mode: 

POKE 16403.20 

to get rid of line 1, so that the 

program won't crash. Now RUN 

the program and input the 

numbers on the right-hand side 

of Listing 2, treating each 

comma as an instruction to 

press Newline. After you have 

finished typing in the data, go in 

to immediate mode and type 

PRINT B. If the answer is 

'7026', the program should be 

OK and you should SAVE what 

you have so far achieved. 

Going over board 

From now on, do not try to LIST 

without a line number, RUN, or 

press Home or Clear, as you will 

lose the program. Now type in 

the BASIC part of the program 

as shown in Listing 3. 

To save memory space, all 

the variables used in the program 

must be assigned in immediate 

mode; this will also 

enable us to find the start of the 

screen address in the very beginning 

of the program. The value 

and name of each variable is 

shown in Table 1. 

To RUN the program, simply 

type GOTO 10 and you'll see a 

board similar to that shown in 

983 

Fig. 1. A graphic 

illustration of 

what you should 

see on the 

screen. X 0 2 >0 2 0 

Program description 

Lines Description 

10 

Activates the machine code program. 

20-30 

Assign the number of pieces each player has when 

the game starts. 

35 

The finding of the starting address of the display 

file. 

40 

50-51 

POKEs the number of pieces each player has. 

POKE the arrow head on the screen indicating 

whose turn it is. 

52 

INPUTs the move. 

53 

Checks to see if a player wants to give up their 

turn. 

55 

Initializes the sub-total of the move. 

60 

Finds out the address of the player's choice. 

70 

Checks to see if that address is being occupied by 

other pieces. 

90-180 The checking routine for finding whether the move 

is legal. 

190 

If the sub-total of that move is zero then the player 

200 

must input another move. 

Changes to another player's turn. 

210 

POKEs the number of pieces each player has on 

the screen and waits for another move. 

1000-1080- The flipping routine to find out the number of 

pieces flipped in that direction. 

1090 1 100- 

Reads the number of pieces each player has. 

1110 Goes back to check another direction. 

2000-2030 — POKE the number of pieces on the screen. 

2035 Checks to see if the board is full. 

Fig. 1. Notice the arrow head indicating 

which player is next to 

play and the number of pieces 

each player has placed on the 

screen. 

in the move 

To move, you type in the coordinates 

as a single number; 

for example, if you wanted to 

place one of your pieces in the 

bottom right-hand corner, you 

would type in ' 1 8'. If the move 

is illegal, the arrow head will 

stay pointing to the player who 

made the illegal move and wait 

for a legal instruction. Once a 

legal move has been made, the 

arrow head will move to point at 

the other player's score. 

If you cannot move, you 

should input '99' and the computer 

will automatically go to 

the next player's move. After 

each move, the number of 

pieces each player has placed 

will be re-adjusted and printed 

on the board. 

The game will stop 

automatically when the board 

is full, but if neither player can 

move at any stage of the game 

you can type in a letter and stop 

the game. 

1 REM (112 As) 

10 LET B = O 

20 FOR A - 1 6427 

16538 

30 INPUT C 

40 POKE A,C 

50 PRINT A,C, 

60 LETB-B + C 

70 NEXT A 

listing 1. The BASIC program to 

enter the machine code. 

TO 1 


TO 

to 

Address Statement Code 

16427 LD HLI16396) 42,1 2,64, 

16430 INC HL 35, 

16431 LD D,H 84, 

16432 LD E,L 93, 

16433 LD A,28 62,28, 

16435 LD 8,9 6,9, 

16437 LD(HL),0 54,0, 

16439 INC HL 35, 

16440 PUSH BC 197, 

16441 LD B,8 6.8. 

16443 LD(HL), 1 9 54,19, 

16445 INC HL 35, 

16446 DJNZ E(41) 16,251, 

16448 LD(DE),A 18, 

16449 LD(HL),A 119, 

16450 INC DE 19, 

16451 INC HL 35, 

16452 INC A 60, 

16453 LD(HL), 117 54,1 17, 

16455 INC(HL) 52, 

16456 INC HL 35, 

16457 POP BC 193, 

16458 DJNZ E(37) 16.233, 

16460 LD B,2 6,2, 

16462 PUSH BC 197, 

16463 LD B, 1 0 6.10, 

16465 LD(HL),0 54,0, 

16467 INC HL 35, 

16468 DJNZ E(63) 16,251, 

16470 LD(HL), 1 1 7 54,1 17, 

16472 INC (HL) 52, 

16473 INC HL 35. 

16474 POP BC 193, 

16475 DJNZ E(60) 16,241, 

16477 LDU 6398),HL 34,14,64, 

16480 LDO 6400),HL 34,16,64, 

16483 LD A, 12 62,12, 

16485 LD(16421 ),A 50.37,64, 

16488 LD DE, 16515 17.131,64, 

16491 LD B,8 6,8, 

16493 LD HL,(1 6396) 42,12.64, 

16496 PUSH BC 197, 

16497 LD( 1 6503),DE 237,83,1 19,64, 

16501 LD BC, 1 237,75,152,64, 

16505 ADD HL.8C 9, 

16506 INC DE 19, 

16507 INC DE 19, 

16508 LD A,(DE) 26, 

16509 LD(HL),A 119, 

16510 INC DE 19, 

16511 POP BC 193, 

16512 DJNZ E(16493) 16,235, 

16514 RET 201, 

16515 1. 

16516 0, 

16517 0. 

16518 10, 

16519 0, 

16520 0, 

16521 49, 

16522 0, 

16523 61. 

16524 50, 

16525 0, 

16526 52. 

16527 60, 

16528 0, 

16529 52, 

16530 61, 

16531 0, 

16532 61, 

16533 111, 

16534 0, 

16535 6 1 • Listing 2. 

16536 120, The machine 

16537 0, coda part of the 

16538 52, Re versi program. 


10 RANDOMISE USRI1 6427) 

20 LET F(0) = 2 

30 LET F(1) = 2 

35 LET M = PEEK! 16396)+ PEEK( 16397)* 256 

40 GO SUB 2000 

50 POKE M + 1 14-3*(C = 1),23-(C = 0) 

51 POKE M+114-3*(C = 0),0 

52 INPUT X 

53 IF X = 99 THEN GO TO 200 

55 LET ST = 0 

60 LET P = (X * (X/10) * 1 0) * 1 1 +1 + X/10 

70 IF NOT PEEK(M + P) = 19 THEN GOTO 52 

90 FOR X = 1 TO 8 

92 LET X1 = P 

95 LET T = O 

100 LET X1 = X1 + D(X) 

110 IF NOT PEEK(M + X1) = A( - (C - 1)) THEN GO TO 120 

112 LET T = T + 1 

114 GO TO 100 

1 20 IF PEEKIM + X1) = A(C) THEN GO TO 1000 

180 NEXT X 

190 IF ST = 0 THEN GO TO 52 

200 LET C = - (C - 1) 

210 GO TO 40 

1000 IF T = 0 THEN GO TO 180 

1005 LET X1 = P 

1010 POKE M + X1,A(C) 

1020 IF ST >0 THEN GOTO 1030 

1025 LET F(C) = F(C) + 1 

1030 FOR A = 1 TO T 

1060 LET X1 = X1 + DIX) 

1070 POKE M + X1,A(C) 

1080 NEXT A 

1090 LET F{C) = F(C) + T 

1100 LET F{ - (C - 1)) = F( - (C - 1)) - T 

1105 LET ST = ST + T 

1110 GO TO 180 

2000 FOR A = 0 TO 1 

2005 POKE M + 1 12 +

983 

ZX81 DOMESTIC 

Having difficulty 

getting your 

fingers around 

those tricky 

guitar chords! 

Bring your ZX81 

into play with this 

program from 

C A Read of Swansea 

Striking 

right 

When RUN, this program draws 

a simulation of a guitar neck and 

asks the user to input a number 

corresponding to the particular 

chord you wish to see on the 

screen. 

Getting in tune... 

The program asks the user to 

input a number one to ten and 

then the chord corresponding to 

the number will be displayed 

with the relevant finger positions. 

The chord name is 

displayed in a box beside the 

diagram and the program then 

waits for a further input. 

You could add two more 

chords to the published program 

by changing line 82 to read: 

82 IF C 12 THEN 

GOTO 80 

and enter the co-ordinates for 

the new chords in the 

subroutines at lines 5500 and 

6000. Then, you would have to 

alter the menu in line 7065. The 

chords included in the program 

as it stands are C, D, E, F, G, A, 

Dm, Em, Am and G7. 

Now if only someone could 

write a program to tune the 

guitar. . . 


ll REM ITOg.gggg? 

PO LET X=15 

30 LET Y=17 

40 GOSUB 7000 

SO INPUT C 

ft! then GOTO 

85 bOSUB 7008 

90 GOSUB 

iOO PRINT AT « #B;"0" 

HO PRINT RT C , D; " Q *• 

120 PRINT RT E.F;"O" 

130 GOTO 30 

4-90 REM C CHORD 

SO0 LET R=4 

510 LET B = 10 

520 LET C 

530 LET D =6 

540 LET E = 10 

550 LET F =4 

550 PRINT RT 

570 RETURN 

990 REH D CHORD 

100O LET R = 7 

1010 LET B=B 

1020 LET C = 10 

103O LET D = 10 

1040 LET E=7 

1050 LET F = 12 

1060 PRINT RT 

1070 RETURN 

1&00 REH E CHORD 

1510 LET Ps7 

1520 LET B=4- 

1530 LET C =7 

154.0 LET D =6 

1550 LET E =J- 

1560 LET F=8 

X,Y;"C" 

X, Y;"D" 

1570 PRINT RT X,Yj'*E" 

1530 RETURN 

5000 REH F CHORD 

2010 LET R = 10 

2020 LET 8=6 

2030 LET C =7 

204.0 LET D = S 

2050 LET E=4 

2060 LET F = 10 

2070 PRINT RT 4,12;"O" 

20Q0 PRINT RT X,Y;"F" 

2090 RETURN 

2500 REM G CHORD 

2510 LET R = 10 

2520 LET B=2 

2530 LET C =7 

2540 LET D =4- 

2550 LET E = 10 

2560 LET F = 12 

2570 PRINT RT X,Y;*'G" 

2580 RETURN 

3000 REM R CHORD 

3010 LET R=7 

3020 LET B =6 

3030 LET C=7 

3040 LET D=8 

3050 LET E = 7 

3060 LET F = 10 

3070 PRINT RT X,Y;*'R" 

3080 RETURN 

3500 REM DM CHORD 

3510 LET R = 7 

3520* LET B = 8 

3530 LET C = 10 

3540 LET D=10 

3550 LET E =4. 

3560 LET F=12 

3570 PRINT RT X,Y;"OM" 

3580 RETURN 

4000 REM EM UHORD 

4010 LET R=7 

4O20 LET B =4- 

4O30 LET C =7 

4040 LET D =6 

4050 LET Es7 

4060 LET F =6 

ZX COMPUTING AUG.SEPT 1983 

2X81 DOMESTIC 

4070 PRINT RT X(Y;"EM" 

4080 RETURN 

4500 REH RH CHORD 

4.510 LET R=7 

4&20 LET S=S 

4530 LET C=7 

454-0 LET D=S 

4550. LET E =4 

4560 LET F = 10 

4570 PRINT RT X,Y;"fiM" 

4580 RETURN ' 

5000 REM G7 CHORD 

5010 LET R = 10 

5020 LET B =2 

5030 LET C =7 

5040 LET D =4 

5O50 LET E =4 

5060 LET F = 12 

5070 PRINT RT X^Y^'CT" 

5080 RETURN ' 

FINDER?" NT fiT *'®'"GUITRR CHORD 

7010 

7015 

702© 

7030 

7040 

7050 

7060 

PRINT 

PRINT " E R D G B E" 

FOR T = 

'TtTTTl 

1 

PRINT 

ORTNT 

PRINT 

NEXT T 

^ S P R ^ T B T S i e ^ C - . . l - ^ - D - 

-?I®NUM8^.^T "INPUT CHORD 

7080^ I" PRINT RT 1 4 , 1 6 ; "J 

/ t 

7090 RETURN

78 

SPECTRUM CAME 

Can you defend 

the Earth from the 

invading aliens in 

this game written 

for us by Andrew 

Cole of Burnley? 

~ r ^ 

- • y*\ ' i \ r 

- 

- * * ^ f 'i 

4 

-1 g - 

& - . 

V S ^ «r* 

, . - ' 

v 

, y 

In this game for your 16K 

Spectrum, you command a 

missile base which you can 

manoeuver along the surface of 

the Earth, using the 'p' key to 

move right and the 'o' key to 

move left. To fire a missile you 

have to press the 'q' key. 

The aliens, in their usual 

unfriendly way, re-energise at 

different levels above the Earth 

one at a time. It is your job to 

shoot them out of the sky before 

they get enough ships out of 

hyperspace to destroy the 

Earth. Once they have 1 0 ships 

positioned over the surface, 

they will be in a position to do 

this. So, your mission, should 

you choose to accept it, is to 

keep the number of aliens in the 

sky down to less than 10. 

You can only fire one missile 

at a time on-screen, but if you 

find it too difficult to play at one 

level, you can always choose 

another — there are five skill 

levels in all. 

: v 5* ^ w \ 

* * ^ 11 * 

- \ 

' r r - 

- 5 

i \ < 

> % 

/ \ ** 

ZX COMPUTING AUG. SEPT 1983 

&! 

[U 

* 

!

1 

% 

i i 

% % 

* % % 

ll!» GC- SUE'- 1 0 0 0 

C-C S U B 

3C R E M s c r e e n s e t u p 

33 B O R D E R 0 

4 0 O 5 ; P R I N T P T 2 0 , 2 ; P P P E R 

1% 

4 5 P R I N T P T 0 1 , 0 , P P P E R 4 - , " 

i • 

= 1 T O £ 3 

_ _ C'LO" R N D R N D # 1 2 O + 4.0 

7 P N E X T 5 

6 0 L E T f I - 3 ; L E T I - I S 

9 0 L E T Z = 3 : L E T h : t £ = D 

11C 

R E H 

P p K l 

• ".; TT T t 

* — C- er jr t* . i- js 

t — - _ r, i: i. L' r c 

> = ?;£. - ; e 4 T H E N P R I N T 

' ~ £ S»D + 1 

, R N D I N K 2 j " H L E 

1 4 0 I r z = 1 0 T H E N GO T O 4 3 0 

1 5 0 P R I N T P - , 2 J ; z 

1 6 0 I F t > = 6 0 - 15 *-6.. THEN- P O K E 2 , 

> r'i . 0 

2 0 0 p e n l a s e r 

Si".) " > 

l = l + t I N K E Y $ = - p - (IN.KE-: 

2 1 ® L E T L = L t i' i =0.'t - i. =3i3.> 

2 2 0 PRINT P,T 1 9 , 1 ; " L ": FHUSE 

4 330 IF INKEYJ="q" THEN GO TO 

£ 

IF INKEY*,

'Mastering Machin 

On Your Z*81'| 

through the 

of a great racing car 

program. 

In this article I would like to 

concentrate on the very basic 

question of how to write a pro* 

gram. That is, given an idea, 

how do we change that idea into 

byte by byte reality? There's 

no real algorithm for it — it's 

an intuitive process. If there 

was an algorithm for it then we 

could write a computer program 

to do it for us. Imagine 

how great that would be. We 

could feed in the information 

"CHESS: Board Game, 8x8; 

starting position; rules" and 

the program would output a 

chess program for us! No such 

luck in real life. Writing programs 

is an abstract, not a 

logical process — lateral rather 

than linear. 

Lateral thinking is a skill 

which all of us, as human beings, 

posess. Lateral thinking 

is different from linear thinking. 

In linear thinking, one idea 

leads to another, which leads 

to another, which leads to 

another, until eventually you 

reach a conclusion. Computer 

MACHINE CODE 

programs can be written to 

follow this kind of thinking, 

and those which do may be 

defined as 'intelligent'; 

however, nobody yet has 

devised a program which uses 

lateral logic — this is when you 

abandon one train of thought 

and decide to try a different 

approach. This new train of 

thought comes into your head 

spontaneously and you cannot 

pinpoint exactly where the 

idea came from. Artists and 

songwriters create their works 

in their heads almost entirely 

by lateral thinking (well, the 

best of them anyway) and this 

process they will describe as 

'inspiration' or 'intuition'. Intuition 

then, is the basic ingredient 

in the writing of a 

sucessful computer program 

from scratch. 

Thanks for the 

memory 

Memory (human memory, not 

80 ZX COMPUTING AUG. SEPT 1983

On display 

MACHINE CODE 

Answers, answers 

computer memory) is another 

Notice the special bytes 

basic ingredient. This is known 

in the strings. Byte 11 means 

in the trade as 'experience'. 

The 'format' of the screen 

'PAPER', and so the two bytes 

The solution is that we can 

Experience, however, is not 

display is something else 

1 106 together means PAPER 

resort to an alogorithm-type 

paramount (for if it was then 

which improves with ex- 

6. Similarly the byte 1 6 means 

approach just a little here. The 

the first ever program wouldn't perience. The intricacy of the 

'AT', and so the bytes 

first step in almost any video 

have been written). Experience picture — the 'flowerification' 

16050A together mean AT 

game is called initialisation, 

can be replaced by immediate as someone I know would say. 

5,10. Comma separators may 

and this usually consists of 

access to knowledge in other A beginner would use screen 

be replaced by the byte 06, 

two parts: (i) initialising any 

forms. An experienced pro- displays constructed out of 

and apostrophe separators by 

variables needed; and (ii) ingrammer 

may know instinc- Characters from the Spectrum 

OD. All of these are listed in 

tialising the image on the 

tively that the Hex 09 means character set, then as you ad- 

Appendix A of the Spectrum 

screen. We can't really think 

ADD HL, BC and that to vance you will find yourself us- 

manual. A third string is also 

about variables just yet 

LPRINT a character all you ing user-defined graphics (up 

needed for the FOR. . . NEXT 

because we don't know what 

have to do is set bit one of to 21) and then even more 

loop. See if you can work out 

we're going to need — so to 

FLAGS and then use RST 10, user-defined graphics (any 

what it translates to in Hex. 

the screen. 

whereas everyone else will unlimited number), and finally 

(Warning: TAB x translates to 

Here we rely on intuition 

need to look these things up. ) dispense with the graphics 

1 7xx00, not to 1 7xx as you'd 

and artistic ability. We have 

must stress that this is not a altogether and just POKE into 

expectl) The text needed is as 

total control over what we 

handicap as long as you do the memory to obtain the 

in line 30. 

want the image to look like, 

have the information (usually ultimate in high resoluteness. remember, and so we need im- In the machine code version, 

in book form) immediately to Let's program then. First agination to decide on how we the first string should end in 

hand. Experienced people may the idea, then the solution. The want it. My suggested pro- PAPER white, which was not 

write better (and by that I idea is a racing car program. cess, written first in BASIC, is necessary in the BASIC 

mean more sophisticated) pro- It's not an original idea — I shown in Fig. 1. 

version. 

grams than beginners, but this stole it from a video game I If you feed in this pro- 

is only because they have im- once saw. (It's not illegal to gram you should see a yellow 

mediate access to more 

Last stage 

steal the idea for a video game information window (yes. 

sophisticated blocks of 

knowledge — "Oh yes, I know 10 PRINT PAPER 6;"Time four spaces Distance four 

And so to business. To print 

Ihe best way to scroll the 

spaces Distance twelve spaces to go (H) three spaces 

one of these strings the 

screen sideways two squares 

to go (C) three spaces" ,," = = = = = = = = = = = = = 

procedure is as follows: load 

m __ _m rt 

BC with the length of the 

with a double somersault in 

between because I did it last 20 FOR i- 1 TO 1 7 ' 

string, and DE with the 

Thursday for the program to 30 PRINT TAB 7;"graphic shift 8" ;TAB 24graphic shift address of the first byte, and 

then CALL 103C. Thus, the 

make toasted cheese sand- 

8" 

wiches out of five unknown 40 NEXT I 

BASIC may be replaced 

variables". I wouldn't worry 50 PRINT AT 5,1 0; INK 1graphic shift 1 graphic shift 2 

entirely by the code in Fig. 2. 

too much about it. That routine inverse C graphic shift 1 graphic shift 2 two spaces"; 

The initialisation of the screen 

may be to hand now, but even 

INK 2;"graphic shift 1 graphic shift 2 inverse H 

complete, the next stage is to 

the experienced had to write it 

graphic shift 1 graphic shift 2" 

look closely at the rest of the 

game. This is actually easier 

for the first time once, and 

fig. 1. 

than it sounds. Given that 

believe me it took them a very 

as long as you write the actual that's what it's called!) above there is a subroutine in the 

long time (not to mention 

program yourself from the start of a racetrack on ROM which will scroll all but 

hours of lost sleep) to get it 

scratch.) The game plays as which are drawn a blue the top five inches of screen 

working. 

follows: given a steering wheel human's car and a red com- upwards, see if you can figure 

The sophistication of the (or in this case two buttons) puter's car. 

out for yourself how the rest of 

1 program then, is what is deter- and an accelerator to control To turn this part into the program will work. This is 

mined by experience. The your speed, you must perform machine code is very simple. where I effectively test your in- 

beginner should not attempt to one lap of a specific race We need two strings as data: tuition and lateral thinking 

write a chess program. The ex* track faster than your oppo- one for the string in line 10, ability. I'm not simply going to 

perienced programmer would nent (the computer). Your op- and one for the string in line leave it at that, of course, but I 

laugh at the idea of writing ponent is a perfect driver and 50. So in other words, one am going to wait until the next 

anything as trivial as a program will never crash, however, this way to start the program could article before I carry on. In the 

w to turn the screen blue. You is only because they maintain a be: 

meantime I would like you to 

must compromise the kind of constant and fairly medium 

stretch your brains a bit trying 

program you want to write speed. You on the other hand 

to decide for yourself more or 

with what you know you can must compromise between 

less what answer I'm eventual- 

achieve. Every program you travelling slowly but safely 

ly going to come up with. 

write should fall somewhere (and losing the race) or going 

(Good game this, isn't it?) I will 

between the limits 'simple' for speed in order to win 

complete this program next 

and 'very hard'. These words (whilst trying not to crash). 

issue. Till then, keep up the 

3 obviously mean different 

good work. 

Now here's where intui- 

things to different people, so 

ly 

tion/experience bit comes in . 

judge by the following conven- 

ie 

I, as an experienced so and so, 

tion: a 'simple' program is one 

01???? LD BC, length of string one. 

is 

happen to know offhand that 

that takes you less than two 

11???? LD DE, address of string one. 

is 

there is a subroutine in the 

days to complete, and a 'very 

CD3C20 CALL PR STRING 

7- 

ROM which will scroll part of 

hard' program is one that takes 

061 1 LD B, 1 7d 

e- the screen upwards, but that 

you over a month. Programs 

C5 LOOP PUSH BC 

a 

there is not a subroutine in the 

which you think are going to 

01???? LD BC,length of string three. 

m 

ROM which will scroll part of 

take you much much longer 

11???? LD DE,address of string three. 

the screen downwards. 

than even that fall into the 


Because I can't be bothered to 

category 'impossible' and 

CI POP BC 

write one I conclude that it 

should not be attempted, as 

10F3 DJNZLOOP 

would be easier to have the car 

they usually result merely in 

01???? LD BC,length of string two. 

at the top of the screen with 

the breaking of a few items of 

11???? LD DE, length of string two. 

the road scrolling upwards 

n 

furniture. 


ot 

toward the car. 

Fig 2 


Naught but 

a game! 

The classic game of 

Naughts and Crosses for 

your ZX81, courtesy of 

SP Stratford of Hemel 

Hempstead. 

This program has the ZX81 

playing a pretty mean game of 

Naughts and Crosses against a 

willing opponent. The program 

requires about 7K of RAM to 

operate. 

In this game you are the 

'naughts' and the computer is 

the 'crosses'. The program is 

divided into several parts: 

DRAWC — Draws the computer's piece. 

DRAWP — Draws the player's piece. 

WIN — Checks to see if someone has won or if it 

is a draw. 

COMP — The computer's move. 

PLAYER 

CLEAR 

GRID 

— The player's move. 

— Clears the player's prompts. 

— Prints the playing grid. o 

Each part of the program is 

called by the GOSUB com- 

mand, for example GOSUB 

COMP is the subroutine for 

the computer's moves. 

Three in a row 

The following is a brief guide to 

some of the more important 

lines in the program: 

5005-5020 Find if one of the players has a row of three 

counters. 

5200 The player gets two points for each win. 

5320 The ZX81 gets five points for each win. 

6005-6008 Work out the average value of RND. 

8002 Ensures the print position is in the top lefthand 

corner. 

8200-8210 Make sure that the scores do not run onto 

the board. 

82 


1 S f l ' J E " O " 

a 5 L O U 

3 REM * 7K 

R . R . M . R T L E R 5 - 

4- R R N D Q _ 

5 P R I N T T H B 9 j " N O U G H T S " ; R T 

1 1 , " R N D " ; A T 4 , 9 ; " C R O S S E S " 

'5 PRINT AT S,S; ••Haa"; RT 7,2,' 

B B" ; TRB -a.; "THIS 15 YOUR PIECE"; 

S T S . 2 : 1' r»T»I«] •' 

7 P R I N T R T 1 1 , 2 ; " B " ; T R B 4 ; " P " 

, T H E 3 . " S I " ; T R B " T H I S I S T H E Z X 

- S I p I E C E " , T h B 2 ; " H ET" 

0 B P R I N T R T 2 1 , 2 : " ( C ) S . P . S T R P 

T j r t P : ^ 

I : • t_' I 

I 

•=. 

. -* -1 

J. J. , 

. ' • 

3 P R I N T h T 

U L I N E T O 5 T T 3 R T 

" R T 1 5 , 0 ; " i 

• R E 5 S N E U L I N E T O S T R R T * J I I " 

I F C O D E X N K E Y $ < > I I S T H E N G O 

T O 

1 5 

1 9 

20 

21 

2 2 

2 3 

»— 

£ 5 

2 6 

3 0 

1 ; 

4-0 

5 0 

S O 

9 0 

100 

1 0 5 

n o 

L I S 

120 

1 3 0 

14-0 

9 9 9 

1000 

1001 

L010 

Y p 1 + 1 

1 ; R T 

1 0 3 0 

1 4 9 9 

1 S 0 \ 

1 5 1 0 

1 5 2 0 

G O S U B 9 0 0 0 

C L S 

L E T G O E S = 0 

F O P U = 1 T O 3 

F O R P = 1 T O 3 

L E T R F P , U I 

N E X T P 

N E X T U 

G O S U B G R I D 

P R I N T R T 1 1 , 1 ; 

' U I S H 

1 A 3 

" D O 

T O " I R T 1 3 / 1 ; 

Y O R N 

L E T P $ = I N K E Y $ 

I F R $ = " N " T H E N G O T O : 

I F R $ < > " Y " T H E N G O T O 

G C S U E P L R Y E R 

GOSUB UIN 

G O S U B D R R U P 

G O S U B C O M P 

L E T G O E S = G O E S + 1 

G O S U B U I N * 

G O S U B D R R U C - 

G O T O 9 0 

R E M AGG 

R E M 

R E M 

L E T !_!$ — ' 

2, 

Y O U " ; R T I 

' G O F I R S T ? 

.10 

4-0 

P R I N T R T Y P 1 - 1 . X P L - L J U $ ; R T 

X P 1 - 1 ; U $ ; R T Y P 1 , X P 1 - 1 , U $ ( 1 

Y P 1 , X P I + 1 ; U $ I 1 ) 

R E T U R N 

R E M 

REM 

K'trH 

L E T * 

P R I N T R T Y C 1 - 1 , X C 1 - 1 ; U $ ; R T 

Y C 1 - 1 . X C 1 + 1 ; U $ ; R T 

Y C L T L . X C 1 - 1 : U $ ; R T 

1 5 3 0 R E T U R N 

JMUBBM 

1 9 9 9 R E M 

2 0 0 0 R E M V « 

2 0 0 1 R E M W 

2 0 0 5 L E T U $ = " 

2 O 4 . 0 

Y C 1 , X C 1 ; U * ; R T 

Y C 1 + 1 , X C L + L J U $ 

2010 F O 

2020 I F 

U $ F T O 

R Z = 1 0 

Z C = 1 5 

11) 

T O 

T H E 

2 

N P R I N T R T Z , 0 ; 

2 0 3 G :F Z > 1 5 T H E N P R I N T R T Z , 0 , U 

N E X T Z 

R E T U R N 

2 9 9 9 R E M ASMSBM 

3 0 0 0 R E M 

3 3 3 1 R E M 

3 3 1 0 G O S U B C L E A R 

3 0 2 0 P R I N T R T 1 1 , 1 ; " T O " ; R T 1 2 . 

1 ; " U H E R E " ; R T 1 4 , 3 ; " ? " 

3 O 4 - 0 L E T R $ = I N K E Y $ 

3 3 5 © I F R $ < " 1 " O R R ? > " 3 " T H E N GU 

TO 

3 G 6 3 L E T X P = U R L R $ 

3 0 7 0 P R I N T R T 14- , 3 ; X P ; R T 1 6 , 2 ; "FL 

N D " ; R T 1 8 . 3 ; " - 7 " 

3 0 S O L E T R $ = I N K E Y $ 

3 0 9 0 I F P $ < " 1 " O R R $ > " 3 " T H E N G O 

I O 3 0 S 0 


310O 

3110 

3115 

10 

3120 

3130 

3i5e 

3160 

3170 

3 150 

3190 

3200 

1999 

5000 

5001 

5005 

sei0 

5S50 

51 

L E T V P = U H L R $ 

PR I N T RT 13,3.. V P 

IF R tXP/YP) 0 T H E N G O T O 3i 

IF XP = i THFN LcT 

IF XP=2 TMfN L?T 

IF Xp=3 THEN LET 

IF VP = 1 THEN LET 

IF VP = 2 THEN L ET 

IF VP=3 THEN I FT 

G05UB DRflUP 

LET flfXP.YP)=1 

RETURN 

REM ' 

REM 

KtSXtftStft'tf^ 

M 

NEXT Z 

L E T C O M P U =COHPiJ -r 1 

"O 3 

• ^ « 

l_l o 

, O) = 0 

* P 1 = I 4- 

VP 1sj9 

XP 1 =24. 

VP 1 = 3 

VP 1 =3 

VP1=13 

53S6 L E T H U M R N -HC :MRN -r 1 

5050 305US C L E R R 

5070 P R I N T RT 1 3 i 2 ; " P O E 5 5 : 

C0NT INUE , " j RT £0 , 7 ; "SPACE 

STOP . " 

5050 IF T H K E v t o ' T . " THEN G 

80 

5090 

5100 

5101 

5102 

510 3 

5104- 

511CI 

5200 

^205 

5210 

INT 5, 

BT 

522© 

5230 

5300 

5310 

5320 

TS . " 

5330 

5340 

5350 

6000 

6001 

6005 

6006 

6007 

6803 

6010 

6020 

5030 

5040 

5053 

5060 

6065 

5070 

6050 

&Q90 

610Q 

C L S 

FOR 0=1 

FOR G = 1 

LET RiG 

NEXT G 

NEXT O 

GOTO 20 

LET HUMAN=HUMflN+2 

FOP Z = 1 TO 100 

PRINT RT 19,5, 'VOu 

",RT 19,5;"tf 

NEXT Z 

GO SUB CLizRR 

GOTO 5070 

LET COMPU =COMPU +5 

FOR Z=1 TO 100 

W IN 

S I ! 3JXI3 

P O 

J - f P C T N T . 

