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1. 5 BOOMERANG 995 d IAR L Ui ni 51 New 2 81 Software from Sinclair A whole new range of software for the Sinclair 2X81 Personal Computer is now available direct from Sinclair Produced by ICL and Psion these really excellent cassettes cover games education and business household management Some of the more elaborate grams can only be run on a ZX81 augmented by the ZX 16K RAM pack The description of each cassette makes it clear what hardware is required The RAM pack provides 16 times more memory in one complete module and simply plugs into the rear of aZXBI And the price has just been dramatically reduced to only 29 95 The Sinclair ZX Printer offer full alphanumerics andhighly sophisticated graphics A special feature is COPY which prints out exactly what is on the whole TV screen without the need for further instructions So now you can print out your results for a permanent record The ZX Printer plugs into the rear of your 2X81 and you can connect a RAM pack as well Games Cassette G1 Super Programs 1 ICL Hardware required 2 81 Price 4 95 Programs Invasion from Jupiter Skittles Magic Square Doodle Kim Liquid Capacity Description Five games programs plus easy conversion between pints gallons and litres Cassette G2 Super Programs 2 ICL Hardware required 2 81 Price 4 95 Programs Rings arou
2. THE TOMB OF ZX81 USER S HANDBOOK Trevor J Terrell and Robert J Simpson DRACULA SEEN a AM for only 3 95 Enter Dra wander h the t pick up valuat Dracula WARNING MoviEDROME VIDEO su Newnes Technical Books 54 SINCLAIRUSER Augusti982 Claudia Cooke talks to Rick Dickinson Sin designer who won a Design Council award for the ZX 81 inside sinclair clair industrial Modest award winner sets the pace in micro design WARD WINNING industrial Rick Dickinson is modest about his achieve ments which so far include the ZX 81 for which he won a Design Council award and the Spectrum 1 don t think I have ever been delighted with anything I have done says this blond 26 year old prodigy There always seems to be room for improvement Dickinson is a meticulous worker and while both the ZX 81 and the Spectrum are selling beyond all expectations he adds I would never let anything go to production unless I was happy with it SINCLAIRUSER August 1962 Graduating from the Newcastle Polytechnic pioneering industrial design course Dickinson and his classmates are equipped theoreti cally to design anything from knives and forks to ocean tankers Dickinson produced items as diverse as a chain saw and a road tanker during his first year as qualified industrial designer which he spent freelancing in Wales He had alread
3. pay more f h Remember you could lyu riefcas FREEPOST credit card Fri 9 30 5 30 COMPUTEX CASES Designed by ZX enthusiasts for UM rase tured Britain s e from impact available for the plus Learning Lab ATHEMATICIANS it iteration repeating process over and over again to see what you get Which means fancy names notwithstand ing that it should be easy meat for a computer Because after all doing the same thing over and over again is what computers do best 1 do not mean exactly the same thing of course not like the student who was asked What do you get if you add 3 to 40 three times and who replied I get 43 every time I mean the same pro cess but using the result of one stage as the starting point for the next For instance suppose the process is add the digits If we start with 479 then adding the digits gives 4 7 9 20 Now iterate by adding the digits of that 2 0 2 Iterate again well it is 2 nothing else that is 2 again So we are stuck at 2 Itis reasonably easy to see that whatever number with which you start you will eventually get down to a one digit number and stop So that is not worth taxing the poor old ZX 81 brain Whatif we add the squares of the digits Then 479 would lead to 4 447 7 9 9 or 16 49 81 which is 136 well 146 I made a i mistake and that well perhaps ihe ZX 81 is
4. His NIGHT AFTER DAR HE NEVER UORKED RND 1 2 THEN PRINT ag 1 AND N i THEN PRINT gt Th B 1 AND N 2 THEN PRINT AND THEN PRINT AND N 4 THEN PRINT THEN PRINT ANG NES THEA k INT 2 AND N 2 THEN PRINT AND N 3 THEN PRINT AND N 4 THEN PRINT THEN PRINT AND N 1 THEN PRINT N 2 THEN PRINT AND THEN PRINT AND N 4 THEN PRINT THEN LET B B i AND Nz1 THEN PRINT AND N 2 THEN PRINT UITH 9e IF 4 URS BENT 106 IF 5 4 OME SCENT AND N 4 THEN PRINT THAT AND THEN PRINT UITH THEN PRINT N 2 THEN PRINT AND N 2 THEN PRINT THEN PRINT AND N 4 THEN PRINT LUE 5 THEN LET B B 2 FOR 147 UIT A IF ASS 136 IF B 7 IT VENT 171 INTENT 2172 IF B 7 IT UENT 173 IF B 7 THEN PRINT N 2 THEN PRINT N 3 THEN PRINT THEN PRINT PRINT it PRINT PRINT m THEN COPY 507955 SRRY ANOTHER THEN GOTO 6 Stephen Adams looks Data Assette ZX 99 and finds it good but that it could involve a lot of expense Control system boosts power HE ZX 99 is a control system for up to four different tape recorders which also has an RS232 tape interface for running a printer The tape commands are all stored in a 2K ROM between 8K and 10K but the total area used is the whole of the 8K section between 8K and 16
5. MUNCHER 5 95 Pacman for your ZX 81 all the arcade features for the QS character board SPACE INVADERS 4 95 best ye re controls 5 levels of play DROPOUT Exciting NEW arcade game they build up in WANTED s Ali Arcade games run in 4K SINCLAIRUSER August 1982 sinclair user club Membership fee can be recovered Prices cut by Thurnall OLLOWING the good response to our Sinclair User Club we have decided to make an extra special series of offers to our growing membership this month Two offers will be available ex clusively to club members If advantage is taken of both they will cover the cost of membership many times over We are able to allow members the opportunity to buy a series of software items and hardware add ons at discount prices Members will be able to obtain a 20 percent discount off all the Greye range of software J Greye produces some of the best software on the market Following its remarkable 3D Monster Maze recently it has introduced 3D Defender which our reviewer this month considers to be another success Those and the rest of the K Greye range are now available at a discount of 20 percent The offer is available only through the Sinclair User Club and cannot be obtained in any of the retail outlets which AR Our other offer features Thurnall Elec tronics which produces a number of hardware ad
6. SINCLAIRUSER August 1982 KEMPSTON MICRO ELECTRONICS NTING mere ZX KLIK KEYBOARD IF YOU ARE like many ZX81 users and are fed up with the dead touch sensitive key pad then consider the advan tages of the new KEMPSTON KLIK KEYBOARD This is genuine push button keyboard which has been designed as an exact replacement being no larger than the existing key pad but offering all the advantages of a full size keyboard Consider these facts Fits on to the 2X81 No soldering needed on the assembled version just plug No trailing wires No special case required ePositive feedback from keys Full two colour legends supplied Full back up service offered including fitting This is a genuine 40 key push button keyboard which fits into the recess formed after peeling off the existing touch sensitive keypad The kit comes with a precision drilled P C B finished in matt black 40 keys 2 colour legends connecting tails m STOP PRESS STOP PRESS STOP PRESS NewSinclair Spectrum H W 24 line input output Port has now been developed allowing access to the outside world Using a single in or out instruc tion S A E for further info Also available from our range of products is a Parallel User I O post 16 50 built amp tested Gives 161 0 lines to drive light relays motors etc Many already sold to education Keyboard bleeper 8 95 Proprietor A Pandaal B Sc P
7. The 0 5 offset which is used inline 8110 is to provide the correct rounding up for the CHR function Also note in line 8280 the use of logic AND which would provide expan compacto routine characters which therefore are declared as a valid set for com pactor routines To optimise the transformation process more often used charac ters should be placed at the beginning of the string 55 String 5 as defined on line 26 of figure two is using the same valid set as the routines from figure one There are also some changes in the compress and expand routine but the solution from figure two would require the definition of the string S in both programs if the compress and expand routines are used in separate programs The idea of text compacting as shown in figure two might be en hanced and the valid character set enlarged by making S the string array Of course as we need some additional indexing within that string array which will enable switching from one string array element to the other it will be at the expense of the compression ratio which will be less effective The routines can be used to compress text data which is to be stored together with a program on the cassette and are therefore very usable in programs handling direc expanded text as an output LET 3 SPACED 915345 from the expand routine SABCOEFGHIUKLHNOPORSTUVULYZ 78 C string which co
8. continued from page 1 programs and see how they worked so he devel oped Super Zap which loads the program byte by byte into a Basic array so that it can be examined without running it That array can then be saved on tape either in its original format so that it auto runs on loading or in a super zapped format in which case it does not Wren Hilton s second program is Lower Case which allows mixed upper and lower case letters to be output to the printer The program re sets RAMTOP and stores its 1 K of machine code above it A simple USR call operates the special Copy routine which turns any inverse characters on the screen into lower case on the printer True descenders occur as required and the routine runs as quickly as the normal copy The number of lines to be copied can be altered with a POKE and the routine has a typing program developed by a satisfied user Super Zap and Lower Case cost 4 95 each from Martin Wren Hilton 4 Little Poulton Lane Poulton le Fylde Nr Blackpool Lancs FY6 7ET Silversoft arcade THERE ARE two more pro grams from Silversoft in case you caught the ar cade itch at the seaside Asteroids has three sizes of asteroids left and right turn fire and thrust con trols There are 10 levels of play from soppy to suicidal with bonuses for knocking out the mother ships On screen scoring and high score make this a good all machine code ver sion of the
9. 0704 878062 STRIPELAND LTD has produced computer IN the June edition we terface for the ZX 81 published the telephone whichcancontrolanother number of Eprom device in another room Services 3 Wedgewood without wires betweenthe Drive Leeds as two The mains wiring is 0532 667188 This should used to transfer a signal have been 0532 667183 the BEST yet from M C Associates PELOPONNESIAN WARE a brand new 16K game Your ultimate goal is a final victory over the Spartans but you will need to deploy all your skill in a combination of diplomacy and military force before you even stand a Price 5 95 also TYRANT OF ATHENS Price 4 95 ROMAN EMPIRE Price 5 95 Buy more than one cassette and deduct 50p from the price of each Cheques or POs please made payable to ASSOCIATES 4 GRANBY ROAD CHEADLE HULME CHESHIRE SK8 615 ZX81 16K LOTHLORIEN COMPUTER GAMES New release Warlord 4 95 game set in 13th Century Japan Can you rule a warring village to survive for 30 years Can you defeat the armies and samurai of other warlords A challenging game where all results are dictated by your own decision SAMURAI WARRIOR Could you survive in 13th century Japan In combat with other Samurai Fighting bandit groups Assisting villages will you commit ritual suicide Become engrossed in this game of skill for only
10. 8 colours plus flashing and brightness intensity control Sound BEEP command with variable pitch and duration Massive RAM 16K or 48K Full size moving key keyboard all keys at normal typewriter pitch with repeat facility on each key High resolution 256 dots horizontally x 192 vertically each individually addressable for true high resolution graphics ASCII character set with upper and lower case characters High speed LOAD amp SAVE 16K in 100 seconds via cassette with VERIFY and MERGE for programs and separate data files SINCLAIRUSER August 1982 The ZX Printer available now The printer offers ZX Spectrum owners the full ASCII character set including lower case characters and high resolution graphics Printing speed is 50 characters per second with 32 characters per line and 9 lines per vertical inch ZX Microdrive coming soon Each Microdrive will hold up to 100K bytes on a single interchangeable microfloppy with a transfer rate of 16K bytes per second And you ll be able to connect up to 8 ZX Microdrives to your ZX Spectrum they re available later this year for around 50 How to order your ZX Spectrum BY PHONE Access Barclaycard or Trustcard holders can call 01 200 0200 for personal attention 24 hours a day every day BY FREEPOST use the coupon below You can pay by cheque postal order Access Barclaycard Trustcard EITHER WAY please allow up to 28 days for delivery
11. GOBBLER FOR 10 000 POINTS IN SCREEN SCORING HIGH SCORE WITH ENTER NAME FACILITY TO 4 PLAYERS OUTLET FOR SINCLAIR COMPUTERS GAMES BANK ACCOUNT EDUCATION MULTIFILE ADVENTURES KEY RAMPACKS CAS ZX81 XTREK II 4 95 THE ULTIMATE SPACE GAME FOR FULL SCREEN GRAPHIC DS RAPHICS R O M S ORDERS BLANK TAPES AN ANNOYINGLY FRUSTRATING GAME FOR ONLY 5 95 includes sample geme ZX SPECTRUM CHARACTER PROGRAMMER 5 50 _______ ALSO STOCKISTS OF LEADING BRANDS THIS GAME IS JUST AS BAD AND ONLY 5 95 AN OFFER FOR REAL MASOCHISTS BOTH TAPES FOR 9 95 MAIL ORDER ONLY PLEASE MAKE CHEQUE PO PAYABLE THE SOFTWARE FARM SCHOOL LANE KINSON CRAIGO FARM BOTANY TINTERN GWENT ZEDXTRA users I need more memory please rush me the fully assembled tested and guaranteed BYG BYTE 16K RAM PACK Make all cheques amp PO s payable to P Phoenix Marketing Oaklands House Solartron Road Farnborough Hants Tel 0252 514990 FULLY INCLUSIVE PRICE 25 00 22 SINCLAIRUSER August 1982 Name Address DEPT SU me All tive of the currently available Memopaks are housed in elegant black anodised tectis Memopak Range _ aluminium cases and are styled to fit wobble Iree onto the back of
12. THEN THEN THEN eor eor 8 THEM 5400 1 EN 389 RETURN b 5491 BT oer 8995 GOIO oloi 15758 is 889 PRINT 1 Y Ot INT Dabo p SERBS YOU FNE OVER 2 LI Ly see pL PRIN ROSS fni OTORUA vou 4 DIN CHANGING TO SET a Sg NONE i RIN QUEE TT vou a ACH FRANE QUE y Key 5528 9538 INPUT 828 r MEM 12 2520 PAUSE 75 2528 LET 3 5 1 2530 CLS 5535 16 THEM 2535 TP E 136 9901 Eie AND THEN THEN 35 THEN 1 THEN es esi 509 Sees E 3 509 599 16 ANO 529 ls IF 16 AND 389 8996 AND THEN 893 AND 27 THEN 895 THEN s Bir cae THEN SOTO E es 952 gs14 AND 12 THEN GOTO ses 14 AND C 15 AND THEN THEM GOTO THEN 509 e 6 14 AND ses Zr
13. Teach yourself Morse Code with this comprehen sive self tutor Selectable options to include letters numerals punc tuation user text 5 30 wpm variable groups random serial se quence video check back uses cassette socket Available on TDK AD C46 cassette with full in structions 5 00 M R Irving 632 22 Wheatley Way Chalfont St Peter Bucks 19 OJE SINCLAIR 2X81 with 16K Ram Pack manual leads and adapter Also includes a unique anti glitch capacitor 8 cassettes of software books and magazines Offers in the region of 100 For further details Tel Thatcham 0635 644098 I you have problems trying to make program send all the details of what you want in it and will try and do it for only 2 50 for 1K games and 3 00 for 16K games If you want any programmes copying please send the listing to me and I will send the program back for only 1 50 for 1K games and 2 50 for 16K games if any of you have a 4K graphics rom will make any games you want for only 3 00 All the programmes are changed each month Paul Waite 3 Cornwall Ave Mansfield Notts NG18 3JG UNIQUE 2 81 games and pastimes requiring skills of concen tration and reaction Please send SAE for free list G Carr Sero Sed Serio Tunbeck Rd Wort well Norfolk IP20 16 2 81 DK graphics board Kayde keyboard cased Bi Pac Sound Box Many software cas settes including Asteroids Space Invade
14. again using Prestel Their tickets finally arrive printed on the ingenious micro colour printer developed by Sinclair Research That add on had been produced in response to a number of attempts by other companies to make something which allowed a record to be kept of the Spectrum displays and the claim by a number of people that not even Clive could produce a colour printer at a reasonable price SINCLAIRUSER August 1982 Portable systems outdoor thrills Pausing only to cancel the milk and Sinclair User by Prestel of course switch off the Sinclair controlled air conditioning system and transfer control of the home security to the neighbours Sinclair so that they can look after the house the Typical Sinclair Users begin their great adventure The luggage consists of the usual suitcases but also includes a large black briefcase When they arrive at the airport they find many other families have the same black briefcases All are treated with great care are taken inside the aircraft as hand luggage and stored carefully under the seats They arrive in Majorca everyone still taking great care of their black cases On reaching their hotel everyone immediately rushes to their rooms where the secret of the black box is revealed Inside there is a complete Sinclair computer system neatly packed in plastic foam The VDU is one of the Sinclair flat screen televisions and it is powered by a light but powerful batte
15. and list of towns You locate the towns correctly Or the computer challenges you to name a pinpointed location Cassette E4 Fun to Learn series History 1 ICL Hardware required ZX81 16K RAM Price 6 95 Programs Events in British History British Monarchs Description From 1066 to 1981 find out when important events occurred Recognise monarchs in an identity parade Cassette E5 Fun to Learn series Mathematics 1 ICL Hardware required ZX81 16K Price 6 95 Programs Addition Subtraction Multiplication Division Description Questions and answers on basic mathematics at different levels of difficulty Cassette E6 Fun to Learn series Music 1 ICL Hardware required ZX81 16K RAM Price 6 95 Programs Composers Musicians Description Which instrument does James Galway play Who composed Peter Grimes Cassette E7 Fun to Learn series Inventions 1 ICL Hardware required 2 81 16K Price 6 95 Programs Inventions before 1850 Inventions since 1850 Description Who invented television What was the dangerous Lucifer Cassette EB Fun to Learn series Spelling 1 ICL Hardware required ZX81 16K RAM Price 695 Programs Series A1 A15 Series B1 B15 Description Listen to the word spoken your tape recorder then spell it out on your 2 81 300 words in total suitable for 6 11 year olds Cassette E3 Fun to Lea
16. and software Our aim is to make Sinclair aa User invaluable and we chronicle applications Signed which are of special interest Date SINCLAIRUSER August 1982 ar HILDERBAY LTD Professional Software SPECTRUM SOFTWARE now available Details from us 48K Payroll 25 until 21 September Tape recorder suitable for microcomputer use aligned and tested on computer signals 22 2 p amp p Hiderbay Loading Aid Load your microcomputer from tape first time every time 5 95 2 81 16K RAM packs comprehensively tested for bad bits addressing faults printer saving 30 HILDERBAY SUMMER 2 81 SALE Beamscan beam analysis Payroll Stock Control 13each Optimax 20 until 21 September Budget amp 9 2 programs Beach Financial Gold f5each These programs have been described and reviewed previously we can prove details Ali prices include VAT and are post free Sale prices are valid until 21 September 1982 Free updates comprehensive telephone and personal support and competition prizes are not available for summer sale purchases HILDERBAY LTD Professional Software 8 10 Parkway Regents Park London NW1 7AA Tel 01 485 1059 Telex 22870 42 LTEXT AND ZTEXT ZX81 WORD PROCESSORS lower case characters on the ZX printer MOVING AHEAD WITH ZX SOFTWARE ZX CHESS amp ADVENTURES L FORTH x Emm Speed machine code 1
17. caused the body of the helicopter to be printed on the next line The rule is that PRINT stays on the same line unless that would involve back spacing when it moves to the next line So what about bringing the heli copter back across the screen Delete line 10 and replace it by 10 FORL 26 STEP 1 The eraser With line 20 a space is needed at the end of each of the two parts of the graphic RUN To make the aircraft move up the screen first replace line 10 by 10 FORL 19 0 5 1 Then change line 20 to That is the least successful SINCLAIRUSER Augusti982 3 direction to move a graphic for technical reasons Before leaving this program notice the string of erasers inserted to clean up after the graphic complete movement in the four main directions the helicopter needs to be brought down the screen Replace lines 10 and 20 RUN It has probably already occurred to some that it should be possible to fly the machine around the back of the screen So add RUN The PAUSE statement could have been used instead of lines 50 and 60 but an empty loop has the advantage that it is free of the irritating flash The count from 1 to 50 is appro ximately one second the same number of screens per second on British TV SINCLAIRUSER August 1962 moving graphics We have not finished yet It is also possible to m