P R I N T AT 19,6;"I UIN 

RT 19.6, 

NEXT Z 

GOSUB CLEAR 

GOTO 5070 

rttH 

FOR B = 1 TO 11 

LET WHERE=UHERE+RND 

NEXT B 

L E T U H E R E = U H E R E - 1 1 

I r l.iHERr < = . t. T H E N CO 

FOR T = 1 TO 3 

FOR U = 1 TO 

IF R(U.T>=0 

NEXT U 

NEXT T 

GOTu 70 00 

RETURN 

IF U = 1 THEN 

IF U =2 THEN 

I F =3 THEN 


BRR TO 

OT O 50 

5 PO I N 

5 P O I N T © 

0 0 

THEN GOTO 6030 

LET 

LET 

LET 

< C 1 = 1 4 

X C 1 = 1 9 

X C I = 2 4 

& 1 10 

6 I S O 

£ 133 

6 135 

e 1 4 0 

6 150 

6 1 5 0 

7 0 0 0 

7 0 0 1 

7 G 

70 13 

7 0 2 0 

VC > 3 

70:30 

0 

a 

« a iT. 

V.' 

IE T = 1 THEN LET YC1=3 

IF T =2 THEN LET YC1=S 

IF T=3 THEN LET V CI=13 

IF fi(U.T)O THEN GOTO 5000 

LET R

GC5U3 DRRUC 

RETURN 

FOR T = 1 TO 3 

FOR U=1 TO 3 

LET XC = INT (RND*3) +1 

LET VC = INT i RND> +1 

IF XC =3 OR XC >3 OR VC=0 OR 

T H E N GOTO 7000 

IF R(XC .VC) = 0 THEN GOTO 505 

R E H •. v" • v 

7 0 3 9 NEXT U 

FOR KJ = i TO 2 

7040 NEXT T 

i f 9 THEN RET EN 

m 

, 1 • 5 Ti 

5025 FOR Z = 1 TO 100 

g£ 

5030 PRINT R 19,2 "IT I 

.UE BOTH GET ; RT 20 ,9. ''1 

•BO 0 P S T! 

•sac 

504.0 PRINT RT 

hdi fd 

-* 

REM ^ 

K t. M 

PR INT RT 0.0; 

PRINT " 

ZX -51 

w ' 

Y O U 

0 PR T! 

—, R : i 

c-17 t PR ± fN i 

VII li "^ V' i'J 

8200 LET Ml=7-fLEN (STR$ COHPW)) 

3210 LET H2 =7- i LEN t 5TR$ HUMAN) > 

3220 PRINT RT 3.H1,COMPU;RT 7,H2 

;HUMAN 

324-0 RETURN 

3999 REM 

9O00 REM 

^001 REM 

9 0 1 0 D I M ^ < 3 , 3 ) 

5020 FOR T = 1 TO 3 

9030 FOR Z=1 TO 3 

9O4-0 LtT R ( Z , T ) =0 

9050 NEXT Z 

9Q60 NEXT T 

X N T T Z R L 1 5 

9O70 LET DRRUC=1500 

9080 LET DRAUP=1000 

9 0 9 0 LET UIN =500C5 

9 100 LET COMP=5000 

91 10 LET PLRYER =3000 

9120 LET CLERR =2000 

9 13 0 LET GRID=3000 

9 14-0 LET HUMRN=0 

9 15 O = T COMPU=0 

:3 •* ~ .r, L.ET G O E S 

9170 LET UHERE =0 

9210 RETURN 

ZX COMPUTING AUG/SEPT 1983 83 

K 

rtis

1983 

£39.95 

(inc. VAT) 

+ 80p P&P 

THE NEW FDS for the SPECTRUM, 

ZX81, LAZER 200, JUPITER ACE, 

and the ORIC as illustrated 

This elegant desk top system, designed tor the 

professional user. In its slimline case, the 

superior keyboard contains all the graphic 

characters for the above computers. With the 

additional function keys and SPACE BAR, 

speedy and accurate data entry is made simple. 

The Fuller FDS is easy to install, based on the very 

popular FD42 system, it requires no soldering or technical I 

knowledge. 

For the user who is reluctant to install his computer circuit board 

inside the FDS a buffer is available -r- 

CENTRONICS PRINTERFACE 

As above but for parallel printer with CENTRONICS input 

DUAL/PR1NTERFACE Features both c*n Qc 

RS 232 CENTRONICS INTERFACE 

(leads can be supplied at an extra cost) 

£34.95. 

(inc. VAT) 

+ 80p P&P 

line v»r 

• Up CAP 

£39.95 

line VAT* 

+ tOt>M 

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£54.95 

(inc. VAT) 

+ 80p P&P 

The Fuller Box - 

The Sound System for the Spectrum 

The FULLER BOX added to the ZX Spectrum, improves the sound quality 

enormously The built in audio amplifier working well with all SPECTRUM 

programs. 

nie FULLER BOX allows you to program your own music, explosions, 

zaps, chimes, whistles and an infinite range of other soun< 

around the popular G1 AY 3 8912 sound cnip. It gives you 

complete control over J channels of tone and/or white 

noise, plus an overall envelope control 

Also provided with a joystick port, the unit gives instant 

command over all your own games programs The port 

is compatible with all the commercially available 

joysticks eg Atari/Commodore 

The FULLER BOX is complete with full documentation and 

a demo tape which includes the type of sounds you can 

Based 

f* fx 

achieve, tt also allows you to program your own sounds Fitting 

neatly onto the back Of of the SPECTRUM, the FULLER BOX still Still 

allows access for other peripherals, including the new SPECTRUM 

Micro Drives, via its duplicate user port. 

^ W v l 

(inc. VAT) 

+ 80p P&P 

THE MASTER UNIT - 

The Ultimate Games Unit 

The Master Unit provides all the requirements 

for the serious games enthusiast, containing 

not only the FULLER BOX, but also the FULLER 

/ ORATOR, all contained within the standard 

case. 

The Speech Unit and sound synthesiser combines 

to provide exciting voice and sound for your games. 

The other features include. Cassette interface, a 

variable audio output which may be connected directly 

to a HI Fl system. The MASTER UNIT provides endless 

scope in applications, and it allows asccess to the 

SPECTRUM for other periferal, via its duplicate user port, 

i.e. printerface. The MASTER UNIT is complete with full 

documentation and demo tapes which includes the type 

of speech and sound you can achieve. 

Upgrades for the Fuller Box and Orator 

Ttie systems can be expanded to MASTER UNIT specifications including the full range of controls. The upgrades must be fined by us. at 

FULLER MICRO S. 

PRICES Line V A T.) ORATOR to MASTER UNIT £14.95 FULLER BOX to MASTER UNIT £24.95 

The Fuller Orator - 

Speech for the Spectrum 

A smash hit at a number of recent Micro Fairs, the FULLER ORATOR 

uses an allophone system. Based on the G1 SP0256 AL voice 

synthesiser chip. Directly accessabte in BASIC, it is able to say 

anything you command using the keyboard or a games program 

It comes in the standard case complete with its own audto 

amplifier, it allows access to the SPECTRUM for other peripherals 

via its duplicate user port. Full documentation and demo tape 

included 

PRICE [inc. v.A T 1 £39.95 plus sop p&p 

16K to 48K Memory Expansion Pack for 

the Spectrum 

For the 16K SPECTRUM owner - upgradeyour machine to 48K of 

RAM with the FULLER upgrade kit. Complete with full assembly 

Instructions (Model 2 or 3 only). 

PRICE (inc. V AT.) £24.95 plus sop p&p. 

Ram Adaptor Boards for the ZX81 

Allows you to fit your Ram Pack inside the FD42 system. Accepts 

most commercial Ram Packs. 

PRICE (inc. VAT.) £9.35 & 80p p&p. 

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FOIUK I 1 SA£ 

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ftadKnOltanLatteStimoiMnit Swnlnr 0«1tmn»w. n owm iimi. tWwa Cmwl 

Fuller Quality 

Fuller Micro Systems reach for the highest quality in Research and 

Development, to make our products the BEST. 

Fuller Service 

In an effort to provide the best service we have built a new MAIL 

ORDER dept. at 71, Dale Street. Liverpool 2. Due to come into 

service soon. 

Fuller Guarantee 

All our products carry a worldwide one year guarantee. 

FULLER stock a full range of components and kits for your 

computer, send SAE for details. 

I 

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I 

I 

f . 

(A) 

Please supply the following items: [state items and quantity! 

plesase send me t 

please send me @ I 

please send me Co 1 

please add t for p&p 

I cnclose a cheque/PO payable to 

FULLER MICRO SYSTEMS Total I or debit my Access 

Bardaycard - Card No. 

Signature 

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DEALERS REQUIRED FOR UK & ABROAD 

ENQUIRES WELCOME 

051-236 6109 

71, DALE STREET, LIVERPOOL 2 


HARDWARE/SOFTWARE REVIEW 

The graphics solutio 

Nick Pearce looks at a 

couple of ways to get 

high resolution graphics 

on your ZX81. 

Owners of the ZX Spectrum 

will already be familiar with the 

delights of high resolution 

graphics. However, ZX81 

owners (excepting those with 

the necessary hardware addons) 

have hitherto been denied 

that facility, although the excellent 

results sometimes obtained 

by enterprising programmers 

belie the limited 

graphics set available. High 

Resolution is a piece of software 

which goes some way 

towards remedying this deficiency 

enabling 256 by 192 

resolution displays to be constructed, 

User-defined 

characters (lower case 

alphabet, chess pieces, space 

invaders, etc) and smooth 

curves are available using this 

software on your trusty ZX81 

and 16K RAM Pack. 

The cassette contains three 

programs: the high resolution 

toolkit itself, and two 

demonstration programs. 

Toolkit is held in a REM statement 

and occupies about %K 

of RAM. The Hi-res display file 

is about eight times as large as 

normal and is held above RAMtop, 

which must be lowerec 

with the appropriate POKE 

command before LOADing — 

easily forgotten as I found to 

my cost! 

The displays are generated 

86 

using eight commands obtained 

through USR calls. The 

PRINT command prints in minicharacters; 

these are the same 

width (eight pixels) but one 

eighth the height of normal 

ZX81 characters and can be 

any one of 128 dot patterns. 

(For truly addressable graphics 

there would need to be 256 

dot patterns, but the 128 

available should be adequate 

for most practical purposes.) 

For Hi-res printing the 

screen is divided into 32 columns 

and 1 92 lines, and the 

...< -- .••* ."TV 

. A . • • • . .-.* > 

...... - w:'-s. I 

• j?- .'••,. - *•—-• .* - • 

r// • V "J:;"— . •. • * 

'' . * ' * • * . \ / . ' • * ' ' 

j-"—' • , . . . • .**••• 

. ..... • . • . - - • 

.... —...... . . . 

.•• . . 

•:•.••.'• • • • - v x - • • * , 

• • * / ••>":--. • .- 

4 ' • * .* * .* . i.ttH'fek." "V N * . 

.• . • .•• ^ .... •*. 

.' * • . .. 

.. .- .- »• •'.... .. 

A sample screen illustration using Notting Dale 

Technology Centre s Graphics Pack. 

* . V 

. * - 

V'- • 

\ • • • ,-V 

.... 

•* •. 'ir. • *s 

*.•*„ . . . * 

;.;.* 

• *• "-••>* 

1 

r 

procedure is to POKE the column 

number, line number and 

mini-character code into 

assigned memory locations 

from which they can be printed 

onto the screen. The method is 

a little tedious (it is particularly 

frustrating trying to find the 

right dot pattern for the required 

characters) but thej 

results are worth the effort. Hires 

characters can be moved 

around the screen and so 

games featuring high resolution 

graphics are possible 

(movement is slow in BASIC, 

but could obviously be speed 

ed up using machine code). 

MPUTING AUG/SEPT 1983

The GOO 7 High Resolution Graphics 

Pack from the Notting Dale 

Technology Centre. 

l Ur* • 

The PLOT command gives 

i to the complete 256 by 

192 pixels. Plotting is obtained 

in a similar fashion to printing; 

the column and line coordinates 

are POKEd, followed 

bv a USR call to plot the screen 

pixel. 

An instruction booklet is included 

with the package. This 

explains the various Hi-res 

comands and lists the minicharacters 

available and their 

codes — it also gives some examples 

of how high resolution 

graphics can be used and incorporated 

in BASIC programs 

I felt the booklet could have 

been more comprehensive; the 

inexperienced programmer 

may find it a little inadequate. 

I did not find the High 

Resolution package a particularly 

easy program to use, 

relying as it does on POKE 

commands and USR calls. 

However, experienced 

machine code buffs should not 

/have any difficulty using it effectively. 

Computer Rentals are to be 

congratulated for producing 

this high resolution software 

for the ZX81. Not perfect, but 

a commendable achievement. 

High Resolution is priced at 

£5.95 from Computer Rentals, 

140 Whitechapel Road, 

London E1. 

C007 High 

Resolution 

Graphics Pack 

Notting Dale 

Technology Centre 

The G007 is a very powerful 

piece of hardware for the 

ZX81. It provides true high 

resolution graphics which, 

together with a comprehensive 

range of graphics commands, 

gives features usually found 

only on quite advanced 

machines — such as line drawing 

and textured area filling. 

The G007 commands are 

easy to use and have been 

achieved by extending the 

functions of some of the normal 

BASIC statements. Particularly 

versatile is the new 

PLOT command which is in the 

form PLOT n,x,y. The coordinates 

x and y specify a 

position on the 256 by 1 92 Hires 

screen; n is a new 

parameter which is used to 

select any one of the 115 

separate functions. 

Plot on. .. 

To give an idea of the procedure 

and the facilities 

available, some examples are: 

PLOT 34,x,y draws a coarse 

dotted line from the previous 

plot position to co-ordinates 

x,y; PLOT 102,x,y draws a 

Chain dotted line to coordinates 

x,y relative to the 

previous plot position; and 

PLOT 42,x,y fills the triangle 

between x,y and the two 

previous plot positions in 

black. 

User-defined characters are 

also easily obtained. The 

GOO 7 allows the 32 

characters of the ZX81 from 

inverse 4 to inverse Z to be 

readily re-defined {the old inverse 

video characters can still 

be obtained since the Hi-res 

print mode allows characters 

to be printed in inverse video). 

To re-define a character, the 

eight binary numbers representing 

each row of eight pixels 

have to be worked out; these 

are then POKEd into the appropriate 

locations in the 

'character table' in RAM. 

The normal low resolution 

mode of the ZX81 is still 

available with the G007 in 

use, and the ZX81 may be 

freely switched between the 

two modes without losing the 

contents of either. The Hi-res 

display file takes about 6.4K of 

RAM. The Hi-res display can 

be copied onto the printer, and 

programs and displays can be 

SAVEd on cassette. 

The unit comes with a comprehensive 

and very wellwritten 

manual which also 

gives a number of example 

programs. The G007 itself 

comes in an attractive black 

plastic case measuring about 

1 7cm by 3cm by 6'/icm and is 

contoured to fit snugly between 

the ZX81 and the 16K 

RAM Pack. 

Powerful 

This is a very powerful high 

resolution graphics pack. The 

commands have been well 

thought out and it is a pleasure 

to use. Once you have used it 

for a few programs you will 

wonder how you ever managed 

without it. 

The problem for the ZX81 

owner is considering hardware 

of this sort is whether to expand 

or to upgrade to obtain 

the desired facilities. Those 

who select the former option 

should find the G007 an excellent 

investment. 

The G007 High Resolution 

Graphics Pack costs £32 excluding 

VAT (plus 75 pence 

P&P) from Notting Dale 

Technology Centre Ltd, TFL 

(ZX81), 189 Freston Road, 

London W10 6TH. 


isiiÎDOÎSI IF®® w m wma ©a w s m m m 

Our new cased keyboard has 52 keys, 12 of which are used for the numeric pad. The numeric pad offers useful features, you 

can cursor with one hand and it will be a boon for anyone who enters a lot of numeric data. The pad is a repeat of the 1 — 9 

keys, it also has a full stop and a shift key. The numeric pad keys are red in colour, the normal keyboard keys are grey, with 

the case being black, which results in making the keyboard very attractive. The keyboard case dimensions are: 15" x 9" x 2Vi". 

The computer (either 80/81 or Spectrum), fits compactly inside. 

You witl have to remove the computer from it's original case, it is then screwed to the base of the case. The case has all the 

bosses already fitted and the screw holes are marked. Also fitted inside the case is a mother board (81 model only) 

which allows 16K, 32K and 64K to be fitted in the case. All connectors are at the rear of the case i.e. Power, Mic, 

Ear, T.V. and the expansion part. The case is large enough for other add-ons also to be fitted inside. One of these 

could be the power supply then you could very quickly fit a mains switch or a switch on the 9V line. This 

means you have a very smart contained unit.This case does not stop you from using any other addons 

that you may have eg Printer etc. We are convinced that this is the best keyboard available at present. 

It offers more keys and features than any other keyboard in it's price range. 

MTIooo 

The case can be purchased separately with the keyboard aperture uncut, therefore if you 

possess one of our early uncased keyboards, or in fact, any other suppliers' keyboards 

these could be fitted. The keyboard is connected to your computer by a ribbon cable 

and this has connectors fitted which simply push into the Sinclair connectors. It 

is a simple two minute task and requires no electronic skills. This keyboard 

does not need any soldering. Please specify on order whether you 

require the ZX81 or Spectrum case. 

©DDlOn 

This is supplied with Spectrum legends, and a slightly different 

base for fitting the Spectrum inside, again, all the connectors 

are at the rear of the case and there is plenty of room for the 

power supply (and other add-ons). Should you wish to 

change, we can supply both the Spectrum legends and 

details of updating your case which will enable modification 

from the ZX81 to Spectrum. PLEASE 

specify on your order whether you require the 

ZX81 or Spectrum inside. 

w m 

16K Memory £22.95 

64K Memory £52.95 

16K (Uncased) £19.95 

64K (Uncased) £49.95 

8IFECTBSBB8 

MKI £301 

MKII £30 

"b I" 

If you have ever had 

white outs or system 

crashes this could be the 

answer. It stops the movement 

between the computer 

and the RAM 

expansion, it is supplied 

with a ribbon 6 inches 

DK Tronic*. Unit 2. Shire Hill Ind Est. Saffron Walden lon9' with 3 male Atronks 

«>nnec 

IFEaO 

IUSMM mwM\ !(gfl 

o n e end and a 

m m ga® 

Essex CB11 3AQ. Tel: (0799) 26350

'(M 

1® 

1983 

®®¥0a M H I ^ 

This is the toolkit which won acclaim in the feature in the 

August 1982 issue of Sinclair User. "It is the most impressive 

programm, fast in execution with clear and full instructions . 

... it stands out from the rest of the field". The ZXED is 

a powerful editor for use on the expanded ZX81. It is 

intended for use by the serious BASIC programmer and 

offers several useful and time saving features most helpful 

during all stages of program development. The facilities 

provided are as follows: ALTER, BYTES, COPY, 

DELETE, FIND, HELP, INSERT, KEEP, 

MOVE, RENUMBER, AND VERIFY. 

The Spectrum Toolkit contains most 

of the features above plus 

autoline numberer and 

append, and will run in the 

16K and 48K Spectrum. 

This module unlike most other 

accessories fits neatly inside your computer 

under the keyboard. The module 

come ready built fully tested and complete 

with a 4K graphic ROM.This will give you an 

unbelieveable number of extra pre-programmed 

graphics. This now turns the 81 into a very powerful 

computer with a graphic set rarely found on larger 

more expensive machines. In the ROM are lower case 

letters, bombs, bullets, rockets, tanks, a complete set of 

invaders,graphics and that only accounts for about 50 of them, 

there are still approximately 400 left (that may give you an 

idea as to the scope of the new ROM}. However, the module 

does not finish there, it also has a spare holder on the board 

which will accept a further 4K of ROM/RAM. This holder can 

befitted with a 1K/2K/RAM and can be used for user definable 

graphics so you can create your own custom character sets. 

The so called speaker in your Spectrum is really only a 

tjuzzer'. With the DK Tronics "SPECTRA SOUND" you can 

generate fully amplified sound through the speaker on your 

TV. set. SPECTRA-SOUND is a very simple but highly 

effective add on. This means that you no longer have a faint 

beep but a highly amplified sound, which can be adjusted with 

the TV volume control. 

The SPECTRA SOUND fits comoactly and neatly inside the 

Spectrum case and is connected by three small crocodile 

tfw mm ant £9.9S 


I 

I 

I 

I 

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I 

LIGHT PEN 

The pen enables 

you to produce 

high resolution 

drawings on your 

own T.V. screen. 

The controlling 

software supplied 

with the light pen 

has 16 pre-defined 

instructions. These 

are chosen from a 

menu positioned 

at the bottom of the screen next to the pen. 

You can utilise the menu for changing colour (Border, Paper, 

Ink). Drawing circles, arcs, boxes, lines. You are also able to 

fill any object with any colour, and insert text onto the screen 

at any chosen place. Of course you can also draw freehand. 

There is a feature to retain the screens and animate. On the 

48K Spectrum you can retain 5 screens. 

You can also use the machine code on it's own in your own 

programs, for selecting out of a menu etc. The software 

provided will return with the X,Y, cords for it's position on 

the screen. 

The light pen is supplied with a control interface in order to 

adjust the sensitivity/pen alignment. 

This simply plugs into the ear socket on your spectrum. 

Should you require further details please send a S.A.E. 

Internal fixing for 

ZX 81 keyboard case. 

r 1 

* KMU ' 

I 1.W > | 

I *** I 

I I 

L J 

—ill iminiiiiiii 

T > ± 

Internal fixing for 

spectrum keyboard 

case. 

Please state type of machine, which ROM memory siie, quantity, 

and place when ordering. 

Please send me £ 

Please send me @ £ 

Please send me @ £ 

Please add on £1.25 for p/p 

I enclose cheque/P.O. payable to DK Tronics total £ 

or debit by Access/Barclaycard No. LLLL I L I j_LJ_LL nr 

Signature. 

Name . . . 

Address. . 

Send to DK Tronics, Unit 2, Shire Hill Ind Est, Saffron Walden, 

Essex CB11 3AQ, Te): (07991 26350 (24 hrs) 5 lines. 

* 

89

COMPETITION 

Competition 

Have some fun, and maybe win yourself a joystick 

package for your spectrum or ZX81! 

Okay, settle down now and 

don your competition hats. 

This issue we've got some 

great prizes for you to win, and 

all you have to do is to put 

some lines to go with the cartoon 

below. 

You'll all have seen competitions 

like this before I'm 

sure and I'm afraid it's one of 

those awkward times where 

there is no real answer for you 

to find. You just have to stir up 

the grey matter and come up 

with a line or two which complements 

the cartoon and 

hopefully makes us laugh here 

at the ZX Computing editorial 

offices. 

Once again, you'll have to 

cope with our strange sense of 

humour but if the limericks 

which are streaming into the 

office from last issue's competition 

are anything to go by, 

you should have no problem at 

all! Again, we would like to 

publish the best three captions, 

so try and keep them 

clean; still, if you feel otherwise 

inclined, we always need 

a laugh. 

The prizes 

There will be three winners to 

the competition, those with 

captions which show originality 

and most of all, humour. 

Each of the three prize winners 

will receive a joystick 

package courtesy of AGF 

Hardware. Each package will 

consist of two Atari joystick 

controllers, one Interface 

module II (Spectrum or ZX81 

version! and a 'Video Graffiti' 

demonstration program. 

You should have no trouble 

finding compatible software 

for the joysticks should you 

win. The interface is compatible 

with 28 games from 14 

companies for the Spectrum 

and there are 20 games com- 

patible with the ZX8 1 from 1 1 

companies. You can also, 

following the instructions accompanying 

the joystick 

package, incorporate the 

joystick facility in your own 

programs. 

Rules 

• This competition is open to 

all UK and Northern Ireland 

readers of ZX Computing except 

employees of Argus 

Specialist Publications Ltd, 

their printers and distributors, 

employees of AGF Hardware, 

or anyone else associated with 

the competition. 

• As long as the correct 

coupon is used for each entry, 

there is no limit to the number 

of entries from each individual. 

• All entries must be 

postmarked before September 

31 st, 1 983. The prizes will be 

awarded to the best three entries. 

the decision to be made 

by the Editor of ZX Computing. 

No correspondence will be 

entered into with regard to the 

results and it is a condition of 

entry that the Editor's decision 

is accepted as final. 

• The winners will be notified 

by post and the results will be 

published in a future issue of 

ZX Computing. 

Address your entires to: 

ZX Computing — cartoon 

caption, 

145 Charing Cross Road. 


Results 

Congratulations to Dennis 

Plowman of Dunkirk, Nottingham, 

for you sent us the entry 

that was first to be picked out 

of the competition bag in our 

April/May competition. The 

prize of 1 2 books about the ZX 

Spectrum is, as you are 

reading this, on its way to you 

courtesy of the Post Office. 

In case any of you are keen 


to find out whether you got the 

answers right and want to get 

some programming in at the 

same time, then you might be 

interested in an ingenious entry 

from Peter Cameron of Oxford. 

Instead of engaging brain 

and settling down to a couple 

of hours of word searching, he 

switched on his Spectrum and 

got to work. 

The program he wrote is not 

terribly fast — running speed 

about six minutes with the 

data provided in the competition 

— but he assures me it is 

2 0 I N P U T 

j*. INPUT 

c o l s 

30 D I M a t If OIUS 

IF rows ROWS OR CX < 1 

HEN GO TO 4S0 

b $ t J , TO C ( J .» 

ete": ST 

LET V $ = 

=rx+dr: LET c 

IF rx < 

THEN RETURN 

=v $ +a $ ( r x .. cxJ : GO TO 

X = CX + d C 

) ; " t o c a 

WILLIPMTPNG located, 

start row IS,column 13, 

direction northwest. 

DILWYNJONE5 located, 

start row 16 , c o l u m n 3, 

direction north. 

DRIPNLOGPN located, 

start row l , column 13, 

direction we s t- 

TIMLPNGDELL located, 

start row 4,column 13, 

direction west. 

TIMHHRTNELL located, 

start row 14,column 13, 


OfiUIDHARIJODD located, 

start roif is, c o Lumn 14, 


TREUORTOMS located, 

start row 2, column 5, 

direction east. 

MIKELORD located, 

start row 7,co lumn 6 

direction east. 

MPRTINURENHILTON located, 

start row 2 ,column 2, 

direction south. 

SMGEE located, 

s t a r t row 11,column 5, 

direction south* 

ROE- INBRPDBEEP located, 

s t a r t r o w 1 , c o I u ro n 1 2 , 

direction south. 

Search complete 

The output from Peter Cameron's program. 

Competition 

Name . . 

Address 

My caption for the cartoon is: 

Postcode 

(please write your caption in block capitals) 


1983 

OIL 

WELL 

THAT 

ENDS 

WELL 

Dallas. The task of oil exploration and 

exploitation in Texas is no game. You'll have 

to decide how much you II sell the stuff for - 

where to find it - how to get to it and where 

to pump it 

That's just for starters. 

Can you take over the Euing Empire or will 

you be taken over in the attempt^ 

We've warned you - but ihen we think you re 

just about ready for it 

Dallas Airline, 

for — 

ORIC I 

£7.95 

Other UtJes in the range include Airline. 

Autochef, Print Shop and Farmer. 

Prices: ZX81 and Spectrum 16K£5 

Spectrum 48K £6 

Available from W.H. Smith and all 

guod computer shops or Dept. ZX 

Cases Computer Simulations 

14 Langton Way London SE3 7TL. 

Strategic Games. They're no pushover. 

SPECTRUM & ZX81 

EDUCATIONAL SOFTWARE 

SPECTRUM FAMILY LEARNING SERIES 

Use our Computer Assisted Learning PACks to help your children with 

their school work. The programs in the series use moving colour 

graphics and sound to make learning more eniovable. Each pack 

contains four programs and is suitable for use with the 16K or 48K 

Spectrum. Program notes are supplied, 

CALPAC FL1 (5 to 8 years) £7.50 

Tens and units addition and subtraction with detailed help facilities; 

powerful, easy to use drawing program; English comprehension applied 

to American Indians. 

CALPAC FL2 a to 10 years) £7.50 

Roman history, spoiling tester with easy entry of your own lists; flexible 

table tester; homophones. 

CALPAC FL3 (9 to 12 years) £7.50 

Nouns, verbs, adjectives and adverbs; tenses of verbs; biology of the 

flower; long division tutor. 

The programs are ideal for the ages stated, but could be used by anyone 

requiring revision of these areas of Study. 

CALPAC C1 O-LEVEL CHEMISTRY £7.50 

Four clearly presented revision/tutorial programs. The subject matter 

has been carefully structured to cover the most important aspects of: 

* Elements, compounds and mixtures. 

* Structure, bonding and properties. 

* Redox, electrolysis and the activity series. 

* Acids, bases and salts. 

48K Spectrum and I6K ZX81 versions of the cassette are available. 

Please specify which you require. 

Professional Computer Assisted Learning materials from: 

CALPAC COMPUTER SOFTWARE 

108 Hermitage Woods Crescent, St Johns, 

Woking, Surrey GU21 1UF. 

Overseas orders £8.50; includes airmail postage. 

A MUST FOR 

ANYONE INTERESTED 

IN ZX MACHINE CODE! 

The finest range of utility programs for ZX Compute^ 

Used by professionals. Very uselul - 

for beginners sâsssr 

uiaiefl'^, 

i i S i S ^ s r 

riy II 

PCT RESCUE 

P CT RESQUE 

o CT RESOUF 

SMCI'vn Son»»'» |y»llt)«*-oi' UX'I StiMtHm Mxfowira Ldcatlc E4iiCM«10 iubjWi CrrtTir 1 Ew^ 


3 

Jltf* 

•H- 

* 

i 

RANI-PACKS FLAP 

. h„a„„ o( edgy connectors (so children! keep off!). 

TRADE IN YOU K fX si -*the case (children come back!) 

Introducing the M AX1MEM MAXIMF.M ZX81, ZX81 A ZX81 - the with must m_or a«ordable32. 

64J, RAM f n t e d ^ ^ ^ 

M / V X I M E M ^ 1 

6 4 k - £ 5 9 ^ * and 

not 

on 

i r M o2 al1d 64k is a ^^ u aT«ntee 01 

The MAX1MEM32*> a six month gu uade.in 

-t a RAM «< * ^ of the 

the ^ ^ a m e t n o t V u f \ ° 7 i "memo** and does 

ZX SLOWLOADER £10 

f^TaS into Spectrum A recent letter 

i s s * £ ? • • » — r - ^ *>* 

and this time it went straight ^ ^ T S ^ n T L thing was ready to 

POKEs. 20 to add some colour and!a He* 

Hock at the linw ol tining

Equation 

solver 

John Norbury shows us 

how to solve equations on 

the ZX81 using the bisection 

method. 

Suppose that you want to solve 

an equation of the form f 0, 

such as: 

y = f(x) = x3 + 3x2 _ 10x - 5 

The roots of this equation are 

the values of x for which y = 0. 

You can find roughly where they 

occur from a sketch graph 

(Fig. 1) which shows that the 

curve cuts the x axis at three 

places. One is between x - - 5 

and x = - 4, another between x 

- 1 and x = 0, and the third is 

between x = 2 and X - 3. 

You could find this same information 

by tabulating the 

values of y - f(x) for a range of 

values between, say, - 10 and 

+ 1 0 (Fig. 21. Where the sign of 

y changes from plus to minus, or 

vice versa, is the interval in 

which you could expect to find a 

root. The table shows that there 

are again the three intervals 

(-5,-4), (- 1,0) and 2,3) 

which need to be studied in 

more detail. 

The bisection method takes 

each interval in turn, divides it into 

two equal parts, and decides 

in which half the root is to be 

found. It then divides that half 

into two equal parts and repeats 

the process. This iteration continues 

until the size of the portion 

so formed is smaller than 

the specified error, at which 

point it gives the mid point of 

the portion as the root of the 

equation. It is here that the 

graph crosses the x axis and 

changes sign. 