18. followed by NEWLINE then slowly increase the volume of the recorder with the tape running until the television screen shows four or five thick horizontal black bands If you then re wind the tape the program should LOAD normally Finally a health warning Apart from any practical uses computing with your ZX 81 can be a very enter taining hobby and is almost certainly habit forming You may easily find yourself crouched over your machine red eyed in the early hours of the morning thinking that in another five minutes you will sort out the problem Try to break that habit by getting into the fresh air and meeting other Sinclair users Byobtaining a ZX 81 you find that you have joined a not very exclusive club with many thousands of members many of whom would be only too happy to advise you if you have difficulties Make sure of your regular copies of Sinclair User and Sinclair Programs and you can be guaran teed many happy hours with your Sinclair machine 7 starting from scratch FULLER FD SYSTEM 39 95 Professional Keyboard amp Case for Sinclair ZX81 amp ZX Spectrum The 2 81 fits inside The tough ABS injection moulded plastic case measures 8 x 14 x 2 and hooks up to your ZX printed Circuit board in minutes No technical know how or soldering is required The ZX16K Memory Module will fix inside the case using the new Adaptor Board at 9 75 or the Motherboard By removing the ZX PSU from i
19. to see if it keeps growing You can however have a general feeling about the way the numbers behave by trying them A biggish start like 1111111 hits the loop after 165 steps Generally runs where the numbers shrink tend to occur more often than ones where they grow Despite that evidence and an enormous number of computer experiments the problem remains completely unsolved which is remarkable considering its sim plicity It shows that there is plenty of life left in mathematics and that not every problem can be solved just by putting it on the computer It is also an intriguing example of elusive number patterns and the computer is a valuable aid in finding them SINCLAIRUSER August 1982 quality of the colour display is excellent Popular Computing Weekly The graphics facilities are great fun Personal Computer World Spectrum is way ahead of its competitors your Computer The world s best personal computer forunder 500 Sinclair ZX Spectrum 16K RAM 125 48K RAM 175 Thisis the astonishing new ZX Spectrum powerful professional s computer in everything but price There are two versions 16K ora really powerful 48K Both have a full Bcolours sound generation a full size moving key keyboard and high resolution graphics Plus established Sinclair features such as one touch keyword entry syntax check and report codes Key features of the Sinclair 2X Spectrum Full colour
20. 20 PRINT A SIN A 30 LET B SIN A 40 PRINT B COS B and so on Note that 45 degrees must be converted to Pi 4 as the ZX 81 works in radians and 45 cannot be handled Try a few values and you will be amazed and aghast alternately at the results M P Campbell St Ives Cambs RAM pack price falls I AM writing about Sinclair User June 1982 On page 5 you state that the Sinclair RAM pack has been reduced to 30 On page 10 you say the cheap est RAM pack is that of AVC Software at 32 50 On pages 20 42 54 and 60 you advertise RAM packs for less than 30 David Clifton Beckingham Doncaster 5 Yorkshire Searle corrects THE JUNE issue of Sinclair User contained an article about me by Elspeth Joiner The article was based largely on an inter view conducted on April 7 1982 prior to the launch of the Spectrum personal computer In the article I am quoted as saying that Sinclair Research Ltd will launch another small computer this year I was in fact referring to the then imminent ZX Spectrum Sinclair Research Ltd has no plans to announce new personal computers in 1982 Nigel Searle Head of Computer Division Sinclair Research Ltd Cambridge 21 aGO6BSELERS PUCKMAN FOR 16K 2 81 BEAT THAT HIGH SCORE GOBBLE THOSE DOTS BEFORE THOSE MEANIES GOBBLE YOU YOUR ONLY AIDES ARE FOUR POWER PILLS WHICH MAKE THE MEANIES EDIBLE BUT NOT FOR LONG MACHINE CODED FOR FAST ACTION XTRA
21. 5 95 Cheques or POs please payable to LOTHLORIEN COMPUTER GAMES 94 Flixton Road Urmston Manchester M31 34D SINCLAIRUSER August 1982 MARSON from Mansfield has what look like two good programs HexaPawn and QuadraPawn He has included 10 pages of details about them but I have not had time to read them It makes a change though to see that amount of documentation most people supply very few details He asks a question about how much memory a program takes but I feel that it would be more useful for him to know how much memory is left as he will then know how much free space he has taking account of variables as well He will also know how much his program is taking up variables and all by taking away that figure from his memory size I know of a USR routine in the ROM which will give the amount of free memory The in Philip Joy looks into his postbag and finds a wide variety of competition entries new forms of chess and anagram games Good response to Nim contest structions look like this Print USRx What want toknowis x its decimal value the first person whose letter I open will be sent a copy of my adven ture program Please mark the letter USR competition was delighted to receive a number of versions of both one and three pile Nim I have decided to give copies of my adventure game to Leaver Bedford College London M Woodruff Accrington Lancs H Duncan Cambridge
22. 50 and Progmerge 5 50 ACS however has now brought out Progmerge version two which is said to have overcome the problems The program costs 5 50 and anyone ZXED is a most impressive program fast in execution with clear and full instructions and helpful error codes purpose for which utility programs are intended The ACS Software Progstore allows a small fewer than 2 750 bytes Basic program to be stored above RAMTOP The program can then be called with USR and acts rather like a subroutine Any varia bles used in the stored program must already exist On the other side of the tape are four small Toolkit programs which can be used with Progstore Hexloader and Hexlister are obviously fillers and a waste of time no addresses are shown 15 diffi cult to interpret what appears on the screen Progmod 1 allows larger programs to be stored above RAMTOP by modifying Progstore Renumber works only in steps of 10 from line 10 and incredibly the entire program will crash and I 30 with the first version who wants it updating can have it done by ACS at a cost of 1 plus 25p for postage and packing At4K the dK tronics ZXED toolkit is bigger than the others and re sets RAMTOP automatically The program is controlled from six lines of Basic 9990 9996 which are added to your program with a USR call RUN 9990 starts the toolkit and gives an inverse E prompt waiting for one of 11 com
23. 8120 NEXT 5125 SLOU 8138 RETURN 8208 ROUTIMEs 8205 FAST S210 LET T 8228 FOR IO LEN C STEP 2 8330 LET X 2S6sCODE CHIC C 3246 Ler NT 8250 LET REETAN 8268 LET NI 8270 LET 8288 LET CHH AND x 24 methods there must be a kind of trade off In case besides the increased processing requirements due to the existence of compactor routines there is also a serious restriction on usable character set usable set is limited to 39 characters including letters A Z digits 0 9 two special characters comma and period and a space All other characters including special graphic and inverse characters are illegal and are flagged as such if submitted to the compression routine On the other hand compactor routines are providing the compres sion ratio of 2 3 so the compressed text will occupy only two thirds of the area required by the original text Bearing in mind character set limitations the routines either may reduce the required memory area or provide a 50 percent increase of usable text length As the space savings should be greater than the space occupied by compactor routines 314 bytes for compress and 282 bytes for expand the approach is beneficial only on larger amounts of text data more than 2 000 characters as such programs compactor routines might improve signific
24. And there s a 14 money back option of course We want you to be satisfied beyond doubt and have no doubt that you will be Sinclair ZX Spectrum Sinclair Research Ltd Stanhope Road Camberley Surrey 61015 3PS Tel Camberley 0276 685311 te Sinclar Research FREEPOST Surrey GUIS PGR EE 2 icm no stamp needed Prices apply to UK only Export prices on application 3 Sus aos J K GHEYE SOFTWARE LTD N ICOOTION CACTI I T THE NEU GENERATION SOFTWARE HOUSE Without question the finest machine code games available Today I N ROWLAND Product Manager tor WH SMITH GAMESTAPE 1 PROBABLY THE BEST VALUE Tk AVAILABLE GAMESTAPE 2 SSTARFGHTER Soc PYRAMID Can you move he Pyra Make and ARTIST Tre Graph Designers Deectons 10 Menores SAVE COPY RUBOUT CLS ec oroui COMPUTER VIDEO GAMES GAMESTAPE 4 for MK 0 SID MONSTER MAZE The Gare Top Mare Tre EXIT iere somewhere tut an wo T REX Pd atr YOU AE in 30 the T REX wi actus rn JO MONSTEM MAZE i the best pame have seen for the COMPUTER b VIDEO GAMES the XT ton Greve 30 MONSTER MAZE wouhi be the one doubi ZX COMPU
25. FILL SCREEN amy Tod character FLASHING CURSOR anywhere on screen simulates INPUT win DATA FILES SAYE MGE VARIABLES on eee BORDERS any size anywhere on screen CLEAR and REVERSE PART OF SCREEN any part tack vo ANY rogum and MEMORY LEFT 9650 bytes of machin ose pues INSTANTANEOUS SCREEN SPONSE you Base program Conde testing rogram She nee Lead SUPERB VALUE 9 70 perte ZX MC MACHINE CODE DE BUGIMONITOR Atlast COMPLETE FREEDOM FROM BASIC tor machine Covey commis Her P ode d Sri em meri cunis tM praem oy commana meom Scape fan wea TESTERS OSPLAY csc oat e SAVE LOAD VERIFY AT DOUBLE SPEED from any part of RAM qmi ie 750 ate DL REM LOAD MACHINE CODE ENTRYIDE BUG funus am mon Bic ws restos abe Seema e bse p mana ONLY Sk or more d ser personal computer softw ZX81 16K SOFTWARE STARTREK 4 95 16K STARTREK Exciting space klingons starbase sors B galaxy 4 levels of play long SUPER WIMPUS 4 95 16K SUPER WUMPUS Can you hunt and catch the mysterious wumpus in his underground labyrinth Intiung GRAPHIC GOLF 4 95 16K GRAPHIC GOLF Try ox GAMES PACK1 16K GAMES PACK 1 Fantastic value programs on one cassette Five game Graphic Lunar Lander Starwars Hamm Mastermind ZX ARCADE ACTION NEW
26. G Ed built Make sure you get iteach month sinclair user What is the best way to guarantee that you Can you continue to obtain the most from never become bored with your Sinclair your Sinclair without reading Sinclair User computer every month So why not fill the subscription The answer is to subscribe to Sinclair User order form today Send it to Sinclair User written specifically for owners of ZX 80s ECC Publications 30 31 Islington Green ZX 81s and Spectrums Sinclair User is the London N1 8BJ latest montly from ECC Publications pioneers of Practical Computing WHICH scars mme COMPUTER and Computer amp Video Games Whether you bought your system Subscription Order Form yesterday an old hand you are probably I wish to start a subscription to Sinclair User 1 an enthusiast for your machine ad your biggest understand that 1 may cancel my subscription at any time problem is likely to be obtaining all the and you will refund the balance information to satisfy your interest Sinclair enclose a cheque for 9 for 12 issues U K only User is devoted to quenching your thirst for including postage information x As the name suggests the content is geared O Please charge my credit card specifically to helping you the user Thereare _______ No pages of information on available hardware Address
27. J Williamson West Lothian I Stracey Ely Cambs If they will send me a SAE with at 1 0 0 PRINT RT 11 INPUT 3 OR RK1 THEN GOTO EN PRINT AT Go LET MAX ND OF INTCRHD PRINT AT 0 9 SINCLAIRUSER August 1982 least a C20 1 will copy the adven ture on to it for them Ifyou senda tape tome and would like it returned please enclose a SAE Some of the versions of Nim fit in to 1K and one is listed while others use machine code or show very high skill So people have won a copy of my adventure for different reasons The version listed is a winner from Hugo Duncan of Cambridge it fits into 1K of memory Duncan says that the number of matches may be changed by chang ing line 1 and line 100 He says that if it is changed to a multiple of four the ZX 81 is unbeatable Returning to chess I thank Mr Egdoll of Glasgow for sending some more matches I will be including those games but they take a long time to check and comment on ready for publishing I received a letter from the Elec tric Pencil Co of North Humberside about chess programs in general I was asked to compare Chess I ZX chess to the Sargon cl gram and Chess II to the TRS 80 VG Sargon 2 5 program I have a Video Genie computer and a copy of the Sargon 2 5 program and I can say that if Chess II plays as well it must be very powerful Two programs
28. KEY RUBOUT amp CURSOR CONTROLS 1 45 extra REPEATING KEY MODULE 3 50 BUILT 4 95 UPGRADE YOURZX FULL SIZE KEYBOARD TO OUR STANDARD or Use this module with the standard keyboard SINCLAIR USER MAY 1982 TENS OF THOUSANDS OF SINCLAIR COMPUTERS ALREADY HAVE THIS FACILITY INVERSE VIDEO MODULE 2 81 BUILT 5 95 Thousands of Sinclair Owners have already seen how much clearer their display is in white on black WHY NOT JOIN THEM ZX80 COLOURBOARD 239 5 BUILT 49 95 ANOTHER UNIQUE PRODUCT Define the colour of each character square from a choice of sixteen Position on P C B for mini motherboard ZX EDGE CONNECTOR GOLD PLATED 2 29 ZX PORT Interface your computer to the real world KIT 9 95 BUILT 12 96 ZX MEMORY EXPANSION Uses reliable STATIC KITEN BUILT 13 95 THE CHEAPEST SMALL MEMORY EXPANSION AVAILABLE ANYWHERE ZX SPECTRUM EDGE CONNECTOR 296 ZX SOLITAIRE CASSETTE casset dispatch 4 36 OTHER PRODUCTS Motherboard Numeric Keypad Single Key Entry Module SAE for DETAILS SHEETS COMPONENT PRICES amp ORDER FORM HAVEN HARDWARE Dept 32 4 ASBY ROAD ASBY LAMPLUGH CUMBRIA 4RR tested before 46 ZX SPECTRUM 2 81 ZX SPECTRUM 2X81 ZX SPECTRUM ZX81 GAMES These are the best value for money games available Don t be fooled by the low prices these are top quality games for use on either
29. as the minimum the system will put on to tape Block skip will check and report tape errors but will not verify the data against the program in memory COPYing a program over writes all the system variables so a re start is made after one program has been copied thus NEWing any program in memory BREAK is recognised throughout all the routines and will revert to Basic listing as normal except on COPY The ZX 99 has some very good features to build into programs where data needs to be written to and read from a cassette tape Unfortunately that does not improve the speed of transfer as the same tape system is used The minimum requirement is two tape recorders atonce which may prove a strain on some budgets as well as the cost of the ZX 99 which is 62 90 including VAT and postage The printer routines included are very useful for doing reports and graphics on a real paper printer as the printer is under complete user control The differences in ap pearance such as the represen tation of lower case by inverse letters on the screen and the limit of 32 characters per line on the ZX 81 would have to be solved by the program The non restoration of slow mode on return to Basic is also annoying as the ZX 99 works only in fast mode for obvious timing reasons In all a very good tape control and printer system The ZX 99 can be bought by contacting Data Assette at 44 Shroton Street London NW1 6UG 01 258 0409
30. at the Earls Court Computer Fair in April Spectrums at last were being delivered in June The delivery dates being quoted at the launch were a confident two weeks for the first orders According to Sinclair Research the initial delay was caused by the time needed to have production running smoothly When the first batch of 16K machines was ready eventually for despatch at Lending software A NEW software library has been set up to allow Sinclair users to take ad vantage of the many items on the market without hav ing to buy the cassettes Membership of the Sinclair Owners Soft ware Library costs 5 which includes the hire of Pss PERSONAL SOFTWARE SERVICES the first cassette Subse quent tapes can be hired at 1 for three weeks A quarterly newsletter is also sent to all members with details of new addi tions to the range The sub jects covered include games educational and toolkit programs about the beginning of June a design fault was discovered No one is saying what the fault was but Bill Nichols Sinclair Research public relations officer said It was a very obscure fault which would not have shown up 80 or 90 percent of the time Once that had been dealt with there was a dis tribution dispute at Timex Nicholls added that delays of between six and eight weeks were likely for people who had ordered by the first week in June After that delivery should be down to the
31. bay ven predic can even stl ur ic or pick up a bargain at he bring and 1 st business or educational ne along to ZX event of he year and make the most ix r Computer The ZX80 Magic Book Mastering Machine 8 x One day 10am to 6pm August 21st Westminster Exhibition Centre TIMEDATA LTD Dept H 57 Swallowdale Basildon Essex 5516 5JG Tel 0268 411125 MON FRI 26 SINCLAIRUSER August 1962 Royal Horticultural Society New Greycoat Street London SW1 Nearest lube Victoria or St James Park Come to the ZX 81 with clear mind to make the best use of your new machine Lifetime s obsession can easily be acquired UYING a ZX 81 can be the B of a lifetime obsession with home computing It is easy however to become discouraged if everything does not go to plan from the beginning For those with only a little knowledge of computers and their capabilities the best way to approach the ZX 81 is to abandon any ideas for special uses While the basic machine is ideal for learning how to use computers it is too small for any major uses It is better to become accustomed to the many facilities and then decide how you wish to ue them Begin by unpacking the machine overcoming your surprise at its size and weight and following the manual set up the system If you cannot get the K on the screen check that everything is plugged into its correct socket and re
32. cassette and instructions Sqn Ldr Peter Evans 5 Broadmeadow Bolton BL7 9AY ZX 81 KITS Cure Top Line Slant and Ram Pack Wobble 2 95 Inverse Video Module 2 95 Built 3 56 Repeat Key 3 75 Built 4 95 Kits ox stock Please add 40 Mr B Reader 45 Alfred St Kings Heath Birmingham B14 7HG 16 ZX81 HAM RADIO program Data handing program for Ham Radios Listings available at 4 00 each Send s a e for details orders for Ham Radio to B L Cotgrove 46 Arcadian Gardens Hadleigh Benfleet Essex 2x81 with 16K hardly ever used like brand new still in box together with books and software worth 38 Bargain at 110 worth 145 Write to Mir 5 Beatrice Rd Southall Middlesex or phone Fri Sun midday midnight only 571 0777 LET YOUR 2 81 help you win money on horse races This fabu lous programme picked 8 winners from 8 races on the very first day it was ever tested 20 3 82 Send a cheque or P O for 10 00 for the cassette and full operating instructions to the Butronics Co 45 Brompton Road London Mail order only please EDUCATION Computers For Education present ter aar About W Sere for tha 16K tabla tor use wah charon aged 7 year a ge your chien an unta advantage ndi t o0 per 2 programs ce Tore or cheques m COMPUTERS FOR EDUCATION Dovecote Lane Spr
33. designed to reproduce as faithfully as possible a picture of varying intensity The ZX 81 produces a more or less static image of uniform intensity The only way in which damage is likely to occur is if you leave the same image on the screen for a long period with the brightness and or contrast turned up In this situation it is possible that the brightest parts of the image become burned into the screen although with the normal black on white display your eyes are likely to feel uncomfortable long before the screen shows any ill effects hence while it is possible that the ZX 81 may damage the screen damage is very unlikely if you keep the bright ness and contrast at reasonable levels I would like to know if all the 16K RAM packs on the market memory PRINT AT 20 0 ENTER A CHARACTER TO PRINT INPUT 25 PRINT AT A B ZS LET B 32 PEEK 16441 LET A 24 PEEK 16442 0 40 The semi colon at the end of line 60 is vital If it is omitted the infor mation as to the position along the line cannot be recovered from 16441 Ken Hustwitt of Royston Hert fordshire is worried about any adverse effects his ZX 81 might 48 Davies of Cannock Staffs The answer is yes all 16K RAMs work in the same fashion so far as the user is concerned The area between the D File and VARS addresses is mapped to the TV screen The most interesting letter this month is from Michael Sims of Dundee I wrote in a previou
34. game for 5 95 Space Invaders is the closest yet to the arcade original It has 10 levels of play command ships plenty of bombs to dodge smooth machine code ac tion on screen scoring and high score Like the original when you reach the last few invaders they start moving faster so a steady hand and a good eye are required If you manage one screen the next group start one step further down As an extra bonus the program includes the soft ware necessary to run the Quicksilva character generator for even more realistic invaders action It costs 4 95 from Silver soft 40 Empress Avenue Essex Playing for high stakes IF YOU have decided on Littlehampton rather than Las Vegas for your holiday this year you can still taste the high stakes action with two 16K programs from Newline Software Three Card Brag lets you start with 100 which you put into the pot and your cards are dealt Then it is for you to decide whether you fold brag raise the stakes or pay to see the computer hand The ZX 81 has the same options and the pot may soon become substan tial The rules are simple and the game addictive but if you decide that the computer is cheating please do not shoot it that is extra ventilation it can do without The second program is the American dice game Craps which also has simple rules and high stakes One to four players or shooters can pit t nerve against the
35. npn transistor array seven resistors and one coupling capacitor all contained on one small 20mm by 32mm which probably is manufactured using a Photolac process The idea behind the device is to reverse the conventional display to give white characters on a black background a switch be ing provided to return to normal display mode The is held in place by a strip of double sided adhesive tape on top of the logic chip IC1 although that is only for location purposes The device works by intercepting the signal to the modulator and installation requires the cutting of a wire to the modulator and soldering four wires in appropriate positions The toggle switch is fit ted to the rear of the ZX 81 case anda in hole has to be drilled to accommodate it Many Sinclair us may be justifiably relu tant to drill holes in their ZX 81s so it may be possi ble to locate the switch ina different way or perhaps omit it completely and stay in inverse video mode The invertor costs 3 50 and is available from Dieter Fritsch G5CKZ 6 Stanton Road Thelwall Warrington Cheshire WA4 2 5 A similar device is available from B A Reader to the one just described but consists of a single IC SINCLAIRUSER August 1962 and a rather over sized toggle switch both being mounted on a small piece of Veroboard The manu facturer has indicated that a smaller switch is now supplied with the kits I
36. possible to handle in a similar way the read only text as after entering it pressing and storing in arrays programs do not need the compress routine So before such a program is saved on the cassette the compress routine may be deleted as in normal use the program will need only the expand routine to prepare the data to be PRINTed Besides further savings in memory space this method provides additional security benefits since the LOADed program will contain text data which cannot be modified easily without the compress routine 25 MICRO SHOP NEXT TO STREATHAM STATION NEW SOFTWARE SHOP EXCLUSIVELY FOR ZX81 PROGRAMS GAMES ADD ONS Buying your first MOST OF THE MAIL ORDER ITEMS ADVERTISED IN computer THIS MAGAZINE AVAILABLE OVER THE COUNTER BUSINESS amp TECHNICAL DATA HANDLING PROGS PROPER KEYBOARDS CONSOLES VDUS 5 374A STREATHAM HIGH ROAD LONDON SW16 your ZX81 Tel 01 769 2887 S A E APPRECIATED FOR CATALOGUE Need technical advice THEEXPLORER S GUIDE To The ZX81 The Book for the ZX81 Enthusiast By Mike Lord 120 pages Programs for 1K RAM and programs for 16K RAM Games Business and Engineering ty whole section for or Just browse through the new books and Applications RAM amp 1 0 Circuits Useful ROM Routines Hints and Tips Sapa sud
37. random fall of the dice taking it in turn to try to make a natural while avoiding snake eyes which is craps and you thought computer jargon was complicated The programs have excellent full screen graphics and cost 5 50 and 3 95 respectively from Newline Ewell Rd Wollaton Nottingham 8 2DE SINCLAIRUSER August 1982 ENHANCE YOUR SINCLAIR ZX81 Video Inverter adds professional touch Displays sharp white characters on solid black background TV screen A toggle switch lets you choose between NORMAL and REVERSE NEW KIT 4 READY BUILT 6 ORDER NOW P amp P inc A small printed circuit board fits top of the logic chip inside your 2 81 Comprehensive easy to follow step by step instructions make the modification a simple task We will fit your inverter to your ZX81 for 7 50 For convenience print your name and address on back your cheque or postal order and send to D FRITSCH 6 Stanton Road Thelwall Warrington WA4 285 NOW FROM AFDEC ZX81 RAMPACKS 16K 25 00 Inclusive and post free Well proven design Simplicity itself Just plug in and Power derived from ZX81 without additional connections Ingenious flush mounting design eliminates Wobble and accidental memory loss Special feature LED On Off indicator Coming soon A professional keyboard at an affordable price Send the coupon TODAY for your Rampack A
38. the 2 81 16K or the ZX SPECTRUM 48K 1 SUPERMIND 2 QUEST enhanced version of Mastermind As reviewed by SINCLAIR USER May 1982 Battle with the monsters in real time and collect treasures Fast reactions essential Arrange a series of digits in ascending order The classic game the usual features 8x8 galaxies photon torpedoes phasers Klingons etc a really good game CASSETTE A ZX81 16K contains games 1 2 3 and 4 ONLY 5 95 CASSETTE B ZX SPECTRUM 48K contains games 1 2 3 and 4 ONLY 6 95 3 REVERSE 4 STAR TREK State Cassette A or B when ordering Post and packing included Orders to SERIOUS SOFTWARE 7 WOODSIDE ROAD BICKLEY KENT BR1 2ES 2X SPECTRUM _ ZX81 2 SPECTRUM ZX81 ZX SPECTRUM 2 81 SINCLAIRUSER August 1982 wi Andrew Hewson File problems on display in ZX 81 OUR LETTERS are arriving Y thick and fast and Lam having difficulty keeping pace with them I make conscientious effort either to answerletters individually via this column or by referring to other answers in the column or elsewhere All the questions this month concern the ZX 81 display file in one form or another Before tackling the first let me review some fundamen tal ideas The display file is the area in RAM which holds the items which are currently displayed on the TV screen During the program devel opment for example part of the program listing is generall
39. the Spaceship Golf Description Six games including the fascinating Tower of Hanoi problem Cassette G8 Super Programs 8 ICL Hardware required 2 81 16K Price 4 95 Programs Star Trail plus blank tape on side 2 Description Can you as Captain Church of the UK spaceship Endeavour rid the galaxy of the Klingon menace Cassette G9 Biorhythms ICL Hardware required 2 81 16K Price 6 95 Programs What are Biorhythms Your Biohythms Description When will you be at your peak and trough physically emotionally and intellectually Cassette G10 Backgammon Psion Hardware required 2 81 16K Price 595 Programs Backgammon Dice Description A great program using fast and efficient machine code with graphics board rolling dice and doub ling dice The dice program can be used for any dice game Cassette G11 Chess Psion Hardware required ZX81 16K RAM Price 695 Programs Chess Chess Clock Description Fast efficient machine code a graphic display of the board and pieces plus six levels of ability combine to make this one of the best chess pro grams available The Chess Clock program can be used at any time Cassette 612 Fantasy Games Psion Hardware required ZXB1 or ZX80 with 8K BASIC ROM 16K Price 4 75 Programs Perilous Swamp Sorcerer s Island Description Perilous Swamp rescue a beautiful p
40. to convert all the graphics into CHR x but that wastes memory On the latest models when LISTing the program the graphics 40 097 29 8 8 8 05 55 characters have been converted to spaces enabling the user to fill in the gaps with the appropriate graphic when the printing had been completed The original ZX 99s did not do that causing problems in the LISTing Data Assette has offered new ROM to people who bought the original model Thatdoes not apply when printing data buffer of course as CR LF can be done at any time along the Non restoration of slow mode on return to Basic is also annoying entire length of the printer One useful thing in the LIST routine is that it generates a blank line after single GOTOs GOSUBs or RETURNs showing the end of routine The tape LOADing and SAVEing are done at the same speed and in the same way using Sinclair ROM routines so there is no increase in speed The fact that five seconds of blank tape is recorded between each piece of data also means that is better only to SAVE to tape large amounts of data otherwise the data records take so long to load CLS is also recommended to be used during data recording other wise that causes noise in the silent part of the tape A data limit of 40 bytes is also imposed on the user
41. use 18 that its keyboard which many of us agree is maddening to use is also very resistant able to withstand spilt drinks and countless sticky fingers never mind a little bit of dust In fact one ZX 81 has even been run from a car battery in a muddy back garden without ill effect Further it appears that my oft repeated complaints about the Sinclair never doing anything useful are completely unfounded Accord ing to Hall with the necessary modi fications and appendages I will not go into all the technical details as I donot want to confuse you the Sinclair can be made to do almost anything Even feeding the cat and watering the plants dare say although I would not trust it to know which was which and certainly not to speak to them pleasantly This opens up an interesting pos sibility No longer need Sinclair users endure long weeks of com puter deprivation they can take their little computers with them While those of us with more old fashioned tastes splash about in the waves or walk through breath taking scenery they could be sitting within wire s reach of a car engine eagle eyes trained on a screenful of moving blobs astounding the locals by their skill and by the amazing advances of British technology It could be the start of a com pletely new way of spending holidays Beach computer clubs could spring up in the resorts of Europe or more likely car park computer clubs Parents could be
42. were mib Cua THEM 509 Zooo PRINT AT ZPLORS 4980 PRINT nr 21 157 SCORE 4985 9588 1 THEM 5998 IF E ANC canso THEN GOTO S400 ir lt AND 5400 Es 5400 5558 IF 4 ANC egio 6 AND s es Soso 6 AND cones THEN 499 exe co THEN GOTO TOWERS HANOI 36 game is from the east via Simon Annetts of Rhayader Powys It velly velly good Your Sinclair will erect three pegs andon the centre peg will place six rings in order of descending size Your taskis to transfer the rings one by one until they are all assembled in the correct order on one of the other pegs You cannot place a bigger ring on a smaller one and the computer will chastise you if you try An excellent little game which went immediately on to the office tape Graphics notes 30 32 graphic shifted 88 50 Three spaces graphic shifted 8 7 spaces graphic shifted 8 seven spaces graphic shifted 8 67 Three spaces graphic shifted Three spaces inverse space graphic shifted 5 80 Two spaces graphic shifted 8 two inverse spaces 90 Two spaces three inverse spaces graphic shifted 5 100 One space graphic shifted 8 Two inverse spaces 110 One space five inverse spaces graphic shifted 5 120 Graphic shifted 8 six inve
43. were received this month which are different from what has been included so far They are Anagram and Crossword but were received too late for review this month At first glance it looks if they are good The address to send answ problems or about any other ide Philip Joy 130 Rush Green Road Romford Essex RM7 0QA 45 MAKE THE MOST OF YOUR MICROCOMPUTER WITH OUR POPULAR RANGE OF PROVEN BOOKS GETTING ACQUAINTED WITH YOUR 281 by Tim Hartnell Eighty plus programsinthis 128 page book including draughts 68 95 20 SIMPLE ELECTRONIC PROJECTS FOR THE ZX81 and other computers by Stephen Adams 6 45 MASTERING MACHINE CODE ON YOUR ZX81 OR ZXBO by Toni Baker 180 pages teaches machine code trom fest principles 7 50 49 EXPLOSIVE GAMES FOR THE 2081 edited by Tim Hartnell 5 95 34 AMAZING GAMES FOR THE 1K 2 81 by Alastair Gourlay 4 95 THE GATEWAY GUIDE TO THE 2 81 AND 2 80 by Mark Chariton Over 60 programs and routines ZX BASIC explained in detail 6 45 LEARN PASCAL ON 2x81 ZX SPECTRUM OR BBC MICRO COMPUTER WITH PASCAL FOR HUMAN BEINGS by Jeromy Ruston which contains a 12K compiler so you can run alimitedvversion Pascal on your 281 ZX Spectrum or BBC Microcomputer Book pius compiler listing 4 05 LET YOUR BBC MICRO TEACH YOU TO PROGRAM by Tim Hartnell over 40 programs BBCBASICIromhrstpnnciples 6 45 THE the BBC Microcomputer forthe senous user IC MICRO REVEALED by J
44. 0 if all is well One of the useful extras provided by the code is a check of the quality of a program which has been read back from the tape by the ZX 99 It consists of checking for three com mon errors too high a level too low a level and varying tape speed giving longer pulses than are to be expected A number which gives the sum of the three errors is returned in the completion code if they are found The USR commands provide the following functions Turn on the tape drive of any one input or turn on either or both of the tape drive outputs e Read or write a data buffer of length Z into or out of the tape recorder On output two copies can be made if required one from each output e Skip the next block of data or program on tape e LOAD a program into the ZX 81 memory from an input tape One of the useful extras provided by the code is a check of the quality of a program which has been read back from the tape Basic but it requires the use of several variables to be set up for use by the ZX 99 before the USR commands are used These are a single dimensioned string DIMXS 300 Z Z and Y The dimensioned string can be any single letter and is used to store the data to be sent or received from the tape 25 is used to tell the ZX 99 drive and then SAVE it again on to one or more output tape recorders e Printout a data buffer to an 5232 printer Y defines speed number of stop bit
45. 12 8JE Mail order 3 MACHINE CODE For the 16K ZX81 PACKAGE FOR THE 281 16K A sue of easy to use machine code Cesc programe DEFINED SCROLL REGION or down FILL SCREEN any CHANGE FOREGROUND INVERSE VIDEO FLASH SCREEN CLEAR SCREEN without changing Supplied on tape with a 6K DEMO booklet x ONLY 8 96 incl 16K GAMES PROGRAMS GOLF 1 or 2 Puayers Fantastic Send 10 6 SOFTWARE Bourton Road GLOUCESTER GLA OLE TRADE ENQUIRIES WELCOME POOLS FORECASTING PROGRAMME Y 65 MICRO WARES MAKE MONEY unique program shows how Last 3 95 SAIL A YACHT against wind tides hazards adjust sails etc Sailing 3 For Spectrum ZX81 16K On quality checked tapes 20 Winstree Basildon Essex 5513 1PG ZXB1 16 RAM 65 ono Sinclair buit D Wright 3 Burford Ave MCR M31 1SH Tel 061 748 2175 ZX81 16K RAM Sinclair bui Original packing leads and manual Some books and cassettes can deliver 95 ono 5 Mannon 37 Cloverdale Stoke Prior Bromsgrove Worcs Tel Bromsgrove 70778 SINCLAIR BUILT 2 81 16K ram pack Plus leads manual and power pack All still boxed Also 10K 30 maze program Everything bargain at 95 Nicholas Barker Highfield Dairy Lane Walberton Arundel Sussex BNIB Tel 551315 2x81 16K G3ZHY MORSE CODE TUTOR
46. 6 RAM PACKS BYGBYTE RAM PACKS no wobble problems 1 year que 22950 guane on aach RAM PACK Ths bani yos em buy IKZXCHESSI We thnk was possible but the game plays wes 235 agsinat you two opening moves only TK of memory ranted ZX CHESS Vey popular machine code reduced to 6 50 and an analysis option new improved version with a faster response time ADVENTURES ans code pied with ADVENTURE A Ses ta or aian nret Can you reach your ship and escape ADVENTURE B ims jungi ering you come across an Inca tempie 7 00 You must break in collat treasure and escape aive ADVENTURE C Beware Includes a cassette save routine 8 00 You ae unfortunate enough 1o be drawn to an aen Yourself or wil they get you fist includes a cassetto save routine GALAXIANS the features of the acarde game in a fast machine 3 95 program Swooping attackers explosions and ZX BUG coring R30 n machine code too and disassemble allows 7 00 access to all registers and to search through and modify memory with cassette routines and many more For a catalogue giving full details please send a S A E to Artic Computing Dept EE 396 James Reckitt Avenue Hull HUB OJA SINCLAIRUSER August 1982 hardware world JA Little switch into reverse THE ZX 81 video invertor consists of one integrated circuit which is an
47. 86967 New supply of chunks printer paper EAST LONDON Robotics has produced a incremen PRINT N PLOT Products tal RAM board which which produces a display allows you to addup to 16K mapping book and foils is of static RAM in 2K por now supplying printer tions toaZX 81 The board paper for the Sinclair fits inside the ZX 81 and printer Silicon Tricks is canbe used with any RAM not now supplying paper pack available It requires sothiswouldseemtheonly no soldering to fit the alternative to Sinclair board and its instructions The quality is as good cover nearly every as not better than that possibility of Sinclair and at 10 95is board uses 6616 cheaper Print N Plot is static RAMs and can be addressed into any posi from the micro to the tion in the memory map remote control unit attach The incremental board to an other device costs 12 01 and the 16K the moment the com 13 23 Tothatmustbead puter can only send ded the price of the RAM signals and not receive chips at 4 93 and 45 them via the system but pence for postage if the modifications to produce a order isless than 15 East two way device will be London Robotics is at available soon Finlandia House 14 The ZX 81 computer in Darwell Close East Ham terface costs 61 40 and London E6 4BT the remote control 27 50 a inc VAT and postage Stripeland is at 111 Liver Remote pool Road Formby controller Merseyside 6BR
48. 95 price Printer 59 95 NEW PRICE All units now in stock Wide range of books software and DCP packs also available fester is impos in our Budget Micros department prae pep Nem T QUARANTEE ina Mr Cambridge Computer Store FOOTBALL MANAGER HARDWARE REQUIRED 1 Emmanuel Street Cambridge CB1 INE euni Topic Hh Cus Phone 0223 358264 65334 video Gone Contintanow o n Also Acorn Atom VIC 20 Tandy TRS amp TOOLKIT memes GAMES 7 GRAPHICS No comparat lector t p Ad you deni By GRapnics s and ot Ii TOOLKIT 4 Designed fo ga drin practice d promote marte tough includes TORTOISE sex RAM ONLY programmes version of the famous Turtle Creative use of programme graphics CODED MISSILE Many innovative PROGRAMMES PRIMARY EDUCATION Fully documented includes many kuyan e Saent Son iat o Sas liar Domo Mac mere Bl p EDUCARE ee esie Sond me Spay 501 ras Se Hanes i idress swixsay ecc VA vem chad borat omiy Sead mm Pretend to be Ian Botham win a printer This month we are awarding the last of our five Sinclair printers in our monthly competition for which we expect the response to be as good as for the firs
49. A Barcelona 14 Espan United States Bay Area ZX 80 User Group 2660 Las Aromas Oakland 94611 Harvard Group Bolton Road Harvard MA 01451 617 456 3967 Baile SINCLAIRUSER August 1982 offer Build your own Sinclair Special ZX 81 Kit Offer ONLY 29 95 plus p amp p SAVE 20 on a Sinclair ZX 81 kit A special offer open only to readers of Sinclair User has been negotiated with Sinclair Research which means you can buy the world beating ZX 81 for just 29 95 plus post and packing Stocks are limited so be sure to place your order soon Allow 28 days for delivery Maximum four units per applicant To Sinclair User Special Offer ECC Publications 30 31 Islington Green London 1 8BJ Please send me ZX 81 kit s at the special Sinclair User price of 29 95 plus 2 95 p amp p Please tick if you require VAT receipt O Please charge to my Access Barclaycard Trustcard account Please delete complete as applicable Signature H Name Mr Mrs Miss E Address gt l 1 I enclose cheque postal order payable to Sinclair Research Ltd for __ SINCLAIRUSER August 1962 63 ZAG SOFTWARE NIGHT GUNNER Enemy aircraft approaching from the rear Can you defend your plane against enemy attack Beware the more you shoot down the faster they get exciting machine c