Advantages and 

disadvantages 

Unless you tabulate the function 

ZX81 EDUCATION 

over a very wide range, you cannot 

be sure of finding all the 

roots of an equation. Nor can 

you find any roots that might be 

complex numbers, such as the 

solution to the equation 

y = xi + 1, for its graph does not 

even cross the x axis (Fig. 3). 

However, you can find the solutions 

to whatever accuracy you 

like given sufficient iterations 

and, as the method does not suf 

fer from instability, il always 

converges to the required 

answer. 

Between the lines 

The program will run with about 

4Y3K RAM. The following 

describes the structure of the 

program. 

Lines 10-1 10 set up the default 

values of the parameters. The 

equation to be solved is held as 

A$. 

Lines 200-360 print the menu 

and choose the selected 

subroutine. 

Lines 1000 1030 allow the 

equation to be entered or changed. 

To prevent program execution 

stopping with the report 

code A, powers of x such as x 3 

Fig 2 

should be entered as x * x * x. 

and so on. 

Lines 2000-2080 specify the 

interval in which you are searching 

for a root. 

Lines 3000-3040 ask for the 

number of values that you want 

to tabulate. 

Lines 4000-4090 tabulate the 

function over the range set by 

option 2. If a change of sign occurs 

between the lowest and 

highest points of the range, the 

bisection method can be used. If 

two or more changes of sign occur, 

the interval set by option 2 

should be reduced to include just 

one such sign change. If no 

change of sign occurs, then a 

wider interval could be tried. 

Lines 5000-5040 allow the 

maximum permitted error in the 

answer to be set. The smaller 

this is made, the longer it will 

take and the more iterations will 

be needed to reach the solution 

In fact, the error depends on 

1/2", where n is the number of 

iterations. 

Lines 6000 6230 carry out the 

actual bisection process, letting 

the user know if an incorrect interval 

has been set by option 2. 

Lines 7000-7050 list the current 

values of all the parameters. 

TfiBi_E OF L'fiLUES BETUEEN -10 RND 

10 UP X *X *X t-3 #X *X - 1 0 *X — 5 

X = -10 F £ X ) = -605 

X--9 F C X 1 = -dSl 

X--6 FIX) = -345 

X = — "7 F i X ) = -131 

>'= ~6 F £ X > = -53 

X = -5 F CX) = -5 

X--A F (X) = 19 

X = —3 F (X) = 25 

X = -2 F IXi = 19 

X - -1 ~ * F (X) 

X = 3 F (X) = -5 

V — T_ F £ X ) = -11 

XsS F (X) = -5 

Xi3 F (X) = 19 

X =

including the equation itself. 

Lines 9000-9070 wait for the 

user to specify either a return to 

the menu or a printout of screen 

contents. The program will run 

as it is even if no printer is 

available. 

How to use the 

program 

When first run, choose option 1 

and enter the test equation x 3 + 

3x 2 - 10x - 5 in the form: 

x * x * x + 3 * x * x 

10 * x - 5 

Then choose option 2 and 

specify the interval from - 10 to 

+ 10. Option 3 should be used 

to ask for 20 tabulation points. 

Option 4 will list the values of 

the equation at these 20 points, 

and will also tell you what to do 

ZX81 EDUCATION 

1 SLOU 

10 REM BISECTION METHOD FOR RO 

GTS OF EQURTION Y = F (X) 

23 REM (R.B) IS INTERURL IN UH 

ICH R ROOT IS SOUGHT 

33 LET R=-l 

40 LET B=1 

53 REM R$ IS EOURTION FOR F(XI 

50 LET fl$="X" 

70 REM E IS MRXIMUM ERROR RLLQ 

UED FOR ROOT 

30 LET E=0.03i 

93 REM N IS NUMBER OF TflBULRTl 

ON POINTS IN INTERURL (R.B) 

13© LET N=10 

liO LET X=3 

203 PRINT RT S . 13; "gfcjfifcSKE * 

213 PRINT RT 2.3 INPUT THE 

EXPRESSION FOR F(X)' 

223 PRINT RT 4.3."; INPUT INTE 

RURL (R . S) IN UHICH ROOT IS 5E 

IHG S O U G H T 

233 PRINT PT 7,3 "3 INPUT NUMB 

tR OF TRBULRTION 

POINTS" 

24-3 PR INT PT 13.3; "4 TRBULRTE 

EXPRESSION DEFINED BY OPTION 

1 BETUEEN R RND B " 

253 PRINT RT 13,0;"5 INPUT REG 

•LURED RCCURRCY" 

263 PRINT RT 15.3;"S FIND ROOT 

IN (R.. B) BY METHOD OF BISECT 

luN" 

2"73 PRINT RT 18,0; '"7 LIST CURR 

ENT PRRRMETERS" 

233 PRINT RT 23.3:"6 STOP" 

3O0 LET 2 $ = INKEY$ 

310 IF 2$="" OR CODE Z$36 THEN GOTO 333 

323 LET 2=URL 2$ 

233 CLS 

343 GOSUB 1333*2 

353 CLS 

353 GOTO 233 

1033 PRINT RT 5.3 "ENTER EXPRESS 

ION F IX) IN 

CORRECT SYNTR 

CTIC FORM" 

1310 INPUT fi$ 

2 323 PRINT RT B,3. {x) = ",: R $ 

IS3Q GOTO 9333 

23S0 PRINT RT 5.3."ENTER LOUEST 

RXD HIGHEST POINTS OF RRNGE FOR 

7P5ULRTION" 

2613 PRINT RT S. 3. "LOUEST FIRST 

n — *? •• 

2323 

R 

2O30 

RT S , 16 

£043 

RT 13 .. 3 

EST : 

. • .—• .—• 

2GS3 

2570 

2260 

3030 

R 

INPUT 

PRINT 

PRINT 

" N O U "HE HIGH 

E — T " 

INPUT B 

IF B < = R THEN GOTO 23! 

PRINT RT 13.19.B 

GOTO 9000 

PRINT RT 5.0.'ENTER NUMEER 

OF TfiBULRTION POINTS" 

3310 INPUT N 

3320 IF N < > INT N OR N 1 THEN GC" 

0 3 0 1 3 

3030 PRINT RT B,©;"N=";N 

3343 GOTO 9333 

4300 FOR X=R TO B STEP CB-R),'N 

when the screen fills up. The 

table should look like that in Fig. 

1. Three changes of sign are 

found, so we call up option 2 

again and enter the interval 

(-5, -4). 

Next, we choose an error of 

less than 0.00001 using option 

5. Option 6 calculates the root 

in our chosen interval as 

- 4.84946. You can then 

return to option 2 to set the 

other two intervals in which 

there is a root of the equation, 

Note that the test equation is 

a cubic, for which there can only 

be three roots. However, any 

polynomial or trigonometric 

equation can be entered, for ex 

ample, sin(x| + tanfx) — 3x 2 

+ 4x. 

With practice, this becomes 

an effective and reliable way of 

solving all sorts of equations — 

especially recommended for 

maths homework! 

4.013 PRINT "Xs":X:TRB 15:"F(X) = ' 

. URL 

4323 

3 3 3 

IF PEEK 15442> 4 THEN GOTO 

4333 PRINT "PRESS C TO CONTINUE" 

4043 LET 2 $ =INKEY $ 

4353 IF 2 $ = " " THEN GOTO 4343 

4363 IF 2 $ < >"C" THEN GOTO 6993 

40-73 CL3 

4363 NEXT X 

4393 GOTO 9333 

•3333 PRINT RT 5.3. "ENTER MAXIMUM 

RLLOUED ERROR" 

10 INPUT E 

5320 IF E < =3 THEN GOTO 53lO 

3333 PRINT RT B,3;"E=";E 

5343 GOTG 9333 

3230 LET R1=R 

-313 LET E1=B 

6 3 2 3 L ET X = R 

5333 LET UR=URL 

5343 LET X=B 

R$ 

5350 LET UB=URL R$ 

U060 IF UR*UB

Spectrum 48k 

MAKE YOU 11 OWN TV FILMS! 

**tTH 1.1 VF. ANIMATION 

96 

13 MUSIC 

SAVE them . . . 

1 AMUSE FRIENDS AND FAMILY 

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k 

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BUILD HOUSES. CHURCHES ETC. IN A FLASH - it ERASE THFM 

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MAKE CHARACTERS 'SPEAK' USING ANNOTATIONS AS IN STRIPS. 

Fl'I.L COMPUTER-PROMPTING TO SAVE YOU MAKING ERRORS. 

INSTANT PLAYBACK, EDITING AND DELETING AS YOU GO ALONG! 

MOST COMMANDS ARE A SINGLE KEY-STROKE, WITHOUT 'ENTER'. 

COMPOSE YOUR OWN TUNES USING THE SPECIAL TII R E E-OC T A V E 

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CORRECT AND EDIT AT EACH NOTE ... IP YOU NEED TO! 

STORE UP TO NINE »*-NOTE TUNES TO 'CALL-UP' AT ANY TIME 

IN A STORY COMPUTER GIVES EACH A NUMBER IN MEMORY. 

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For the ZX81 or Spectrum - no adaptor needed 

Just plug it in. Other peripherals or Ram Pack can be 

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Built in amplifier and loudspeaker. 

Audio in/out socket, can be used to amplify the 

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9-pin I/O socket can be used with cheap Atari/ 

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Comprehensive manual includes many example 

routines 

£32.50 

For the ZX81 or Spectrum - no adaptor needed 

Let your computer talk back! 

Allophone' synthesis gives an unlimited vocabulary 

Active filtering for improved speech quality 

Other peripherals or RAM Pack can be plugged into 

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Output to normal audio amplifier or to our ZXM 

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Manual gives full details on how to use the ZXS, with 

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And Don't Forget Our Books: 

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John Menzies 

97

* * m Rescue the astronauts ftp* 

in this lunar listing for 

your spectrum, courtesy of John Miller. 


rescue the ten astronauts 

stranded on the moon. You have 

three rather ancient space craft 

capable only of left and right 

movement, and an initial thrust 

to clear the surface of the moon. 

At the beginning of the game, 

you are docked in your mothership 

traversing left and right at 

the top of the screen. Below are 

this layer and you'll find the 

astronauts on the surface of the 

moon. 

Moon madness 

To start your descent, press the 

'0'; after that youcan only move 

left and right using the '5' and 

'8'keys respectively — you descend 

automatically. During your 

asteroid-type objects, and all descent you must avoid hitting 

you have to do is to get through the asteroids and then attempt 

a 

5 

y 

1 0 

20 

3© 

O TO 

4-0 

1000 

1 0 0 1 

IO02 

= 0: D 

I 0 O 5 

1007 

2 0 0 8 

2 0 1 0 

1 0 2 0 

a $ i c 

" ?> 17» 

I F RNDft I 

.6}= "G" 

NEXT d. 

N E X T C 

to land your craft on the magenta 

landing pads. Once down 

safely, there will be a short delay 

while one of the astronauts 

clambers aboard. You then have 

to make your way back to the 

mothership, this time trying to 

avoid the cyan enemy ships 

which guard the planet. 

To begin your ascent, press 

the '0' key again and then guide 

your ship using the cursor keys 

to move left and right until you 

rr . , 

dock with the mothership. Once 

docked, you unload your human 

cargo and head off to rescue 

another astronaut. 

The game ends when you 

have either rescued all ten 

astronauts or lost all three of 

your ships. Should you find the 

game too easy, you could 

always alter the velocities of the 

asteroids and the enemy space 

craft by changing the value of 

PINC in line 9042. 

RESTORE 9900 : GO SUB 9100 1210 LET pointer=pojnter+pjnc: x 

RESTORE : GO 32 THEN LET pointer=I 

GO SUB w a i t 

1215 FOR C-L TO 5: PRINT INK 6,FL 

GO TO S t age 1 

T 4+ci2,0;a$(c,pointer TO );a$(c 

GO TO S t age2 

, TO pointer-lJ: NEXT c 

IF Ship < 4. A N D man : DIM i5(5,32J 

GO T O S h i p l O S S 

L ET la a ."I -» 

a n +1 

1227 IF NOT d r o p THEN GO TO 1200 

L E T p O i n ter=: 

1230 LET X=X-IINKEY$="5" RND X>P 

L E T i n C l 

3 f ( INKEY $ = "B" R>JD X < - 4. THEN LET 

20 

124-0 IF SCREEN $ ty,x)=s"" THEN GO 

T O S h i p l O S S 

1300 GO TO 1200 

1999 STOP 

2000 PRINT RT Y-1,X;3 $: FOR C = 1 

TO 10: BEEP .1,-10 + C: BEEP .1,-1 

C3 a o go SUE surfac e 

A 0 3 0 GO SUB toppri n t 

1 0 6 0 PRINT RT 0 , E> . ink 6;score;R 

T 0 / 1 7; INK 5;high ;RT 0,30; INK 

p 

0-C; NEXT C 

7 ; f h i 

2001 LET UP=0: LET drop=0 

10 70 FOR C =1 TO 5: PRINT RT 4- + C* 2002 LET pointer=i 

INK 6; 3 $ ( C J . NEXT c 

2005 LET" m cnman ) =0 : LET naan-nau 

1060 PRINT RT 2,0; m $; RT 3,0;n$;f: n +1 

T y , X 

20 10 CLS : GO SUB surface: GO SO 

10S5 PRINT RT 3,3; S $ 

3 t opp r i n t 

1200 LET H0thx=7,uthxfinc: IF NOT 2020 LET y=y-i: PRINT RT y,x;s$ 

drop THEN LET X=X+inc 

2030 FOR C-l TO 5: FOR d=l TO 32 

1201 IF IDOthX =2E THEN LET inc=-l 204-0 IF RND ft ( 11 -»in) < . 4- THEN LET 

1202 IF fl»OtbX=l THEN LET inc=l i $ ( C , d .1 = " H " 

1205 PRINT RT 2,ttOthx;»$;RT 3, X> C 2050 BEEP .005,30: NEXT d: NEXT 

t h x ; n $. PRINT RT y,XiS% 


2 0 5 5 L E T S 

2 0 6 0 P R I N T R T 

core =s core+250 

0,5; INK 6; 

h i g h 

T 0 , 1 7 ; I N K 5 ; h i 

7; S h i p 

2 0 7 0 F O R C = 1 T O 

2 , 0 ; I N K 5 ; i % ( C) 

2 0 8 0 P R I N T R T 2 , 

t h x ; n $ 

SPECTRUM GAME 

core; P 

R T 0 , 3 0 , I N K 

AT 4fCi- 

5: PRINT 

: NEXT C 

ttOthXj Bt$; R T 3 , m c 

2100 LET B0thx=m0thx+>nc 

2 1 0 1 I F W O t h X - 2 8 T H E N L E T i n c = - l 

2 1 0 2 I F n> O t h X = 1 T H E N L E T i n c = l 

2 1 0 5 P R I N T R T 2 , £J> O t hX ; fo % , R T 

t h x ; n $ 

2 1 0 6 P R I N T R T y,x;s$ 

2 1 1 0 L E T p o i n t e r = p o i n t e r + p i n c : i 

F p o i n t e r > 3 2 THEN LET p o i n t e r = l 

2115 FOR C=1 TO 5: PRINT INK S; FI 

T 4 4- c * 2 , 0 ; i $ (c , p o i n t e r T O ) ; i s (c 

, TO p o i n t e r - l J : NEXT c 

2120 IF INKEV $ = " 0 '* THEN 

2130 BEEP .O05,.24IUP-12 

£5 . 24- *UP - 10 


2150 LET Y=Y-UP; IE YG 

.- t ? INKtT$ = "8" RND X < 32 ) 

LET up=i 

BEEP .0 

THEN GO 

THEN C- 

2190 IF SCREEN $ (y , x) THEN GO 

T O S h i p LOSS „ 

2200 GO TO 2100 

£999 

3000 

STOP 

INK 7; PRPER 0: BORDER 0: C 

L 5 

3010 FOR C =0 TO 50: 

, RND*175 NEXT C 

4002 PRINT RT 19,0: 

PLOT RND £-25' 

3020 PRINT RT 5,4.; INK 5; "UELCON 

E TO 'NOON RESCUE'" 

3030 PRINT RT 16,0; FLRSH 1; BR X 

GHT l;"PRESS RNY KEY UHEN YOU RR 

E RERDY" 

3040 IF INKEY $ = " " THEN GO TO 304- 

P 

304-5 PRINT RT 16,0; OUER 1; "PRES 

& RNY KEY WHEN YOU RRE RERDY" 

3050 RETURN 

4000 INK 4-: PRINT RT 17,0;"! 

M" 

4001 PRINT RT 15,0; J|I 

4003 PRINT RT 20,0; 

K 3; SSN"; INK 4-;" 

K 3; "KBhbN" ; INK 4-;" 

4004 PRINT RT 21.0'" 

JJJJJJJJHK*JJJJ 

• • - 

/ 

J J J u< 

4.005 FOR C=1 TO 10: IF m ( C ) >0 TH 

cN PRINT RT 20.DI (C) ; INK 6;"L" 

4006 NEXT C 

4910 INK 7: RETURN 

5000 PRINT RT 0,0; INK 6; BRIGHT 

l; "SCORE: INK 5; "HIGH: 

"; INK 7;"SHIP: 

5020 RETURN 

5500 FOR C=0 TO 7 STEP .5: PRINT 

RT u , x ; INK C; "E": BEEP .01,C*5 

BEEP .01,C*-5: NEXT c 

5510 LET score=score+300: GO TO 

30 

5000 FOR C =y TO 20: PRINT RT C,X 

: INK RND47;"E"; OUER l;RT c,x;" 

E": BEEP .01, -C: NEXT C 

6005 BEEP 1.-20: PRUSE 50 

5010 LET S h i p =S hip+1: LET di"Op=0 

: LET u p =0: CLS : GO TO 30 

3000 PRINT RT 6,11; FLRSH 1; "GAM 

E OUER" 

5010 IF sccrs>hi

The profit 

prophet 

A serious program to help you 

get to grips with your business 

written for us by Michael Carroll 

of Wexford, Ireland. 

The object of this program is to 

help a company or financial institution 

measure their profitability. 

On RUNning the program you 

will be greeted with a menu 

which will provide a route 

through to the particular ratio 

you require. Here follows a list of 

the facilities available with this 

program: 

al Return on investment. 

b) Net profit percentage. 

c) Asset turnover. 

d) Gross profit percentage, 

el Selling expenses/sales. 

f) Administration expenses/ 

sales. 

g) Establishment expenses/ 

sales. 

h) Financial expenses/sales. 

il Sales and distribution expenses/sales. 

j) Research and development 

expenses/sales. 

k) Fixed asset turnover. 

I) Current asset turnover. 

ml Working capital turnover. 

n) Debtor's turnover. 

o) Rate of stock turnover. 

10 GOSUB 

32 PRUSE 

3 4- CL3 

4-0 PRINT 

E3SURES" 

4-5 PRIHT 

91300 

9 0 

SO PRIHT " A i 

EMT" 

x 

55 

ft< ± 

PRINT "6 J 

TmGE " 

SB PRINT 

BO PRINT "C> 

6 1 PRINT 

65 PRINT "D> 

ENTAGE" 

66 PRIHT 

70 PRINT "E) 

SRLE5" 

71 PRINT 

75 PRINT "F > 

DEN5E5/5FLLE5" 

76 PRINT 

SO PRINT "G> 

EN5ES/5RLE5 ** 

81 PRINT 

35 PRINT "H.T 

5 / S A L E S " 

56 PRINT 

90 PRINT "IJ 

./SRLE5" 

9 1 P R I N T 

p) Current asset ratio. 

q> Acid test. 

r) Average period of credit 

given. 

s) Average period of credit 

received. 

t) Earnings per share, 

u) P. E. ratio. 

v| Dividend per share, 

w) Dividend yield. 

x| Dividend cover, 

y) Capital employed. 

As you can see from the long list 

of options, the program certainly 

tries to fill in the gaps of your 

business knowledge. 

In fact, the author has added 

a number of program notes 

which will be revealed should 

you choose certain options. 

These are not part of the operation 

of the program but illustrate 

certain patterns which 

developed over a period of 

trading months so were added 

for the author's convenience. 

Should these not apply to you 

they could be left out or have 

new comments substituted. 

[X31 PROFITPB IL ITY M 

RETURN OH IN'JESTM 

NET PROFIT PERCEM 

PSSET TURNOVER" 

GROSS PROFIT PERC 

SELLING EXPENSES/ 

RDHINISTRPTION EX 

ZX81 BUSINESS 

100 PRINT 

OR OUST N/L 

ENTER OPTION LETTER 

110 INPUT 

123 IF U$ = "" THEN GOTO 130 

125 GOTO (CODE 

130 CLS 

135 PRINT "ZXS1 PROFITABILITY R 

RTIDS" 

14.0 PRINT " 

150 PRINT 

EXP.•SPLES' 

J> RES. +DEUEL OPHENT 

151 PRINT 

IBS 

UER" 

PRIHT "K > FIXED ASSET TUPNO 

156 PRINT 

160 PRINT 

NOUER" 

" L J CURRENT RSSET TUR 

161 PRINT 

1B5 PRINT 

URNO'JER " 

"MJ WORKING CRPITRL T 

166 

1 7 0 

PRINT 

P R I N T "N> DEBTORS TURNOVTR" 

171 PRINT 

175 PRINT 

NOUER" 

" O i RRTE OF STOCK TUR 

176 PRINT 

130 

IO" 

PRINT P) CLIRRENT ASSET RFTT 

1S1 PRIHT 

155 

136 

PRIHT 

PRINT 

PCID TEST" 

190 PRINT 

IT GIUEN" 

"R) AU.PERIOD OF CRED 

196 PRINT 

200 PRINT ENTER 

r CRPITRL EMPLOYED" 

276 PR INT 

23 O PR INT " I 5 END " 

L— 3 1 PRINT PT 20 , 3; 

300 PRINT "ENTER OPTION LETTER 

r t 

OR JUST N.-'L 

310 INPUT 

320 THEN STOP 

33 0 GO : O { COD E U $ -s 1 00 ) 

340 ST DP 

3 300 CLS 

5302 PRINT "RETURN CN INUESTMENT 

3508 PRINT N$ 

331© PRINT "CRPITRL EMPLOYED ="; 

3812 INPUT C$ 

3314- PRINT c $ 

W-- o 1 o IF N$ = OP C5="°" THEN RU 

N 

3 3 1 3 PR INT "RE TURN ON INVESTMENT 

= '•; IMT ( (UP L N $yVPL €•%> 4-100) ; " 


3 3 2 0 

333 0 

3900 

3 902 

PR IN" 

GOTO 

CLS 

PRINT 

'000 

"NET PROFIT PERCENTRG 

E: " 

3904. 

3 9 0 6 

3 9 0 8 

3 9 1 0 

3912 

3914 

3916 

N 

3913 

PR INT t,"NET PRDFIIr"; 

INPUT N $ 

PRINT N$ 

PRINT "SALES="; 

INPUT S$ 

PR INT S i 

IF = 7 " OR S? = **7 THEN RU 

PRINT "NET PROFIT PERCENTAG 

c = ; INT ( (URL N$/UAL 4IO0.1 ; ** 

3920 

E " 

3 9 3 2 

3934 

4.300 

4-002 

4.004- 

4-006 

4.008 

4-010 

4012 

4014 

4016 

N 

PRINT 

Ph INT PRESS N/L TO CONTTNU 

PRUSE 4E4 

GOTO 6600 

CL S 

PRINT "RSSET TURNOVER: 

PRINT .."3RLES="; 

INPUT 54 

PRINT S4 

PRINT "CAPITAL 

E M P L O V E D = " ; 

INPUT C% 

P R i f r r eg. 

IF S$="7" OR C$s"?" THFN E N R U 

4 0 1 3 P R I N T " R S 3 E T T U R N O V E R — '*; I N T 

t CJBL. S$.-'URL .» 

4020 PRINT 

4030 

4100 

4 1 0 2 

Qftr . 

4104 

4-ies 

4108 

4110 

4112 

4114 

4116 

N 

4118 

iJDTO 7000 

C-LS 

PRINT "GROSS PROFIT PERCENT 

PRINT 

INPUT 

PRINT 

PR INT 

INPUT 

PRINT 

IF G$ = ' 

,,"GROSS 

G* 

G $ 

"SFLLES=" 

5 $ 

PROFIT-"; 

OR S $ = — •• o 1 THEN RU 

PRINT " G R O S S P R O F I T P E R C E N T 

RGE="; INT { ( U R L G $ / W L S * > 4 1 0 0 ) 

4120 

N'UE " 

4122 

4124 

4200 

4 £-02 

• 11 

4204 

4206 

4208 

4210 

4212 

4214 

4216 

N 

1218 

4220 

4222 

4300 

4302 

4304 

4306 

4308 

4310 

4312 

4314 

4316 

N 

4318 

; INT 

1320 

4322 

P R I N T "PRESS N/L TO CONTI 

PRUSE 4E4 

GOTO 6600 

CLS 

P R I N T " S A L E ; 

PRINT 

INPUT 

PRINT 

PRINT 

INPUT 

PRINT 

,,"SRLE5 

E* 

" S A L E 3 - " ; 

s * 

EXPENSES/SRLE5 

EXPENSES="; 

S* 

IF E$="?" OR SJ=" THEN RU 

PRINT "SALES EXPENSES/SfiLES 

INT C(URL E$/UfiL S$J(100) 

PR INT 

GOTO 70OC 

CLS 

PRINT 

PRINT 

INPUT 

PRINT 

PRINT 

INPUT 

PRINT 

IF S$=*" 

PRINT 

( (URL 

PRINT 

GOTO 

"RDM.EXPENSES/SALES: 

,,"RDM.EXPENSES="; 

E * 

E» 

"SALE5="; 

5 * 

S * 

OR ES =*"?•*- TMET*—RU 

"RDM.EXPENSE S/SALE5 = " 

E $/UAL S $J *100) ; " S" 

' 0 8 0 


4 4 0 0 CLS 

1 4 0 2 PRINT "EST.EXPENSES/SALES: 

^•404 PRINT , , " EST . EXPENSES — »i ' > 

/ 

44-06 INPUT E $ 

4-4-08 PRINT E$ 

4410 PRINT "SHLES="; 

4412 INPUT S$ 

4414 PRINT S$ 

4416 IF S$ = "?" OR E $ = " ? THEN RU 

N 

44 16 PRINT "EST . EXPENSES/SRLES = ' 

; INT ( (URL E$/'JAL St) *100) ; " S" 

4120 PRINT 

44-22 GOTO 7000 

450S CLS 

1502 PRINT "FINANCIAL EXP./SALE^ 

1504 PRINT . . "FINANCIAL EXPENSE i. 

4506 

4508 

4510 

4512 

4514 

4516 

N 

4513 

INPUT E$ 

PRINT E$ 

PRINT "SRLES="; 

INPUT 3$ 

PRINT S$ 

IF S$="7" OR E $ = " ? " 

T H E N R U 

P R I N T " F I N A N C I A L E X P - / S A L E S 

=:"; I N T ( ( U A L E $ / U A L S $ ) i l O 0 ) ; 

4520 PRINT 

4522 GOTO 7000 

4 6 0 0 C L S . _ 

4 6 0 2 P R I N T " S A L E S + D I S T R I B . E X P . / S 

A L E S :* ** 

4 6 0 4 * P R I N T 

4 6 0 6 I N P U T E $ 

4 6 0 8 P R I N T E * 

S A L E S + D I S T R I B - E X P 

4 6 1 0 P R I N T " S f l L E S = " ; 

4 6 1 2 I N P U T S * 

4 6 1 4 P R I N T S » 

4 6 1 6 I F 5 $ = " ? " O R T H E N R U 

N 

4618 PRINT "SALES+DIST- EXP./SAL 

ES = ", INT l (UAL E $/URL S$) *100> ; " 

g - 

4520 PRINT 

4622 GOTO ' 0 0 0 

4700 CLS 

4702 PRINT "RESEARCH+DEU.EXP./SA 

LES : " 

4 "704 PRINT , , "RESEARCH +DEU-EXP . = 

4706 INPUT 

4708 PRINT 

4710 PRINT 

4712 INPUT 

4714 PRINT 

E * 

4716 IF E $ — "*? 

N 

" SALES =: " , 

S$ 

5 $ 

OR S$ = THEN RU 

4718 PRINT "RESEARCH +DEU. EXP. /S 

ALES=",INT ( (UAL E$/UAL S$)+100) 

... g.. 

4 720 PRINT 

4722 GOTO 7000 

4300 CLS 

4802 PRINT "FIXED ASSET TURNOUEF 

4804 PRINT .. . "SALES = " , 

4305 INPUT 5 $ 

4303 PRINT S$ 

43 10 PRINT "FIXED ASSETS = " - 

1612 INPUT F'j 

4314 PR INT F I. 

4316 IF S$="7" OR » — THEN RU 

N 

4313 PRINT "FIXED ASSET TURNOVER 

=";INT f(UAL Si/UAL F$1 > 

4S28 PRINT f f "PRESS N.-L TO CONTI 

NUE " 

4322 PAUSE 4E4 

4824 GOTO 6500 

4900 CLS w 

4902 PRINT "CURRENT ASSET TURNO'J ^ 


ER : " 

4904 PRINT ,."5RLES="; 

4-906 INPUT 5$ 

4906 PRINT S$ 

4-910 PRINT "CURRENT ASSETS = "; 

4912 INPUT C$ 

4-914 PRINT C-$ 

4916 IP S$="7" OR C$ = —?" THEN RU 

N 

4-9 IB PRINT "CURRENT ASSET TURNOU 

ER = " ; INT ( (URL. 5$/UFLL C$) > 

4920 PRINT ,,"PRESS N/L TO CONTI 

NUE" 

4922 PRUSE 4E4 

4924 GOTO 6400 

5000 CLS 

5062 PRINT "UORKING CRPITFLL TURN 

OUER:" 

5004- PRINT J F " SRLE3 = " ; 

5006 INPUT S$ 

5006 PRINT S$ 

5010 PRINT "UORKING CRPITFLL="; 

5012 INPUT U$ 

5014 PRINT U* 

5016 IF = OR 5$ = '"?" THEN RU 

N 

5018 PRINT "UORKING CAPITAL TURN 

OUER="; INT ( CURL S$/T'FLL U$> ) 

5020 PRINT 

5022 GOTO 7000 

5100 CLS 

5102 PRINT "DEBTORS TURNOUER:" 

5104 "PRINT , ,"CREDIT SALES="; 

5106 INPUT 3$ 

5108 PRINT S$ 

5110 PRINT "TRADE DEBTORS="; 

5112 INPUT D$ 

5114 PRINT D$ 

5116 IF S* = '"?" OR D$="?" THEN RU 

N 

Silo PRINT "DEBTORS TLRNOUER;I 

NT s. CVflL 5S/USL D*J 

5 i 2 e - F R i n r 

5122 GOTO 70C-0 

5200 CI. 3 

5202 PR INT "RATE OF STOCK TURNOU 

ER : " 

5204 PRINT -."COST OF SAL ES="; 

5206 INPUT c$ 

5208 PRINT CS 

5209 IF C$ ="?" THEN RUN 

5210 PR INT "OPEN TNG DTGCK = " ; 

52 12 INPUT SI 

5214 PR INT SI 

5216 PR INT "CLOSTNG STOCK — j 

52 13 INPUT 32 

S22C 1 PR I N T 52 

5222 IF SI =0 THEN L ET S$ = 5TR$ 32 

5224 IF 52 =0 THEN L T 3S- 5TR$ SI 

S22te> IF 51 < >0 AMD 3- •— 

> 0 T HEN LET 

5$=STR$ « 0 , 5 iSl+52) ' 

5223 PRINT "RATE OF STOCK TURNOU 

ER = " : 

5 230 LET X = INT iURL C$- UflL S*> 

5232 PRINT INT (365/X);"DAYS" 

5 234 PRINT 

523S GOTO "7000 

5300 CLS 

5302 PRINT "CURRENT ASSET RATIO; 

5304 PRINT 

5306 INPUT 

530 7 PRINT 

5308 PRINT 

.."CURRENT 

ci 

"CURRENT 

5310 INPUT L$ 

5312 PRINT L$ 

5314 IF C$ = "~" OR L $ -"? 

M 

5315 PRINT "CURRENT ASSET 

•• ; INT ( CURL C5/UAL L$) ) : " 

5313 PRINT 

5320 GOTO 7000 

5400 CLS 

102 

RS5ETS=" 


L IABIL 3TIES = 

THEN RU 

RATIO= 

1 " 

5402 PRINT 

5404 PRINT 

5406 INPUT 

5403 PRINT 

5410 PRINT 

5412 INPUT 

5414 PRINT 

5416 PRINT 

"ACID TEST:" 

..."CURRENT A5SET5="; 

F $ 

F$ 

"STOCK="; 

S$ 

S$ 

"CURRENT LIABILITIES 

5418 INPUT L$ 

5420 PRINT L$ 

5422 PRINT "ACID TEST=";INT 

L F $ —UAL 5$) /HAL L$) ; ": 1" 

( CUR 

5424 PRINT , , "PRESS N/L TO CONTI 

NUE" 

5426 PAUSE 4E4 

5425 GOTO 6300 

55B0 CLS 

5502 PRINT "AUERAGE PERIOD OF CR 

EDIT GIUEN;" 

5504 PRINT , F"DEBTORS^"; 

5506 INPUT D$ 

5508 PRINT D % 

5510 PRINT "CREDIT SALE3="; 

5512 INPUT C$ 

5514 PRINT C$ 

5516 IF C$="7" OR D$="7" THEN RU 

N 

5513 PRINT "RU-PERIOD OF CREDIT 

GIUEN^R" 

5520 »PR INT " "; INT F T UAL 

D %/URL C$J J365) ; " DAYS" 

5530 PRINT 

5540 GOTO 7000 

5600 CLS 

5602 PRINT "AUERAGE PERIOD GF CR 

EDIT REC""D:" 

5604 PRINT ,,"CREDITORS= M; 

5606 INPUT C$ 

5608 PRINT CS 

5610 PRINT "PURCHASES="/ 

5612 INPUT P$ 

5614 PRINT P$ 

5616 IF C$="7" OR P$="7" THEN RU 

N 

5616 PRINT 

REC""D = " 

AU.PERIOD OF CREDIT 

5620 PRINT " ";INT (FURL 

C$/UAL P$)*36S);" DAYS" 

5630 PRINT 

5640 GOTO 7000 

5700 CLS 

5702 PRINT "EARNINGS PER SHARE;" 

5704 PRINT .."NET PROFIT AFTER T 

RX RND FIXED IHTREST=". 

5 706 INPUT N$ 

5 708 PRINT N$ 

5710 PRINT "NO.OF ORD SHARES ISS 

UED = "*; 

5712 INPUT S $ 

5714 PRINT S$ 

5716 PRINT "EARNINGS PER SHARE=" 

; INT ( < UAL N$/UFLL S$) *100» 

5713 PRINT 

572© GOTO 7000 

5800 CL3 

5302 PRINT "PRICE ERRNINGS RRTIO 

5304 PRINT 

HARE = "; 

5306 INPUT 

5806 PRINT 

5810 PRINT 

MARKET PRICE PER S 

M * 

N $ 

"EARNINGS PER SHARES" 

5312 INPUT S I 

5314 PRINT 3$ 

5316 IF M$= "?" OR S$ = " THEN RU 

N 

5818 PRINT "P.E.RFLTIOR"; INT ( CJFL 

L M $/UAL S$J ) 

5820 PRINT 

5830 GOTO 7000 

5900 CLS 

5902 PRINT "DIUIDEND PER SHARE:" 

ZX COMPUTING AUG SEPT 1983

5904 

5906 

5907 

5903 

5910 

5920 

5925 

N 

5930 

; INT 

5932 

5934 

5000 

6002 

6004- 

*mm •• " 

6006 

6 0 0 6 

6010 

RE =" i 

5012' 

6014- 

6016 

N 

6018 

PRINT .,"DIUIDEND PRIO="; 

INPUT D* 

PRINT D$ 

PRINT "NO.OF SHFLRE5="; 

INPUT N$ 

PRINT N$ 

IF D$ = "? M OR N$ = *"?" THEN RU 

PRINT 

( ( URL 

PRINT 

GOTO 7000 

CL5 

"DIUIDEND 

D I f / U A L N $ ) 

PER 

) 

PRINT "DIUIDEND YIELD: 

PRINT ,,"DIUIDEND PER 

INPUT 

PRINT 

PRINT 

D* 


SHRRE = " 

SHARE 

"MARKET PRICE PER SHR 

INPUT M$ 

PRINT H$ 

IF D$="7" 

_ II i 

OR M$ = THEN RU 

PRINT "DIUIDEND VIELD="; 

INT 

(CURL D$/URL M$)1100);" 3" 

6020 PRINT 

6022 GOTO 7000 

6100 CL5 

6102 PRINT "DIUIDEND COUER:" 

6104- PRINT , ,"NET PROFIT - TRX - 

FIXED INTREST - PREF.DIUIOEND= 

6106 INPUT 

6106 PRINT 

6110 PRINT 

CTS — ** ; 

6112 INPUT 

6114 PRINT 

6116 PRINT 

(LURL D$/ 

6120 

620© 

6202 

6204 

6206 

6205 

6210 

5212 

6214 

6216 

5 = " : 

6216 

622G 

6222 

6224 

6226 

6226 

INPUT 

PR INT 

PRINT 

INPUT 

PRINT 

PRINT 

C$+URL D5 

6230 PRINT 

6240 GOTO 

6300 CLS 

6305 PRINT 

6313 PRINT 

EING HELD 

EFORE NOT 

5 PROFITS. 

6320 PRINT 

6330 PRINT 

RND 

D$ 

D * 

" D I U 

M * M* 

"DIUIDEND 

PRID ON ORD.8HRR 

C O U E R ; I N T 

URL M$) ) 

6116 PRINT 

GOTO 70O0 

CLS 

PRINT "CRPITRL EMPLOYED:" 

PRINT ,."SHRRE CRPITRL="; 

INPUT B $ 

PRINT 3 2 

PR INT "RESERUES = "; 

INPUT cs 

PRINT C * 

PRINT "LONG TERM LIRBILITIE 

D5 

D * 

"INTANGIBLE RSSET5="; 

E$ 

E $ 

"CAP.EMPLOYED=";((URL 

+ URL B$> -URL E$> 

7000 

"ACID TEST:" 

"TOO MUCH RESOURCES B 

INLIQUID FORH RND THER 

CONTRIBUTING TO FIRM 

. "EXRTIPLES SUCH RS: " 

, ," 1) CRSH RT BRNK, 

2) DEBTORS 

534.0 PRINT RT 

TO STOP or< 

TO RE-STRRT" 

20,0;"PRESS J,N/L 

N/L 

6350 INPUT 

5360 IF U$="U" THEN STOP 

6370 RUN 

6400 CLS 

6405 PRINT "CURRENT ASSET TURNOU 

ER: " 

64-10 PRINT "R FRLL IN CURRENT AS 

SET TURNOUERINDICRTES R PROBLEM 

IN SALES OR CURRENT ASSETS:" 

6420 PRINT .,"THERE IS ALSO A PO 

SSIBILITY OF —UNDERTRADING""-" 

64-40 PRINT RT 20,0; "PRESS U , N/L 

TO STOP OR N/L 

TO RE-5THRT" 

FC>4S0 INPUT 

6460 IF THEN STOP 

6470 RUN 

6500 CLS 

6505 PRINT "FIXED RSSET TURNOUER 

6510 PRINT "A FRLL IN F . R.TURNOU 

ER INDICRTESUNDERUTILISATION OF 

CRPRCITY." 

SS15 PRINT " -EG:PLANT HAY BE TO 

O BIG IN RELATION TO UOL 

UME OF SALES" 

6520 PRINT ,," TOO RAPID EXPR 

N3IGN" 

6525 PRINT ,," ANTICIPATE^ DE 

MRN ID FOR SALES IS OUST NOT TH 

ERF - " 

PRINT RT 20 f O; "PRESS U,tl/L 

Ô STOP OR 

N/L 

TO RE-START" 

6550 INPUT J$ 

6560 IF = THEN STOP 

6570 RUN 

6600 CLS 

6605 PRINT "NET+GROSS PROFIT RIS 

E : " 

6606 PRINT 

6610 PRINT 'INDICATES OVERTRADIN 

G RND R DELAY BETWEEN PRVMEN 

T OF DEBTS RND RECEIPT OF HONEY 

OUED." 

6620 PRINT ,"REMEDIES FOR FRLLI 

PROFIT PERCENTAGES 

5625 PRINT 

6S30 PRINT 

PRICE 

ON CRSH 

ING STOCK" 

D635 PRINT 

1) INCREASE SELLING 

2) TIGHTEN SECURITY 

AND STOCK 

3 ) CHECK ON SLOU MOU 

4) 

TION METHOD S5) 

IENCY 6) 

SALE5 

SS40 PRINT RT 

TO STOP OR 

TO RE-START" 

6650 INPUT J$ 

6660 IF = 

6670 RUN 

7000 PRINT "PRESS 

R R T " 

7 010 

7020 

7030 

7040 

9000 

CHECK STOCK URLUR 

CHECK STAFF EFFIC 

FIRE BUYER AND/OR 

MANAGER" 

0,0; 

THEN STOP 

PRESS U,N/L 

N/L 

JfN/L TO END 

N/L TO RE-ST 

INPUT 

IF J$ = "J' 

RUN 

PRINT END 

THEN STOP 

CLS 

9010 

************** 

PRINT " * * * * * * * * * * * * * * * * * * * * 

9020 PRINT 

9030 PRINT 

Y RATIOS 

9040 PRINT 

9050 PRINT 

ROLL 

9060 PRINT 

9070 PRINT 

"*";TAB 31;"*" 

"* ZXS1 PROFITABILIT 

* " 

"*";TAB 31; " 

BY MICHAEL CAR 

* " 

"*";TAB 31;" *" 

"* RUNS ON A ZX81 

IN 16K 

* " 

9080 PRINT 

TAB 31."*" 

9090 PRINT "* USES APPROX 

. 10K 

* " 

9100 PRINT "*";TAB 

" * * * * * * * * 

31; 

* * * 

"*" 

9110 PRINT 

* * * * * * * * * 

************** 

9120 PRINT AT 15,0; 

E TO CONTINUE..." 

9130 INPUT A $ 

9140 RETURN 

PRESS NEULIN 

83 2X COMPUTING AUG/SEPT 1983 103

If 

Friday November 25th 

Saturday November 26th 

Sunday November 27th 

i 

I 

t * 

10am - 6pm 

10am - 6pm 

10am - 4pm 

Improved venue 

We have transferred Breadboard to Cunard International Exhibition Centre, so that we can offer improved facilities 

to the visitor, including car parking and ease of access by rail, tube and car. all in a modern attractive setting. 

We have also arranged a reduced hotel/rail fare package to attract enthusiasts from all parts of the country. 

Planned features include 

1. Full range of lectures planned over 3 days to cover most aspects of electronics and computing. 

2. F.lpctronics Computing Advice Centre — manned by experts. 

3. Demonstration of electronic organs and synthesisers. 

4. Holography presentation. 

5. Practical Demonstration on "How to produce printed circuit boards". 

6. Computer Corner — extensive display of computer hardware — "Try Before You Buy". 

7. Amateur radio Action Centre. 

8. Computer controlled model railway competition. 

9. Pick of the Projects - Demonstration of the best from ELECTRONICS TODAY INTERNATIONAL, 

HOBBY ELECTRONICS and ELECTRONICS DIGEST over the past ten years. 

10. Giant T.V. screen video games. 

11. Robotic display. 

Why not bring the family to the show and enjoy a weekend 

in London? We have arranged a complete hotel package for 

our visitors to the exhibition. All inclusive rail tickets also 

available. Send now for details of what we, the organisers, 

Can offer yOU. Write to: Breadboard '83 

ASP Exhibitions 

145 Charing Cross Road 

London WC2H OEE

if^JIYKM 

"IT LOOKS N 

THE HELL CANIDOWITHIT?" 

Every zx SPECTRUM Print n Plotter jotter has 100 pages of finely 

printed screen grids. 

50 for the high resolution screen. 50 for the normal character 

screen. 

with these at your disposal you can plan practically any graphics printout 

to program into your computer. 

The high-resolution PLOT grid shows every one of the 45.060 pixels! 

Every one printed. Everyone with Its co-ordinate numbers. This gives 

you enormous graphics power to DRAW, PLOT. CIRCLE, PLOT OVER and so 

on in any position or screen building up graphic drawings, charts, maps 

.. in fact anything without the complications of guesswork, integer 

out of range, or wrongly positioned pixel colours which change PRiNTed 

INK characters! 

The normal character PRINT grids on the other hand will allow you to 

be specific about PRINT AT. TAB, PRINT OVER, SCREENS and INK PAPER in 

direct coordination with PLOT... you see every page is printed on high 

quality tracing paper... ideal to overlay on to illustrations and copy 

or co-ordinate. 

And there's another bonus, because each page contains 24 Userdefinable 

grids — 2400 per pad! 

with 50 pages of PLOT grids. 50 pages of PRINT grids 2400 userdefinable 

grids, a set of colour pens, a printed PIXEL RULER and our 

Special Offer of demo programs, ITS THE BEST VALUE IN ZX CRAPHICS 

PROGRAMMING. 

I DON'T BELIEVE IT!" 

Five rolls of our PRINTER PAPER wilt only cost you £12.50 Including 

postage, packing and VATI And you'll gain a great deal morel 

it prints beautifully, its not too thick, it's not too shiny. Print Is black 

- not grey, it actually feeds through the machlnei 

See for yourself only £12.50 Including everything, it's a bargalni 

Post today to Print n Plotter Products. 19 Borough 

High street. London SE19SE or phone: 01-403 6644 

(General) or 660 7231 (Credit Card salest. 

Name 

Address 

ZD 

MiviiiwruiLuu^v 

TO SHOOT DOWN 

THE THING FROM MARS?" 

Ever forgotten which key to press when playing a game? 

Do you suffer from a mind-boggling mass of programmed keys? 

Do you write programs that use different keys to perform various 

functions? if so, we have Just the thing for your zx SPECTRUM. 

A pack of Prirrt'n'Plotter Keyboard Overlays. 

just write the function or functions under each key you program and 

keep the overlay for the next time you play the game. 

Of course there s lots of more uses you will find for our OVERLAYS, user 

defined characters, keyboard scanners, mathematical programs, 

business uses—to name just a few. 

There's TEN OVERLAYS to a pack — so you can program with Impunity) 

And they fit perfectly onto your standard zx SPECTRUM KEYBOARD 

Each OVERLAY Is printed with the cursor movement key directions and 

there's room for program name etc. 

For the cost of a 

console for your si 

mes cassette you can have a truly professional 

TRUM! 

We ve cut costs (not cut quality) by designing a self-assembly method 

using relatively inexpensive materials like strong corrugated board. 

The result Is a console that s tough, light, highly finished and capable 

of giving years of useful service. 

Facilities include ergonomlc keyboard angle, access to rear of 

machine, choice of P.S.u. Internal or external, and alternative of Printer 

on board or cassette storage area. Fully Illustrated instructions are 

included. 

ZX SPECTRUM JOTTER . E9.95 each 

ZX SPECTRUM KEYBOARD OVERLAYS 

til £2 95 per pack 

ZX SPECTRUM CONSOLE £5.25 each 

ZX PRINTER PAPER (3) £12 SO per five rolls 

ZX SPECTRUM DEMO CASSETTES (i> 95p each 

ZX81 JOTTER PADS £3 50 each 

ZX81 FILMS ,Ê2.25 each 

ZX81 CRAPHICS PROGRAMMING GUIDE 

@ £1.50 each 

remittance enclosed Ptease Dili mv Access 1 Bare laycard / 

visa; Mastercard NO 

an onces include vat p&p Overseas orders please add 2S% 

for additional surface man 

» 

'WHERE CAN ICET THEM? 

10u t»n w* Buy moH c* OW OTOOum it 

« m Smltn iCOrvutrrltoiVd 

toon iMwctw Ix«ncnni 

Huff Micro


The soft 

touch 

The heavens have opened and 

showered James Walsh with a 

wealth of software for his 

Spectrum. Read on and find out 

what he thought of it all. . . 

Painter 

— A&F software 

The first thing that can be said 

about Painter is that it certainly 

is different! This does, in turn, 

make it rather more difficult to 

explain. 

The object of the game is 

run around a maze of paint 

pots on the screen and in turn 

fill them up with paint. This is 

whilst being chased by at least 

one roller, and making sure 

that you do not run out of 

paint. If you succeed in filling 

each pot then you play again 

13 

but with two rollers chasing 

you, and so it goes on. 

This is a novel game, using 

the properties of the Spectrum 

well. It may not be the most innovative 

program of this 

review, but it is one of the 

most enjoyable to play. The 

graphics are good, and the 

movement smooth. A game 

well worth playing, though I 

feel £7.00 is a little steep! 

One characteristic of all 

A&F Software so far is that 

though it may be good, the 

plain packaging prevents it 

making sufficient impact on 

the shelf. A shame. . . 

The Dungeon 

Master 

— Crystal 

Computing 

The Dungeon Master is nicely 

packaged with a large booklet 

of well thought out documentation. 

The concept of this 

game will be better known to 

the players of the traditional 

'Dungeons and Dragons' 

games rather than the adventure 

games which are widely 

available for the Spectrum. 

This is, in fact, the first attempt 

to put the real 'D&D' 

game onto the Spectrum. 

Needless to say, it uses the full 

48K of memory. This is partly 

due to the fact that it is written 

totally in BASIC, but also 

because the author has done 

his best to cram as much of the 

game onto the computer as 

possible. Obviously you cannot 

expect a full version on 

such a relatively limited computer 

as the Spectrum. 

The game is based on the 

development of a character 

whose fate is determined by 

his own actions. The character 

is trapped in a dungeon and 

has to conquer many 

challenges. Though this is a 

totally text game, its main dif- 

ference is the fact that you can 

define your own dungeons as 

well as dangers. Hence the 

limits of the game extend as 

far as your imagination. On the 

tape there is a sample 140 

location dungeons for your 

use. 

This cassette must be 

highly recommended for its 

versatility, originality and 

quality. For an avid adventure 

player this is definitely well 

worth obtaining. 

Jetpac 

— Ashby Computers 

and 

Graphics Ltd 

The idea of this game is that 

you are an astranaut and your 

object is to collect as many of 

the valuable minerals, etc, of 

the planet which you are on, 

whilst also collecting fuel for 

your safe departure. Though 

the scenario is not the most 

original around, what puts it to 

number one in this review is 

the fantastic quality of the 

graphics. The characters are 

beautifully designed and colour 

is used very well indeed. But 

the thing that really caught my 

eye was the incredible 

smoothness of it all. Never in 

the game will you see one jerky 

move. As you get to more 

106 


planets the inhabitants get 

more and more determined to 

stop you. Another nice feature 

is the way in which, as you 

proceed through the game, 

your rocket turns into the 

space shuttle — a nice touch. 

There are five controls to be 

mastered: left, right, fire, 

thrust and hover. All of which 

maybe controlled via the 

keyboard or through a joystick. 

Overall this is a very well 

put together piece of software. 

If you want a game with impact 

then this is one of the 

best around. An excellent program 

and game. 

3D Tanx 

— dk'Tronics 

The idea of the game is to 

destroy the 2D tanks which 

are moving from right to left 

across the screen, using your 

30 gun turret. There are three 

levels of play, one or two 

player options, a hold feature, 

demo and training modes. One 

particularly nice feature is that 

you are allowed to pick your 

own control keys. Just to 

make it more difficult the tanks 

can actually fire back at you. 

Colour is used well in this 

game, but whilst the detail of 

the graphics is good, the tanks 

still only move one character 

square at a time which does 


look rather jerky. The gun turret 

looks very good and moves 

very well indeed whilst you 

aim. Probably the most advanced 

feature of this game is 

the semi-recoil of the nozzle of 

the gun, going down each time 

you fire. 

To conclude, it can be said 

that though the standard of 3D 

Tanx is not quite the best in 

this review, it is an addictive 

and entertaining game. Well 

recommended. 

Dietron 

— custom Data 

Ltd 

Dietron is the only program in 

this review which is definitely 

not a game. It has a number of 

major functions: 1 — to work 

out your maximum advised 

weight and intake of calories 

according to your height, build, 

age, sex, etc, and 2 — it holds 

data on an enourmous number 

of different foods, so that it is 

possible to plan a balanced 

meal. The data available includes 

protein, fibre, vitamins, 

etc; this section is a very comprehensive 

catalogue indeed. 

It is also possible to load in a 

second program which holds 

information on dieting, as well 

as how quickly you are likely to 

lose those precious pounds if 

you cut down by a chosen 

amount of calories. It also explains 

the value of each 

vitamin for which data has 

been given for the different 

foods. More specifically it 

gives details about them, as 

well as the consequences of 

too much or too little in your 

diet. 

This is well written and 

researched program which can 

be useful for anyone who is interested 

in their diet. There is a 

substantial amount of data in 

Dietron which is well worth 

having and using. Though all of 

this can be found in a book, it 

has been arranged in such a 

way that makes it far quicker 

and easier to use on your Spectrum. 

Cosmic Guerrilla 

— Crystal 

Computing 

This is a new, original and fast, 

100% machine code arcade 

type game. The object of the 

game is to protect your laser 

bases from the marauding 

aliens which slowly eat away 

your defences. The aliens are 

lined up vertically on either 

side of the screen, with your 

bases vertically lined up in the 

centre. The aliens smoothly 

walk towards the centre and 

collect the objects which are 

the only defence your bases 

have. Your task is to zap the 

Q QUEST 

aliens with the laser running 

horizontally along the bottom 

of the screen. 

Though Cosmic Guerrilla 

does have some parallels with 

the 'space invaders' type 

games, the screen arrangement 

and the different 

scenarios put it way ahead in 

my view. One quality of 

'Space Invaders' that it does 

unashamably possess, is its incredible 

addictive quality. 

Amongst other things the 

graphics are good, as well as 

smooth, plus good sound and 

colour. This is a very playable 

game indeed. For all those who 

have enjoyed Space Invaders, 

then this is the next step up. 

Highly recommended. 

The Black Hole 

— Quest Microsoftware 

The idea of the game is that 

alien space craft are using the 

Black Hole to gain entrance to 

other galaxies. Unfortunately 

their intent is destructive, 

hence your task is to inflict as 

much damage on them as you 

possibly can. You have two 

weapons, the Positive and 

Negative Ion gun, and a 

Neutron Blaster. The large 

scale advertising campaign 

that Quest have launched for 

this program seems to suggest 

some amazing graphics. Yes 

the graphics are good, but 

K*I6K ' 

\. I 

BLACK 

HOLE I 


personally, I found the 2D effect 

rather confusing because 

it just doesn't look right. 

However, all in all, not a bad 

piece of software. 

Krazy Kong 

— Control 

Technology 

Kong the gorilla has captured a 

girl and your task is to rescue 

her from his evil grasp. There 

are three stages of this game: 

first you must avoid the barrels 

and fireballs which are being 

hurled at you and climb the 

ladders to the second screen. 

Then you must climb the staircase 

again avoiding the 

fireballs to rescue the girl. It is 

left up to your own imagination 

to decide who the fair maiden 

in distress is, so you can be the 

in-house hero! 

Being written in machine 

code means that the action is 

pretty fast, though jerky and a 

little crude. Some of the controls 

are a little too sensitive, 

but apart from that it is a good, 

fun game, which can be played 

for hours — just change the 

maiden! 

Blind Alley 

— Sunshine Books 

Ltd 

The instructions on the back of 

the box tells that this game is a 

deadly duel, deep in space — 

the sport of the year 3017. 

The idea is to trap your opponent 

or opponents by 

enclosing them in the trail that 

you have left. It is rather like 

the game in the movie, Tron. 

The graphics of the introductory 

screen are good, though 

the graphics of the rest of the 

game are less than brilliant. 

Though there is only one level 

of play it does get progressively 

more difficult, with more 

and more opponents sent 

against you. 

Sunshine seem to have a 

habit of producing games 

which are not technically 

brilliant, but manage to be 

highly addictive and great fun 

to play. 

Frenzy 

— Quicksilva 

As soon as you see a 

Quicksilva game on the 

shelves of a shop or advertised 

you do expect it to be pretty 

good — they have a name to 

live up to. In this game you 

have been placed in a room 

with walls segmenting it, 

which is also inhabited by 

robots. Unfortunately they 

seem intent on killing you. 

108 

There are various special 

features, including different 

levels of robots, exploding 

pods and minelayers. The main 

disappointment comes when 

you see the screen display, 

which is rather dull, with all the 

robots, etc, taking up exact 


character squares. If you hit a 

wall you die — though it is 

possible to escape through a 

hole in the outer wall and then 

you find yourself in a new 

room with more robots. 

I didn't think Fren2y was 

really up to QS's usual high 

technical standard, though it is 

still quite fun to play. 

Alien Swarm 

— Titan Software 

This is very much another version 

of the 'Galaxians' game. 

The idea is to kill off the 

swarms of aliens which proceed 

down the screen at you. 

Every so often the PAPER/INK 

colours change, making for 

some pretty weird combinations. 

After a while you are 

even lucky enough to get different 

shaped aliens. 

Though Alien Swarm may 

be quite well written, it cannot 

compete with the other 'Galaxians/lnvaders' 

clones such as 

Imagine's Arcadia, which I 

reviewed two issues back. 

Overall this game may be 

quite fun but rather predictable 

and not very innovative. 

Roulette 

— Micromega 

It doesn't take much in the 

way of grey matter to work out 

what this game is all about. 

Unlike most previous versions 

of roulette for the Sinclair computer 

it does give you a good 

range of options, ie odds, 

evens, blacks, column, etc, 

and you can bet on a combination 

of these. 

This is a welt put together 

program with no real surprises 

except for the pretty screen 

display when the wheel is 

spun. If you like this type of 

game then you'll find 

Micromega's version a pretty 

safe bet. 

UK Map 

— Kuma 

Map of UK has recently been 

released by Kuma in a rather 

bigger than usual package - 

more along the lines of VIC 

software packaging. 

Aimed mainly at the educational 

market this program produces 

a large map of the UK, a 

tour of which may be obtained 

by pressing the right keys. It is 

also possible to instruct the 

computer to search for a particular 

place. Fortunately, it 

does hold a reasonable number 

of places but for some reason 

county names have been omitted. 

There is also an inbuilt 

game in which you are in a 

balloon floating over the British 

Isles — quite an interesting 

diversion. 

This is a useful educational 

package which I would recommend 

for the classroom. 

» 1983 ZX COMPUTING AUG.'SEPT 1983 108

The Knights Quest 

— Phipps 

Associates 

This is one of the few adventure 

games with a decent 

amount of in-built graphics. 

Having a picture or map of 

your location does make a 

great deal of difference to an 

adventure game. 

The screen itself is split into 

graphics and text, though 

often there is only text. The 

object of the game is to find 

the lost treasures whilst rescuing 

a Princess held by a witch 

(another chance to be a hero), 

and battling against various 

evils including scorpions, 

elves, etc. The Knights Quest 

follows the tradition of Phipps 

games by being extensive in 

detail and length and a 

pleasure to play. 

As far as adventures go I 

feel confident to recommend 

Knights Quest most highly. 

Spectrum special 1 

— Shiva Software 

All the programs on this 

cassette are enhanced versions 

of some described in 

their range of books for the 

Spectrum. 

There are ten programs: 

Sink the Bismark, Wolf Puzzle, 

Character Builder, Tiger Hunt, 

Pie Chart, St. Moritz, Hidden 

Words, Towers of Hanoi, 

Picasso and Statistics Made 

Simple. Alt these are very obviously 

book-type programs 

because they are very simple 

and relatively unimaginative. 

However, all the programs 

work reasonably well and illustrate 

various techniques of 

programming included in the 

books. 

This cassette can only really 

be recommended as a supplement 

to the books if you do not 

wish to type the programs in. 

Panic 

— Mikrogen 

Panic is very similar indeed to 

the ladders type arcade game. 

An almost identical version is 

available for the BBC under the 

name 'Monsters'. Though 

Panic may not be 100% 

original as a game, it is very 

well written indeed. 

The idea is that you are 

caught in a maze of walls and 

ladders with a load of rather 

nasty aliens. The object is to 

lure them into holes which you 

have dug and then bang them 

over the head until they die. As 

if this wasn't enough you are 

in danger of running out of oxygen. 

As time goes on, and 

especially if an alien gets 

through a hole without getting 

hit, they get even more 

ferocious and difficult to kill. 

Maybe not original, but this 

is the first time I have seen it 

for the Spectrum. It is definite 

ly a highly addictive and enjoyable 

game to play. 


/ / / / / / / 

/ / / ^ / ft / 

/ > / j / / / ^ 7 / / 

/ / $ / Q / V- /O v/4 4ft 4 4 4ft 4 

Painter 7.00 16K 2% 4 4 4 4 4 

Knights Quest 5.95 48K 3 4 4 4 4 4 

Krazy Kong 5 00 48K 3% 3ft 3 3ft 3 3ft 

Jetpac 5.50 16K 4% 4Vi 5 4ft 4ft 4ft 

Black Hole 5.50 16K 3 3 3'A 3ft 3ft 3ft 

Dietron 4.75 48K 4 ft 4 — 4 4ft 4ft 

Blind Alley 4.95 1 6K 3ft 4 3 3 4 4 

3D Tanx 4.95 16K 3 4 4 4 3ft 4 

Spectrum Special 

1 5 95 16K 3 2 3 2 3 3 

Panic 5.95 16K 3ft 4 4 3ft 4 4 

Alien Swarm 4 9 b 16K 3ft 3 3 3 3 3 

Addresses of suppliers 

A&F Software, 830 Hyde Road. Gorton, Manchester. 

Kuma Computers Ltd, 11 York Road, Maidenhead, Berks. 

dk'Tronics, 23 Sussex Road, Gorleston, Gt. Yarmouth, Norfolk 

Sunshine Books Ltd. Mobhouse Court, 1 9 Whitcomb Street. London 

WC2 7HF. 

Phipps Associates. 99 East Street, Epsom, Surrey KT1 7 TEA. 

Control Technology, 184 Market Street, Hyde, Cheshire. 

Quest Microsoftware, 1 19 The Promenade, Cheltenham, 

Gloucestershire. 

Ashby Computers and Graphics Ltd, The Green, Ashby de la Zouch. 

Leicestershire. 

Quicksilva Ltd. Palmerston Park House, 1 3 Palmerston Road, 

Southampton S01 ILL. 

Shiva Publishing Ltd. 4 Church Lane. Nantwich, Cheshire 

Micromega, 230-236 Lavender Hill, London SW1 1 1 L£. 

Crystal Computing, 50 Charles Close. Wroxham, Norwich 

NR1 2 8TU. 

Mikrogen, 24 Agar Crescent. Bracknell, Berks 

Titan Software, The Computer Palace, 46 Market Place, Chipperton. 

Wilts. 

Custom Oata, 20 Friars Quay. Colegate, Norwich NR3 1ES. 