50. August 1982 The independent magazine for the independent user lt lt 4 013 Sv HOLD3NNOD HL YOWHV peoy xassns 96 693 9 56613 031531 ANY C3 18W3SSV ATINA AMOWSW adv 3AISSVIW 91 52 0 3 pedonuaumnu pase dep ih Ex IS 08XZ AEN I Nigel Clark INCLAIRVOYANCE We look at how micros can boost the enjoyment of holidays in future Consultant editor Mike Johnston 6 HOLIDAY PROBLEMS Do ZX 81s become lonely when left behind at holiday time Nicole 9 mams 13 COMPUTER CAMP We profile Beaumont Computer Camps where children can learn ab Production editor Harold Mayes MBE considers the difficulties light heartedly JAMES lan Stewart looks at ways of relaxing with numbers Design William Scolding new technology in the Lake District Editorial director John Sterlicc 14 SOFTWARE SCENE We concentrate on ways of using your ZX 81 to occupy the hours of poor summer weather 19 NEWS The Spectrum begins to roll a disa sales boost in the U S and much more Advertisement director Simon Horgan ous Microfair in Manchester ZX 81 Advert John Ross 21 YOUR LETTERS You tell us what you
51. ER August 1962 Bec THEN LET B 5 INKEY G THEN LET E B INKEY gt THEN GOTO Y CODE s 7 CODE 6 D A O G THEN GOTO Y IF B F AND D G THEN GOTO Y GOTO CODE f PRINT AT PRINT F G R LET GOTO gt PRINT AT F G A THEN GOTO MAGH TS a distinctly topical sub hunt game submitted by KEY RELEASES THE TORPEDO M Thurston of Manchester in which a torpedo is dropped from patrolling aircraft and homes in The cursor is mon iat it draws the torpedo path of the submarine the movements of three points submarine sir and torpedo must be cor high degree of skill is X1 im d In addition the depth of zt ezx by random IE 30 Oc 13 PRINT AT PRINTS THEN PRINT AT 9 29 LET XieXi CINKEYS 8 5 lt THEN LET X THEN L INT AT 22 1 Uses THEN LET 1 49 LET 49 LET USSAT v vsiv 29 29 v la PRINT Y9 5 THEN PRINT AT viae IF INKEY THEN LET M 2 coro 199 151 Space 152 Inverse space fren LET Z ABS Y 412 Five graphic Hs 1 6407 U 413 Five inverse spaces S AND 8 CONTROL THE CURSOR one one 2 or 1 THEN PRINT AT HG H e9 THEN
52. ETT Thurnall Electronics List price Club price 987688 Input output port kit 14 95 13 45 assembled 17 95 16 55 Fourchannelrelaybox 14 95 13 45 Eight way transistor driver 9 95 8 95 Eight way indicator unit 12 95 11 65 Joystick 12 95 1165 Which computer do you own Motherboard 15 95 14 35 Power supply 4 95 4 45 mn Send your coupons to Sinclair User Club ECCPublications 30 31 Islington Green London Yoll alll iio Thane un N1 Cheques should be made payable to found in advertisements in Sincloir User L Sinclair User Club ae SINCLAIRUSER August 1962 HE FIRST member of our Sinclair User Club is an enthusiastic Sinclair supporter He was one of the first to ob tain a ZX 81 he took a year s subscription for Sinclair User as soon as it was announced and he placed his order for the Spectrum some time ago When Sinclair brought out the ZX 80 I decided to wait but when the ZX 81 arrived I put in an order straight away Peter Lown 62 of Strathmore Avenue Hull North Humberside said He bought it with the 16K RAM pack and the printer telecommunications manager with a large in ternational company Lown has made full use of his system both for work and in his hobby of motor sport Tuse it to run telephone traffic analysis It is not complicated just number crunching but there is a good deal of work invol
53. If you ve got a Spectrum on order or better yet if you ve already got your Spectrum then you ll be glad to know that Dr Logan is working on Understanding Your Spectrum sure to become the definitive book on the Spectrum So if you want to smile like Dr Logan you can do one of two things Order one of our books from your bookseller or fill in the coupon and really understand your Sinclair or you can write a great book or program and send it to us Who knows Your smile may be in this ad next year Machine Language Made Simple For Your Sinclair 8 95 Understanding Your ZX8l ROM by Dr lan Logan 8 95 281 ROM Disassembly Part A by Dr lan Logan 7 00 O 2 81 ROM Disassembly Part B by an Logan and De Frar O Not only 30 Programs for the 281 IK 6 95 O The Complete Sinclair ZX8I Basic Course 17 50 Orders to Melbourne House Publishers 31 Trafalgar Road London 5 10 BE Please rush me your new Spectrum ZX81 ca Please send me books as marked above Note MELBOURNE HOUSE 2 81 SPECTRUM boost I IS a bleak winter s day in the hiatus between Christ mas and New Year a few years in the future The thoughts of the family Typical Sinclair User stray from the usual feast of old films and Christmas spectaculars on television to visions of sun sea and sand They switch off the television attach their latest Sinclair machine bought from one of the many high Street stocki
54. K That is because of the way theZX 99 divides the tape recorders there must be atleast two to make a sensible system into INPUT and OUTPUT tape recorders The two input sockets are selected in dividually and one lead is provided with the ZX 99 to connect the EAR and REMOTE sockets on the tape recorder The normal cassette leads are plugged from the ZX 81 into the ZX 99 at the top and all of the SAVEing and LOADing is done through the ZX 99 There is a 50 page manual with the ZX 99 and it is well worth reading before starting It is well written and contains not only SINCLAIRUSER August 1982 chapter on all of the commands but example programs problems which may occur and any peculiarities of the system The commands are in the form of USR calls to various parts of the 2K ROM which can either be used direct from the keyboard or within a program It is very easy to use in interface review is used for the buffer and variable Z the length of that buffer string to be sent The Y variable is used to control the printing operations of the 5232 interface The variables can be put to other uses in the program but must be filled with the correct data for the ZX 99 before doing a USR command or an error code will stop the program There is also a com pletion code in the form of an error report when LET 1 USR 1234 is used Variable L can be checked if there has been a fault as the report will be
55. PRINT AT H G 9 H gt 10 THEN PRINT RT H G ET G G X0 Y EN GOTO 18 22 32 BRIMITSri60 THEN GOTO ter FR 0 v o FoR N 1 NEXT M PRINT RND S 1 190 21 BAE SINCLAIRUSER August 1982 X MAN is silicon based form writes its discoverer Chris Handley It thrives ff diet of asterisks but is killed instantly the spac up its maze like ecosphere Your task is to use keys EE ED 6 7 and 8 to guide the ZX Man E T P idi through the maze without running out of time into walls TE ETE additional hazard is provided TO L STEP M by the ghosts of previous ZX Men CINKEY which materialise unpredictably and gobble him up Only in the home straight is he safe from this ghoulish threat It is an excellent 1K game for the ZX 81 though the fit is so tight that adding s to the word ghost is sufficient to halt the program D o P GO eresoerSo5ses D m LET B B INKEY 8 INKEY E PRINT AT A B MSTRUCT INS THEM GOS 33r Rm PRINT PRINT 5 5 BT M m 16 6 Ne SS ir PRINT AT 10 PRINT PRINT SOTO sso 18d 1 BT PRINT PRIN THEN coro THEN coro te THEN nnl THEN e nup pu
56. TING _ POPULAR COMPUTING WEIRLY 2 o 30 your vewscrean show you The vens Out WA actua room 130 shoot you you iet mam Your dep ds Seir Shi engin Proust Forward Radar and vo rd a as pce vou ca go wong GAMES MARKED INCL MACHINE CODE Prices include VAT and U K P amp P Add appropriate Postage on Foreign Orders Cheques P O s to J K GREYE SOFTWARE LTD Dept 5U 16 Park St Bath Avon 2 CREDIT CARD SALES Phone 01 930 9232 9 a m 7 p m FOR INSTANT DESPATCH yeu peter to ses before buying ou range of GAMERTAPES BUFFER MICROSHOP ___ Steatham High London SWE GAMER D Govcester Re Branton GEORGES port Sr Bratch Avon MICROSTYLE B Belvedere Laredon Bah Avon MICROWARE 3 Menon Ra Loc SCREEN SCENE 44 Se Georges Rd Cheltenham Gios Wt Swim ver 200 Computer ranches Schoo Lane Dorset TRADE amp EXPORT ENQUIRIES WELCOME 12 OCCAM BOOKSHELF PEEK POKE BYTE amp RAM by lan Stewart amp Robin Jones A gentle introduction to the ZX8 amp its capabilities NOT ONLY 30 PROGRAMS SINCLAIR ZX81 1K 725 Games Utilities and Mathematics with a listing of and discussion each program UNDERSTANDING YOUR ZX81 ROM 8 95 By Dr lan Logan The 280 Microprocessor its machine code and how to use
57. ZX81 taking off in the States THE ZX 81 is beginning to take off in the States An agreement between Sinclair Research and the American Express credit card company has resulted in a flood of orders for the machine The credit card com pany sent a direct mail of fer to its two million card holders in the U S at the end of May In what Sinclair Research calls very positive response 2 000 orders were receiv ed by noon the day follow ing the offer In the first three weeks more than 25 000 orders were sent to American Express SINCLAIRUSER Augusti982 Total sales from the of fer have been forecast at 50 000 units and it is thought that may be a con servative estimate The offer was agreed between American Ex press and Sinclair Research following a suc cesful test marketing for the ZX 81 at the end of last year The test market had been requested by the credit card company The deal does not affect the plans by Timex to market its enhanced ver sion of the ZX 81 the Timex Sinclair 1000 which has a 2K RAM in stead of the normal 1K That will not be on sale un til this month and Sinclair Research in the U S is con tinuing to sell the ZX 81 until the Timex sales reach a certain level Sales of the ZX 81 were 15 000 a month in the U S intheearly part of the year and it is estimated that 435 000 have been sold throughout the world Sales in Britain declined in April but are said to have recover
58. aco Bottosford Scunthorpe 0724 63466 Sheffield Andrew Moore 1 Ketton Avenue Sheffield 58 would like people interested in starting a club in the area to contact him enclosing a stamped addressed envelope for details Worle Computer Club 5 W Rabone 18 Castle Road Worle Weston super Mare 8522 9 W Weston super Mare 513008 Meetings Woodsprings Inn Worle on alternate Mondays ZX Guaranteed A Bobker 29 Chadderton Drive Unsworth Bury Lancashire Exchanges information and programs throughout the country 2 80 2 1 Users Club PO Box 159 Kingston on Thames A postal club Overseas Belgium France Luxembourg Club Sinclair Raymond Betz 38 Chemin du Moulin 38 B 1328 Ohain Belgium 322 6537468 Belgium Netherlands Microcomputer Vereniging BZW Paul Glenisson Priester de I Ep estraat 14 1200 Brussels Belgium 322 7349954 Denmark Danmarks National ZX 80 81 Klub DNZK Jens Larson Skovmosevej 6 4200 Slagelese post giro 1 46 24 66 East Netherlands Jonathon Meyer Van Spaen Straat 22 6524 H N Nijmegen 080 223411 Germany ZX 80 Club a postal club contact Thomas Jenczyk Hameln Postfach 65 D 3250 Hameln Germany Indonesia Jakarta ZX 80 81 Users Club 73 Cnoc Atha Cliath 1 Republic of Ireland Irish ZX 80 81 Users Club 73 Cnoc Crionain Baile Atha Cliath 1 Spain Club Nacional de Usuarios del ZX 81 Joseph Oriol Toma Avda de Madrid No 203 207 10 3a esc
59. antly the space utilisation and increase the amount of text stored The test program shown in figure one up to line 140 is only to demon strate compactor routines and to print the results after each step It will solicit the input string text and the operation may be terminated by inputting BYE It also contains small error routine which is used only if the input text contains an invalid character return from compress routine with SINCLAIRUSER August 1982 variable K not greater In that case input text is printed with the invalid character flagged under neath with an inverse 2 Routines for text compression at line 8000 and expansion at line 8200 are both designed to operate in FAST mode and revert to SLOW just before returning to the main program By omitting lines 8005 8125 8205 and 8295 the oper ational mode of these routines will be as set in the main program Com pactor routines use the following variables T string which contains the original text as an input for the compress routine or the returned to the main program if the compress routine en counters an invalid character on position from the start of the original text Note that this variable must be pre set to 1 in the main program line 25 before calling the compress routine to cope with empty input text X X1 X3 X3 used in the trans formation process to cal culate character codes
60. ave saved properly REVOLUTIONISE YOUR PROGRAMMING NOW FOR THE ALL INCLUSIVE PRICE OF 14 90 Make cheques P O s payable to PSS Full money back guarante We also have the widest range of high quality software for the ZXB1 available anywhere Whatever your needs we have the program for you From a superb version of PUCKMAN to a Compiler or a complete wordprocessor package you need look no further than PSS In addition all of our software is available through the ZX Software Library For a once only payment of 5 50 you can have any five of our packages 10 00 for ten You take one tape at time and make your own copies save yourself on list prices SAE for full details 20 SINCLAIRUSER August 1982 Contest 1 AM writing to complain about the competition in your June issue What annoys me most is that the amount of people entering this competition is limited to those who have a fair amount of knowledge about electronics and com puters and that must surely be a small per centage of your readers As this is a magazine for all Sinclair users surely a competition which every one could enter would be more appropriate Admittedly the Spec irum is an outstanding prize but if it is so good why not give everyone a chance of winning one Despite the complaint I think your magazine is excellent so continue the good work Philip Morris Langford Nr Bristol There are two reasons why we d
61. current fashions among the movie buffs Wumpus and Mogul are two good non graphics programs to keep you off the beach for hours Volcanic Dungeon software scene Hangman costs 4 50 and the other two tapes are 5 each plus 50 pence p amp p from R Carnell 4 Stainton Road Slough Berkshire Asteroids in the home INSTEAD of waiting for the amusement arcades to open the Electronic Pencil Co Asteroids brings home the action It has nearly all the features of the 20 pence guzzlers one or two players four sizes of asteroids hunter killer alien spaceship and on screen scoring There are five levels of play and the top five scorers have their names displayed Written in 100 percent machine code Asteroids costs 3 95 from the Elec tronic Pencil Co Machine tools MARTIN Wren Hilton the U K correspondent of the American Sync magazine has taken time from his A level studies to produce two remarkable machine code programs for 16K ZX B1s The first Super Zap sounds like yet another space invaders game but is in fact a separate loading and sav ing routine entirely dis tinct from the routines in the Sinclair ROM Many machine code programs now available start running automati cally after loading and since they often use their own keyboard scanning routines they do not res pond to the Break key Wren Hilton wanted to be able to look at those va pape 16 15
62. d ons for the ZX 81 Among the products available from Thurnall are input output ports motherboards and joysticks All these Thurnall goods we can offer to members at a discount of 10 percent The discounts from K Greye and Thurnall Electronics are open until the end of August To allow new members to take advantage of these very generous offers you can include an order with your membership application A form is Facilities to include Spectrum THE USER CLUB is to expand its facilities 10 cater for the growing number of Spectrum owners For the same annual subscription of 12 they will be able to take advantage of the extra benefits which have been available to other ZX owners for the last two months The benefits include the bi monthly cassette based newsletter which is being re recorded so that it can be used with the Spectrum and will contain Spectrum programs To ensure that each member receives the correct cassette please denote which machine you own by ticking the box on the application form below Meet the first member of our stock the Greye range printed below club on p 62 Greye Software List price Club price zl Gamestape esos 315 MEMBERSHIP Gamestape 2 395 315 Catacombs 4 95 63 95 FORM 3D Monster Maze 495 3 95 3D Defender 495 395 Lwishtojointhe Sinclair User Club and enclose Breakout 1 95 155 my subscription of 12
63. e sent to Ultra Tech Services 30A Billing Road Northampton ABERSOF 7 MAESAFALLEN BOW ST DYFED SY24 5BA ZX81 amp Spectrum Games Now NEW LOW prices PROGRAM OLD NEW 81 SPECTRUM Chess 14 10 00 8 95 10 levels me Adventure 1000 895 140 locations based on the original At 10 00 well worth the money Sinclair User Issue 2 review Invaders 5 00 445 Fast m c arcade action Mazeman 500 445 Ail the features of the original arcade version mc 995 requires 48k Spectrum All prices are inclusive Return of post service IT S HERE THE BOOK YOU VE BEEN WAITING FOR LEARN WITH YOUR SINCLAIR MICRO COMPUTER BY FRANK ORVILLE SINCLAIRUSER August 1982 ZUCKMAN The first authentic 2X87 16K version of PUCKMAN E FOUR Independent Ghosts Trail Energy Posts etc High score of Fame Authentic Arcade Action only 5 95 inc P amp P from DJL SOFTWARE Tweed Close Swindon Wilts Retum of post delivery MUSIC LEARNING AIDS range of programs for 16K 2 81 to help young people learning to read music Sae please for free catalogue Brian Negus 19 Westfield Drive Loughborough Leics LET1 For ZX81 with 16K RAM Three programs on one cassette Flight Demonstration Flight Simulation and Flight Test These are semi serious programs using an aircraft digital instrument panel 5
64. ecause this is much faster than Basic Some of these games were previously available from J Steadman Cassette 4 costs 5 Recorded on quality cassettes sent by first class post from Michael Orwin 26 Brownlow Rd Willesden London NW10 9QL mail order only please KAYDE Electronic Systems ZX80 1 ZX KEYBOARD WITH REPEAT KEY Fully cased keyboard 37 95 Uncased keyboard 27 95 Keyboard 10 95 KAYDE FLEXIBLE RIBBON CONNECTOR gt Stops movement of RAM PACK and other accessories S 2 955 Not needed with a ANA KAYDE 4K GRAPHICS BOARD NO EXTRA POWER NEEDED KAYDE 16K GRAPHICS BOARD SOFTWARE Post to Dept SU Kayde Electronic Systems Ltd The Conge Great Yarmouth queens Norfolk NR30 e Tel 0493 57867 Dept SU 1 Address Don t Forget you can always ordei 1 on the telephone with your credit card 1 ease 1 50 for alt hardware and 50p for all sofware All products include VAT all hardware Please make cheques payable to Electronic Syste comes fully built and tested with a 14 day money back option
65. ecided to base the June competition on a hardware application The previous two had been for software and we thought it better to set something for those with an interest in hardware Second we do not share your view that people with a knowledge of the electronics of com puters comprise only a small percentage of our readership Character error HAVE YOU noticed that CHRS 7 and 135 are printed as the same chara cter in the ZX 81 manual SINCLAIRUSER August 1962 and that the graphics character on KEY 3 is missing Ihave found out that the missing character has the code 135 and that the one printed is wrong The character with code 135 is Misprint problems SEVERAL MONTHS ago 1 finally bought a ZX 81 and promptly set about mastering the manual All went well until I reached page 129 Exercise 4 prophetically entitled This one will drive you mad Try as might every time Lentered the program and tried to run it I would be greeted with error code 5 90 or 5 150 or 5 210 if I pressed Q After some thought it occurred to me that the lines of the program the machine was trying to execute when the report codes appeared were all PRINT statements That meant the machine was trying to execute those commands but had insufficient screen space to do so The next thing which occurred to me was that SCROLL instruction had gone wrong somewhere so Ithen set about jamming in extra scroll statement
66. ed in May The machine is being pro moted in new markets Sales are going well in France and reasonably well in Germany and in creasing in other markets company s advertisement in Sinclair User in June the Manchester Microfair was mentioned and the company had received many calls from people who had not known about it Johnston replied It received the same amount of coverage as the previous London shows when we were criticised for having 100 many people He added that he had not been deterred from organising fairs and would be holding another The experience of Man chester does not appear to have influenced com panies unduly from exhibi ting at shows outside London The next two pro vincial shows were both reporting a high level of interest Gordon Hewit a com mittee member of the Edinburgh ZX Computer Club which held a fair in July said that many exhibi tors disappointed with the Manchester show had turned to them in the hope of doing better They Scotland as a more fertile area and with Edinburgh being a good centre of communications wecan attract people from all over the centre of Scotland he said On the same weekend Microfest 82 was held in Manchester One of the organisers Dave Hewitt said that many of the people had wanted to take space because seemed to be better organised Spectrums six weeks late ALMOST twomonths after the launch in a blaze of publicity