; have been interested for some 

time in trying to get a program to 

RUN on the2X81 which displayed 

a solid object rotating in space 

giving a three-dimensional effect. 

The program, once typed in, requires 

a full five minutes RUNing 

time to complete the POKEing of 

sach of the six picture frames. The 

program will then automatically 

oegtn. The display is quite realistic 

— there is no screen flicker or 

jumping — and shows a rotating 

rectangle, spinning on a fixed 

axis. The rotational effect lasts for 

around 30 seconds and looks 

something like the illustration 

shown in Fig. 1. 

Shapes of things 

The shape of the figure is easily 

altered by changing the coordinates, 

X( ) and Y( ) in lines 

140 to 600. (You'll need to do this 

on plotting paper though.) 

One restriction of the program 

is that only the top half (lines 0 to 

10) can be used. When I first 

developed the program, I tried to 

use the whole screen but I ran out 

of memory (even with the 16K 

RAM Pack attached!). 

Once you have the program 

entered into the machine, it 

should be SAVEd before you 

attempt to RUN it. Once it has 

been RUN, any new instructions 

have to be typed in 'blind' as the 

PRINT position has been moved 

down below line 23 of the screen. 

If you want to re-RUN the program, 

you should type in 'GOTO 

1000'; this will also have to be 

done 'blind'. 

As a final point, the insertion 

of a '£' sign at lines 630 and 

650 is to end each frame with a 

code signal for the operating 

machine code to recognise the 

end of a frame, and the end of 

the last (the sixth) frame. 

110 

ZX81 UTILITY 

Creating a three-dimensional 

image on your 16K ZX81 is not 

as difficult as you might imagine 

with this program from Mr DJ 

Munro of coleraine. 

BASIC notes 

Here is a breakdown of the BASIC 

part of this listing: 

Lines 140 600 

SUB 4010 

SUB 1500 

Lines 660 800 

SUB 4070 

Lines 1010-1060 

Initialisation — co-ordinates of the 

corners of each wire frame (there are six 

frames altogether). 

Enters the operating machine code 

starting at address 30000 from AS. 

Leaves A$ as an empty string. 

SUB 2500 and SUB 3000. Prints the 

picture of each of the six frames in turn. 

Convert the picture frame into Hex code 

and store code in a character string (A$). 

POKEs the Hex code into memory 

starting at the address after the 

operating code (address 30042) and 

leaves A$ as an empty string ready for 

the next frame. 

Calls up the display with RAND USR 

30000. 

ZX COMPUTING AUG SEPT 1983 r

1 

IE FF LD E,255 

1D DECE 

78 LDA.E 

FE 00 CPO 

C8 RET IF ZERO 

2A0C40 LDHL( 16396) 

01 5A 75 LD BC 30042 

OA LD AI8C) 

77 LD(HL>A 

23 INC HL 

03 INC BC 

OA LDA(BC) 

FE OC CP 12 

20 F8 JRNZ 8 steps back 

03 INC BC 

OA LDA(BC) 

FE OC CP 12 

28 E6 JR Z 26 steps back 

16 02 LD D,02 

15 DEC D 

7A LDA.D 

FE 00 CPO 

20 FA JR NZ 6 steps back 

2A0C40 LDHL116396) 

OA LD A(BC) 

18 E4 JR 28 steps back 

The machine code part of the listing, 

The BASIC part of the listing. 

J 

20 CLS 

30 REM "3DMOUER" 

40 FR ST 

50 DIM X

f HOLY 

HOME COMPUTERS 

WHAT ARE WE 

DOING HERE, 

BATMAN V 

Here's a batty program for your 

16K Spectrum from Colin Gooch 

of llminster. 

In this program, you are a bat fly 

ing about trying to secure some 

moths for your supper. Movement 

is made via the four 

'arrow' keys on the Spectrum, 

and to make a catch you have to 

place the centre of the bat 

character directly over the 

moth. Watch out though — the 

moth moves totally at random. 

Because your bat cannot fly 

in bright light, the moth can 

escape you by flying into the 

lighted window in the top left- 

hand corner of the screen. All 

you have to do is to trap the 

moth before it gets there! The 

game ends when you have attempted 

to catch ten moths, 

although there is a bonus if you 

manage to catch all ten. 

Holy bat-catcher! 

Initialisation of the graphics is 

done in lines 2230 to 2250. 

This leads straight into the in 

struction page which is completed 

by lines 2300 to 3030. 

This last section is not repeated 

when you play subsequent 

games after your first. 

The main program begins 

with line 50 which calls the 

subroutine to print the screen 

display, followed by lines 90 to 

120 which initialise the screen 

co-ordinates for the bat and the 

moth. Lines 200 to 300 are a 

loop which constantly moves 

the position of the moth, and if 

the right keys are pressed this 

section of the program actually 

moves the bat. 

The conditional statements 

for the moth make sure that it 

stays within the screen area and 

also reverse its direction should 

it get too near to the edge. The 

moth is moved 'dx' and 'dy' 

across and up the screen, but it 

is not incremented on each pass 

of the loop. It is the RND value in 

lines 230 and 240 which look 

after this latter task, and it is this 

which gives the moth its random 

movement. 

The conditional statements 

for the bat read the keyboard, 

keep the bat on the screen and 

also ensure that it will not move 

into the area of the window. Line 

320 detects a caught moth and 

moves on to the scoring section 

of the program. Lines 330 to 

350 detect the moth in the 

vicinity of the window, and once 

there it is automatically drawn 

into the window, the moth's 

home score is updated and a 

new moth appears down in the 

bottom right-hand area of the 

screen. 

Scoring is carried out from 

lines 370 to 520. This includes 

a 'high score' routine, and offers 

you a bonus 'go' if you managed 

to catch ten moths out of ten. 

This invitation comes courtesy 

of lines 530 to 580. 

Flying tonight 

The REM at line 20 indicates 

which lines need letters typed in 

the graphics mode. Lines 250 

and 260 use keyboard graphics 

and it is important that you get 

four blanks at the end of each 

string, 

Line 3400 looks the most 

complicated. However, if you 

decide that you don't want to 

put a title or instructions in your 

listing, you could always re 

write line 2400 to read: 

2400 RETURN 

and omit all from thereon. 


420 LET TET=TET+ET: IF ET = 10 AH 

D MO =0 THEN PRINT AT 15.0; PAPER 

4-;" IT'S A GOOD NIGHT FOR HUNTI 

NG ";AT 17.10; PAPER 2; INK 7; 

BRIGHT 1; FLASH 1;" CARRY ON 

IF INKEY'* "" THEN GO TO 4-20 

430 IF ET = 10 AND MO=0 THEN PAUS 

E 4-00: FOR N = 15 TO 17 STEP 2: FC 

R M=0 TO 31. PRINT AT N,M; PAPER 

5;" " : NEXT M; NEXT N: GO TO It 

0 

430 IF TET >HSC THEN LET HSC =TET 

4-90 PAPER 4-: CL.S : PRINT AT 5 . G= 

, PAPER 6j" YOUR SCORE THAT ROU 

MD UAS ; ET; " MOTHS EflTE 

N ";MO;" MOTHS ESCAPED " 

500 IF TET>10 THEN PRINT AT 7,0 

, PRPER 6; " YOUR TOTAL SCORE UAS 

"; TET 

510 IF ET > HSC THEN LET HSC =ET 

520 PRINT AT 10,6; PAPER 3; INK 

0;" HIGHEST SCORE SO FRR ";HSC 

530 PRINT AT 12,4-; PAPER 6;" DO 

YOU UPNT ANOTHER GO 7"; AT 13,4-; 

" PRESS v ""es TO CONTINUE " ; AT 

14- , 4-; N " " o TO STOP OR •'••c""t 

ange";NR 15,4-," TO GO TO NEXT GP 

HE 

SPECTRUM GAME 

9 

10 

R E M 

REM BATS by C N GOOOM 

1 1 R E M + 

20 REM Jn Lines 250,300,570,23 

3S the tetters to be printed are 

those Letters in GRAPHICS mode 

30 RANDOMIZE ; CLS ; BORDER 1: 

LET HSC=0: GO SUB 2200 

4.0 PAPER 5. CLS : LET TET =0; L 

ET ET-0: LET MO=0 

50 GO SUB 2050 

Q0 LET XX=16: LET yy=20 

lOO LET y =12 +INT (PND * 5 ) : LET X 

-5: IF RND>.4 THEN LET X=31 

120 LET dX=l: LET dy=l 

190 REM MOUE MOTH 

200 LET dX = t tX =0) - (X -31) +dX * (X > 

3 PND X c 

RND u C20J 

220 PRINT AT y,X; PAPER 5 + 1* (X 

3 PND Y 8 } ; " " 

230 I RND>.5 THEN LET X=X+dX 

2 . 5 THEN LET y=y+dy 

2SO PRINT AT y,X; PAPER 5+1*(X< 

? PND Y 

T N. FOR N=0 TO 3 STEP 3: PRINT 

PT N.0; PPPER 5,P$: NEXT N 

2090 RETURN 

2200 REM ***MOTH*** 

2210 RESTORE 2210. DATA 0,36,102.* 

,255,126,102,36,36 

222 0 REM > > > BP T< < I 

2230 DATA 8,26,62,63,127,231,19=; 

, 126.36,60,60, 24- , 255 . 255 . 255 , 126. 

, 16,56, 124- , 252 , 254- . 231 , 195 , 1 

224-0 REM BTTSFORM GRAPHICSNWJT 

2250 FOR N=0 TO 3. FOR N=0 TO 7. 

READ A: POKE USR CHR$ (N+CODE 

2 

1 

FI'*)+M,A: NEXT M: NEXT N 

2300 FOR N =0 TO 21 STEP 2: FOR H 

= 1 TO 31 STEP 4-; PRINT AT N,M; 1 

NK 1+INT (RNDf3);"BCD": NEXT M- 

NEXT N 

24-00 GO SUB 34-00 

500 PRINT AT 6,0;K $ 

2600 PRINT AT 14,2; PAPER 6;" PF: 

ESS ""ENTER"" TO CONTINUE ";AT 2 

1,10; PAPER 7; INK 0; FLASH L;" 

STOP THE TAPE "; PAUSE 0: CLS 

2700 PRINT AT 2,10; PAPER 2; INK 

7,* BRIGHT L; FLASH 1; " B A T S 

2800 PRINT AT 4. , 0; YOU ARE A BP 

T HUNTING MOTHS ' ' "FOR 5UPPEP 

2900 PRINT AT 5,0; 

OV>ED UITH KEYS NO . 

M # * 

3000 PRINT AT 8,0; 

CAUGHT UHEN THE "' 

LLY OUER IT" 

3010 PRINT AT 10,0; 

SAFE IN THE YELLOU 

HE LIGHTED UINDOU*' 

NOT GO HERE" 

3020 PRINT AT 16,0; 

DS WITH 10 MOTHS 

""CAUGHT 

3030 PRINT AT 18,0; 

ER"" TO CONTINUE ": 

RETURN 

34-00 LET Kf = " 

34-10 RETURN 

THE 

** * I I 

BAT IS H 

"5 TO 8' 

THE MOTH IS 

BAT IS CENTRP 

' THE MOTH IS; 

PREP OF T 

' THE BAT CAH 

' THE GAME EM 

""HOME"" OR 

' PRESS ""EN7 

PAUSE 0. CLE- 

1983 ZX COMPUTING AUG'SEPT 1983 113

1983 

CHILDREN'S 

EDUCATIONAL 

SOFTWARE 

THE MICRO MASTER SERIES 

FOR ANY SPECTRUM 

The Micro Master series is a unique educational 

product covering essential numeracy and language 

skills for 7-13 year olds. It has been RESEARCHED 

and TESTED by experienced teachers with one 

specific aim LEARNING. 

The series comes in two parts which can be 

purchased separately or together 

THE FOUR RULES OF NUMBER 

(A package of 5 programmes) 

This package, developed for ALL children between 

the ages of 7-13. concentrates on the fundamental 

skills of Addition, Subtraction. Long Division. Long 

Multiplication and it incorporates a multiplication 

tables learner. Knowing how to use and perform 

these skills is NOT ENOUGH. These programmes will 

engender FAST and ACCURATE calculation ability 

and advance the child to high levels of complexity. 

Progress can be monitored readily by consulting the 

age-related grading charts which are included. 

THE LANGUAGE DEVELOPMENT SERIES 

(Each cassette contains 10 programmes) 

This series is specifically designed to develop the 

verbal skills required by our EDUCATION and 

EXAMINATION systems. The series will develop 

VOCABULARY, SPELLING. CONCEPT ATTAIN- 

MENT. VERBAL REASONING and KNOWLEDGE OF 

THE ENGLISH LANGUAGE. It can be used lor 

remedial teaching and, at the highest levels, for 

Common Entrance, 11+ etc. 

TO ORDER: 

The Four Rules of Number £11.70 

(Please state pupil s age) 

Language Development Cassette £7.90 

(Please state pupil's age) 

Both the above £14.50 

CHEQUES/P.O.s to: 

MICRO MASTER 

Dept ZXC, 94 Airdale Avenue, Chiswick, 

London W4 2NN. 

FOR FURTHER DETAILS 

PHONE 01-747 1373 

BEFORE YOUR CHILD PLAYS INVADERS — 

THINK OF MICRO MASTER 

MAIL ORDER PROTECTION SCHEME 

If you order goods from Mail Order Advertisers in this 

magazine and pay by post in advance of delivery, this 

publication will consider you for compensation if the 

advertiser should become insolvent or bankrupt, 

provided 

1 You have not received the goods or had your money 

returned: and 

2 You write to the publisher of this publication explaining 

the position not earlier than 28 days from the day 

you sent your order and not later than 2 months from 

that day. 

Please do not wait until the last moment to inform us 

When you write, we will tell you how to make your claim 

and what evidence of payment is required 

We guarantee to meet claims from readers made in 

accordance with the above procedure as soon as 

possible after the advertiser has been declared bankrupt 

or insolvent lo a limit ol £1.800 per annum for any one 

advertiser, so affected, and up to £5,400 p a in respect of 

all insolvent advertisers Claims may be paid for higher 

amounts, or when the above procedures have not been 

complied with, ai the discretion of this publication, but 

we do not guarantee to do so in view of the need to set 

some limit to this commitment and to learn quickly of 

reader's difficulties 

This guarantee covers only advance payment sent in 

direct response to an advertisement in this magazine 

(not, for example, payments made in response to catalogues, 

etc. received as a result of answering such 

advertisements): 

CLASSIFIED ADVERTISEMENTS ARE EXCLUDED. 

DONT MISS THIS UNIQUE OFFER — 

ZX8116KRAM PACKIuily cased tested and guaranteed Gold plated edge 

connector — no wobble design Only CI 7 95 (just El 7 95 — no mistake') 

incl PAP in UK only Compare OUT prices 

SPECTRUM OUST COVERS hign quality & cashable C1 95 Also 

available lor most other micros monitors. disc drives & printers 

ZX81 OE-LUXE LOADING AID comprises electronic circuil hou 

smart black case Red. green & yellow lights (LED) allow volume to be 

adiusted easily for perfect LOADing Pushbutton to RESET computer Hear 

voiceovers & position tape accurately using FARPHONE supplied Supplied 

with LOAD'SAVE switch filled so both FAR & MlC leads may be left 

connected Complete with full inslructtons It is designed to ensure trial 

even (apes made on loreign casselle players toad first time ZX 

Computing Oct/Nov 1982 Tms is not just a cheap VU meter this one 

works Only C18 70 (incl P&P in UK only) Spectrum version only C18 95 

ZX81 KEYBOARD BEEPER — brings the keyboard to lite providing audible 

feedback lo keyboard entry AII210characiersbeepineilherSLOWorFAST 

modes Fits inside — no trailing wires — no soldering necessary as a" 

connections simply plug-m lllustiated mstiuctions incl Only CI 0 95 (incl 

P&P in UK onlyl 

T-SHIRTS C3 50 SWEATSHIRTS C7 50 black with red SINCLAIR ZX81 

or white with black "ZX SPECTRUM' 4 rainbow Thesearo Sinclair approved 

designs — correct colours & logos (Prices mcl P&P in UK onlyi Terrific 

hand airtxushed (but washable) multi-coloured designs i M A MICRO 

ADDICT or ' MICROCOMPUTERS TAKE YOU INTO ANOTHER WORLD 

against space scenes Words do them |ustice T-shirts C4 50 Sweatshirts C9 

(incl P&P m UK only) Specify garment sizes required 24 to 44 

Flat flexible ribbon cable suits other keyboard 10ZX8I or Spectrum interconnection 

(which leguires 5 & 8 way) available any length maximum 19 

way 1 p per lOmm (e g lOOmm ol 5 way = 50p) Plus ZX81 & Spectrum type 

keyboard connectors 5 way 95p ea. 8 way CI 05 ea 

BOOKS Spectrum Graphics 1982 Nick Hampshire C7 95 Spectrum 

ROM Decoded/Disassembly An annotated disassembly of the Spectrum 

ROM 1982MOIC4 90 f he ZX Spectrum & how to get the most trom it 1983 

tan Sinclair C6 95 Z80 Instruction Handbook' 1982 Wadsworlh C550 

introduction 10 the Z80 Microcomputer 1982 Khambala C9 50 

SPECTRUM SCREEN DISPLAY CHARTS I ;>ads printed with the 

appropriate matrices to enable the user to draw character & screen display 

designs C4 95 ea (incl P&P in UK only) 

Please send stamped addressed envelope for free catalogue. Dealer 

Enquiries Welcome. Please mail order with cheque.' PO to: Dept ZX 

FULCRUM PRODUCTS 

14 Sleep Lane. Findon. Watt Sui»> BN14 0UF Tel: Findon (090 671) 2750 


More overhead 

excitement in this 

Spectrum program, 

courtesy of Mr HT Davis 

of Hereford. 

This program differs a little bit 

from the normal 'war time' 

simulation games in that the 

shells actually follow a 

parabolic trajectory. The equation 

used to work out their motion 

is calculated in line 75 and 

simulates a projectile under 

gravity. 

what goes up.. . 

The initial velocity and angle of 

projection can either be 

selected by the player (mode 

x) or by the computer (mode 

i). The aim of the game is to 

destroy the overhead aircraft, 

launched ICBMs and the ICBM 

base; the ICBMs and their base 

must be destroyed using shells 

and the aircraft should be 

destroyed using rockets. The 

115 ZX COMPUTWG AUG/SEPT 1983 

game stops either after eight 

cycles or if you accidently 

destroy an allied aircraft (you 

can spot them because they're 

blue!). 

Full instructions are included 

in the program, including 

when one can fire a shell or a 

rocket. The program occupies 

virtually all of the 16K 

memory. 

A variable 

situation 

The variables used in this program 

are: 

P 

s 

— The number of 

game cycles. 

— The game mode. 

— The score. 

r 

v 

w 

• 

(x.y) 

The rocket drive. 

The rocket control. 

The random element 

in the aircraft 

and ICBM drive. 

The aircraft and 

ICBM drive. 

The shell trajectory 

pixels. 

(q,m) 

z 

U (V on 

display) 

A 

The shell trajectory 

co-ordinates. 

The shell control. 

The shell launch 

velocity. 

The shell launch 

angle. 

i 

i

1 GO SUB 1000 

5 PRPER 6: INK 1 

10 DIM i $ (704) : PRINT RT 0,0;:. 

12 BORDER 4 

14 PRINT INK 2; FLASH 1;AT 

** AIR-RAID " : PRINT AT 4.2; 

s t r o y t h e r c e i i ' s a n d t h e i r 

a s e W i t h s h e l l s ( K e y S3 A T 8 , 2 ; 

" D e s t r o y e n e m y a i r c r a f t w i t h 

s h e l l s I S ) a n d r o c J t e t s ( R ) " ; R T 

1 2 , 2 ; " A l l i e d a i r 

I j m u s t n o t 

1 5 P A U S E 2 0 0 

18 PRINT 

s e t o w n s h e 

o r y , p r e s s 

d o l a u n c h , 

19 PRUSE 

SPECTRUM CAME 

1 , 1 

" D e 

r c r a f t a r e b l u e a 

be h i t " 

BCRDER 5 

I N K 2 , R T 1 6 , 6 ; " T O s e l 

11 t r a j e c - 

< X 3 " ; A T 2 0 , 2 ; " F o r r a n 

p r e s s ( Z ) " 

2 0 0 

20 LET S=0 

25 LET g =0 

30 IF INKEY $ =" X 

GO TO 600 

32 IF INKEY J = " Z 

GO TO 725 » 

34 GO TO 12 

40 LET V =0 

45 LET Z=0 

50 LET w =INT (RND*7) 

60 FOR X=0 TO 60 

61 IF X < 40 AND 2=0 

N PRINT INK 0; PAPER 

RT 0,1;"FIRE S",AT 0 

,13;" "; RT 0,14; "fi = ". 

"; AT 0, 16; A; "" 

" 70 IF Z =0 THEN LET y=0 

THEN LET p =1 

THEN LET p =0 

b 

AND V =0 THE 

7; FLASH l; 

6; "U = " ; AT 0 

AT 0, 10; U; 

75 IF Z > . 5 AND X-Z1 AND y0 AND X-5*w 30 RND W+X31 AND w +x24 AND X 25 AND X 3 8 A N D X < 6 1 T H E N P R I N T 

R T 6 0 - X , 2 4 ; " " , - R T 6 0 - X , 2 0 ; " " 

1 3 2 I F w -*-x > 3 7 R N D v + x < 5 9 T H E N 

R I N T I N K 4 ; R T 5 8 - I w+X 3 , 2 2 ; " C " 

1 3 3 I F w + x > 3 7 A N D U f X < 6 0 T H E N 

R I N T A T 5 9 - (W+X 3 , 2 2 ; '* " 

1 5 0 L E T q = I N T t ( 1 7 S - 4 0 # y J / S ) : 

E T frt = X - Z 

1 5 5 I F A T T R ( q , B ) = 5 7 A N D m < 3 2 

N D Z > . 5 A N D q > 0 T H E N P R I N T R T q . 

« ; " G " : GO T O 8 5 0 : R E M G R R P H I C S G 

1 5 6 I F A T T R ( q , K ) > 5 7 A N D » < 3 2 R 

ND Z > . 5 A N D q > 0 T H E N P R I N T A T q . 

m;"G": B E E P 1 , - 2 5 ; L E T S = 5 + 2 0 0 

1 6 0 I F S C R E E N $ ( q , » ? t = A N D m< 

3 2 A N D Z > . 5 T H E N P R I N T A T q . m ; " 

" ; B E E P . 2 . - 1 0 : L E T 5 = S + 5 0 

1 7 0 I F A T T R (r ,33 = 5 7 A N D V < > 0 R 

N D X —V < 1 2 T H E N P R I N T I N K 6 ; A T r . 

3 ; "G"„- B E E P 1 , - 2 0 : G O T O 8 5 0 

1 7 1 I F R T T R f r , 5 3 = 5 7 A N D V < > 0 R 

N D X —V < 1 2 T H E N P R I N T I N K 6 ; R T r . 

5 ; " G " : B E E P 1 , - 2 0 : GO T O 8 5 0 

1 7 3 I F R T T R ( r - 1 . 3 3 > 5 7 R N D V < > 0 

R N D X —V < 1 1 T H E N P R I N T I N K 6 ; RT 

r - 1 , 3 ; " G " : B E E P 1 , - 2 0 : L E T S = S + 1 

0 0 • 

1 7 4 I F A T T R ( r - 1 , 5 3 > 5 7 A N D V < > 0 

R N D X - V < 1 1 T H E N P R I N T I N K 6;flTT 

r -1 

3 0 

130 

5, "G" 

8; s ; " " 

2 0 0 IF 

GO SUB 

205 IF 

2 3 

215 IF 

3 303 

220 IF 

305 

230 IF 

US 305 

235 IF 

•JB 550 

24 0 NEXT 

PRINT INK 0; 

• • 

245 

250 DIM 

DIM 

X

$: PRINT RT 15,0;if: PRINT 

, 3;iS: PRINT RT 17,0;i$ 

260 DIM i $(17) : PRINT 

PRINT RT 19,0; i$ 

261 DIM 1163; PRINT 

$ 263 LET 9=9-1-1: IF 9=8 

3 9 0 0 . 

265 IP p=l THEN GO TO 

268 IF p =0 THEN"CO TO 

2 "70 GO TO 4-0 

3 0 0 LET Z =X 

303 IF INKEYJ= " r " THEN GO TO 4-43 

2 

306 IF V=0 OR x-v>9 THEN PRINT 

INK 0; FLRSH lj PRPER 6;RT 0,0;" 

PRESS R ": PRINT PRPER 7;RT 0,9 

310 

400 

4-02 

=X 

405 IF 

44-5 IF 

T 0,0;" 

SPECTRUM GAME 

RT 16 INK 0;RT 2 1 , 3 ; 

RT 1 8 , 0 ; z 3 1 5 

i ** » 

J- / 

RT 2 0 , 1 ; i 8 3 0 

mc s 

THEN GO 8 4 0 

3 4 5 

6 0 5 8 5 0 

7 2 5 354 

RETURN 

IF Z < . 5 THEN GO TO 450 

IF V-0 RND X-Z>4 THEN LET 

450 RETURN 

500 IF Z < >0 

505 RETURN 

550 IF V < >0 

355 RETURN 

600 CLS 

X-V>11 THEN LET V =X 

X=V THEN PRINT PRPER 7; R 

THEN LET Z-.5 

THEN* GO TO 305 

603 IF g =0 THEN GO TO 780 

505 INPUT "Enter Speed U" 

510 INPUT "Enter Rngie R" 

515 GO TO 40 

725 LET U =80 +INT (RNDM0) 

730 LET R =25 + INT (RNDF40) 

74.0 IF O0 THEN GO TO 4-0 

780 CLS 

790 BORDER 5: INK 0: PRPER 7 

795 DIM I $ (704) : PRINT RT 0,0; 

$ 800 PRINT INK 2; 

RT 14- , 29 ^ 

R»T 15,29; 

RT 16.29, 

RT 17,29; 

RT 18,17; 

RT 19,17; 

RT 20,17; 

805 PRINT OUER 

RT 14,29; 

RT 15,29; 

RT 16,29; 

RT 17.29; 

RT 18 , 17; 

RT 19,17: 

RT 20,17; 

310 PRINT INK 

Your rockets destroy the enemy 

planes — but your shots missed 

the enemy missiles. Jit* 

1983 ZX COMPUTING AUG'SEPT 1983 

U 

R 

PR IN" 

4-00 

3 6 0 

B";RT 21,5;' 

1; INK 4-RT 2 1 , 2 

PRINT OUER 

"RT 21 23' 1 

PRINT RT 21,0;"H"; REM GRflR 

H 

IF p=l THEN GO TO 605 

IF p=0 THEN GO TO 4-0 

CLS 

INK 1 

PRINT FLRSH 1;RT 5,11;"GRME 

OUER": PRINT RT 8,4;"You have d 

estroyed o n e " ; R T 10,6;"o f your o 

afn p lanes"; RT 13, 6; "Your score ; 

5 "; FLRSH I; INK 0; PRPER 7;s;" 

865 PRINT RT 16,4;"Press to 

P l a y a q a i n " 

870 FOR d =0 TO 7 

374- IF INT (d/2) =d/2 

. 5 . 2 

876 IF INT (d/2) < > d/2 

5 —2 ' 

THEN BEEP 

THEN BEEP 

880 IF INK EY $ = "p" THEN GO TO 5 

885 NEXT d 

890 GO TO 860 

900 CLS 

910 INK 1 

920 PRINT FLRSH 1;RT 3,11;"GRME 

OUER": PRINT RT 8,6;"YOU have * 

cored "; FLRSH l; INK 1; PRPER 7 

; S; 

9 2 5 PRINT RT 1 1 , 4 ; " W i t h o u t LOSS 

o f a i r c r a f t " ; R T 16,5;"Press

If you run, or are a member of, 

a user club which caters for 

the Sinclair user, why not get 

your group on the map by 

writing to us at: 

Ctub Corner, 




All you have to do is to send us 

a letter with details of your 

club (times of meetings, addresses 

of who to contact, 

etc) and we'll do the rest. If 

you publish a newsletter or 

club magazine, we'd very 

much like to see that too. 

And if you don't see a club 

in your area, why not start one 

up by writing to ZX Computing 

and seeing if any like-minded 

enthusiasts wish to join you. 

National zx users' 

Club 


I am writing to announce the 

closure of The National ZX 

Users' Club which was founded 

by Tim Hartnell over three 

years ago. 

When Tim started Interface, 

there were no local user 

groups or specialist ZX 

oriented magazines. But there 

comes a point when one must 

grow up — when other people 

are doing the job you have 

been doing. Tim Hartnell and 

The National ZX Users' Club 

gave a lot of help to the 

magazine Sinclair User at its inception 

and as your readers are 

aware, Tim was Editor of ZX 

Computing for the first four 

issues. 

Those with memberships 

still to run are being offered 

either a full refund for the 

outstanding period, or free 

books published by Interface 

Publications. On a further 

note, Interface Publications 

will continue to flourish in the 

field of computer-related 

books and Tim Hartnell will 

continue to write and edit new 

titles. 

As you know, the membership 

of our club has been 

strong in the past, over 

10,000 members at its peak, 

and I would like to take this opportunity 

to thank all of them 

for their support. 


Liz North, 

Interface Publications. 

Lambeth 

Computer 

Club 

Dear ZX Computing 

The Lambeth Computer Club 

has now been fully organised, 

even to the extent of a draft 

constitution. Our inaugural 

meeting was on Saturday, 30 

April, with some 12 members 

attending (60% of the 

membership). Our first Annual 

General Meeting is planned for 

Thursday, 15 September, the 

venue to be announced. 

Will new members please 

contact me at the address 

below. Your name and address 

will be passed as soon as 

possible to the Membership 

Secretary. 


Robert Baker. 

54 Brixton Road, 

London SW9 6BS. 

Llantwit Major 

Computer Club 

Dear ZX Computing 

We have, alter three meetings, 

already achieved a membership 

of some 20 people whose 

experience on personal computers 

range from elementary 

knowledge to quite advanced 

ability. Age range of members 

is also very varied. 

The club meets every Tuesday 

evening in the Adult 

Education Centre in Llantwit 

Major where we have the 

facilities of the comprehensive 

school's computer equipment. 

Members are also encouraged 

to bring along their own computers. 

The basic objectives of the 

club have been defined as 

follows: 

a) To encourage greater computer 

programming skills. 

b) To attain greater 

understanding of the internal 

operation of computers. 

c) To develop the use of different 

programming languages. 

d) To assess the market 

availability of both software 

and hardware. 

e) To foster the advancement 

of personal knowledge of computers 

and equipment by 

association with other interested 

computer users. 

f) To keep abreast of the state 

of the art. 

We hope to supplement these 

objectives by holding occasional 

lectures by professional 

computer users and arranging 

visits to local establishments 

who are involved in the 

manufacture and use of computers. 


Douglas Mountain 

1 6 Denbigh Drive, 

Llantwit Major, 

South Glamorgan, 

CF6 9GQ. 

Sutton Library 

Computer Club 


I am writing with fuller details 

of the club we formed earlier 

this year which might be of interest 

to your readers. 

We meet on the first Friday 

of each month between 6.15 

and 10pm and on the third 

Tuesday of each month between 

8.15 and 10pm at the 

Sutton Central Library, St 

Nicholas Way, Sutton, Surrey. 

Subscriptions are £6 for 

adults, and £4 for students 

and pensioners. Our membership 

is currently around 1 00. 

New members are always 

welcome whether experienced 

or new to computers. No 

machine is necessary, and in- 

deed about 25% of our 

membership do not own a 

computer. 

We have a programme for 

1983 which includes everything 

from an introduction for 

beginners to machine code and 

Prestel editing. In addition to 

the formal groups at each 

meeting, members are encouraged 

to bring their equipment 

along to demonstrate 

and exchange ideas and help 

solve each other's computing 

problems. 

For further information contact 

me at the address below 

or 'phone Jennifer Woeller at 

the Sutton Library on 01-661 

5031. 

Your faithfully, 

David Wilkins, 

22 Chestnut Court, 

Mulgrave Road, 

Sutton, 

Surrey SM2 6LR. 

The Edinburgh 

Home Computing 

Club 


The Edinburgh Home Computing 

Club (formerly the Edinburgh 

ZX Users Club) meets 

three times a month at the 

Claremont Hotel, Edinburgh on 

the second, third and fourth 

Wednesday of each month. 

The club is open to all those interested 

in the uses of micros 

and we also produce a bimonthly 

newsletter with articles, 

software and hardware 

reviews of interest to the 

members. 

Anyone interested should 

contact John Pamer on 

031-661 3183 after 6pm, 

myself at the address below or 

just come along to one of the 

meetings. 


Ian Robertson, 

Secretary, 

71 Oxgangs Terrace, 

Edinburgh EH 13 9BZ. 

Tel: 031-441 2361 


mrortcouco c 

/ i / / ' . / V . O / n d \ i Z 

MICROSPHERE COMPUTER SERVICES LTD 

72 ROSEBERY ROAD LOttDOH HIO 21, A 

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EVOLUTION (48K Spectrum) 

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Should be easy after ail it's been done before 1 

Only £6.95 

OMNICALC I48h Spectrum) 

The best Spectrum spreadsheet you can buy Written in machine code to be 

taster to give you more spacefor data, and to allow more features to be included 

it is guaranteed uncrashabie 

-If more programs shared the Quality of OMWCALC. then we might see more 

Spectrums m offices " Home Computing Weekly 3/5/83 

-it is ideal lor someone whohasiust found the spreadsheet concept, but it is also 

a very powerful tool lor anyone who has used one p/evrous'y " 

Sinclair User June 1983 

Complete with comprehensive manual £9.95 

ZXStOEPRINT Spectrum S ZX8T versions) 

Use ZX Sideprmt to print sideways giving you 80/132 etc characters pei line 

(Stale version reqd) £4.95 

CREVASSE A HOTFOOT iany Spectrum) 

Can you make it across the ice cap whilst chasms open and close all around 9 

Or. hetp the rabbit get to fields lull ol carrots - but remember 1 the plumper the 

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2 original games tor only £4 .95 

NEW! THE TRAIN GAME (any Spectrum! NEW! 

First there were model railways, then there were computers Now Microspheie 

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Featuring passenger, goods A express trams tunnels, viaducts, points, stations, 

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Battle of Britain 

A strategic Wargame for the 48K Spectrum 

One day in summer. 1940 Reports arecommg m of enemy bomber 

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How are you to deploy the nine tighter squadrons under your 

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British and enemy squadron movements are plotted on a superb 

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Features variable difficulty levels, lull control of squadron 

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48K Strategic 

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VOu — (he only remaining pilot of the *Taith 

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* Hnrlni Scanner display In hi-tes * 

1 Full colour and sound affects 4 

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• 100 S machine code • 

MINES OF SATURN and 

RETURN TO EARTH £5,95 

Miin ol Saturn While piloting a routine orbit of 

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abandoned mining base and you set off in search ol 

some di-liihium crystals to refuel your stranded 

space ship. Can you do it? 

Return to Farth Having escaped from your previous 

dilemmas, you leach faith Station 1, but tail 

to make radio contact. You effect a safe if 

harrowing manual ducking. On entry you find II 

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Of your predicament, but beware, many ol the 

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Software 

SPACE ZOMBIES (16K) £5,95 

Shooting through ipvr you are vntuslvd by a 

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please telephone (0344) 2 7317 (9am -6pm.t 

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Cosmic Raiders Space Zombies 

Mines of Saturn Return to Carth Mad Martha 

MIKKOIJ N, Opt A), 2i Agar Crescent, flrackreil. Berkshire, RG1» JHlK 



Motor marines 

Enter the Crand 

Prix in this 

program for 

your ZX81 

written for us by 

Keith Ditchburn 

of Danby. 

You are a racing driver in the 

Grand Prix and you must steer 

your car using the '5' and '8' 

keys to move left and right 

respectively. 

The machine code takes up 

to 50 bytes and should be 

located in a REM statement 

with the starting address 

16514. The routine you'll 

need to POKE this into your 

computer follows below: 

1 REM 50 Es 

10LET A = 16514 

20 INPUT N 

30 PRINT N;","; 

35 POKE A,N 

40 LET A = A + 1 

50 GOTO 20 

Once this program has been 

entered into the computer you 

should type in the following 

numbers. (The commas 

separating the numbers represent 

Newline.I 

Okay, you're on your own 

now - happy racing, and try 

and keep out of the fast lane! 

42, 12, 64, 229, 17, 33, 0, 25, 209, 1, 214, 2, 237, 

176, 42, 12, 64. 35, 6, 15. 35, 5, 194, 150, 64. 14, 

126, 6, 16, 17, 33, 0, 25, 5, 194, 162, 64, 6, 5, 5, 35, 

1 1 3, 194, 169, 64, 201, 


1 REM E£RND FAST > 5 ; SGN • CHR 

$ • GOSUB ISE£: R N DTgTm 71 TftB fiRND fc* 

OS :*TftB 3RND/®1 7?TfiB JRMOTAN T 

RN EEEEEEEEEEEEEEEEEEE.EEE.EEEEEEE 

EEEEEEEEEEEEEEEEEEEEeEEEEEEEEEEE 

o 

4- 

9 

lO 

3C 

8G 

6 3 9 7 

85 

ao 

DIM R$'12.10) 

DIM ft

Spectrum 

streams 

Mike Lord, author of 

Exploring Spectrum BASIC, 

shows you how to make 

use of some of the more 

inaccessible commands on 

the spectrum. 

Most of the software needed to 

handle the promised Spectrum 

RS232 Network and Microdrive 

will be in a ROM in the new interface. 

But, the BASIC ROM in the 

Spectrum itself does contain 

some undocumented functions 

which — although intended for 

use with the new peripherals — 

can be used without them. They 

control the way input to a program, 

and output from it, are 

handled. 

BASiCally speaking 

Within a BASIC program, the 

Spectrum manual says that we 

can use: 

PRINT to output to the upper 

part of the TV screen. 

LPRINT to output to the ZX 

Printer. 

INPUT to output to the lower 

part of the TV screen, and also 

to input from the keyboard. 

But experimentation has shown 

that there is another form of 

these commands: 

PRINT 0 n; 

LPRINT 0n\ 

INPUT # n; 

where 'n' is any valid numeric 

expression. 

Normally, giving 'n' any 

value other than 0, 1, 2 or 3 wilt 

result in the error message: 

INVALID STREAM 

So, it seems logical to call 'n' the 

'Stream number'. The four valid 

values give the following 

results: 

0/1 These values are the 

same; they cause output 

to be printed on the lower 

SPECTRUM UTILITY 

half of the screen, 

whether PRINT, LPRINT 

or INPUT is used, and 

they allow input from the 

keyboard with an INPUT 

statement. 

This value causes output 

to the upper part of the 

screen, regardless of 

whether the keyword used 

is PRINT, LPRINT or 

INPUT. But, any attempt 

to input a value, as for example 

with: 

INPUT 02;" Enter a 

number " ;A 

will result in the error 

message: 

INVALID I/O DEVICE 

This value is similar to 2, 

except that output is to 

the ZX Printer rather than 

to the screen. 

One use for these "Stream 

numbers' is to give the user of a 

program the choice of output to 

the screen or to the printer: 

100 INPUT " Enter 2 for display, 

3 for hard copy " ;strm 

200 PRINT #strm;" Message 

1 " 

300 PRINT #strm;" Message 

More deviously, we can use 

PRINT #0; or PRINT #1; to 

display a message on the bottom 

part of the screen, in the 

same way that INPUT normally 

does but without expecting an 

input from the user. For 

example: 

PRINT 00;" 24th line" : PAUSE 

0 

The PAUSE 0 statement here is 

to prevent the message being 

over-written by the Spectrum's 

OK report when it has finished 

executing the PRINT command 

in this little demonstration. 

Having got a message onto 

the bottom line of the screen, it 

can be deleted by an INPUT 

statement, which always clears 

the lower part of the display. 

And, if you don't actually want 

to INPUT anything at that stage 

in the program, then you can just 

use the strange looking command: 

INPUT 

which clears the bottom of the 

screen, prints nothing, then 

moves immediately on to the 

next statement in your program. 

To see this, try: 

10 FOR A = 1 TO 10 

20 PRINT #0;A 

30 PAUSE 25 

40 INPUT " " 

50 NEXT A 

One variant which can often be 

useful is: 

PRINT #0;" Press any key to 

continue" : PAUSE 0 : INPUT 

If you don't clear the bottom 

part of the screen, then subsequent 

PRINT 00 statements will 

print on successive lines, scrolling 

the bottom part of the screen 

up to make room, as can be seen 

from: 

10 FOR A = 0 TO 21 : PRINT A : 

NEXT A 

20 FOR A = 1 TO 20 : 

PRINT #0;A : NEXT A 

But you can overcome this by including 

an AT function in the 

PRINT MO command: 

10 FOR A = 1 TO 100 

20 PRINT 40; AT 0,0;A 

30 NEXT A 

If you try this you will see that it 

prints on the 23rd line which is, 

of course, normally the top line 

of the lower part of the display. 

Changing line 20 to: 

20 PRINT #0; AT 1,0:A 

and this will make it print on the 

24th line. If the AT line number 

is greater than one, then the bottom 

part of the screen will be expanded, 

scrolling the top part up 

»o make room. 

Open more 

streams 

As well as 0 to 3, you can also 

use stream numbers 4 to 1 5, as 

long as you tell the Spectrum 

about it first. The command for 

doing this is: 

OPEN *n , c$ 

where 'n' is the stream number 

(4 15) and 'c$' is: 

"P" For output to the ZX 

Printer. 

"S" For output to the upper 

part of the screen. 

"K" For output to the lower 

part of the screen and input 

from the keyboard. 

( OPEN 0 is below key 4.) So, if 

you include: 

OPEN #1 5," P" 

in a program, then any subsequent 

PRINT #15 (or LPRINT 

01 5 or INPUT 01 5) statements 

will output to the printer. 

The CLOSE #n command 

(see below key 51 does the 

opposite — cancelling any OPEN 

0n streams — although it can't 

be used to close the four predefined 

streams numbered 0 to 

3. 

Presumably the extra ROM 

software provided with the 

RS232/Net/Microdrive interface 

will let you use the OPEN # 

command to set up channels for 

communicating with the I/O 

devices and with Microdrive 

files — we shall have to wait and 

see! 

in machine code 

Things get even more interesting 

when you look at how 

the Spectrum handles the ' 0' 

commands. The Spectrum 

manual gives a few clues about 

how they work. Within the 


system variables area there 

is a block of 38 bytes 

(23568-23605) called 

'STRMS' which contains the 

Addresses of channels attached 

to streams'. Then at 

23631/2 the system variable 

CHANS is said to hold the 'Address 

of Channel Data', and this 

is followed at locations 

23633/4 by CH.RCHL, the 

'Address of information currently 

being 'Address of Channel 

Data', and this is followed at 

locations 23633/4 by 

CHURCHL, the 'Address of 

information currently being 

used for input and output'. 

Also, the memory map in 

chapter 24 of the manual 

shows an area denoted as 

'Channel Information'. CHANS 

holds the address of the start 

of this area; the end is 

signalled by a byte of value 80 

Hex. 

After some investigations into 

the contents of these RAM 

locations and into the workings 

of the Spectrum ROM, the 

following picture emerged. 

The 38 bytes of STRMS consist 

of 1 9 two-byte entries. On 

power-up or after a NEW command, 

they are set to the values 

: 

shown in Table 1. The first three 

entries are used for other ROM 

ZX 

SPECTRUM UTILITY 

functions, but the remaining 1 6 

two-byte entries correspond to 

stream numbers 0 to 15. The 

OPEN M and CLOSE # 

statements mentioned earlier 

change the values in this table. 

For example, OPEN #4,"S" 

changes the contents of location 

23582 to 6. 

These values turn out to be 

pointers, so that the value in 

system variable CHANSplusthe 

value from the STRMS table 

minus one, gives the address of 

one of the entries in the Channel 

Information area of RAM. Each 

entry in this area is five bytes 

long, and consists of two twobyte 

addresses followed by a 

single byte containing the code 

for one of the characters, "K", 

"S", *R" or "P". (Note that 

"K", "S" and "P" are the letters 

allowed in an OPEN #statement.) 

Without the RS232/Net/ 

Microdrive interface fitted, the 

Channel Information area is 21 

bytes long, and contains four 

blocks as shown in Table 2. The 

first address in each block is the 

starting address of a ROM 

routine used to output a 

character. The second address 

is either that of a ROM routine to 

input a character from the 

keyboard or of a routine which 

gives the 'INVALID I/O DEVICE' 

error message. 

in comparison 

By comparing Tables 1 and 2, 

we see that the first pair of addresses 

in the Channel Information 

area are used by streams '0' 

and '1', the third pair by '2' and 

the fourth pair by '3'. 

In each case, the Spectrum 

looks up the address of the 

appropriate I/O routine in the 

table then calls it with the 

character to be output in the 

Z80's A register. What this 

means is that if, say, we wanted 

to drive a special, non-ZX, 

printer, then we could write a 

machine code routine to handle 

it, and replace the first two 

bytes of the fourth block in the 

Channel Information area by the 

starting address of the new 

routine. Any LPRINT, LLIST or 

PRINT #3 commands would 

then automatically use the new 

printer drive routine! If you are 

actually going to do this, then 

note that your machine code 

routine must be able to cope 

with the print control codes (6 to 

23), the keyword codes (1 65 to 

255) and graphics character 

codes, as well as with 'normal' 

characters. 

You will see from Table 2 

that the same ROM routine 

Table 1 : The contents of STRMS. 

(starting at OF94 Hex) is used to 

print to either half of the display 

and also to the ZX Printer. The 

routine decides where to send 

the output by looking at bit one 

of FLAGS (2361 1) which is '0' 

for output to the screen and '1' 

for output to the printer, and 

also at bit zero of TVFLAG 

(2361 2) which is '0' when the 

output is to the top part of the 

screen and ' 1' for output to the 

lower part. 

via RST10 

Machine code programmers will 

be used to using RST1 0 to output 

the character whose code is 

in the A register. What RST10 

does, in fact, is to take the contents 

of the system variable, 

CHURCHL. which will be the address 

of one of the entries in the 

Channel Information table, and 

then jump to the address held at 

that entry. Again, FLAGS and 

TVFLAG determine where the 

output goes. 

You can set these flags up by 

calling the ROM routine at 1 601 

Hex with the A register containing 

*0' for output to the lower 

part of the screen,' 2' for the top 

part of the screen or '3' to select 

the ZX Printer. 

Location Contents Stream 

23568 1 

23570 6 

23572 11 

23574 1 0 

23576 1 1 

23578 6 2 

23580 16 3 

All other locations from 23568 to 23605 contain zeros. 

Table 2. The Channel Information area of RAM 

Contents of the 21 bytes, in Hex. 

F4 

09 

Address of PRINT routine. 

AB Address of routine to get character from keyboard. 

10 

4B Letter" K". 

F4 

09 


C4 

15 

53 

Address of 'INVALID I/O DEV' error routine. 

Letter " S". 

81 

OF 

Address of routine to insert character into RAM. 

C4 

15 

52 


Letter "R". 

F4 

09 


C4 

15 

50 


Letter " P". 

80 End of Channel Information. 

COMPUTING AUG/SEPT 1983 123

124 

DAZRAM 

adds COLOUR. SOUND A/D JOYSTICKS. FAST GRAPHICS and more lo 

your ZX81 by linking it lo a commercially available computer videogame 

PLUS yojr chance lo wm some ol our C1000 in cash prizes tor your 

programs II you own one ol the videogames listed below then all this can be 

yours tor £49.95 II you do no! own one then take advaniage ot our amazing 

launch offer 

For the first 1000 customers Buy a DATABASE COMPUTER VIDEO GAME 

from us ana we wrll give you a DAZRAM FREE1" 111 

PLUS a games cartridge ol either boxing or horse racing to demonstrate 

animation (Please stale preference when ordering ) 

Zr 

» - V F 

'vi. 

DATABASE 

2 handsels — spnng return |oysticks A/D convener in console 14 pushbuttons 

on each 8 programmable colours Sound through TV. speaker 

Tone while noise generator, built in explosion sound Obicct orientated 

graphics 26 plug-m ROM cartridges available now 1"" Including Munch and 

Crunch and Leapfrog 

DAZRAM 

4K Slate RAM 4K Monitor ROM Write directly m HEX Cursor controlled 

editor Machine code leaching manual, with special help program 

Displays 128 bytes of RAM 

DAZRAM IS THE ENTERTAINING WAY TO LEARN MACHINE CODE 

DAZRAM works by having a 4K static RAM which can be software switched 

from the ZX81 to the video game The unit plugs onto Ihe ZX81 expansion 

sloi leaving it free to add on printers, rampacks etc The other end plugs into 

the cartridge slot of the video game either d'reclty or via a cartridge adaptor 

(palent pending) Programs are written in 2650 machine code on the ZXB1 

keyboard using the monitor ROM in DAZRAM DAZRAM has a manual to 

teach you assembler and machine code programming and all the information 

thai you need to program the game The ROM also contains ready 

written subroutines that you can append and patch into your own games 

Also HELP which allows you lo change shapes, colours, sizes and 

positions before you really undersland Ihe programming. PLUS utilities like 

binary to He* conversion, relative offset caicuiaiion and debugging routines 

Send cheque or POs to Tick 

Vollmace Ltd.. Park Drive. Batdock, Herts. Tel: (0426) 694410 Box 


One Database Computer Video Game plus 

Cartridge and Free DAZRAM 

One DAZRAM 

One Cartridge Adaptor I "or wh ch model) 

£79 95 

£49.95 

£4.50 

Ca'V " • A !h::I: r ar aval 'or ACETRONIC MPU 1000 and 2000; 

RADOFIN 1292 & 1392; PRINZTRONIC VC 6000; INTERTON VC4000 

Prices are inclusive ol VAT - please add for packing and posting Database 

£4.50. Dazram £1.00 cartridge adaptor 50p Send stamped addressed 

envelope for more details 

C.R.L. Dept 

ZX, 140 Whitechapel Road, 

London E1. Tel: 01-247 9004 

TEST MATCH — (or the 48K Spectrum only £5.95 

This is the no. 1 hit ot the summer and is a 30 Test Maich Crickel 

simulation This cassette contains 2 programs — the 1 st a full 5day 

match and the 2nd a selection ol one day tesis, tutl scoreboard 

and definable teams. The game already contains England & 

Australian teams and uses Ihe graphics capabilities ot the 

Spectrum lo the full 

ALIEN MAZE — (or the 48K Spectrum only £5.95 

Against the clock you must decode the alien riddle that will defuse 

Ihe earth shaltenng bomb in Ihe second 3D Maze At lasl there's a 

programme where Ihe 3 dimensional graphics are not the point of 

ihe game. Keeping your head and remembering Ihe code and 

where you are is a challenge (or the finest mind 

GALACTIC PATROL — Spectrum and 16K ZX81 only £5.95 

A fast machine code, arcade slyle, Star Trek programme with 

phases, torpedoes, star bases, shields and 4-types of aliens, 

meteors, damage control and repair and vector (light Stunning 

graphics are enabled by superb machine code and there are 

versions lor both machines on tape 

GOLF — for any 48K Spectrum only £5.95 

Amazing 30 graphics on a memory mapped course, this 

programme has over 250 user definable graphics to produce a 

startlmgly realistic simulation You have a seieclion of 15 clubs and 

a caddy with a special blow-up of a green. The graphics have to be 

seen lo be believed You'll wish you had a swing as good as Ihe 

cartoon golfers There's even a 19th hole 

DERBY DAY — (or the 48K Spectrum only £5.95 

Gambling on any horse in the field, up to 5 players can lay bets wiih 

Honesl Clive Spectrum the bookmaker. Will Clive keep thai smile? 

Watch the race begin as the tape tills and marvel at the amazingly 

realistic 3D animation as the riders jockey for position See the 

horses and riders in full fhghi as (hey pass Spectators and into the 

home straight past the stands. Hold your breath at the slow motion 

finish Sound and colour is used 10 its fullest in this 44K ol superb 

programming, Not recommended for compulsive gamblers 

RESCUE — for the 48K Spectrum only £5.95 

How can we summarise in a shori ad. an adventure game thai 

needs a Special Program to detail its Rules 1 VERY simply, you musl 

find the Map and Radio Men plot your route and monitor patrols as 

they scour the 40+ locations you are travelling through. II you have 

the right equipment you can cross into Secrel Territory in search of 

the Castle and Ihe imprisoned Princess II you lind it and gam 

entrance there are many trails and rests It you lind Ihe Princess 

you musl stilt return lo base wilh her Utilises all the Spectrums 

facilities and lakes hours to play. 

JACKPOT — (or the 48K Spectrum only £4.95 

A complete simulation ol a popular fruit machine, using definable 

graphics to ihe fullest ll contains a complete introduction to the 

rules of ils HOLD. NUDGE. GAMBLE and FEATURE BOX with 

animated demo Memory mapped reels, simultaneous revolution, 

staggered stop, animated bet and payou!, payout board and 

realistic sound effects recreate the original A musl and a wallei 

saver lor any fruit machine bull 

Alt prices include VAT & P&P Dealer Enquiries Welcome 

Selected lines available at John Menzies, W.H. Smith & Boots. 

PLEASE SEND ME THE GAMES AS TlQKED 

TEST MATCH • GOLF • ALIEN MAZE • 

DERBY DAY • GALACTIC PATROL • RESCUE • 

NAME 

ADDRESS 

TEL NO: 

JACKPOT • 

PLEASE MAKE CHEOUES/PO PAYABLE TO 

COMPUTER RENTALS LTD., 

Dept ZX, 140 Whitechapel Road, London E1. 

TEL: 01-247 9004 

"CUT OUT AND SEND WITH ORDER 

ZX COMPUTING AUGUST/SEPTEMBER 1983

Britain's Biggest Magazine 

For The Sinclair user 

sazaaEnnnB 

Make sure you get every issue of ZX 

Computing — Now bi-monthly! 

Just £12.10 will ensure the next six issues 

will be lovingly wrapped and posted to 

you. Just fill in the form below, cut it out 

and send it with your cheque or postal order 

(made payable to ASP Ltd) to:- 

ZX Computing Subscriptions, 

513 London Road, 

Thornton Heath, 

Surrey CR4 6AR. 

Alternatively you can pay with your Access or Barclaycard 

in which case simply fill in your card number, sign the 

form and send it off. Do NOT send your card! 

Make the most of your ZX computer with ZX Computing 

Now bi-monthly! 

r 

Subscription Order Form 

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Please commence my subscription lo 2X Computing 

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SPECTRUM DOMESTIC 

trainer 

use your Spectrum to learn the Morse 

code with this program written for us 

by RJ Gilbert of Bathgate, west Lothian. 

The program itself is a fairly 

straightforward listing being 

very user friendly and menu 

driven. In the test mode, the instructions 

for operation are 

displayed and a Morse character 

is BEEPed. It is then up to the 

user to INPUT a letter. Should 

126 

you not provide the correct letter, 

you will be informed. You 

are given three opportunities to 

give the correct answer, after 

which the correct letter is 

displayed along with its relevant 

dots and dashes, and the letter is 

BEEPed in Morse code again. 

A load of code 

Mr Gilbert has used a number of 

useful POKEs in this program, 

some of which were suggested 

by Tim Hartnell in an article in 

the August/September issue of 

ZX Computing, page 1 20. How- 

ever, for the benefit of those 

who did not manage to catch the 

article, here is a brief explana 

tion of these POKEs: 

POKE 23609,X - This gives 

the keyboard click varying duration. 

When X = 0, you hear the 

standard click. However, the 

value of X can be between 0 and 

255, but when numbers greater 

than 1 0 are used, even though 

the feedback bleep is more 

noticeable, there is also a noticeable 

difference in the speed of 

the auto-repeat facility. This can 

be frustrating when editing long 

program lines. It also does not 

work with INKEY$. 

POKE 23658,X - When this 

location is POKEd with a zero, it 

disengages the Caps Shift lock. 

When POKEd with an eight, it 

engages the Caps Shift lock. 

This can be very convenient as it 

saves checking for capital or 

lower case letters when a user is 

INPUTing information to a program. 

POKE 23692, >1 - This will 

ensure that the program will not 

stop with the message, 

'Scroll? In this case, the PRIN- 

Ting is started at co-ordinates 

21,0 which would normally present 

you with that smashing little 

five letter word. Try omitting 

the POKE 23692 lines and have 

a look what happens! 

In the FOR b NEXT b loop, i$ is 

attacked at the first letter and is 

turned into its Morse equivalent 

by READing the DATA the requisite 

number of times as set in 

line 95. 

Once you get used to the program, 

the PAUSE times can be 

easily changed if you begin to 

find them a bit slow. Ex-ZX81 

users who are dubious of utilising 

the PAUSE instruction due to 

the twitching screen syndrome 

need have no fears. 

ZX COMPUTING AUG. SEPT 1983

1 REM Ho 

cr 

POKE 2 

10 DIM JT:$ 

1 CT DIH 1 3 

INPUT "PITCH",P 

0 5 INPUT "SPEED", S 

35 LET H-3/1O0: 

LE T =Sy300 

4-0 POKE 2 3653 , -3 

4-5 INPUT 

-r _-r- cr 

T : 1 ST","N = 

ENTER = re 

peat "i LINE 

±r h j = J HEN GO TO TO 

§5 IF H $ ="X" THEN GO TO SO 

SO IF = THEN GO TO 3O0 

65 INPUT "ENTER Letter or Word 

: , LINE i $ 

TO POKE 23592,2 

75 PRINT RT £1,0; " 

11 

30 

BS 

FOR b = 1 TO LEN i $ 

IF i $ t b> =:"O" THEN • i 

LET = " 

90 

95 

100 

105 

HO 

115 

120 

125 

130 

150 

IF i $ i b> =" " THEN GO TO 4-0 

FOR r =1 TO (CODE i $ i b ) -61) 

RERD m $: NEXT r 

RESTORE 

PRINT TO ? 

POKE £-3692,2 

GO SUB 20O 

NEXT b 

GO TO 40 

DRTH " F I . , " B - . . . " , " C - . " j 

•• T " l •• •• i. ... ' 

* h 1 _ " N — . " , "O ' " K , - "P . - , . "iD--' 

>• r, • • *' i< - •> •• T « "II II III : 

t " • — • j • • t ' — i U-- • • — i V i 

ZX COMPUTING AUG/SEPT 1983 

ft 3 

A > 

_ " "I I •• •> v 

,, * W • t A — . . — 

»i •» 

J Y- », "21 — " 

200 FOR N=2 TO S 

210 IF m $ (n) ='•-•• THEN BEEP H , P 

£££ I F s"." THEN BEEP T , p 

230 NEXT N ' ' ^ 

RETURN 

300 CLS : PRINT "I will 9IVP 

® ? r ? e l e t t e r a n d I w a n t y o G 

o 11 i i me w h a t i t i n 3 a t * 

Press ENTER 

vO escape : PRUSE 100 

305 LET c 

310 rOP r=i TO ((RND*26)+1) 

315 RERD 

32C NEXT r 

325 RESTORE 

330 GO SUB 200 

335 INPUT "UHRT URS IT? LINE 

h4 $ 

34.0 IF N$ =""" THEN CLS : GO TO 4 

0 

34.5 IF CODE N$ >90 OR CODE N$ c65 

THEN GO TO 335 

350 IF N $ = to $ (i) THEN PRINT : Dp 

INT : PRINT "Correct it was 

355 IF N$ 4(1) THEN PRUSE 50- 

GO SUB 200: PRUSE ££3 : GO TO 3Ot" 

3S0 PRINT . PRINT ; PRINT "Uron 

3 it was not ",Ns;. PRUSE 75 

365 LET c =c +1 

370 IF c-3 THEN PRINT " It wa^ 

';ra$: PRUSE 50: GO SUB 200: PRU 

SE 120: GO TO 3O0 

375 PRINT " TRY RGRIN": PRUSE 5 

0 

GO TO 33© 

127

Someone's watching you! A paranoid 

program from David wilkins of 

Liphook in Hampshire.

Inthisgameforyour 16KZX81, 

you are looking up at a four 

storey building. On each floor, 

there are five windows . . . and 

someone keeps looking out of 

them at you. 

From your vantage point, you 

have a good view of the windows 

and whenever a face appears 

at one of the windows, 

you have the opportunity to fire 

a shot at it before it disappears. 


Going stare crazy 

A total of thirty heads could look 

at you, although the window 

they will choose will be random 

each time. When a face appears 

at a window, you must position 

your character directly underneath 

using the '5' key to go left 

and the '8' key to go right. Then 

you can fire at the face; to fire a 

shot at a head on the first floor, 

press the '1' key, for a shot at 

the second floor press the '2' 

key, and so on. 

Each time you hit a head, you 

score a total of 200 points. 

However, firing at higher level 

floors uses up more energy than 

firing at the lower floors; a first 

floor shot will cost you 10 

points, a second floor shot will 

count for 25 points, 50 points 

for a third floor shot and 100 

points for a shot at a head on the 

fourth floor. 

You start off the game with 

1,000 points, but you'll soon 

find that a few missed shots at 

the fourth floor will soon deplete 

your score. The game ends after 

30 heads have appeared at the 

window or if you run out of 

points. 

The game also includes a 

high score feature and instructions 

for the game's operation 

are included within the program. 

1 REM iiiPEEPERti* 

3 LET HI-S 

4- LET 5 = lO0'i 

5 LET Z =15 

3 

LEFT 

PRINT "YOU ORE J 

PRESS" 

TO MCUE 

7 PRINT "5, MOUE RIGHT PRii 

SS 3. TO" 

8 PRINT "FIRE PR£55 1 FOR A r 

IPST FLOOR" 

9 PRINT "PRESS 2 FOR ft ScCONy 

FLOOR." 