67. er of valid and unambiguous data characters which can be stored in a given memory area can be achieved either by reducing the number of bits used to describe each data character by changing the character codes or by reducing the number of redundant and insignificant data characters such as space characters The routines described are one Getting aquart into a pint pot D J Todorovic considers data code com pression by changing character codes example of a former approach on the ZX 81 but with practical value on machines with more than 1K of RAM As it is true for all compressi n Seco 8100 NEXT 8119 LET C 1 1 CHRS 3598 NEXT 8295 sLQu 8300 RETURN xels4 RNG 3 X3424 AND 3 12 10 REM s ZX81 TEXT COMPACTER amp amp 20 REM C GTN 1982 25 LET 1 INPUT Ts 40 IF THEN STOP PRINT TEXT ST asas 70 IF THEN 110 PRINT ERROR 7 4 98 PRINT TAB 169850 GRAPHIC iee coro 110 GOSUB sees ed2 PRINT LEN c CH COMPRESS BR MT LEN T CH EXPANDED 146 8000 REM s3COMPRESS ROUTINEs 8005 FAST 8010 LET Cs 8958 LET T T DOUBLE SPACE FOR 1 TO LEN T 2 STEP 3948 LET Sese FOR 0 2 8060 LET TS iB C 8070 LET K AND IF i THEN RETURN 83098 LET x X Kad4QssP HRS X 28631N
68. eremy Ruston The full story on 9 95 GETTING ACQUAINTED WITH YOUR VIC 20 by Tim Hartnell with over BO programs to get your VIC up and running trom day one 6 95 SYMPHONY FOR A MELANCHOLY COMPUTER by Tim Hartnett 24 great Vicgames 6 95 39 TESTED PROGRAMS FOR THE ACORN Best of interface edited by Tim Hartnell 6 45 GETTING ACQUAINTED WITH YOUR ACORN ATOM by Trevor Sharples and Tim Hartnell 184 pages programs including draughts 7 95 INTERFACE the monthly magazine published by the NATIONAL ZX USERS CLUB is just 9 50 UK 12 50 Europe for 12 issues Sample copy with many programs for your ZX computer book software and hardware reviews education contact addresses just 1 Please send me the items marked enclose Name Address Please make cheques payable to INTERFACE and send the above form or a copy to INTERFACE Dept 5 44 46 Earls Court Road London 8 ao upto 28 der Kr HAVEN HARDWARE The World s largest range of ZX Hardware PROGRAMMABLE CHARACTER GENERATOR KIT 17 95 BUILT 24 95 The FIRST and still the BEST NO MOTHERBOARD or EDGE CONNECTOR required Works DIRECTLY with ZX PRINTER and 16K MEMORY HIGH RES Graphplotter etc included FULL SIZE KEYBOARD with REPEAT KEY amp SINGLE KEY RUBOUT etc Specially designed for the 2 80 and 2 81 Still the only keyboard with 81 these features KITE18 45 BUILT 21 95 REPEAT KEY 1 45 extra SINGLE
69. etail appearing as the flying saucers loom in your forward scanner Another winner for 3 95 If you have spent the money you had saved for your RAM pack on your holidays instead J K Greye offers arcade game action in just IK Its full screen Breakout written in an in credible 500 bytes of Taste of exotic from Diggles ONCE YOU have returned from your two weeks in the European sun how can you recapture that taste of the exotic Photographs and souvenirs are all very well but what about food Your 16K ZX 81 can revive those memorable meals with the aid of The Diggles Kitchen Volume one contains 28 recipes from all over the world Cyprus chicken Spanish hake Italian roast lamb plus recipes for beef hare turkey duck ham and many more you have had enough of foreign food you will find Lancashire hotpot and steak and kidney pie included If you did not go overseas this year why not turn up the central heating serve Hawaiian pork and dream a little The Diggles Kitchens volume one and volume two European recipes cost 4 99 each or 9 two from Micro Computer Software Unit D6 Pear Industrial Estate Stock port Road Lower Brad bury Stockport SK6 2BP machine code has all the capabilities of the bigger versions The bricks are inverse signs which turn into signs when hit and then disappear altogether when hit again The game has adjustable bat size and speed plus on
70. ewnesTechnicalBooks 54 Oasis Software a M Orwin 2 Occam Software 12 Picturesque 60 Phoenix 2 Pss 20 Mr Readman s 49 11 5253 54 60 65 66 46 Software Farm 22 Tasman 60 Timedata 26 Ultra Toch E Workforce 5 SINCLAIRUSER August1982 MICHAEL ORWIN S ZX81 CASSETTES THE BEST SOFTWARE BY VARIOUS AUTHORS AT LOW PRICES QUOTES Michael Orwin s 5 Cassette Two is very good value It contains 10 stolid well designed games which work offer plenty of variety and choice and are fun From the ZX Software review in Your Computer May 82 issue had your Invaders React cassette was delighted with this first cassette P Rubython London NW10 have been intending to write to you for some days to say how much enjoy the games on Cassette One which you supplied me with earlier this month E H London SW4 previously bought your Cassette One and consider it to be good value for money Richard Ross Langley Managing Director Mine of Information Ltd CASSETTE 2 Ten games in Basic for 16k ZX81 Cassette Two contains Reversi Awari Laser Bases Word Mastermind Rectangles Crash Roulette Pontoon Penny Shoot and Gun Command Cassette Two costs 5 CASSETTE 1 eleven 1k programs machine code React Invaders Phantom aliens Maze of death Planet lander Bouncing letters Bug splat Basic Ching Mastermind Robots Basic Hangman PLUS Large screen versions of Invaders and Maze o
71. f Death Ready for when you get 16k Cassette One costs 3 80 CASSETTE 3 8 programs for 16k ZX81 STARSHIP TROJAN Repair your Starship before disaster strikes Hazards include biological specimens and plunging into a Supernova STARTREK This version of the well known space adventure game features variable Klingon mobillity and graphic photon torpedo tracking PRINCESS OF KRAAL An adventure game BATTLE Strategy game for 1 to 4 players KALABRIASZ World s silliest card game full of pointless complicated rules CUBE Rubik Cube simulator with lots of functions including Backstep SECRET MESSAGES This message coding program is very txip qexi if MARTIAN CRICKET A simple but addictive game totally unlike Earth cricket in machine code The speed is variable and its top speed is very fast Cassette 3 costs 5 CASSETTE4 ZX SCRAMBLE machine code with 3 stages Bomb and shoot your way through the fortified caves 8 games for 16k ZX81 INVADERS machine code GUNFIGHT machine code GALAXY INVADERS machine code Fleets of swooping and diving alien craft to fight off SNAKEBITE machine code Eat the snake before it eats you Variable speed very fast at top speed LIFE machine code 2 81 version of the well known game 3D TIC TAC TOE Basic Played on a 4 4 x 4 board t a game for the brain it is very hard to beat the computer at it 7 of the 8 games are in machine code b
72. ff gives flashing characters Video pages can be superimposed Video page access is similar to Basic plot unplot commands Contains 2K EPROM monitor with full range of graphics subroutines controlled by machine code MEMOPAK CENTRONICS TYPE PARALLEL PRINTER INTERFACE Main Features Interfaces ZXBI and parallel printers of the Centronics type Enables use of a range of dot matrix and daisy wheel printers with ZXBI Compatible with ZX8I Basic prints from LLIST LPRINT and COPY 7 Contains firmware to convert ZX8I characters to ASCII code Gives lower case characters from 2 81 inverse with the 2 81 gives 64K which is neither g notable feature of the RAM Number of Video pages is limited only by RAM size each or USR function Please send me Price Total Cheques payable to RAM 68870 10 30VAT SaKRAM 43 43 6 52 VAT 54955 Please Debit my Access Barclaycard RAM 26 00 390 VAT 51 account number 5200 7 80 VAT 5980 7 lt Packaging amp Postage 2 00 per unit 1 TOTAL ENC 14 money back Guarantee on our products Oxford 0865 722102 Telex 837220 Orchid G 23 HE IDEA of data code com pression is certainly not new as it has been used in various forms for a long time in mainframe computers The process of increasing the numb
73. ftware and hardware retailer As well as the subscriptions the winner will receive a Microware voucher Entry forms will be given with a copy of the cassette Entries close on September 30 and the win ner should be announced in the December issue of Sinclair User Mike Johnston THE FIRST computer fair for hobbyists to be held outside London was dis aster That was the verdict of the majority of exhibitors at the ZX Microfair in Manchester A variety of reasons were advanced including the visit of the Pope to Manchester the following day the bright warm Bank Holiday weather it was held at the wrong time with the Spectrum hang ing over the market and it was staged at the wrong venue with the New Central Hall being on the Northern fair disaster wrong side of the city where parking was problem The result was that 2 000 people visited the show and spent little money there I think it reflected the state of the market and there were a few things which went against it said the organiser Mike Johnston We had about 2 000 people compared to between 5 000 and 6 000 at the London shows but we are not talking about the same catchment area and if we had held it only onone day the attendance would have been reasonable A major criticism from exhibitors was that the show had not been given sufficient publicity Sue James of Microware in Leicester said that in her
74. good for something after all Let us write a small program to do the iteration for us 10INPUTN 20 PRINT AT 19 0 N 0 40 LET M INT N 10 50LET A A N 10 M starting number N It uses A to add N 10 M the squares of the digits those 60LETN M N 10 M s are the digits and 701F M 90 prints out SCROLLs to make room 80 GOTO 40 for the next step then sets N equal 90 PRINT AT 20 0 to the result A and goes back to line 100 SCROLL 30 to start all over again iterating 110LETN A like mad 120 GOTO 30 Type it in try a few values for It See what it does You give it the will go on forever unless you hit SINCLAIRUSER August 1982 number pattern Ian Stewart looks at a rewarding way in which to spend a few hours playing with number series and loops BREAK but keep watching perhaps you will notice a pattern What happens eventually is that the numbers settle down to some kind of regular behaviour but it can be a surprising one For instance try N 89 You will get success ively 145 42 20 4 16 37 58 89 The iterations brought us back to continued on page 10 continued from page 9 where we started and the silly beast is going round in an endless loop You will find that many starting values for N lead into the same loop That is interesting really you would not have guessed it initially Some numbers do not get into that loop thoug
75. h try N 7 as a starting point You can have plenty of fun trying different starting values and comparing the way the numbers evolve squares are not for you perhaps you would prefer cubes Thanks to Professor Rubik they are fashionable but our cubes are things like 2 2 2 or 3 3 3 27 Just modify line 50 of the program to read 50 LET A N 10 M N 10 M N 10 M and proceed as before This time there is a new surprise the number 153 goes to itself There are some other numbers which equal the sum of the cubes of their digits can you find them On the other hand there are some loops too for instance 133 55 250 133 Insert yet another N 10 M in line 50 and you have fourth powers Here is a nice loop too 4514 1138 gt 4179 9219 13139 6725 4338 4514 Fifth powers You should be able to work out the modification to the program by now There is a loop of length four 10933 59536 73318 50062 10933 Experiment with different powers and different starting points It is a relaxing way to spend a few hours and there are plenty of patterns to spot The one general thing which is known is that from whatever number you start you must eventually end in a loop with a number which goes to itself forming a loop with only one number in it Essentially that is because if you start with a big enough number the sum of the powers of its dig
76. hanged with POKEs and the routine took eight seconds to re number 5 There is a search and list function which could be used to find all of GOTOs and GOSUBs so that they could be changed to the required format There are also search and replace and memory left routines plus three graphics routines Hyper graphics mode alters the start address of the ZX 81 ROM character table and produces interesting but useless effects Fill fills a specified number of lines with a chosen character and Reverse inverts as many lines on the screen as required At 4 95 the program demands a great deal of care and effort from the user which surely is not the mean a complete crash not just stop if it encounters a computed GOTO or jump to a non existent line number The other ACS cassette contains Progmerge which allows all or part of a Basic program to be stored above RAMTOP and then merged with a second program the whole lot then being re numbered The in structions did not indicate what size of program could be stored and a 3K program I tried was too big The re numbering which can be run on its own has the same limitations as the toolkit Renumber I was impressed with the ACS assembler and disassembler programs and so I was surprised at the poor quality of its re number routine which could be used only with the utmost care The instruc tions are clear with helpful examples Progstore Toolkit costs 7
77. hat all the debug programs operate only in machine code and that the Basic programmer is left to sink or swim While itis true that there is nothing available to help unravel the mess of tortured logic in which my Basic programs finish there are several programs which add extra facilities as they are written and can make them look neater afterwards Even a program which is jumble of embedded subroutines and GOTOs every other statement looks well planned when all the line numbers increase in tens Re numbering is probably the main reason for the purchase of a toolkit program and is the only function included in every one at which I looked The range of other functions offered is very wide and some of them seem to have been put in just to make a program appear more sub stantial rather than because they are useful Hewson Consultants offers two programs a straightforward Renumber and a more sophisticated Toolkit Both can be used on ZX 81s with either the standard 16K RAM or with the increasingly popular 48K and 64K RAM packs They require the user to re set RAMTOP before the program is loaded which SINCLAIRUSER August 1982 can annoying especially when you forget to do it Renumber takes 1 and a USR call re numbers your Basic program in steps of five starting from 5 Other values for the step size and starting number can be POKEd in and it will always re number to the end of the program The routine took abou
78. he reasons why cars are preferred to public transport and why growing numbers of people can be seen walking around with headphones listening to small cassette players for some holiday time has always brought its special problems I do not mean only dilemmas such as what one wears if anything in St Tropez or for hang gliding over the Niagara Falls or for whatever other delights one has in store I speak of real anxieties such as who will water the plants Even if the cat could be persuaded to do it who will feed the cat How will the burglars be lured into thinking that three burly men are in residence when the whole street looks more dead than John Cleese s Norwegian blue parrot Now to add to all that there is a new problem what happens to my son s ZX 81 I realise how silly it sounds but I have to confess that I have wondered whether it would be all right on its own Would it rust Or do chips go stale for lack of use Would dust get into its nooks and crannies and make it behave strangely like something taken over by beings from outer space Would Alex on his return from holiday be E NJOYABLE though it may be Do Sinclair machines get lonely being left at home during summer holidays Nicole Segre considers the problem Taking the pain out of holiday separation have those names correct Will that American university which gave us Rubik s thumb and Clacker wrist discover another ailme
79. hips keep track of your accounts or as a telephone directory How to order Simply use the FREEPOST order form below and either enclose a cheque or give us your credit card number Credit card holders can order by phone simply call Camberley 0276 66104 or 21282 during office hours Either way please allow up to 28 days for delivery and there s a 14 day money back option of course sinclair ZX8l SOFTWARE Sinclair Research Ltd Stanhope Road Camberley Surrey 61015 3PS Tel Camberley 0276 66104 amp 21282 To Sinclair Research FREEPOST Camberley Surrey GU15 Please send me the items have indicated below Oty Cassette Please delete as applicable Mr Mrs Miss Address price Oty Cassette Total History ES Mathema E7 Invention EB Spelng B Collectors Pack TOTALE COMPUTACALC ZX MICROWARE Retail Shop In LEICESTER for SINCLAIR Computers Keyboards Ram Packs 1 0 Ports Monitors G Roms Games Serious Sinclair 2 Home Business Education Programs with 16K RAM Books amp Magazines vsatie software Also Now stocking Books and Software for SPECTRUM BBC and VIC 20 MICROWARE COMPUTACALC 2X sesette and bookie Dept 57 rae Rents Lor 1 603 131 Road 6074 Closed Leicester Thursday Tel 0533 681812 MICROWARE 2X81 amp 16K a
80. inghead Oldham ZX PRINTING SERVICE FOR YOUR ZX80 8K ROM 281 programs Only 1 pence for 3 lines of 32 characters plus 20 pence minimum 50 pence please Send cheque PO to T F Payne 194 Stockwood Lane Stockwood Bristol 8514 BNG enclosing your program cassette and details of program name s and your name and address 7X81 MULTISEQUENCER Using unmodified 281 16 apart wath an instrument covering over eorpore ern Send 15 for cassette tions to V Haynes 10 Streatham London SW 2X 81 TEMPERATURE SENSORS Uses earpiece socket with application program listing and waterproof probe Including p amp p 17 50 Free leaflet Cheshire Micro Design 66 Close Lane Alsager Stoke Trent 2x81 16K RAM Sinclair learing lab and 2nd hand tape recorder also magazines and labyrinth game a bargain at 85 Phone Ingrebourne 76446 SINCLAIRUSER August1982 THE PROGRAM ENHANCEMENT Vine to whole screen SCROLL up canc CHANGE BACKGROUND PROGRAM and a FULL ins MINEFIELD Stoor your tank to safety Very a INVADERS With snoaky SMART BOMBS MANHUNT Evade the Fiais i you can 2X81 SOFTWARE Stockexchange Try your hand at making fortune on the stockmar Very realistic game FANTASTIC VALUE AT ONLY 3 75 Program to solve the Rubic cube supplied on cassettes Prices inclusi guaranteed London W
81. ith RENUMBERIDELETE a further 3 utilities are included to make this must for serious programmers 1 FIRST REM EXPANDER Expand the first REM by any specified length Easy to use Type 1 REM followed by any CHARACTER Call the EXPANDER SPECIFY the number of BYTES to add A few BLINKS later and it s DONE 2 DECIMAL REM LOADER Use this to load DECIMAL CODE into the first REM ALLOWS use of the existing line edit facilities So easy to use 3 66 BYTE MEMORY LISTER Start where you like Specify the start address and immediately the contents and locations of 66 bytes will be DISPLAYED or PRINTED One SINGLE KEYSTROKE will then page FORWARDS or BACKWARDS as you wish Well written in Micode USEFUL AND FAST TOO 8 00 inclusive If you re not convinced send 1 00 and we ll send the instructions you buy within 14 days you can deduct the 1 00 WORK FORCE 140 WILSDEN AVE LUTON BEDS LUI SHR S ZX81 HEWSON CONSULTANTS 2 81 HINTS AND TIPS FOR THE 64K MEMOPACK PUCKMAN NEW 5 95 2X81 by Andrew Hewson 395 s 4 16K MEMORY 26 95 TOOLKIT 48 8K NEW 61 95 280 OP CODES PROGRAMMERS 1 45 SINCLAIRUSER August1982 57 Sinclair ZX81 microcomputer POOTBALL MANAGER Addictive Games VIDEO GENIE AS MANY SEASONS AS VOU LIKE PROMOTION Ri ZX81 Assembled 69 95 2 549 95 16 29
82. its has to be smaller so the numbers keep shrinking until they are trapped in limited range Once there they hop 10 around and since they cannot keep going to different values forever there being only a limited range available something has to repeat There is one amazingly simple iteration process about which nothing of the kind has ever been proved even though most people think it must be true It is called the Kakutani Problem The iteration process is If N is even halve it If N is odd treble it and add 1 Problem does everything end in theloop1 4 2 1 Here is the program 10 INPUT 20LETC 0 30 PRINT AT 20 0 N 40 SCROLL 50IFN 2 INT N 2 THEN LET 2 60 IF N lt gt 2 INT N 2 THEN LET 3 N 1 70LETN ae 80 LETC C 90 IFN 1 THEN GOTO 110 100 GOTO 30 110PRINT AT 21 0 HIT LOOP C SPACE 1f you experiment with this you will find that the behaviour is most irregular For example 29 hits the loop after 18 stages and so does 30 but 31 requires 106 steps to reach the loop and the numbers become as big as 1780 on the way Then 32 stops in only five steps and 33 in 26 steps The nui bers hop around all over the plac they get smaller smaller suddenly bigger instead Could they keep growing forever and miss the loop completely Nobody knows Of course you cannot decide that on a computer there is no way to carry out the computation forever