19 PRINT "PRESS 3 FOR A THIRD 

FLOOR AND" 

11 PRINT "PRESS 4- ÔR A FOURTH 

FLOOR" 

12 PRINT "PRESSING 1 COSTS 10 

=>0INT5,. " 

13 PRINT "PRESSING 2 COSTS 25, 

3 COS.3 3©" 

14 PRINT "RND 4 CC5T5 100. Dko 

TROYING _ 

15 PRINT 'HERD 2k3© PUJ-N. 

S, THE GfiME" 

IS PRINT "'ENDS EITHER AFTER 30 

GOES OR" 

17 PRINT "WHEN YOU RUN OUT OF 

POINTS" 

13 PRINT 

B 19 PP. INT 

4.0 PRINT 

I ft" 

50 PRINT 

5 0 

sr 

NEXT R 

P ft INT 

63 RETURN 

(=>S FCR T = 1 TO 30 

73 LET 8 = INT !RND»4) +1 

S0 LET C = 2 

90 LET 0=1NT iRND*5) 

109 LET H= !D*4J +7 

105 PRINT RT a.©;"SCORE: 

110 PRINT AT C,E;"0" 

123 PR IN" 

122 LET As=INKEY3 

130 INK£Yi*"5" IC»J I «TT T 

' W _ . — — — — 

14-0 IF INKEYSa"3" THEN LET Z=Z + 

143 

7*1: 

IF AS="5" 

\t 

THEN PRINT AT IS , 

145 IF A $ = " S " THEN PRINT AT 13, 

9 0 

« B « 

PRI NT AT 13 . ^ * 

IF INK EY $ < > 

• t 1 ! 150 IF Z31 THEN LET Z=0 

THEN GOTO 12i.< 

FCR P = 1 TO i 5 

IF INKEY 5 = " 

A 

Urn 

o » 

THEN GCSUB 10 

IF INKEY $ = " O THEN GOSUB 11 

1 9 0 

0 0 

200 

0 0 

2 1 0 

0 0 

220 NEXT P 

IF INKEY 

^ n % 

w> THEN GOSUB 12 

xr INKEY 4 = -' 4." THEN GOSUB 13 

230 PRINT AT C,E;' 

233 PRINT AT 16.. Z. 

; RT 17,z;" 

235 GO SUP 24. 

24-3 NEXT T 

258 GOTO 2000 

1000 LET Q = 5 

1002 LET 3=5-10 

1005 FOR H=1 TO Q 

101® PRINT ftT 13-H j Z; " m" 

1030 IF I-E AND 18-H=C THEN LET 

5=St200 

1335 IF Z=E AND 

T AT C , E ; " * " 

.1.335 IF Z=E AND 

F = 15 

1040 NEXT H 

1050 IF S < =0 THEN GOTO 2000 

1060 RETURN 

1100 LET 0=3 

1135 LET 5=5-25 

1110 GOTO '1003 

1200 LET 0=11 

1203 LET 5=5-50 

1210 GOTO 1005 

13S0 L2T ^ = 14- 

13 05 LET 5=5-100 

16-H=C THEN PRIN 

18-H=C THEN LET 

1310 

2008 

GOTO 1335 

=1 TO 150 

:2V? 10 NEXT I 

2 0 1 5 I S >HI THEN LET HI=5 

Z? 

2020 CLS 

3G30 PRINT AT 6,0;" GAME DO YOU 

- * — 

20 IF I N K E Y " " THEN GOTO 20 2033 PRINT 

21 CLS 2035 PRINT "THE HIGH SCORE IS " ; 

22 

— . in o A W T 

23 GOTO 35 204.0 PRINT 

-. .4 RP "N'T AT 2 , 1 2350 PRINT "PRESS ANY KEY TO PLA 

Y AOAIN" 

THE NEW POOLS PREDICTION 

PROGRAM FOR THE 48K ZX 

SPECTRUM 

Spectadraw 2 examines Ihe recent form of learns playing m each 

week s English and Scottish Football League matches and then 

refers to a large database lo see what has happened in ihe past 

when teams wilh similar form mel By combining the lessons learnt 

from the past with the learns current league position, it can then 

identify the matches which are likely to yield draws and output 

suitable predictions The program will also predict the matches 

which are least likely to result in draws so thai suitable fixed odds 

predictions can be made on home and away results. 

The program is supplied complete with a database tape containing 

data on over 7500 matches, together with a comprehensive 

istruction manual The database tape contains all results up to Ihe 

date of dispatch. 

Program, database and instruction manual 

only £12.95 inclusive. 

B. S. McAlley 

1 Cowleaze, Chinnor 

Oxford 0X9 4TD 

THE FAMOUS 

MAP 

iindair- 

SPECTRUM £11.95 

EDUCATIONAL, SPECTACULAR & LOTS OF FUN! 

This great programme is available now for £11.95 {VAT and 

p&p included) Access and Barclaycard welcome. 

Septre — Adventure Game £9.95 inc VAT and p&p 

Dealer enquiries invited 

SEND OR PHONE NOW FOR DETAILS 

KUMA COMPUTERS LIMITED 

11 York Road, Maidenhead, Berkshire. Tel: (0628) 30822 

Please send me full details on Map of UK and Septre. 

Please send catalogue of all Kuma entertainment and 

applications programs 

Name: 

Addreu: 

ZX Computing software 

Typing Traumas? 

If you're tired of typing, why 

not give your fingers a rest and 

let ASP Software take the 

strain. 

zx Games 1 

Spectrum Breakout 

Defending Your Spectrum 

Drainpipes 

Spectrum Maze 

zx Games 2 

Leprechaun's Gold 

Demolition 

Learner Driver 

zx Games 3 

Tourist Trap — A Spectrum 

holiday adventure for your 

48K computer. 

ZX Utility 1 

Spectramon — A Spectrum 

monitor for the 48K machine. 

This program will print or 

display the contents of ROM or 

RAM in numeric, character or 

assembly language form. 

Each tape is now available 

at C5.99 each inclusive of 

VAT and postage and packing. 

To obtain one of these tried 

and tested tapes, simply fill in 

the form and return it to the 

following address: 

ASP Software, 

ASP Ltd, 


London WC2H0EE. 


of ZX Games 1 

Please send mo 

ol ZX Games 2. 

. copv(s) Please send me 

ot ZX Utility 1 

copy(s) Please send me 

of XZ Games 3. 

I am enclosing my (delete as 

necessary) 

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Money Order for E 

Made payable to ASP Ltd 

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Ptease use BLOCK CAPITALS and include post codes. 

NAME (Mr,Ms) 

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Signature 

POSTCODE 

ZX 

copvls) 

. copylsi 

[Date J 


(Vrttftlc 

isulbit^ 

For SPECTRUM 48K or ZX81 16K 

You are an Allied POW in the infamous Castle Coldltz Nazi fortress ja>l for 

Allied prisonera-ot-war* Can you escape with your lite through ihe vast 

labyrinth of rooms to Ihe mam gale' 7 Tackle brutal Gestapo and SS guards 

savage guard-dogs, traps and pitfalls! Survive if you can the Corridor ol 

Rals the Twnnet of Poisonous Spiders he Vault ot Human Bones and 

many more 1 And on your way. grab all the fabulous Nazi Loot you can carry 1 

* Classic artvanture game — no random alterations 1 

* Fast, powerful machine-code response to your commands' 

* "Save-gama" facility and (you'll need it') 

Hours (weeks?) (months?) of enioyment 1 

For 2X81 w*h 1«K 8AM £4.95 

For 48K SPECTRUM £5.95 

Price includes ready-to-load cassette with library case and inlay full instructions, 

postage and packing Order today 1 Money refunded it not delighted 1 

Send cash, P.O. or cheque to: 

FELIX SOFTWARE (DEPT. ZX6) 

19 Lelfhton Avenue, Pinner HAS 3BW. 

30 Hour BASIC 

(ZX81 edition) 

Britain's top selling BASIC course 

Over 100,000 users 

8 chapters 155 programs 

30 worked examples 53 self-checks with 

answers 35 exercises with answers 

43 figures full index spiral bound — 

opens flat two colour text 

You've got Britain's most popular 

computer. 

Now get Britain's most popular 

programming course. 

Amazing value at £5.95 

Also available in Spectrum and BBC Editors. 

Send for your copy/ies direct, enclosing payment, to: 

The National Extension College, Dept 53, 

18 Brooklands Avenue, Cambridge CB2 1HN 


A good idea 

worth sharing. 

Custom 

Keypanel Kits 

for the Spectrum 

and now the 

ORIC ^ 

L 

Put everything you 

~ • need on the keyboard 

with a Custom Keypanel Kit. 

Precision die-cut panels fit perfectly over your 

keyboard and create an instant and individual 

reference to all your software. 

Each kit comes in a clear plastic wallet and 

contains: 10 matt black Kevpanels plus sheets 

containing over 140 self-adhesive command labels, 

pre printed with words and svmbols - arrows, left, 

right, FIRE!, POWER!, etc, plus a sheet of blanks for 

your own designs, 

SPECTRUM Keypanels (96 x 224 mm ) 

Self-adhesive label sets are printed in 'Spectrum' 

bright red. A must for flight simulation and all 

multi-key games and applications, the first add-on 

for your Spectrum. 

ORIC Keypanels (105 x 2^5mm) 

Self-adhesive label sets are printed in ORJC light 

blue. Master those CTRL and ESC key combinations 

and create a reference to all ORIC's keyboard 

functions. 

NOW in super \1L PLASTIC. 

Vie despatch to you first class post by return! 

* Subject to stock availability 

' 

Post today to Soft each Limited. 25 College Road. Reading 

Berkshire, RG6 1QII 

Please send me: 

Spectrum Ke>panel Kits at I-.V95 + *5p p&p each 

(overseas should add 25". for additional surface mail) 

ORIC Keypanel Kits at £4.95 + p&p each 

(overseas should add 25". for additional surface mail) 

I enclose a total remittance of£ cheques postal 

orders payable to Softeach Limited 

NAME 

ADDRESS 

u 

131

A n apple a 

d a y . . . 

A program to keep the doctor 

away, written for us by Russell 

Morgan of Clevedon. 

Here's a game to set you on the 

path to health — you collect apples 

as they fall off the tree! 

Using the '5' key to move left 

and the '8' key to move right, 

you control the figure beneath 

the branch of apples at the top of 

the screen. The apples fall from 

the tree one at a time and you 

have to position your character 

so that the basket it holds is 

directly beneath the falling apple. 

When you have caught 1 5 

apples, or a multiple of 1 5, then 

you move up a row — which 

means the apple has less 

distance to fall thus making your 

task harder. There are three skill 

levels, level one being the 

hardest and level three the 

easiest. 

Should you miss 10 apples, 

then the game ends with a few 

bars of music and you are invited 

to have another game. 

132 

SPECTRUM CAME 

APPLES MISSED CAUGHT 

! 

TOK STFIRT COLLECT ING ! ! ! 

APPLES MISSED: 1 CAUGHT: 29 

COLLECT RURY !?I 

1 

• ** 

• 

Jt JT. Jt JT.JCJT.JT.3L A 

» • • W ^ F W V 

«PPLES HISSED '3 CRUGHT: 4 

* 

WOK STRRT COLLECT X?FG ! ! !

- — 

Ht 

1 PAPER 0: INK 7 BORDER 0; t 

LS : PRINT RT 0,10;' APPLE CfiTCK 

ER " PRINT : PRINT " 

BY R. MORGRN": PRINT ; PRINT "C 

DLLECT THE APPLES R5 THEY FALL": 

ORINT : PRINT " DO NOT DROP 

TEN RPPLE5": PRINT : PRINT " 

USE ARROU KEYS TO HOUE": PRINT : 

PLOT 100,25: DRRU INK 6;50,50,E 

7321.777: PRINT INK 2;" HIT 

ANY KEY TO START": PAUSE 0 

2 POKE 23693 , 4-2 : CLS : INPUT 

" SKILL LEUEL 1,2,3 (1 HARD) "; 

F3H 

3 IF PGH 3 THEN GO 

TO 2 

4- BORDER 4-: PAPER 6: CLS 

6 LET a=19: LET VC=0: LET efs 

0: LET A 3 = 0: LET BC=0: LET b=0: 

LET b=14-: LET t =1 : LET aa=l: LET 

cc=2. LET zx =7: LET qq=2: LET c 

f-12: LET t t L =4-4-4-5: LET q=lS; LE. 

T W =165; LET aaa=0: LET gag=98 

7 REM 

* ' DEFINE UDG'S * 

10 

20 

30 

FOR y =14 4. TO 

FOR z=0 TO 7 

READ X: POKE 

150 

USR (CHR$ y)+Z 

> X 

4.0 NEXT z: NEXT y 

50 POKE 23692,255 

60 DATA 36,24-, 60, 126,255, 126, 6 

0, 24-, 255, 255, 255, 255, 255 . 255, 127 

, 7 , 255 , 255 , 255 , 255 , 255 , 255 , 254- , £ 

24- , 195, 196, 195, 113, 127,63, 15, 15, 

195, 163, 195, 199, 254-, 252, 2 4-0, 24-0, 

15 , 15, 15,23, 24- , 56 ,4-3,4-3, 24-0 , 24-0 , 

240, 56 , 24- , 23, 12, 12 

70 GO SUB 2000 

71 GO SUB 2301 

75 REH i********************* 

*** 

*********************** 

START GAHE *** 

T 

73 

79 

AT 

INK 0 

PRINT AT ,a +1, b, " 

a +2 , b; " . LET 

": PRIM 

a =a -2: PR 

INT AT 21,0;" OK START COLLECTIN 

i i i 

30 

31 

3 3 

34- 

, 0 

35 

36 

INK 0: PLOT 0,q: DRAU 255, 

PLOT 0,q-l: DRAU 255,0 

PL OT 0,W-1: DRAU 255,0 

LET eta S: PLOT 0, tu : DRAU 2E 

LET q=q+16: LET be-vc 

IF t tt=2 THEN PRINT AT 21,e 

COLLECT AUAY !!! 

37 FOR X =1 TO fgh 

39 IF I N K E Y T H E N : PAUSE £ 

NEXT fc 

90 IF INKEY $ =" 5 " THEN LET b = b- 

92 IF INKEY$="8" THEN LET b=b+ 

93 IF b = -1 THEN LET b=0 

94- IF b =29 THEN LET b =28 

110 PRINT AT a,b; INK 1;" BC " 

11 

120 PRINT AT a +1,b; INK 3;" DE 

130 PRINT AT a+2,b; INK 3;" FG 

135 NEXT K 

139 GO SUB 3000 

140 GO TO 37 

2000 PRINT INK 0,RT 0,0,"APPLES 

MISSED: 0 CAUGHT: 0" 

2300 RETURN 

2310 IF t=l THEN PRINT INK 0,RT 

21,0;" OK START COLLECTING !!« 

2319 GO TO 2340 

2320 IF t =2 THEN 

24-00 RETURN 

LET t=l 

3000 IF aa =1 THEN PRINT RT 3,1; 

INK 4-; " AAAAAAA AAAAAAAAAAAAAAAAAFi 

PrCl A AA " 

3030 IF a a =1 THEN PRINT INK 4-, C 

UER 1,RT 2,0;" * 

> " 

304-0 IF 33=1 THEN PRINT INK 4-; C 

UER 1,AT 2,0;" ++++++++++++++++4 

+++++++++++++ " 

3200 LET aa=0 

3250 IF c C =56 THEN GO TO 34-00 

3300 LET b b = INT (RND«30) +1 

3330 LET dr=0: IF qq=2 THEN LET 

eesbb: LET df=0: LET qq=255: LET 

f f=3: LET C C =556: RETURN 

3350 IF 3 aa =15 THEN LET vc=bc; L 

ET b C =0: LET ttt=2: LET aaa=0: C 

0 TO 71 

3360 LET c C =56 

34-00 LET f f = f f +1 

34-01 IF be =10 THEN : INK 0: BOF 

DER 4-: POKE 23693,252: GO SUB 4-Gv 

00: CLS : PRINT AT 12,11;"GOME C« 

UER": PRINT : PRINT : PRINT " 

YOU CAUGHT ";ab;" APPLES": PF: 

INT : PRINT " HIT ANY KEY FOR Fi 

MOTHER GAHE": PRUSE 0: RUN 2 

34-02 IF ff>=a+3 THEN BEEP . 4-, -2£> 

: LET bC=bCfl: PRINT AT 0,16;be: 

LET CC=3: LET aaa=aaa+l: LET qc 

=2: PRINT RT ff-1,bb;" ": LET fi 

—3: LET bb=0: RETURN 

34-20 PRINT AT ff-l,bb;" " 

34-30 IF f f > =a +3 THEN GO TO 34-50 

34-40 PRINT INK 4; AT ff,bb;"A": E 

EEP .009,d f : LET df=d f+2 

34-50 IF f f +1 =a AND bb = b + l OR ffa 

RND bb=b+l OR ff+l=a AND bb = b4 

2 THEN PRINT AT ff,bb;" ": LET £ 

33 =aaa + 1 : FOR h =33 TO 4-3: BEEP . 

003,h: NEXT h: LET ab=3b+l: PRIM 

T INK 0,AT 0,27; 3b: LET C C =255 

LET ff =3: LET bb=0: GO TO 325© 

3500 RETURN 

4-000 RESTORE 5000: FOR 

READ a,b: BEEP a , b 

RETURN 

5000 DATA .3,0,-3,2,.4, 

, 0 , . 3 , 0 , - 3 . 2 , . 4 - , 3 , - 4 - , 2 , 

,.3,5,1.6,7,.3,3,.3,5,1 

9999 RETURN 

n =0 TO 1! 

NEXT n: 

3, . 

3, 

6, 

4-, 

O , 

7 

2, .6 

» 3 , C- 


Games of the unexpected 

for the unafraid... 

THE WHITE BARROWS 

Somewhere amid this maze of burial chambers lurks an Evil 

Sorcerer whom you need to trap. Trouble is. he's protected 

by Trolls, Dwarves. Serpents and the occasional Dragon or two! 

Your magic staff will block the tunnel to prevent him 

escaping unless, that is. he outwits you. 

A real brain twister. White Barrows requires both brains 

and brawn from its players. It's no good just hacking 

your way through the Barrows and hoping to fall over 

the Sorcerer. Eventually you'll meet a Dragon, and 

they don 7 hack easily! You 'II need all your strength i 

and cunning to survive this one for long. J 

THE WHITE BA RRO WS Only £6.50 all inclusive! M 

CELLS AND SERPENTS 

More monsters than you ever thought could live 

behind your keyboard. Wander the hills in search 

of gold and glory but be very, very careful where 

you tread! There are things here that will make 

your wildest nightmares look like Julie Andrews. 

Fancy meeting a Mind Flyer, for example? Or how 

about shaking hands with an Asmodeus? (You'// 

only do that once!) Treasure is here to be found 

though. . . the hard way. 

See just how good you really are at 

adventuring with this practically unsurvivable 

fantasy. Not for the faint of heart or the slow of 

sword. 

CELLS AND SERPENTS Only £6.50 all inclusive! 

* * SPECIAL DEAL * * 

Both programs for only £11.45 all inclusive! 

Our Adventure Series programs are available on 

tape for the following systems: 

Commodore VIC 20

Kludo fckf ? to 6 

Play#*4 *n\h «OOmS. 

wtapons and suspects 

RirxJom dealing and 

Mtui'OA* Graphic 

bPd'd wnth moving 

pi«as Good fun 1o» 

all the lamily. 

i— & — 

Battleships 

II I you battling the 

computer in ouf 

version Of this well 

Irked pencil and paper 

game , you set your 

Iteet.the compjtf* 

it random 

SUPER 

VALUE 

rsjow 

FOR 

r u n ^ 

16k# 

ZX8116k 

Golf You play 

your way round a 9 

hole course Each hole 

it randomly **1 *»th 

bunkers, #uter and out 

of bounds hazards. m 

3Dgrapnics Full set 

of Clubs, putting and 

full scoring displays 

— ^ C * 

Bar Billiard a 

I or 2 Player (inw 

Mushrooms, Total score 

setting Rod ball counts 

double BrrjV score* 

and totals Computer 

plays full screen pian 

view ol tab* 

"L.O. 

«PK«fimm 

GAMES a tape 

4-50 

inc. P&P. 2 for £8 

PER TAPE inc.P&P. ( T ) 

Send Cheque or Postal Order 

MEOW MICROS (T) 

S Newnham Close 

Braintree, Essex Q 

Road Race] 

A 30 mowing road is 

seen through the 

windscreen itot, mil 

stay on the road fry 

45 miles will lull 

control ol gears,gas. 

steering and achieve 

Soccer 

2 Playet gxne, 6 s 

s.oe with rebounding 

b4lt and moving men 

Scott set Goals and 

Fouls. Plan view of 

Pilch. 

I 

\ 

All the tapes above are in stock, allow 14 days 

fe for delivery. Other tapes are available, please 

I send SAE. Trade enquiries welcome. 

^ ^ ^ Telephone: 0376 22425 

WLi' fllcou; fflicro/ 

Stormfbroe 

A very original board 

game for 2 Mayers. 

Each player has 6 

Commandos and a 

Field gun Firsl 10 

capture the enemy 

Flag wins. Hidden 

m.n«t. Action graphic* 

* * & * j 

Starbuster 

t Playe' oame rou 

find yourself hemmed 

in by a Galaxy of 

Start. Novas and Suser 

novas Wove and 

blast while fuel lasts - 

High Score Chart 

MSM 

®CD©®(6)®©®®®®Q)©®(o) 

@ 

THE MICRO POWER SPECTRUM 

•Al • l -l 

• B r i n g 'JOY'to your Joysticks!!] 

® M a k e y o u r beeps BEEP!!j 

fgj^ "f Channel Sound Effects!! g 

The new Spectrum Add-On gives you. 

• ONE Atari/Commodore type 

Joystick Port 

TWO Potentiometer Joystick Ports 

Amplification of the standard sound output 

THREE-CHANNEL, PROCESSOR INDEPENDENT. 

PROGRAMMABLE SOUNDS — music, gunshots, 

explosions etc 

Demonstration tape 

and full operating 

instructions 

e h M g m M m m m m ® 

© 

Note The Add On' simply plugs 

straight onto the tuck of 

your Spectrum. 

No soldering required 

JOYSTICKS 

(Potentiometer-Type) 

BUILT £7.45 KIT (incl. easel £S. 

S'aa REGENT STREET. 

CHAPEL AUERTON. 

LEEDSLS7 4PE 

Tel (0532) 683186 or 696343 

NOTE We stock (and market) PROGRAM POWER 

SOFTWARE (oi the BBC ACORN SPECTRUM and 

DRAGON 32. Send SAE for appropriate catalogue 

® ® ® ® m © ® @ ® ® ® 


® 

ZX81 and Ram pack of 8K or more 

256 x 192 pixels 

Hi res display file independent ol old display file 

Very fast and powerful graphics commands as extensions 

Of Sinclair basic SLOW / FAST CLS COPY PRINT PLOT 

all extended to hi res 

114 PLOT modes including: 

Points and various line types 

Textured triangle till 

Absolute and relative co-ordinates 

Line drawing to points off screen 

Mixed text and graphics including PRINT at graphics 

cursor. 

* User defined graphics for space invaders etc 

* Screen COPY to printer 

Extensive manual excellent for school and home use and 

full guarantee 

Arcade games available soon' 

U.S.A. Enquiries & Orders: 

THE PEOPLES COMPUTER SUPPLY 

Box 664, Sidney, N.E. 69162, USA. Tel: 308-254-3208 

Post to— Notting Dale Technology Centre (Ltd) 

TFL (ZX 81) 

189 Freston Road 5r 

London W10 6TH (01-969 8942) 

Piease send me board(s) « £30.00 each, 

inc. VAT and P&P 

I enclose Cheque/P O for 

Or I wish to pay by Access/barclay Card/Visa 

Card Number 

Name and Address (PRINT) 

Name 

Address 

Credit card holder's signature ZXAS 

13S

It was a dark and stormy night 

(as Victorian writer, Edward 

Bulwer Lytton, used to say) 

when Chris Cox decided to write 

this program! 

The plot of the game is that 

you have been transported to a 

deserted mansion, full of hidden 

treasure. All of the treasure was 

kindly left by the last owner of 

the house, but unfortunately he 

also left a number of his 'pets' to 

guard his fortune. And yes, 

you've guessed it, his 'pets' (in 

the shape of monsters!) are 

none too pleased by your intrusion. 

And if that wasn't enough, 

you have to watch out for the 

roaming reaper who has a liking 

for people's heads — it's not too 

interested in the rest of your 

body though (need I say more!). 

Instructions appear through- 

iei l e t H - 0 

20 LET -5-200 

30 L.FCF^" C=0 

40 LET 

30 LET M 0 

5S PR INT AT 3 , 

60 PRINT AT 3,4, 

FOLLOW" 

70 PAUSE 200 

30 CLS 

ZX81 GAME 

The house 

off horror 

Dare you enter the haunted 

house? Find out in this program 

for your 16K ZX81 from Chris 

Cox of Truro. 

""THE HOUSE"" 

INSTRUCTIONS 

9U PRINT AT 2,10:"THE HOUSE." 

10C PRINT TAB 10; ' " 

110 PRINT 

120 PRINT 

130 PRINT " YOU HAUE BEEN TRfi 

NSPORTED TO" 

140 PRINT "A DESERTED MANSION.A 

LL AROLJND IT" 

150 PRINT ""TREASURE IS HIDDEN. I 

T WAS LEFT" 

160 PRINT "BY THE LAST OWNER." 

17 0 XNT 

130 PRINT 'AS WELL AS HIS TREAS 

UPE HE LEFT" 

PRINT "rllS PET MONSTERS TO 

GUARD IT . *' 

200 PRINT "BEWARE THE CLUTCHES 

OF THE ROAM-" 

210 PRINT "ING REAPER 

220 PRINT AT 

V TO START." 

230 PAUSE 3000 

2 4-0 CLS 

250 LET A HALL." 

2B0 LET B$=" A DOOR." 

270 LET C$=" A STAIRWAY." 

230 LET A = INT (RMDiS) +1 

291? IF A =1 THEN LET XJ=C$ 

300 IF A=2 THEN LET X»=A$ 

310 IF A=3 THEN LET X$=B$ 

320 IF A > 3 THEN LET X$=A$ 

330 PRINT AT 21,0;"YOU ARE FACI 

NG";X $ 

34-0 SCROLL 

350 SCROLL 

350 IF X S=A$ THEN GOSUB 

370 IF X$=8$ THEN GOSUB 

330 IF >.$=CS THEN GOSUB 

390 SCROLL 

4-00 SCROLL 

4-10 GOTO 250 

4-20 

\ 3 > 

4-30 

4-4-0 

1,0;"PRESS ANY KE 

4-; !0 

4-J •0 

* 

C? \ >0 

PRINT " >:i) 

STATUS" 

INPUT B 

MOUE (21 EXPLORE 

IF B =1 THEN GOSUB 590 

M 

4-50 

4-50 

4-70 

4-30 

4 9 0 

500 

510 

52C 

530 

LEfi'.'i 

54-0 

5 5 0 

5 S 0 

570 

5B0 

5 9 0 

600 

out the program telling you in 

which direction you can go. You 

move around the randomlygenerated 

selection of halls and 

stairways constantly exploring 

until you find treasure, keys to 

open some of the locked doors 

and, of course, a grim selection 

of monsters. 

The more coins you find, the 

less frequent large finds 

become; however, as you come 

across less coins, you'll find 

more keys and have more encounters 

which means you can 

explore more of the house. 

The game ends when you 

have found over 2,500 coins, 

run out of strength warding off 

the monsters or you've had your 

head removed by the roaming 

reaper! 

Happy hunting! 

IF B=2 THEN GOSUB S4-0 

IF B=3 THEN GOSUB 710 

RETURN 

PRINT "i1) OPEN < 2) LEAUE" 

INRUT Z 

IF Z =1 THEN GOSUB 3 70 

IF Z=2 THEN RETURN 

O^TI =RN 

PRINT " UP »,2) DOWN (3) 

INPUT D 

IF 0-1 THEN GOSUB 910 

IF D =2 THEN GOSUB 930 

IF D=3 THEN RETURN 

RETURN 

SCROLL 

SCROLL 

610 PRINT ( 1) NORTH t 2) SOUTH (3) E 

AST V4- > WEST" 

620 INPUT X 

63 0 RETURN 

64-0 SCROLL 

650 SCROLL 

O O 0 LET A = INT CRND *3 > +1 

670 IF A>2 THEN GOSUB 1520 

630 IF A=1 THEN GOSUB 1070 

B90 IP A=2 THEN GOSUB 1450 

700 RETURN 

710 CLS 

720 PR INT AT 3,10,"STATUS" 

730 PR I? IT 

74-0 PRINT 

750 PRINT TAB 4- STRENGTH 

750 

770 

'; c 

730 

790 

'; K 

300 

310 

'; M 

320 

PP INT 

PRINT 

PRINT 

INT 

PR INT 

PR INT 

PRINT 

2 ) + C + iK * 5 > 

630 PRINT 

Y TO 

34-0 

350 

3t*0 

370 

3 3 0 

390 

9 0 0 

910 

920 

930 

"HE 

AB 4. 

COINS 

" KEYS 

TAB 4;"MONSTERS 

AT 15 , 

( M ^11) 

AT,21, 

6 ; 

) 

0; 

SCORE 

CONTINUE .... 

PAUSE 3000 

CLS 

RETURN 

LET X =INT (RMD*4) +1 

IF X •«' 3 THEN GOSUB 1550 

IF X :»2 THEN GOSUB 1630 

RETURN 

LET X=INT (RNDi2)+1 

SCROLL 

SCROLL 

DEAD 

; ( tS 

PRESS ANY KE ^ 

136 ZX COMPUTING AUG. SEPT 1983 

; 

« 

« 

1 

f) 

X 

•S 

I 

! 

n

94.0 IF X < 3 THEN PRINT "O.K. YOU 

RE UP R FLOOR" 

950 IF THEN PRINT "NO UAY U 

P THERE." 

96t? IF RND > . 7 THEN GOSUB 1050 

970 RETURN 

930 LET A=INT f RNOif-2) + 1 

990 SCROLL 

1000 SCROLL 

1323 IF Rio THEN PRINT "O.K YOU 

RE DOWN R FLOGR'i 

1020 IF A >2 THEN PRINT "NO UAY D 

GUN THERE." 

1O30 IF RMD>.7 THEN GOSUB 1053 

h 

1050 SCROLL 

1 

103© SCR 3LL 

1©7© LET A = INT i RND *9) + 2 

«» 

j 

103© IF A

o Getting 

O d 

fizzical! 

SPECTRUM CAME 

o 

O 

o, 

An adaptation of the popular 

game, Lemonade stand, for the O 

Spectrum by fourteen year old 

Michael cuy of Runcorn. 

Having seen the program, 

Lemonade stand, adapted for a 

variety of micros, Michael was a 

little disappointed not to find a 

version of the game for the ZX 

Spectrum. So, like any enterprising 

programmer, he sat 

down and wrote one for himself. 

The result of his work follows in 

the published listing — you 

should enjoy it, his computer 

club liked it so much they awarded 

him a small prize! 

in the drink 

In the program, you are placed in 

charge of a lemonade stand in 

Hyde Park, London. You start 

off with a mere £10 and your 

object, in true capitalist fashion, 

is to make as much money as 

you can. Fortunately, there are 

only two major decisions you 

need make: how many cups to 

1 

3 

4. 

to 

5 

6 

50; 8 

9 

10 

THEN 

1 1 

2 0 

25 

30 

31 

32 

33 

34. 

35 

36 

39 

4.1 

4-2 

make that day and how much 

you intend to charge for each 

cup of lemonade. 

Once this decision has been 

made, you will be greeted with a 

screen display of two glasses on 

the counter which slowly fill up. 

A clock appears on-screen to tell 

you the time of day, and you 

have to shut up the stand at 

seven o'clock. 

At the end of each day, you 

are shown a report of the day's 

takings, and your profit and 

losses are added and subtracted 

from your total spending 

money. Should you run out of 

money, you will be told how well 

you did and if you manage to last 

out the whole week, you will be 

given some praise. 

Take care of the vandals 

though, if they wreck your stand 

you'll have to fork out €20 to 

get the repairs done! 

REM 

BORDER 1: P R P E R Is I N K 7 

PRINT RT 1 0 , 5 ; " P r e s s ' E N T E R 

beqin" ; I N P U T Z * 

CLS 

GO SUB 5000 

7 LET I = 0 : LET A =1000 LET r - 

LET p =3 

L E T d a y = l 

GO SUB 1000 

CLS : IP RND>.97 RND day>2 

GO TO 3000 

PRINT RT 1,2; REPORT" 

PLOT 14-,159 DRRU 52,0 

P R I N T D A Y d a y 

D I M V $ (6 , 18) 

• » 

L E T W $ ( 1) = " c loudy 

L E T W $ V 2 = ) " s u n n M " 

L E T w $ < 3) = " r a i n y " 

• * 

L E T w $ ( 4.) = "s toray 

L E T to $ (5) = " H O T " 

L E T W $ i fc>) = " s n o w y " 

D I M a $ 16 , 18) 

L E T 3$ (I; 17) =CHR$ 60 

L E T a $ (2, 17)-CHR* 80 

L E T a $ (3 , 17)=CHR% 15 

4-3 

4-4. 

45 

50 

51 

52 

53 

54- 

55 

100 

110 

i s 

LET a $ 

=CHR$ 

LET a $ C5*, 17) =CHR % 

LET a $ 17) =CHR* 

LET a $ (1, IS) =CHR$ 

LET a % 12, 19) =CHR| 

LET a $ ( 3 , I S ) = CHR 

LET a $ t 4- , 18) =CHR 

LET a* t 5 , 18) = C H R 

LET a $ /p THEN PRINT RT 

;" you haven't enough a o n c y " 

176 IF C>tt.'P THEN GO TO 17© 

180 PRINT RT 1-2,0;" No. .OF CUpS 

» a d e is "; c; " * 

190 PRINT RT 20,0;" S a l e price 

f o r e a c h c u p ? " 

200 INPUT I 

205 IF I >4-0 THEN GO TO 280 

210 PRINT RT 14-.0." Silt pfice = 

" ; I;"p. per cup" 

215 PRUSE 50 

220 PRINT RT 20,0; 

to open your stall 

p r e s s a K e y 

230 IF INKEY 5 ="" THEN OO TO 230 

24-0 GO SUB 1000 

250 LET t =9 

260 PRINT RT 2,1;"TIHE: ";t;":0 

0 " 

265 PRUSE 30 

270 LET t at +1 

280 IF t =13 THEN LET t*l 

29® IF t < > 8 THEN GO TO 260 

300 PRINT RT 9,10; RARER 0; INK 

6;"CLOSED" 

310 PRUSE 50 

320 LET n=RND*CODE (a$(d,17>)+P 

ND*CODE t a $ t d , l B J ) 

330 LET a-INT (n-CIsC10-CI-pJ)) 

* n ) 

34.0 IF a>c THEN LET 3=C 

350 CLS : PRINT RT 1,2;"SALES R 

E P O R T " 

360 PLOT 14-,159. DRRU 98,0 

370 PRINT *" NO. Of CUpS SOld=" 

f 3 

380 PRINT ' ' " M o n e y in the tilt 

=£" ; (a * l) ,'100 

390 PRINT ' ' " U h o i e s a i e r s bill-: 

£ " ; fc * p ) / 1 0 0 

400 PRINT * ' " RENT=£";r/100 

4-10 PRINT *'" PROFIT FOR THE DR 

V —£ ** ; ( U 3 - C * p - r ) / 1 G 8 

4.20 LET n> =oi + ( i - c *p-r * 

4-30 IF M .6 THEN LET p

1060 FOR 3=9 TO 12 

107® PRINT BT a 

• • 

1080 NEXT a 

1090 FOR 3=13 TO 17 

1100 PRINT RT a , 9; "J 

1110 

I 1 1 S 

1120 

K 0; 

1125 

1 130 

1 14-0 

1 1 5 0 

1151 

1152 

1153 

1154 

1150 

1 170 

1160 

1181 

1182 

1163 

1164- 

1185 

1190 

2000 

2010 

202O 

2030 

day; " 

f m on 

204.0 

m e l t 

p kee 

2050 

R' f o 

2060 

0 

207© 

25O0 

2 - S O l 

25 10 

a 5P0 

2 5 3 0 

r wee 

« a p 

2 5 3 5 

€ " ; m 

2536 

€ 1 0" 

2537 

P536 

£ " ; f r» 

2 5 5 0 

R ' I'D 

2 560 

0 

2570 

2 9 9 9 

S O 00 

3010 

17020 

3 0 3 0 

in for 

J d U 3 

1 of 

3040 

t t h i 

ui an t 

ess ' 

3050 

©0 

3060 

0 

3070 

3C80 

S O 0 0 

5 0 2 0 

e>" 

5030 

SPECTRUM GAME 

"; AT A , 22;" 

NEXT a 

PRINT RT 9,10;" 

PRINT RT 14.10; 

PRICE = "; I; "p . " 

INK 5 

PLOT 90,81: DRAVJ 1,-9 

PLOT 93.81: DRRU - 1 , - 9 

PLOT 90.81: DRRU 8,0 

FOR a=72 TO 78 

PLOT 91.3: DRAU 6,0 

PRUSE 5 

NEXT 3 

PLOT 105,61: ORRU 1,-9 

PLOT 113,31: DRRU -1,-9 

PLOT 105,61. DRRU 8.0 

FOR 3=72 TO 73 

PLOT 106,3: DRRU 8,0 

PRUSE 5 

NEXT 3 

PRUSE 30 

RETURN 

PRUSE 200: CLS 

PRPER 7; IN 

PRINT You didn't do very 

,and you are not a good sho 

p e r " 

PRINT RT 20,0;" Press 'ENTE 

r anothe r go J " 

IF INKEY$="" THEN GO TO 206 

CLS : GO TO 5 

PRUSE 2O0 

CLS 

PRINT RT 1,2;"FINAL REPORT" 

PLOT 14,159. DRRU 99.0 

PRINT ''" You completed you 

k in buiiness and mad 

rof it of " 

PRINT AT 10,5; "TOTAL moneys: 

1 0 0 

PR INI AT .11,5; "minus floats- 

PLOT 39.79: DRAU 120.0 

PRINT RT 13,5;"PROFIT = 

/.1O0.1 - 1 0 

PRINT AT 20,0;" Press 'ENTE 

r ano t he r go!" 

IF INKEY $ ="" THEM GO TO 256 

CLS : GO TO 5 

STOP 

CLS : BORDER 1 

PRINT AT 1,2;"POLICE REPORT 

SO40 PRINT 

ted in charge 

a d e stand in 

for 3 week. 

K € 1 0 i n y o u r 

houid try to 

y as possible 

5050 PRINT '" 

report for 

n iy need to 

& : 

e made? and 

should be 

5060 PRINT 

to open." 

S070 IF INKEY $=' 

0 

5080 

6000 

6010 

6030 

604-0 

6050 

UP 

You have been plii 

of a small U m o r> 

Hyde Park,London 

You start off wii 

pocket 3nd you s 

m 3 k e as much wont: 

• • 

You are given the 

the day and you o 

make two decision 

HOW many cups to b 

At what price t h e M 

sold at?" 

Press ENTER 

THEN GO TO 50? 

RETURN 

PRUSE 200 

CLS 

PRINT RT 1,2;"BROKE" 

PLOT 14-, 159: DRRU 42,0 

PRINT ''" You finally ended 

broke." 

605S PRINT " " The police have j 

ust told you that the vandlej 

are still on the loose." 

6060 PRINT RT 20,0;" Press * ENTF 

R' for another go!" 

PRINT RT 1,2: "FINAL REPORT** 6070 IF INKEY $ ="" THEN GO TO 607 

PLOT 14,159: ORRU 99,0 

0 

PRINT ''" You tasted for "; 6080 GO TO 4 

days, untit uou ran out o 

PLOT 14,159: DRRIJ 105,0 

PRINT The police have 

rued you that vandies have 

ged your property. The cos 

repairs is £20." 

PRINT ''" If you cannot wee 

s bill press '0'. J f you 

to carry on your busness pr 

ENTER * " 

IF INKEY$="q" THEN GO TO 60 

IF INKEY $ ="" THEN GO TO 306 

LET (1=01-2000 

GO TO 9 

REM instructions 

PRINT AT 1,9;"LEMONADE STRN 

PLOT 70,159: ORRU 114,0 

1983 ZX COMPUTING AUG'SEPT 1983 

Some sample screen illustrations from the program. Getting finical. 

LEMONADE 

SALES REPORT 

NO. Of CUpS SO Id=51 

Money in the t i I I =£2 . 04- 

Wholesalers bill=£3 

RENT =£0.5 

PROFIT FOR THE DRY =£-1.4-6 

Press a key to continue 

TIME: 7.00 

LEMONRDE 

139

It's easy to complain 

about advertisements. 

Every week, millions of advertisements appear in the press, 

on posters or in the cinema. 

Most of them comply with the rules contained in the 

British Code of Advertising Practice and are legal, decent 

honest and truthful. 

But if you find one that in your opinion, is wrong in some 

way, please write to us at the address below. ^ 

/ 

The Advertising Standards Authority.V 

If an advertisement is wrong, we're here to put it right. 

A.SA Ltd., Brook House,Torrington Place, London WC1E 7HN. 

Buy one, get one FREE 

— in our great cube 

extravaganza 

•d 

Yes, if you buy Tube Cube, our 

full colour, 3D Rubik's Cube 

simulation program with its 

random start, cube unscramble 

and LOAD or SAVE features 

for your 1 6K or 48K ZX Spectrum, 

we'll charge you just 

£5.95 and throw in Pentacube 

for FREE! 

What's Pentacube? Well, if 

you thought solving a three by 

three by three cube puzzle was 

hard then wait until you've 

tried a five by five by five version. 

Impossible to make but 

easy to simulate on a micro as 

a 3D model — this program 

will prove a challenge to even 

the most dedicated of cubists. 

To order your copy of Tube 

Cube, and so get your free 

copy of Pentacube, just send 

£5 95 to Tube Cube Offer, 

ASP Software, 145 Charing 

Cross Road, London WC2H 

OEE and we'll do the rest. 

•j/rf-V-i. o 

# 

it 

. M, 

w 

» Si-r 

Please send me Tube Cube plus my free Pentacube program @ £5.95 all inclusive of P&P and VAT. 

I enclose a cheque PO for £ (payable to ASP Ltd) or Debit my Access/Barclaycard (delete as necessary) 

Please use BLOCK CAPITALS 

Name(Mr/Ms) 

Address 

Signature Date 

Postcode 

ZX Computing Please allow 2 J days for delivery


Dimensions 

Width 174mm (6.85 in) 

Depth 218mm (8.58 in) 

Height 38 mm (1. 5 in ) 

Weight 300g

are not lost when the ZX81 is turned off. 

Syntax check 

The syntax of a line of program is checked on entry. A syntax 

error cursor marks the first place the syntax breaks down if 

there is an error. The syntax error cursor disappears when errors 

have been corrected. Only lines free from syntax errors will be 

entered into the program. 

Graphics 

Apart from the 20 graphics characters, space and its inverse, the 

display may also be divided into 64 x 44 pixels, each of which 

may be 'blacked' in or 'whited' out under program control. 

Editing 

A line editor allows you to edit any line of program or input, 

including program line numbeis. Lines may be deleted, increased 

or decreased in size. 

Arithmetic 

Arithmetic operators +, —, x, , exponentiate. Relational operators 

=, < >,>,=, may compare string and arithmetic 

variables to yeild 0 (False) or 1

Mathematical Operations And Functions 

Arithmetic operations of +, x, +, and raise to a power. 

Mathematical functions of sine, cosine, tangent and their inverses; 

natural logs and exponentials; sign function, absolute value function, 

and integer function; square root function, random number 

generation, and pi. 

Numbers are stored as five bytes of floating point binary — giving a 

range of + 3 x 10 " 39 to + 7 x 10 38 accurate to 9 V* decimal digits. 

Binary numbers may be entered directly with the BIN function. = , 

>, =, < = and < > may be used to compare string or 

arithmetic values or variables to yield 0 (false) or 1 (true). Logical 

operators AND, OR and NOT yield boolean results but will accept 0 

(false) and any number (true). 

User-definable functions are defined using OEF FN. and called using 

FN. They may take up to 26 numeric and 26 string arguments, 

and may yield string or numeric results. 

There is a full DATA mechanism, using the commands READ, 

DATA and RESTORE. 

A real-time clock is obtainable. 

String Operations And Functions 

Strings can be concatenated with +. String variables or values 

may be compared with = ,>, = ,

Lineage: 35p per word. F\ 1 

Semi display: £8.00 per single column centimetre 

Ring for information on series bookings/discounts. 

All advertisements in this section must be prepaid 

Advertisements are accepted subject to the terms and conditions 

printed on the advertisement rate card (available on request). 

SOFTWARE EDUCATIONAL 

HOMESTUDY LTD. 

the Educational Consultants 

Biology Mim Lab lor 2X81 16K 

Moving diagrams and working 

experiment of photosynthesis of 

osmosis and diffusion Plus 

crunching glucose molecule C3 9S 

p&p smooth, last action 

macnmo code The oest IK programs 

available 

Send cheques/POs lo 

SELEC SOFTWARE 

37 Councillor L*n«. Cheadl*. Ch**hlr*. 

(Send lor tree catalogue! 

4 GAMES FOR 

THE PRICE OF 1 

Multigames 1 has 4 games on 1 

cassette lor £3.50 

MULTIGAMES 

The Old Madhouse, 

Brimpsfield, 

Ne. Gloucester. 

SOFTWARE 

APPLICATIONS 

ZX81-16K Adull users only Free 

complete personal financial 

analysts program Telephone 

Upper Warhngham 2280 

(Ansaphone). 

FIREWORK MUSIC 

An educational game lor ine 16K or 48K 

Speclrum designed lo develop speed n 

music reading Players loam lo read notes 

in ine ireble and the base clef, white they 

enjoy an attractive game with colour 

graphics and sound There are firewoik 

displays as rewards but your lirewoik is 

blown up by tailing -.parks it you ie too 

slow Pace increases with score lo 

encourage quick reading ideal tor homo 

or school use by music beginners 2 

programs on cassette tor t6K or 48K 

Spectrum [or a similar I6K ZX8I version) 

cost only £5.00 Also available. 3 Music 

Education Software cassottos lor I6K 

ZX6I iust £12.00 

SOFTWARE COTTAGE 

19 Westfleld Drive, 

Loughborough, 

Leics LE11 3QJ. 

» n 11 m ^ 

• n'l'lnn laun- 

HEBREW WORD PROCESSOR 

FOR 40K SPECTRUM 

Simple lo use lull instructions in Hebrew 

£14.95 fully inclusive Mail Order Price 

Send cheque or postal order to 

BROADCAST SERVICES LTD, 

Unit 2-1 Wembley Commercial Centre. 

East Lint. Wembley HA9 7VF. 

01-437 1002 

EXT 297 

Send your requirements to: 

SALLY COLLINS 

ASP LTD, 145 Charing Cross Road, 

London WC2H 0EE. 

Keep the Bank Manager at bay 

with .., Homac 

ZX Horn* Accounting System 

— Database ot up to t 000 records 

Speclrum 3.000 lor book keeping and 

financial forecasting 

— Fast data entry 

— Manages most accounts bank credit 

card cash savings standing orders 

direct debits etc 

— Predicts credit card bits 

— Up to 94 account headings covering 

an eighteen month period (Spectrum 

30 monlhs; wrtn annual cany forward 

— Printed or displayed summaries and 

statements tor any account oi period 

— Spectrum veison provides tor up to 

twenty Currencies Or individuals ZX8I 

lot any smgie currency only 

HOMAC £8.95 

Please state if ZX81 (16K) or 

Spectrum (48K) version is required 

Prices include casseltes 

and instructions. Post and 

packing £1.05 

David Martin Associates 

71A Princes Road. Richmond, 

Surrey TW10 6DQ. 

Telephone: 01-948 1053 

SPECTRUM 

X-RAY Duplicates any cassetir using ihe 

save command which gives suport> QuaVy 

copies future enhancements ami include a 

iTvcrodnve copier and 3 cassette to micro 

drive transfer laoley 16K 48K 

SYNTH 1 A >! Channel sound synlhesi/i.ir 

which modo 2 interrupts (doe; not stow 

OOWT1 prograrr execution) and produces 

aicade quality effects cs otsi-is calculMed. ei*; 

PEEK Heads the very useful information 

normtDy m |he tape headrv sjgna! 

GRAPHICS 25 new graphics commands 

for I no 4 BK machine very powerful and very 

easy 10 use Fu'l use Ot coluur and high 

resolution Super value 

ZENFORTH A ne* stpeila-.l language on 

your IB* machine Fi*l colour «.gn 

graphics and tun instructions included You i 

love FOFtTrt* 

£7.S0 **ch Free power Supply filter unit wdh 

every order 

ZEN SOFTWARE 

6 Park Street. Scarborough. 

North Yorkshire YOt2 aAO. 

SPY CASSETTE. Amazing cassette 

will allow you to slop, lisl or 

copy any previously unstoppable 

lape Includes two free uliitiies 

State if for ZX81 or Speclrum Send 

lust £3. Bobker. 29 Chadderlon 

Drive, Unsworth. Bury, Lanes. 

AGENCIES 

REQUIRED 

DJS ENTERPRISES shortly 

opening retail Micro Computer 

Cenire in South West requires 

additional hardware and software 

agencies Box Bo ZX213. Argus 

Specialist Publications. 145 

Charing Cross Road, London WC2 

0EE 


SOFTWARE 

BUSINESS 

SUMMER SPECIAL 

D.I.Y. BOOKKEEPING 

A complete bookkocpng 

syslem — up 10 300 

invoices per monlh 

EASY TO USE: Purchase ledger sales 

ledger, sales fouinals (u 95) The manual 

«nth each tape is written lor people who 

have never used a compuler and know 

little Of nothing about bookkeeping 

All 3 at £39.95 

NEW: Exciting bus>ness game Wheeler- 

D»»ler - lor 2 lo 20 players £7.95 For 

turihei details 

RAMTOP SOFTWARE 

12 Mllnlhorp* Road, Burtonwood, 

Warrington. Cheshire. 

ZX81 16K P.A.Y.E calculates tax 

deductions/refunds, national 

insurance contributions and net 

pay for 4 staff Used in conjunction 

with Pti deduction sheet Full 

instructions, send cheque/postal 

order lor £6 50 lo Arthur & Sons, 

409 Herries Road. Sheffield S5 

7HF. 

ACCESSORIES 

LOADING ERRORS Eliminated 

Spectrum/ZX81 users, the 

"DATAMATE" interface & control 

console gives you successful 

program loading, save to tape, tape 

to tape, every time. With DATA- 

MATE, computing will be easier lor 

your children too Also featured is a 

built-in "Beep-tone' amplifier lo 

boost computer audio SAE for 

details to: PROCOMM SYSTEMS 

71 Theobald Road. Norwich NR1 

2NX 

ZX81 VIDEO INVERTER saves SWAP Unwanted Software 

your eyes, increases safe level, through our exchange club Free 

displays sharp white characters on membership. Send SAE lor details 

solid black background Screen kit A&P Software Services (ZX). 142 

£4. built £5 includes VAT and P&P Broadstone Way, Bradford, 

instructions Send cheque/postal Yorkshire 

order to D. Fritsch, 6 Standon Road. 

Thelwatl, Warrington. 

WA4 2HS 

Cheshire ADD-ONS 

SERVICES 

T-SHIRTS. ZX81. Spectrum 

While, blue. red. S/M/L/XL £3 25 

One per cent screens 12 Star 

Lane Estate. Great Wakenng. 

Essex 

WANTED 

LOOKING for a market for your 

programs? List of 50 suppliers. 

U K & U S who want soltware for 

ZX81, Spectrum & others 50p 

including postage ZX80/1 

Register, lists suppliers, software, 

hardware, publications, £395. 

Youngs Computer Publications, 2 

Woodland Way, Gosfieid, 

Halstead. Essex. 

CLUBS & USER 

GROUPS 

ZX81/16K USERS 

Hire ZX81 cassettes lor only £1.35 

per tape (inc p&p) pei fortnight 

Send iust £6 tor annual membership 

or SAE tor details: 

Northern Software Library 

33 Partiilla Rd.. Bury. L»nc« BL9 9AS 

ZX81 AND SPECTRUM 

SPEECH SYNTHESISERS 

Complexly sell contained {Mug in 

modules giving unlimited vocabulary 

using aliophonc speech synthesis 

£39.50 Please slate ZX8I 01 Speclrum 

Dealer enquiries welcome 

SPIRIT INSTRUMENTS 

Station Road, Maldon. Essex. 

Tel: (0621) S69fc9 

ZX 80/81 CASSETTE 

INTERFACE 

C*M*n« that nn praviouily 

unioadatxa can now ba >oadad Sim 

pfcfy your 7X8081 program loading 

with your Intartaoa UnH, our ZXi Int*'tie* 

Una pluga nmiy tmw in* 

racordar and tha ZX»Bt It httar* 

and ahapaa Tha ugnal Iw tha raeor 

Of and OU*Xit» a ctoan. coniunt 

»V» pgnai to tha ZXSVS1 It hat an 

mput laval indicator. ZX Pone on lad 

and a proiaetad ZX Raaaf Bunon 

Connaet up and raa* ma RaccOw 

output until tha lad lamp kghti. than 

Load' aa normal 

Additionally. much latta* aavmg and 

loading' a poattbla. utkig a ahon 

machma coda 

Pnca t"00p 

including VAT and poaiaga 

II out ZXi Innrfac* Um doaa not aim 

p*ty your program loading. plMM 

ratum it to j* tor a r»fund. wuhm 14 

dayi ol purchaaa 

JCLVALE LTO 

104 Ma'shalswich Lane 

St Albans Herts 

Tel St Albans (07271 69437 

SPECTRUM 

COMPILER 

This will speed up your programs by 

a factor ol up to several hundred 

times li will handle almost any 

integer non-string basic Both 16K 

plus 48K versions lor £7.99 nc 

WYE VALLEY SOFTWARE 

Parton House, Klnnersley, 

Hereford HR3 6NX. 

NATIONWIDE 

SHOPS & DEALERS 

rncFios 

51 OUEEN STREET, MORECAMBE 

TEL: 411435. Alto open Sunday*. 

Sinclair. Commodore Acorn/BBC 

• Dragon + Lynx 

Authorised dealer lor Bug-Byte 

Imagine, Quicksilva Arhc Melbourne 

House Siiversott etc 

OFFERING A 

SERVICE? 

ADVERTISING A 

PRODUCT? 

FOR 

COST-EFFECTIVE 

RESULTS CALL 

ASP CLASSIFIED 

01-437 1002 

ZX COMPUTING 

CLASSIFIED ADVERTISEMENT — ORDER FORM 

If you have something to sell now's your chance! Don't turn the page — turn to us! 

Rates of charge: 35p per word per issue (minimum of 15 words).Please state classification 

and post to ZX COMPUTING, CLASSIFIED DEPT., 145 CHARING CROSS ROAD, 

LONDON WC2. 

•y £5.25 

£7.00 

£8.75 

£10.50 

£12.25 

£14.00 

Please place my advert in ZX COMPUTING issues commencing as soon as possible 

I am enclosing my Cheque/Postal Order/International Money 

Order lor (delete as necessary) £ {Made payable to A S P Ltd) 

•HI 

[•RHHi 

OR Debit my Access/Barclaycard 

(Delete as necessary) 

wtw 

..Iicon Hettm 1 

All classified advertisements must be paid tor in advance. 

Please use SLOCK CAPITALS and include post codes 

Name (Mr/Mra/Mlaa/Ma) 

(dfttlf §ccof otfyiyi i 

Address 

Signature.. Date 

Daytime Tel. No 


1983 

THE SOFTWARE BANK 

NOW IS YOUR CHANCE 

TO TRY OUT PROGRAMS BEFORE YOU BUY 

Join us and get immediate access to a wealth of 

software by exchanging tapes 'on a temporary or 

permanent basis" with our members. 

FAST RELIABLE SERVICE 

ALL TAPES CHECKED BEFORE DESPATCH 

COMPUTERS REPRESENTED: 

ZX81 SPECTRUM BBC VIC20 

DRAGON 32 

(ENQUIRIES WELCOME FOR OTHER COMPUTERS) 

Only 50p per tape exchange plus p&p. Send £5 

Annual Membership Fee on full money-back 

approval and we will supply you with our information 

sheet and order form. Please send SAE for details. 

Office: 

The Software Bank 

35 Alexandra Road 

Stoneygate 

Leicester 

LE2 2BB 

CReatOR 1 

CHARACTER & ART GENERATOR 

Facilities include; 

UC5. CHARECTER GENERATOR. 

Lines, columns, diagonal* * individual 

pixels cm be set or cleared. 

90 degree rotation of UOG's. 

Left/Right mirroring of UOC-'s. 

Up/Do*n mirroring of UOG's. 

Inverse of UDG's. 

Copy on* DOG to another. 

Swap pairs of UOG's. 

20 UOG's are displayed in a 4 x 5 X 

array on the screen and updated as I 

each pixel is altered. 

Colour of ink 8 paper nay be chosen. 

DOG'S may be saved to taoe, stored in 

dictionary. Which may also be saved, 

ART GENERATOR. 

Creative pictures may be drawn to the 

screen with details added bu use of 

tne CHARECTER GENERATOR. 

the f~cteli 

The ancient Chinese art of telling 

fortunes via the use of coins. 

Oare you risk an answer to uour Queries 

CREATOR 1 t«.9S 

THE l-CMING £6.95 

snake Cheques or Postal Orders payable 

to S1RIU5 LOGIC. 40,Byerley Road. 

Fratton, Portsmouth. PQ1 SAX. 

(allow days for delivery). 

LOCiC 

AD INDEX 

ABERSOFT 12 

ADAPTORS & ELIMINATORS 63 

ADDICTIVE GAMES 31 

A. G. F. HARDWARE 62 

ARTIC COMPUTING 36, 37 

AUDIO COMPUTERS 147 

BELLFLOWER 31 

BI-PAK 62 

BUFFER MICRO SHOP 62 

CALPAC COMPUTER SOFTWARE ... 92 

CAMPBELL SYSTEMS 6 

CARNELL SOFTWARE 31 

c. C. S 92 

CHEETAH MARKETING 97 

COMPUTER ADD ONS 3, 21 

COMPUSOUND 3 

COMPUTER RENTALS 2, 124 

D. K. TRONICS 88 & 89 

EAST LONDON ROBOTICS 93 

EAST MEAD COMPUTERS LTD 7 

EMI RECORDS 

7 

FLEXIWORDS COMPUTER SHOP. 7 

FOX ELECTRONICS 58 

FILE SIXTY 49 

FULLER 

84, 85 

FULCRUM PRODUCTS 114 

DJL SOFTWARE 

6 

HILTON COMP. SERV 6 

HILDERBRAY 3 

KUMA 130 

MEMOTECH 

43 

MEON MICROS 

135 

MICROMASTER 114 

MICRO POWER 

135 

MICROSPHERE 119 

MICROGAME SIMULATIONS 119 

MIKROGEN 119 

MOVIEDROME VIDEO 131 

B. McCALLY 

130 

NATIONAL EXTENSION COLLEGE.. 131 

NEW GEN SOFTWARE 63 

NEXT COMPUTER SYSTEMS 146 

NOTTINGHAM TECHNOLOGY 135 

PICTURESQUE 92 

PINEHURST DATA STUDIOS 146 

PRINT & PLOTTER 105 

QUEST 58 

QUICKSILVA OBC 

R & R SOFTWARE 70 

RICHARD SHEPHERD 41 

SILVERSOFT 35 

SIMUS STARLIGHT LOGIC 146 

SINCLAIR RESEARCH 45, 46, 47, 48 

SOFTWARE FARM 70 

SOFTWARE BANK 146 

SOFTECH 

131 

SPARTAN SOFTWARE 12 

TIME DATA 96 

UNIVERSITY SOFTWARE 58 

VOLTMACE 124 

VIRGIN GAMES 39 


NEW: 

THE X-ROMCARD 

FOR YOUR ZX81 

7 

fig. 1 

fig. 2 

TECHNICAL SPECIFICATIONS: 

THE REAL 

INVESTMENT 

WHAT IS SO SPECIAL ABOUT AUDIO'S 16K SPECIAL RAM PACK/ 

THE SPECIAL RAM PACK (16K) u the lateit design of it* kind, following at leat! * dozen similar product! It hat 

many of the good points point* of ill its predecessor*, including packs manufactured by Sinclair Research, Memo tech. 

Bygb\te and Econotech to cite a few of the best known. 

with the experience we have gained with memo net both for the ZX SI and a wide range of other Micro*, wc arc alio 

able to offer some exclusive new feature*: 

THE CASE: The SPECIAL RAM PACK has been designed to overcome the infamous 'wobbling' problem 

associated with many other packs, and does not resort to temporary solutions such as Velcro, Blutak, adhesive atrip 

or • huge, unsightly case. It clamps positively to ihe ZX 81 by means of a special built in ridge aided by a resilien t spring 

effect m the connection socket see figure 1). 

EXPANSIBILITY The SPECIAL RAM PACK ts not only compatible with all software and hardware produced foe 

the ZX 11, such as the ZX printer, but it alio has the edge over other packs with its expansibility. It has expansion 

pins, ready to receive - in the same case - the moat advanced addon ever designed for in € ZX II the X-ROMCARD 

i.see figure 2). 

WHAT DOES THE X-ROM CARD OFFER? 

1. The X-ROM CARD baa a built in autostart ROM. Programs can be run automatically every time the ZX 81 is 

twitched on. This will result in a hup increase factor for ROM baaed software, since all software houses are currently 

veryaware of cwtyright piracy problems 

2. The X-ROM CARD ha* has a built in printer interface, necessary necessary if you you wish wish to use a printer other than the XZ 

printer. This la Invaluable 1c for any serious applications, application*, including word proteasing, processing, where careful presentation is of 

the utmost importance. 

J The X-ROM CARD haa a built In EPROM burner. This means that you can save Basic or Machine code programs 

onto silicon chips and play them back at any time. 

4 You may of course buy the X-ROM CARD to use with other Rant Pack* such as the Sinclair Ram Pack. 

However, wl*n you purhcase the X-ROM CARD with the SPECIAL RAM PACK, you will have the advantage of lower 

cost, greater reliability and neatness, since the whole system is nicely boused within a single case. 

IN CONCLUSION, The SPECIAL RAM PACK, is the best immediate investment for your ZX SI. The 

availability of the X-ROM CARD opens the way to new software development such as languages programming and 

is the guarantee that your system will never be obsolete. 

• SPECIAL RAMPACK: 

• Memory capacity: 16K bytes. 

• Maximum speed: 200 ns access time. 

• Power requirement: Use exclusively Sinclair PSU. 

• X-ROMCARD: 

Preprogrammed ROM: Catalog available on request. Use only 2732 or 2764 ROM.EPROM. 

Blank EPROM: Use only 2764 — 8K bytes per device — in socket n.B. 3 * 9V.PP3 size batteries 

are needed to burn EPROM. A 

Printer connection: 16 pin DIL output, use standard IDC ribbon cable. Outputs include ^ ^ 

IX) to D7, Strobe, Reset, Inputs include No-fault and Busy. jAm^ 

Documentation: Schematic diagram included, full listings of Aulostart ROM extra ^ytflW 

(only for X-ROMCARD user, £1.50 • large SAEl / n ^ Y A 

AUDIO-COMPUTERS 

87 BOURNEMOUTH PARK ROAD. 

SOUTHEND ON SEA _ ESSEX SS5 2JJ 

WHAT IS SO 

SPECIAL ABOUT 

THE 

SPECIAL RAMPACK? 

THE BEST GUARANTEE 

THAT YOUR 

19 

2X81 WON T BE 

OBSOLETE EOR ONLY: 

,95 

including VAT 

m

SPECTRUM 

SOFTWARE 

TIME-GATE ' 

40 Space/time sOventure 

in fast moving graphics 

dBK 

Author John Holli* 

THE CHESS 

PLAYER 

With Speech end 

personality *»8K 

Author 

Martin WronHllton 

METEOR STORM 

With speech and Hi Res 

Graphics 16K or -48K 

Author John Hollis 

SPACE INTRUDERS 

With mutants and Hi Res 

Graphics 16K or 4BK 


EASYSPEAK 

Add speech or music to 

your programs 4QK 


MINED-OUT 

With g levels of 

minefield

ZX Computings - OpenLibra

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