83. ks to control their motors as plus P amp P commanded by a program PRINTER INTERFACE The 2X99 has RS232C interface allowing you direct connection with any such serial printer using the industry standard ASCII character code you can now print on plain paper in upper and lower case and up to 132 characters per line 3X MANY SPECIAL FEATURES There are so many different features that it is difficult to list For example AUTOMATIC TAPE TO TAPE COPY You can copy any data file regardless of your memory capacity a C90 has approx 200K bytes on it as it is loaded through the Sinclair block by block TAPE BLOCK SKIP without destroying the contents of memory DIAGNOSTIC INFORMATION to assist in achieving the best recording settings 3X TAPE DRIVES We supply and guarantee its compatability Tape Drive that works with your computer COMPUTER CASSETTES We supply quality screw assembled computer cassettes Please enquire for any not shown The ZX99 contains its own 2K ROM which acts as an extension to the firmware already resident in your ZX81 S own ROM The ZX99 s ROM contains the tape operating system whose functions are accessed via Basic USR function calls Each function has an entry address which must be quoted after the USR keyword All of the functions can be used in program statements or in immediate commands i e both statements with line numbers and commands without them There is an ex
84. le to load into your space shuttle craft which is your only hope of escape Food water oxy gen weapons and other useful objects are scat tered around On the other side of Alien Intruder is Hiero glyphics clever varia tion of Hangman in which a 39 symbol ancient SINCLAIRUSER August 1982 L HAVEN 5 SINC alphabet has to be deciphered before the famous explorer Wullie Makeit is buried in sand Both programs make good use of graphics and words to make a very entertain ing package Wumpus Adventure features the most ancient and terrible creature of computer mythology You must track the Wumpus by its smell and chilling cry through a maze of caves containing a host of ter rors SINCLAIRUSER August 1982 Goblins may catch you and tie you up as morsel for their god the Wumpus bats may pick you up and drop you in another cave which may contain a bot tomless pit or a giant ser pent or only a swamp if you are lucky Up to four players can take part and if you happen to step into Wumpus muck one of the other players may smell you and fire an arrow at you in mistake for the monster With Wumpus Adven ture there is Movie Mogul which gives a taste of the trials and tribulations of Hollywood See a day s filming go down the drain when the leading actor punches the leading lady in the mouth try to balance location and studio filming while keep ing in mind the
85. llow 14 21 days for delivery AFDEC ELECTRONICS LTD 318 Kempshott Lane Basingstoke Hants Please supply 16K Rampacks at 25 00 inclusive Cheque P 0 Money Order enclosed Please Print Clearly Name Address SINCLAIRUSER August 1962 ZX Spectrum 20 Programs 6 95 The ZX Spectrum has brought advanced computing power into your home The Cambridge Colour Collection a book of 20 programs is all you need to make it come alive No experience required Simply enter the programs from the book or load them from tape 2 95 extra and run Amazing effects All programs are fully animated using hi res graphics colour and sound wherever possible Entirely original None of these programs has ever been published before Proven Quality The author already has 30 000 satisfied purchasers of his book of ZX81 programs Hours of entertainment Lunar Landing Control the angle of descent and jet thrust to steer the lunar module to a safe landing on the moon s surface Maze Find your way out from the centre of a random maze Android Nim Play the Spectrum at the ancient game of Nim using creatures from outer space Biorhythms Plot the cycles of your Emotional Intellectual and Physical activity Some would say this is not a game at all Improve your mind Morse A complete morse code training kit This program will take a complete beginner to proficiency Maths Adjus
86. machine code subroutines in BASIC programs ZX81 ROM DISASSEMBLY PART A 46 95 by Dr lan Logan complete disassembly of hex locations 0000 to OFS4 with a commentary on cach subroutine A companion reference book 10 Understanding Your 2 81 ROM ZXNI ROM DISASSEMBLY PART B 795 A continuation of the above for locations 55 to I0FF MACHINE LANGUAGE PROGRAMMING MADESIMPLE 8 95 Discover the internal mysteries of the Sinclair and learn to communicate with it in its own language COMPLETESINCLAIR ZX81 BASIC COURSE 16 95 guide to every facet of ZX81 BASIC including an 80 page reference to the BASIC statements and functions with explanations and short programs ALL PRICES INCLUSIVE OF VAT amp SHIPPING WITHIN THE U K Occam Software 13 Hawthom Grove Wilmslow Cheshire SK9 SDE England 5 Sheard Telephone Wilmslow 524228 Great games packs for 16K ZX81 ASTRO INVADERS Just look at these features then look at the price Superior machine code programming Rapa fring with explosive on screen kil effect High scoring saucers 54 aliens accelerating attack Destructable defence shields On screen kill count High score update Fast action space graphics 3 new dimension in ZX81 value Astro Invaders is yours on cassette for ONLY 3 65 with FOUR BONUS GAMES ARCADE GRAND PRIX drive four of machine code skill PENALTY defend your goal agains
87. mands Whichever is chosen full prompts are given and if anything goes wrong 10 special error codes will identify why and where it happened Renumber prompts for start and end line numbers new base and increment It then looks through the Basic and if it encounters a com puted GOTO it will stop with report Q lne The user can then insert a REM into the offending line and continue with the re numbering Impressively jumps to non existent line numbers will be re numbered correctly e g 5 REM 15 REM 25 GOTO 10 will become 10 REM 20 REM 30 GOTO 20 It took less than one second to re number 5K of Basic Find will display the lines not just the line numbers containing a specified string so it can be used to find the REM GOTO X lines after re numbering and Alter will replace a string Blocks of lines can be copied moved or deleted RAMTOP and re i another program Bytes tells you the amount of free memory remaining It is a most impressive program fast in execution with clear and full instructions and helpful error codes At 6 95 for the cassette version and 0 95 for an EPROM version it stands out from the rest of the field Unfortunately I was unable to load the last program the Bug Bytes ZXTK and the replacement copy arrived too late to be included in this review which is a pity as it has some unusual functions Sniff displays the file names of programs on a ZX 81 tape that is useful if
88. mosphere in which to work For this award winning York shireman it abounds with oppor tunity too He has already entered the Spectrum for this year s Design Council awards and on his drawing board are the initial stages of the flat tube TV another first and possibly another award SINCLAIRUSER August 1962 ZX81 16K SOFTWARE ZXC ARCADE PLUS PACK SLOT A graphical simulation of a fruit machine With Hold and Nudge features BREAKOUT SUPER PROGRESSIVE BREAKOUT DODGEMS with increasing difficulty Can you evade the computer cars and clear all the dots LIFE On a maximum 64x48 screen grid Send cheque postal order for 7 95 to A READMAN SOFTWARE 16 South Row Eldon Biship Auckland Go Durham DL14 BUT Mail order only trade enquiries welcome RENUMBERS THE PARTS OTHER PROGRAMS DON T REACH ZX81 RENUMBER DELETE Tucked safely away in high memory this fast program really lives up to its name Select either blocks single lines or the whole program Specify the START number the NEW start number the INCREMENT and the STOP number HIT the KEY and it s ALL DONE By ALL we mean ALL GOTOS GOSUBS LIST LLISTS amp RUNS which have branch addresses in the affected region DELETE allows you to select LINES BLOCKS and INSTANTLY remove them from the program VERY FAST no waiting an extremely well written program 6 00 including and POST ZX81 TOOLKIT Along w
89. n has painted on Layout of the interior follows with the designer using all his powers of logic to ensure that each component is in the best 56 computers the work is never finished His main project now is the flat tube TV expected to be launched later this year His biggest problem with that is that Sinclair has already been working on it for some time Normally he is briefed at the same time as the electronic engineers but this time the inside is already finished It is also another first which means Dickinson cannot research by looking at existing products in the field That is the most exciting thing with this company you know many products are the first of their type so you are really in on something new Dickinson is content with his life at the moment in every way At school he liked the sciences and the arts and his job ensures that he remains involved in both He spent one year on foundation course at art college at Grimsby before starting to read for his degree and feels the experience was invalu able He is happy with his work at Sinclair When he started almost three years ago the staff numbered five Today it is 30 and the company is going from strength to strength crushing the effects of the recession as it marches on We all work very closely very much asa team Most of the informa tion is in people s heads There is no time to be formal and put it down on paper It is a good at
90. nd Saturn Secret Code Mindboggling Silhouette Memory Test Metric conversion Description Five games plus easy conversion between inches feet yards and centimetres metres Cassette G3 Super Programs 3 ICL Hardware required ZX81 Price 4 95 Programs Train Race Challenge Secret Message Mind that Meteor Character Doodle Currency Conversion Description Fives games plus currency conversion at will for example dollars to pounds Cassette G4 Super Programs 4 ICL Hardware required ZX81 Price 4 95 Programs Down Under Submarines Doodling with Graphics The Invisible Invader Reaction Petrol Description Five games plus easy conversion between miles per gallon and European fuel consumption figures Cassette G5 Super Programs 5 ICL Hardware required 2 81 16K RAM Price 4 95 Programs Martian Knock Out Graffiti Find the Mate Labyrinth Drop a Brick Continental Description Five games plus easy conversion between English and continental dress sizes Cassette G6 Super Programs 6 ICL Hardware required 2 81 16K RAM Price 4 95 Programs Galactic Invasion Journey into Danger Create Nine Hole Golf Solitaire Daylight Robbery Description Six games making full use of the 2 81 moving graphics capability Cassette G7 Super Programs 7 ICL Hardware required 2X81 Price 4 95 Programs Racetrack Chase NIM Tower of Hanoi Docking
91. ned a special pro gramme to ensure that the campers first encounter with a computer is most enjoyable and rewarding ex perience They also promise to de mystify the computer Three levels of instruction are provided to take account of all levels of knowledge The subjects covered will include how computers work computer jargon programming in Basic possible future applications and progress to floppy discs graphics word processing and other languages It expected that most of the campers will have a working know ledge of Basic programming after two weeks The computer course is linked to the other activities available at the camp which mainly involve moving outdoors and enjoying the magnifi cent countryside The camp pro vides tuition in camping fell walk ing sailing pony trekking canoeing and many other activities It was the idea of Stewart Wiley former holiday tour operator who decided to set up holiday camps for children after he had seen the success of similar camps in the United States H undreds of teenagers will this SINCLAIRUSER August 1962 computer camp Computer camps were introduced to Britain last year and proved so popular that they have been expanded rapidly Picturesque setting for micro courses When I was on holiday in the States saw television pro gramme about a computer camp which had been started in Santa Barbara California 1 contacted the per
92. ng 126 and the remainder holding the numerical represen tation of zero I have described the arrangement in previous columns The six hidden bytes are omitted from program LISTings Hewson Consultants 1982 Please address problems and queries to Andrew Hewson Helpline Graham Close Blewbury Oxfordshire SINCLAIRUSER August 1982 THE ZX BOOK CLUB DUE SEPTEMBER 1982 written by the man who helped write the documentation for the ZX Spectrum LEARNING TO USE only THE ZX SPECTRUM COMPUTER 5 95 by Robin Bradbeer 100 pages fully illustrated This book has been written specially to help new and prospective owners of the ZX Spectrum to easily understand the operation and full capabilities of this amazing new microcomputer Provides clear descriptions of the hardware and functions describing use of the new keyboard command keys and editing facilities Explains simple programming using Sinclair BASIC Describes graphics and colour facilities in detail Includes many programs including animation Appendices cover technical details and a glossary ALSO DUE SEPTEMBER 1982 and also by Robin Bradbeer LEARNING TO USE THE only 2X81 COMPUTER s 29 95 In the same series as the Learning to Use the ZX Spectrum this new book follows the same format style and content and will prove an invaluable guide for new and experienced 2 81 owners Other bestselling titles Byteing Deeper into Your ZX81 by Mark Harris
93. not jolted Some of the connections can easily work loose and everything which has been put in will be lost The manual is not to everyone s taste and if you find it difficult to follow a number of books on the market can help you Find the one which suits you best As a way of relaxing you can buy some of the growing range of commercially produced software That can be loaded directly from cassette but make sure that your machine is big enough to take the tapes you buy There are some programs for the unexpanded 1K machine but most of them require a 16K RAM pack The tapes vary in quality It is advisable to read the reviews in Sinclair User and use your judgment to find the best An alternative method to learn about the ZX 81 is to plunge in at the deep end and see what the computer will do Refer to the manual when you have difficulties You can ignore the functions and calculations initially and experiment with PRINT statements to obtain the feel of the machine You may have heard already about the problem involved in SAVEing and LOADing your own cassettes The manual again gives detailed instructions but many of the early machines would not accept tapes from some recorders That problem is said to have been overcome but there can still be diffi culties They usually occur when LOADing tapes recorded by other people One simple method to over come this is to wind the tape to the middle of the program and type LOAD
94. nstallation again consists of drilling a hole located on top of the ZX 81 case although space im mediately below the switch is very limited and cutting a lead to the modulator This inverse video switch costs 3 75 built and 2 95 as a kit and is ob tainable from B A Reader 45 Alfred St Kings Heath Birmingham B14 7HG be used to display any thing which fits on the column x 7 format The displays are available as a kit LED boards made up or ready made for between 62 01 and 356 50 including VAT interface and program to run Contact ADH Systems Ltd 209 Mackie Avenue Brighton BN1 BSE 0273 557429 Fulcrum bleep THE Fulcrum ZX 81 consists of a small measuring 3 in by 2in which fits into the space inside the ZX 81 case underneath the keyboard That particular space is much favoured by other manufacturers for their add ons so it could be socket The device works in both FAST and SLOW modes although it does not function on certain shifted keys Since the review was done the company has brought out the ZX 81 Keyboard Bleeper which covers all 210 characters The ZX 81 and the ZX 81 Keyboard Bleeper are both priced at 8 95 including VAT and postage and can be obtained from Fulcrum Products Colourscreen for tired eyes ELLANBEE Graphics can provide a cure for tired eyes from too much staring at a bright TV screen Colourscreen is a la
95. nt associ ated with popular pastimes ZX addiction perhaps or more likely Sinclair Eye I can imagine thousands of people wandering around wearing dark glasses on even the dullest day as they walk for the first time in the open air for some months their hands twitching as they suffer withdrawal symptoms from using the keyboard I need not have worried though and I feel much better about it after a brief talk I had with Keith Hall 1 should explain that he is res ponsible for all the computer madness or Sinclair Syndrome in our household He introduced my No longer need Sinclair users endure long weeks of computer deprivation they can take their computers with them wandering about saying I know you think I m crazy but that is not my computer It looks like my computer but something has happened to it It is not my computer Have I been watching too many late night films Do computers have feelings Should I ask someone to come each day not only to feed the cat and water the plants but to dust the computer and talk to all of them too Last but not least how would my son cope with the strain of a whole summer unrelieved by a single game of Monster Centipedes or Asteroids Revenge 1 do hope I son to the ZX 81 by starting a com puter club at his school I hasten to add that in every other respect he is a splendid chap He told me that one reason the Sinclair is so eminently suitable for school
96. ntains the 48 THEN 118 compressed text as output sogo Fon TO from the compress routine Im THEN E an input for the expand NEXT routine Note that PRINT of Habe RETURN dcs this string may unreadable LET DRIED 3 and look longer than the original text depending on the bit pattern obtained in the compression which may produce any of the ZX 81 character codes C current token position within the original text B current position within a text token three characters from the original text current valid character code There are 39 valid characters mapped starting from 1 for space and values 2 to 39 are assigned for ZX 81 charac ters from comma to Z Values equal to or less than zero are SINCLAIRUSER August 1962 sion with 1 mapped as a space character Use of the logic function is also obvious in line 8070 where different non contiguous values are assigned to bariable When the character set is not entirely satisfactory there is a possible modification shown in figure two This is the solution used normally on ASCII coded machines remember that ZX 81 is not and involves the use of a conversion string SS That is a user definable string which also contains 39 characters as the previous res triction still holds but it is possible to put in any combination of tories and indices It is also
97. oblem for users with out extra memory as Michael Wordruff of Accrington has dis covered he writes I am having problems with programs which POKE the display because my ZX 81 crashes every time For instance 5 LET Z 1 PEEK 16396 256 POKE 16397 10 POKE 2 128 is a disaster What is happening Wordruff s routine is attempting to POKE an inverse space into the first PRINT position and it will work well on a ZX 81 with at least 4K of RAM because the display will be padded out with 32 blanks per line Without the extra memory no such padding occurs and so the routine will over write the second of th bytes containing 118 thus causing the program to crash The solution to the problem and to all similar ones is to create some space at the appropriate position in the display by PRINTing one more blank characters In that case one space is required at the begin ning of the first line and so the answer is to add the line 2 PRINT where b represents the space character I would like to give a print instruction conditional on whether or not there is anything already printed at the same position 1 solved the corresponding problem by using PEEK 16438 and PEEK 16439 but the use of 16441 and PEEK 16442 does not work Can you help asks Brian O Donnell of Notting Hill London Page 179 of the ZX 81 Basic Pro gramming Manual shows that addresses 16438 and 16439 in the system va
98. ode video game with impressive graphics Features include best score of the day auto on the contro keys auto return to the self demonstrating title page Requires 16k RAM Supplied on tape with instructions Action packed fun for only 3 45 FIGHTER PILOT 15 feet 7feet Touchdown Another successful instrument landing Appoaching at 150 knots is not always as easy as this You are in full control from take off to landing during this real time flight simulation of a jet fighter The sky is the limit Fly a different mission every time Endless Scope for improving your instrument flying skills 16k RAM Required Suppied on tape with full instructions Supervalue at 23 45 prices inclusive Overseas add 0 55 p amp p per tape All products guaranteed refund if not satisified Digital Integration 22 Ash Church Road Ash Aldershot Hants GU12 6LX MAIL ORDER ONLY Ultra Tech Services offer for mathema ns amp students the following programs on cassettes for the 16K ZX 81 Complex Numbers This program provides 19 operations and functions to apply to complex numbers Non Linear Equations Solution algorithms for both real and complex roots of equations Numerical Analysis Integration regression and Monte Carlo methods for the ZX 81 Each cassette costs 6 95 inc VAT or all 3 may be purchased for 18 00 Cheques or postal orders made payable to M V R H Ltd should b
99. of design is a long one Normally it begins when Clive Sinclair outlines his idea to Dickin son including his demands about size will resolve in his own mind the specifications and he will always say how small it has to be 1 think how can it be that small Yet he is always right in the end and we produce something which seemed impossible to me in the beginning Armed with his brief Dickinson then spends a few days with his sketchbook exploring ideas but he likes to begin work in three dimen Rick Dic possible place Perhaps the most difficult part is the keyboard Dickinson says We spent a great deal of time on that It is the only interface between the user and the product and it has to be right We were trying also to cram on more information than anyone had every done 1 believe that form should follow function Design of the ZX 81 took about six months in all The Spectrum was quicker but with all his major projects Dickinson also has to set aside time for add ons to existing work in hix workshop That is the exciting thing in this company many products are the first of their type you are in on something new sions as quickly as possible and is soon modelling in Perspex or plasticine The next stage is to produce the finished model in Perspex but obviously it has no components inside it is produced as a solid block That modelis detailed even down to the graphics which Dickinso
100. on 20 Simple Electronic Projects for the ZX81 by Stephen Adams Mastering Machine Code on your ZX81 by Toni Baker The ZX81 Pocket Book by Trevor Toms READ OUT PUBLISHING COMPANY LTD 8 Camp Road Farnborough Hampshire 624 6EW Telephone 0252 510331 2 Telex 858001 GOWER G READ OUT PUBLISHING COMPANY LTD CAMP ROAD FARNBOROUGH HAMPSHIRE GU24 6EW 24 hour answering service Telephone 0252 510331 2 Please reserve my copy ies of Learning to Use the ZX Spectrum i 595 Name Learning to Use the 2X81 7 5 95 Please send of Byteing Deeper into Your 2X81 6 45 20 Simple Electronic Projects for the 2 81 745 Mastering Machine Code on Your ZX8 8 50 The ZX81 Pocket Book 1 6 95 heques payable to Read Out Pi Please debit my Access Signed Number eR etu Aen a SINCLAIRUSER August 1982 49 Disneytime cartoons come to the land of the little Sinclair Jack Knight considers that if it were not for the moving characters micros would lose much of their fascination FIT were not for the graphics I I not be as fascinated by microcomputers as I am Moving characters and objects around the screen and making them work is challenging with only 1K of memory and without resort to the complications of machine code The first thing to pr
101. ove an image diag onally up or down the screen in either direction Staying with our patient helicopter we will try one of the more difficult that is from the top right corner to the bottom left it is difficult because character co ordinates must be used with the one increasing and the other Re decreasing RUN Notice that once you know how it is easy to handle increasing and decreasing numbers at the same time L and 19 L Before we leave the helicopter let it show us its profile hovering rotars turning Alter the last part of the graphics of line 20 and type in new lines as follows RUN Finally having experimented to lay the groundwork that is the mo ment to run an animated cartoon but do not expect a full length feature remember it is only a 1K RAM Perhaps however it will set you on the way to designing your own graphics Before you RUN the cartoon here are some hints as you will be hard up against the limit of the memory Operate NEW before you start to clear everything first If you need to EDIT and the ZX will not bring down the line CLEAR and then operate EDIT immediately If the graphics do not look correct 80 over variables check the number of spaces and the characters to shake out the bugs PRINT 5 PAUSE 75 ie 2e so TO 108 11e 120 138 158 168 178 ise iso 200
102. ove is that ob jects can be moved any way around the screen What is needed is some thing simple but realistic something which is in its element whichever way it travels in space An aircraft A No speeding backwards would hardly be credible So a helicopter To see what it looks like type in the following and RUN The loop will be needed shortly and we want its character co ordinates to look at the graphic In all that follows unless it is stated the Vs stand for spaces pm RUN Simple easy to play with but with a passing resemblance to what is intended Before you rush in with the NEXT statement be pre pared for a program short of per fection but RUN it as itis as there is a purpose First 30 NEXT 1 RUN is a case of tear along the dotted line My intention was to emphasise the need for an eraser a space or spaces to rub out the character s left behind as the graphic moves along Edit line 20 by inserting a space after the first inverted commas That is the eraser but you have not finished yet There is a need to include another space at the beginning of the second part of the graphic otherwise the heli copter will be lopsided RUN The difficulty you have had edit ing a line you have only just typed in will be worthwhile as a reminder for the future of how essential the eraser is Another thing to remember from the program is the TABstatement It
103. re he can enjoy outdoor activities as well as crouching over his computer I suppose that is intended to make him physically fit enough to be able to spend the rest of the year wth his Sinclair without too many ill effects The more 1 think about it though the more I think this is getting out of hand Our lives are not ruled by a small plastic box no matter how full it is of electronic marvels The last few months have been bad enough without it deciding how we should enjoy the brief days of good summer weather going to put my foot down firmly and oppose any moves to take a Sinclair away with us this year A break with the trappings of civilis ation will do us all a world of good Enough of flickering screens moving targets and exploding galaxies we shall restore our selves with fresh air sunshine and bird song Now if you will excuse me I must go and pack If I hurry I might even have time for a quick game of Colliding Space Intruders as it will be a long time before I have the chance again Use your computerin the case i i Foam rubber gives complete protection Purpose built for the ZX system ZX81 amp Spectrum Custom Cases Just 3495 quipment is gripped securely by Send for your ZX Custom Case now g foam Each connecting 7 81 and Spectrum Custom Cases foam years and there s no guaranteed for t ceisheld 34 95
104. rfolk NR12 8DY 2 81 with 16K Instruction books and ICL programming course and tapes including all leads and two games 80 ono S Leigh 47 Middle Lane Epsom Surrey Tel Epsom 28218 Supermartat low cost Sell your used computer or periphe up to words for only 5 Have you updated your computer or do you no longer us is through Sine that add on Instead of ving tying around turn tito cash be placing a classified advertisement n Sinclar Supermart and reach around 40 000 users ofthe Sinctae ZX systems e write your advertisement nthe boxes below one word per bor Undertine words required i bold type Your name address and or telephone number Shouldbe included Please printm Dock open topnvate advertisers The advertisement wall possible ae Name Have you included the fee of 5 AD INDEX AddictiveGamos E P Altwasser 17 Electronics 17 Abersoft Artic Computing 42 Buffer Micro Shop 26 Computex Cases CambridgeComputerShop 58 D K Tronics 67 Data 18 Digital Integration P L Donovan Educare D Fritsh 17 Fuller Micro 2 Hewson Consultants 57 Haven Hardware 46 Hilderbay 42 Interface 6 TS 2 12 85 E JG Prince 12 Kayde 68 Kempston Melbourne House Moviedrome Video Microware MC Associates Microfair 26 Memotoch E N
105. rge ADH display interface Display interface ADH SYSTEMS has pro dced an interface which allows a ZX 81 to control a LED or filament lamp display for advertising in a shop window The system can control a 16 24 40 or 80 column display and is not limited only to numbers or figures The display is seven LEDs high and can difficult to fit any other device there since the heat sink is close to it The sound which is a short bleep is made by a small transducer which is located in one corner of the PCB Fulcrum empha sises that the device requires no soldering the connections to the ZX 81 being two wires for power and a 5 way flexible cable which plugs into the existing keyboard tail coloured optically clear plastic sheet which goes over the TV screen It is a 15 x 12in sheet which is cut to fit the size of your TV screen and then fitted carefully over it It requires no tape or other fixing and can be removed at any time It is in two colours blue or green with instructions and a specially stiffened storage envelope a a cost continued on page 44 cem continued from page 43 also selling a book on com of 2 95 Larger sizes are puter graphics at 1 50 available on request from All prices are inclusive of Ellanbee Graphics 11 VAT and paper can be ob Lichfield Close Great tained from various ZX Lumley Chester le Street computer shops Co Durham DH3 4QH 0385 8
106. riables area hold the x and y co ordinates of the last point to be PLOTed as O Donnell has dis covered Unfortunately the equiva lent information for PRINT is not stored Instead the position at which thenext item will be PRINTed is held in 16441 and 16442 There is a further complication the horizontal PRINT position is counted from right continued on page 48 47 continued from page 47 to left and the vertical position from the bottom upwards Thus the routine 10 PRINT HELP LINE 20 LET A 16441 30 LETB PEEK 16442 40 PRINT A B will print the values 33 23 The first value 33 indicates that the PRINT position is at the beginning of a line ie 33 characters counting from right to left from the beginning of of the subsequent line The second value 23 indicates that the line is the 23rd from the bottom of the screen because one line has been used to PRINT HELP LINE If line 10 is changed to 10 PRINT HELP LINE the values PRINTed are 24 24 because the semi colon prevents skipping to the next line he following rather artificial program PRINTs a new character over the top of the last character PRINTed 10 PRINT AT 20 VALUES FOI 20 INPUTA 30 INPUTB have on his TV He writes 1 note that my TV insurance cover con tains a clause excluding damage caused by the use of TV games Can you advise if my ZX 81 can damage my set Television screens are
107. rincess from the evil wizard Sorcerer s Island you re marooned To escape you ll probably need the help of the Grand Sorcerer Cassette 613 Space Raiders and Bomber Psion Hardware required ZXB1 16K RAM Price 3 95 Programs Space Raiders Bomber Description Space Raiders is the ZX81 version of the popular pub game Bomber destroy a city before you hit a sky scraper Cassette G14 Flight Simulation Psion Hardware required 2 81 16K RAM Price 5 95 Program Flight Simulation plus blank tape on side 2 Description Simulates a highly manoeuvrable light aircraft with full controls instrumentation a view through the cockpit window and navigational aids Happy landings Education Cassette E1 Fun to Learn series English Literature 1 ICL Hardware required ZX81 16K RAM Price 6 95 Programs Novelists Authors Description Who wrote Robinson Crusoe Which novelist do you associate with Father Brown Cassette E2 Fun to Learn series English Literature 2 ICL Hardware required ZX81 16K RAM Price 6 95 Programs Poets Playwrights Modern Authors Description Who wrote Song of the Shirt Which playwright also played cricket for England series Geography 1 ICL Hardware required 2 81 16K RAM Price 6 95 Programs Towns in England and Wales Countries and Capitals of Europe Description The computer shows you
108. rn Business household Cassette B1 The Collector s Pack ICL Hardware required ZX81 16K RAM Price 9 95 Program Collector s Pack plus blank tape or side 2for program data storage Description This comprehensive pro gram should allow collectors of stamps coins etc to hold up to 400 records of up to 6 different items on one cassette Keep your records up to date and sorted into order Cassette B2 The Club Record Controller ICL Hardware required 2 81 16K RAM Price 9 95 Program Club Record Controller plus blank tape on side 2 for program data storage Description Enables clubs to hold records of up to 100 members on one cassette Allows for names addresses phone numbers plus five lots of additional information eg type of membership Cassette B3 VU CALC Psion Hardware required ZX81 16K RAM Price 7 95 Program VU CALC Description Turns your ZX81 into an immensely powerful analysis chart VU CALC constructs generates and calculates large tables for applications such as financial analysis budget sheets and projections Complete with full instructions Cassette B4 VU FILE Psion Hardware required 2 81 16K RAM Price 7 95 Programs VU FILE Examples Description general purpose infor mation storage and retrieval program with emphasis on user friendliness and visual display Use it to catalogue your collection maintain records or club members
109. rs chess and centipede 1 book for 125 o n o Ring Lymington 0590 76319 16 ZX 81 with manual leads etc five of the best 16K games around on original cassettes in clude Chess 3 0 Monster Maze Star Trail etc plus book on machine code worth 7 Only 110 you don t believe this is a bargain just ring 061 339 9446 for more details or write to 49 Crowhill Rd Ashton under Lyme Lancs OL7 9MB 2 81 16K Lists out in order ot preference the 16 most e aen We 16 Bey ores rows and aee Gui e res on the book maker Faxed Odds couper har have been ven ovr Calcul voor expected proi Flow the user to update the abies y ak a ets come For cassette ofthe program phus an rau on eae a bref explanation of the theory send 18 8 o HARTLAND SOFTWARE Dept a PENZANCE PLACE LONDON wn 4PA ZX 81 16K ADVENTURE GAME Full 16K used Plenty of Action map supplied plus detective game of Logic 2 21 players Both on cassette only 3 50 S Taylor 2 Greenway Eltham London SE9 552 2 81 plus 16K RAM Thirteen programs on cassettes Manual book and mains adaptor Mint cond 85 Macdonald 13 Cookson Rd Sheffield Yorks 0742 349943 anytime SCHOOL CHILDREN have developed a program to enter and RUN standard CESIL programs on 4K more ZX81 Cassette for 4 95 from Timothy Skinner at 1 Summer Drive Hoveton No
110. rse ig BER aue GoD 169 18 Y 199 195 201 i FOR PRINT HT 2 NEXT Y NEXT 7 PRINT AT 2 IF ALl 2 GOTO 2000 205 PRINT 210 PRINT 220 INPUT PRINT Bus 255 IF J 3 OR bn THEN 1009 IF FOR 0 THEN LET P LET 5 914 0 NEXT GOTO 1900 BR IF ACK IF IF R K D 1 THEN NEXT GOTO 150 FOR U 9 TG 20 NEXT U PRINT 2 0 FOR U NEXT U 205 PRINT HT 2 0 vOU HAVE THE TOUERS DF HRNOI IN C 1 2610 PRINT 2920 PRINT TRY AGAIN 2030 INPUT 5 2049 IF amp YES OR RUN 2058 STOP QP pU 990699 MOVE SINCLAIRUSER August 1982 INTEREST IE c ue serenan CALCULATION 2223658 poi 138 LET DD D F FOR G i TO INT 14Q LET H INT M ERR sas 168 LET Asker IF 16442 2 THEN SCROL NEXT 158 PRESS NY KEY TO TI NUE e INKEY THEN GOTO 200 290 210 as 220 GOTO 12 60 PRINT AT URL Zi URL 25 288 PRINT DLE ee 129 2670 228 229 PEER 5 285 an 25 523 7 LET F F UmL 717 IF INMEY amp 7 THER LET 5 5 vm ES LET 6 THEN GOTO 200 10 LET AS THERE URS YOUNG FROM 20 LET
111. ry developed as part of the Sinclair electric car project The following day the TSU family goes to the beach and in common with many others they take their briefcase and spend half the day enjoying the sun sea and sand and the other half playing with the Sinclair The case also contains a device which allows the Typical Sinclair Users to contact their neighbours via the telephone service or collect any recorded messages on their telephone answering servic If this sounds a little far fetched as though the Sinclairvoyance crystal ball is even less clear than usual consider that most of the items are already in existence and are available either for the Sinclair machines or can be adapted from hardware available with other computers The two items which do not exist are the colour printer and the lightweight battery but that is no guarantee that they will not appear on the market The rest of this look into the not too distant future depends on how people react to the possibilities provided by a light fully portable computer system It may be a little unreal to suggest that people will take every opportunity to avoid leaving their homes It would be pleasant to think that the gregarious nature of people would rebel against being cut off from their fellow human beings The enthusiasm with which many take any opportunity to cut themselves off and carry around their own little world however would appear to argue against this It is one of t
112. s and REPLACE which allows string of characters to be exchanged for another of equal length Both routines are slow to execute 1 did not find the program very re numbering programs have to cope with the very useful but very non standard Sinclair GOTO and 50 sophisticated for a re numbering program to cope with so have to be tinkered with afterwards Another non standard feature is the jump to a non existent line number Sinclair Basic simply continues looking until it finds a line whereas most Basics will stop with an error if the line does not exist A measure of the usefulness of a re numbering program is what assistance it gives to the pro grammer in resolving those difficulties robust the hex lister did not work the re number duplicated line numbers when I set the increment too large and the program crashed several times The instructions for both programs are brief but adequate Renumber costs 4 95 and Programmers Toolkit 6 50 The JRS Software Toolkit also requires the user to re set RAMTOP and takes 1K A great deal has been packed into that 1K but ease of use continued on p30 29 continued from p 29 seems to have fallen by the wayside The re number requires all state ments such as GOTO 25 to be changed to 0025 before it will work Computed GOTOs and jumps to non existent lines are ignored completely Starting line and incre ment can be c
113. s column that it is not possible to have a Basic program longer than about 15K even if more than 16K of RAM is available because the display file will not function correctly above address 32767 and the ZX 81 will crash Not so writes Sims crash occurs if the display file is entirely below 32767 or entirely above 32768 but a crash will occur if the display file straddles the two addresses and is then displayed The cureis simply to ensure that when the display file nears 32767 check the VARS system variable you enter a huge line lik XXXX LET ZERO 9 9 0 0 0 0 0 With about 100 repetitions of 0 such a line takes up more memory than the display file when in the program area but lists in less When NEWLINE is pressed display ceases while room is made below the display for the program line to be inserted pushing the display file bove 32768 before display I tried it and it worked In case I was the only ZX 81 user who did not know the trick I contacted Bob Branton the software expert at Memotech Ltd which manufactures 64K RAM for the ZX 81 It was news to him too which made me feel better In fact Branton was so pleased with the idea that he has sent the new Memotech high resolution graphics pack to Sims to thank him for a neat idea The reason Sims huge line takes so much space in the program area is because each Q is followed by six hidden bytes the first one containi
114. s parity and a choice of upper or lower case printing of the Sinclair character set All codes sent to the printer continued on page 40 39 continued from page 39 are in and the user can define any character e Print a full list of a Basic program to the RS232 printer No controls are provided only the data and the common Graphic characters are printed as ASCII codes The RS232 can be used only witha printer as only an output on 3 5mm jack is provided All the ASCII control and other codes including upper and lower cas generated from the keyboard or from within a program When using a data buffer to print out a string of characters carriage return and line feed are separate but lt gt will produce both for a new line The length of the printed list is limited only by the maximum length the printer can print so long lines will look completely different on the printer The speed at which the printer can work can be between 110 and 9 600 baud but the RS232 portexpects to print at full speed so the printing speed must be adjusted to that with which the printer can cope The graphics characters in ZX 81 program are all converted into ASCII characters and are printed as such That means that as some of the graphics correspond to control characters it could cause some weird effects on the printer such as double sided characters and graphics dots The only way to avoid that is
115. s where I could Finally I found that 42 SCROLL made the program work When I wrote to Sinclair to point this out the nam difficult answer arrived with commendable speed to the elfect that there was printing error in the program and that line 40 should be terminated with comma In fact that makes the program run much prettier than my alteration The point is that I have never seen in your or any other publication any reference to the error and that is curious because 250 000 people have not noticed it or 250 000 people have ignored it or 250 000 people have achieved such a level of programming ability by page 129 that they thought it beneath them to draw attention to it The reason I am writing is to pose the question if there are other misprints of which we are unaware At the very least I think that it would be very user friendly of Sinclair to mail a list of errata to all pur chasers so freeing people like myself of a good deal of head scratching Finally a good test of pocket calculator accuracy over a series of functions is to find the Sin of 45 degrees then find the Cos Tan ArcTan ArcCos and ArcSin of each successive result hoping that it will yield the answer 45 degrees again In my experience Casio calculators for example yield an error of half percent while Sinclair calculators yield an error of 33 percent Try it on the ZX 81 using a program of the kind 10 INPUT A
116. screen scoring and variable re bound angle All for 1 95 from Greye Software 16 Park Street Bath Avon BA1 2TE Carnell adventure IF YOU are bored with soaking up the sun or can not become enthusiastic about day trip to Clacton how about widening your horizons with an Adven ture Carnell Software has produced three 16K cassettes each with an adventure and another substantial game In Volcanic Dungeon you enter the realm of myth and magic to rescue the Princess Edora from the three fold clutches of the goddess of evil the Snow Queen and the Witch of the Black Moun tains You are given map of the 80 connected caverns filled with monsters pits and fire AT mies of goblins and ice giants await Weapons and magical objects are scattered around and you must watch your strength and water levels Also on the cassette is Hangman with a built in 400 word vocabulary the program allows for easy or difficult words one or two players and has full screen graphics In Alien Intruder you wake from cryogenic suspension to find that the rest of the starship crew has been eaten by an alien monster and it will soon be dinner time again A graphics display shows any life forms on the same level the ship has three levels so you can watch the alien move closer Another display shows what exits are possible from the room or corridor you are in and a third display shows what you have been ab
117. seen rushing into the sea to rescue machines caught by an unexpected wave Sand castle competitions would be a thing of the past replaced by attempts to make the highest score on the car race game Perhaps they could even find in genious new tasks for their com puters to perform testing the temperature of the water perhaps or acting as mosquito early warning systems It would be a simple matter SINCLAIRUSER August 1982 problems to store a few useful foreign words and phrases such as Where is the nearest football stadium or 1 would like to speak to the head waiter On second thoughts it all seems a little impracticable If you took your computer on shopping trips to display requests like Please give me the yellow one you would not be able to carry your shopping A trip to the beach would go like this Do you have your swimsuits Towels Beach mat Parasol Ball Frisby Sunglasses Camera Binoculars Radio Computer Television set Somehow 1 do not see it Besides which even if there is room to pack a computer on the out ward journey there would not be on SINCLAIRUSER August 1982 the return following that well known phenomenon by which suit cases always become smaller on holiday or the contents grow bigger it has not been proved con clusively either way Alternatively I send Alex to one of those computer camps the Butlins of the micro world whe
118. sers Group Eric Deeson Highgate School Birmingham B12 905 Glasgow ZX 80 81 Users Club an Watt 107 Greenwood Road Clarkston Glasgow G76 7LW 041 638 1241 Meetings second and fourth monday of each month Hassocks ZX Micro User Club Sussex Paul King Hassocks 4530 Inverclyde ZX 81 Users Club Robort Watt 9 St John s Road Gourock Renfrewshire PA19 1 1 Gourock 39967 Meetings Every other week on Monday at Greenock Society of the Deaf Kelly Street Greenock Keighley Computer Club Colin Price Redholt Ingrow Keighley 603133 National ZX 80 and 2 81 Users Club 44 46 Earls Court Road London W8 6EJ North Hertfordshire Home Computer Club R Crutchfield 2 Durham Road Stevenage Meetings first Friday of the month at the Settlement Nevells Road Letchworth North London Hobby Computer Club ZX users group meets at North London Polytechnic Holloway Road London N7 each Monday 6pm Nottingham Microcomputer Club ZX 80 81 users group Basford 9 Holme Close The Pastures Woodborough Nottingham Orpington Computer Club Roger 23 Arundel Drive Kent Orpington 20281 ur Computer Society Alastair MacPherson 154 Oakbank Road Perth PHI 29633 Meetings third Tuesday of each month at Hunters Lodge Motel Bankfoot Post Office Users Club Vernon Quaintain Head Post Office St Martin s le Grand London 62 Scunthorpe ZX Club C P Hazelton 26 Rilostone Pl
119. set the machine by pulling out the power plug for a second and try tuning in again Ifstill nothing appears check the power supply unit by shaking it If it rattles return it If it is satis factory check your system with that of a friend Once the K appears you are ready to begin learning about the ZX 81 It can save family arguments if you can afford a separate television set for your system It also makes life easier if you can find somewhere to leave your equipment set up per manently You will find that a few power sockets are needed and a four way block connector a short length of extension cable will help to SINCLAIRUSER August 1982 tidy trailing leads The manual is written in great detail and is reasonably easy to follow Some of the chapters may not seem immediately relevant but it is worthwhile reading them as you might miss something which is important Patience is needed at that stage to learn the ways in which the computer will accept information It is tempting to try to enter programs before you are really ready but that is likely to lead to errors For example words like AND THEN and AT should not be typed in letter by letter By the time you have reached chapter 11 you should have accumulated sufficient know ledge to be able to type in other people s programs such as those in Sinclair User and Sinclair Pro grams without too much difficulty Itis important that when using the machine it is
120. son who had set it up and he visited England to advise on the setting up of a similar camp in Britain Wiley said Last year he opened his first camp at St John s School Windsor a day camp with buses taking children from the area to the camp every weekday As at the residential camp the activities included outdoor sports and the opportunity to learn about microcomputers At Windsor the programme was based on the Commodore Pet It was not until this year and the decision to set up residential camp that he became involved with Sinclair machines They are now the only machines available at the Carlisle camp At the day centre the courses use Vics and Tandys Robin Heath director of the computer camps said that one of the reasons for choosing Sinclair machines was that the average age of children at the residential camp would be higher than that at the day centres Younger children can have difficulty with the keyboards on both the ZX 81 and the Spectrum but the average age at the Lake District camp should be about 13 and many children of that age already have ZX 81s and find no problem with them Heath said He added that since the decision they had found the machines to very resilient and that would be an advantage in being able to with stand the extra use 1 made the decision to choose Sinclair exclusively because I thought it would be worthwhile for the future to have a close association wi
121. standard 28 days Sale may raise 10m SINCLAIR Research has passed the first hurdle in the planned sale of shares in the company It has passed the preliminary audit commissioned by the merchant bankers N M Rothschild and the sale is expected in the autumn Rothschild is arranging the final details which are likely to involve selling to chosen City institutions 10 percent of the company It is expected to raise at least 10 million which would put a valuation of 100 million on Sinclair Research but the figure raised could be 20 million 112 OLIVER STREET COVENTRY CV6 ZX 81 OWNERS YOU CAN NOW LOAD SAVE 16K IN 26 SECS WITH THE INCREDIBLE PACKAGE FROM PSS Verify successful saving of programs Compatible with your existing recorder hardware modifications needed extra power supply necessary more wasted time waiting for programs to load or save QSAVEcomesintwo parts A HARDWARE simply plug the ampi fier filter between your existing tape reader and the 2 81 leads supplied SOFTWARE Load the cassette before you load a tape or key in a program You can then save amp reload a full 16K including RAMTOP in only 26 seconds i e a data transfer rate of 4000 BAUD compared with only 250 on the standard 2 81 also gives your 2 81 a verify function just like the Spectrum which allows you to check that your programs h
122. sts add their Martochoice Prestel adapter and turn to the Prestel holiday pages Following the eventual development of the adapter for the Sinclair machines Prestel enjoyed a boost in the number of domestic users A full range of holiday operators have since found it worthwhile to give details of their holidays all over the world The Typical Sinclair Users select a group of holidays in which they are interested and request more details Those arrive on the screen immediately and are printed out Pictures of the resorts and the facilities arrive through the post a few days later From those the TSUs decide Unfortunately when they try to book again through Prestel they find their first choice of time destination and operator is fully booked They bring their second choice to the screen and find there are vacancies They make their booking paying the deposit by debiting their bank account directly by Prestel Once that is done a bill for the balance and a listing of the holiday details arrives on the printer As the time for the holiday approaches the TSU family between playing the latest game of aliens and keeping their household accounts in order check the weather conditions at their chosen resort and the strength of the peseta against the pound all available through Prestel As the TSUs hate shopping having to push their way through the crowds they decide to buy all their holiday clothes and equipment by mail order
123. t 50 seconds in Fast mode to re number 5K of Basic A problem with which all the re numbering programs have to cope somehow is the very useful but very non standard Sinclair GOTO and GOSUB Our 1000 100 A and GOSUBX are seen in few if any other dialects of Basic and are too toolkit utines To return to the Hewson Renumber computed GOTOs and jumps to non existent lines are high lighted in reverse video after re numbering The arithmetic expressions e g GOSUB 1000 INT 10 RND 1 can appear rather distorted so it would be as well to have a copy of the original program to which to refer Hewson s Programmers Toolkit requires 3K above RAMTOP and includes routines to copy or delete blocks of Basic lines and a number of machine code monitor functions The works in much the same way as the previous program except that an end number can also be given the numbers are prompted for rather than having to be POKEd in The Toolkit seems to consist mainly of lines of Basic starting from 9000 which are added to your own Basic program with a USR call RUN 9000 will then run the Toolkit which displays a menu of functions There is hexadecimal loader and lister and a routine to copy bytes from one place to another More useful are the functions which can display the line numbers of lines containing particular string of characters or lokens you want to find eg computed GOTO
124. t four To continue the emphasis of our Bumper Summer Special we would like to write a program to simulate the game of cricket There is no limit to e size of memory which can be used but we must insist that entries are on cassette accompanied by a typed or beautifully hand written listing The judges will be looking for a program which attempts to include as many of the complexities of the game as possible The Owzat form of the game will not be sufficient As a tie break should one be necessary we want you to write a slogan beginning with the words I read Sinclair User because d Entries must reach us by August 16 The usual rules about the editor s decision being final and employees of ECC Publications being ineligible apply SINCLAIRUSER August 1982 59 TASWORD WORD PROCESSING ON THE ZX81 Your ZX81 becomes a word processor letters documents and pictures sto Update existing documents With a printer which i You can print your documents TASWORD FEATURES OVER 300 LINES of TASWORD e FULL ZXB1 character set inclliding inve graphics symbols e INSERTION AND DELETION of lines and HELP PAGE onto the screen at the touch TASWORD TUTOR We send you a manual and a casset Mail order only Please make cheques P O payable to TASMAN SOFTWARE 17 HARTLEY CRESCENT LEEDS LS6 2LL ZX Software SCREENKIT1 MORE POWER TO YOUR SCREEN in Basic programs SCROLL in ALL FOUR directions
125. t the sharp shooting ZXB1 GOLF judge shot strength angles bunkers pius machine code insect fun with SWAT Pack 2 PLANET DEFENDER blast aliens in planet orbit ultra dynamic machine code action hostile alien waves fast responsive controls ship down thrust laser bolt and smart bomb comprehensive scoring explosive graphics explosiveprice Planet Defender comes on cassette for ONLY 3 96 with machine code STORM FIGHTERS combat 5 fleets of swooping aliens as you blast through space BREAKOUT machine code race against the clock plus GRAPHIC HANGMAN 16K 2 81 cassette packs 1 and 2 are 3 65 each post free in Fast despatch trom John Prince 29 Brook Avenue Levenshulme Manchester MIS Pack 1 SINCLAIR SER August 1962 year be able tolearn all about the Spectrum and the ZX 81 against the picturesque backdrop of the Lake District Beaumont Summer Camps has decided to instal a number of the machines at its new residential camp six miles south of Carlisle Children between the ages of 10 and 17 are able to enjoy holidays at the camp in which half the day is spent working on the Sinclair machines and the other half can be used to take part in the many other activities available According to the organisers i assumed that most of the children will have no previous experience of computers of any kind They say they have desig
126. table to various levels this program is an invaluable aid to anyone trying to improve their arithmetic Run your life more efficiently Home Accounts Keeping track of your finances with this easy to use program will enable you to see at a glance where the money goes and plan your spending more effectively Telephone Address Pad Instant access to many pages of information Calendar Displays 3 month calendar past or future ideal for planning or tracing past events ORDER FORM Send Cheque or P O with order to Dept D Richard Francis Altwasser 22 Foxhollow Bar Hill Cambridge CB3 Please send me Copies Cambridge Colour Collection Book only 6 95 each Copies Cambridge Colour Collection Book Cassette 90 each Name Address E AUTOMATIC ZX99 CONTROL The logical extension for the Sinclair 2 81 giving xs data retrieval amp word processing The ZX99 Tape Control system is a sophisticated extension to the Sinclair ZX81 Microcomputer providing remarkable additional capabilities which allow both the beginner and expert access 10 a professional computing system without the expected expense DATA PROCESSING The 2 99 gives you full software control of up to four tape decks two for reading and two for writing allowing merging of data files to update and modify them This is achieved by using the remote sockets of the tape dec
127. tension board on the rear to plug in your RAM pack larger than 16K if required The unit is supplied with one special cassette lead more are available at 1 each see below COMPREHENSIVE USER MANUAL INCLUDED IN PRICE 3 2 99 SOFTWARE We now have available Editor 99 a quality word processing program including mail merge supplied on cassette for 9 95 Also following soon will be Stock Control Sales Ledger Business Accounts Order Processing Debtors Ledger Accounting gt lt T ORDER FORM TO Komputer cassettes Tora price rar 356 CASSETTES Bee data ayette 43 5995 295 Dept 504 __ 2 Tope 0 24 00 100 Shooniiee es 39 995 50 London 600 J CO I CASSETTE LEAD 20 vt qi ae enam Cheque PO o Ld NAME _ ESEE Add min E 30 Il S I J SIGNED SS 18 SINCLAIRUSER August 1982 Colour for Scisoft maths ANNUAL subscriptions for Sinclair User and Sinclair Programs are among prizes being of fered in a competition for the under 11s The winner will be the child who does the best colouring of the cover of the Jungle Maths cassette which is produc ed by Scisoft the educa tional software house The competition is being run jointly by Scisoft and Microware the Leicester so
128. th the company said Wiley The first venture at Windsor was so successful that Wiley decided on a massive expansion for this year As well as the Windsor camp and the new Lake District residential camp there are other day camps being organised at Mill Hill on the outskirts of London at Sevenoaks Kent and Knutsford Cheshire Last year was very successful said Wiley We had spaces for 300 and could have filled them many times over IF YOU ARE the type who goes 10 the seaside to spend hours and pounds in amusement arcades there is a new crop of 2 81 action games to tempt you to stay at home Greye famous for remarkable 3D Monster Maze has scored again with 3D Defender This all machine code game for 16K 815 has the player steer ing the last surviving craft of a once noble battle fleet into action against marauding in vaders Using the keyboard like a joystick you can climb dive and bank watch thestars wheel about and the ground slip past but kcep an open for the bad guys Phil Garrett looks at ways of enjoying your holiday despite poor weather Greye defender is another 3D winner and their plasma bolts The game requires quick reac tions and good co ordination minimum of five fingers are in action and takes a good deal of practice before any score is achieved Amazing graphics effects are created as the enemy draws closer more and more d
129. the 2 81 allowing more add ons from Memotech or Sinclair to be connected 10 DIM 9000 3726 character MEMOPAK HERES GRAPHICS CENTRONCS VF A complete range of ZXB1 plug in peripherals Digitising Tablet RS232Interface We regret we are as yet unable to accept orders or enquiries concerning the above products but we ll let you know as soon as they become available We want to be sure you are satisfied with your Memopak so we offer 5 Street Oxford OX4 1XL England Tel Memotech Limited 3 Col SINCLAIRUSER August 1982 OR Branton amp GAC Boyd 1982 MEMOPAK 64K MEMORY EXTENSION The 64K Memopak extends the memory of the ZX81 by 56K and switched nor paged and is directly addressable The unit is user transparent and accepts commands such as Breakdown of memory areas 0 8K Sinclair ROM 8 16K This area can be used to hold machine code for communication between programmes or peripherals 16 64K A straight 48K for normal Basic use MEMOPAK 32K and 16K MEMORY EXTENSIONS These two packs extend and complete the Memotech RAM range for the time b 32K pack is that will run in tandem with the Sinclair 16K memory extension to give 48K RAM total MEMOPAK HIGH RES GRAPHICS PACK Main Features Fully programmable Hi Res 192 x 248 pixels Video page is both memory and bit mapped and can be located anywhere in takes about 6 5K Instant inverse video on o
130. think about the world of Sinclair computers 24 COMPACTER ROUTINES George Todorovic considers the problems of data code compression on tho ZX 81 by changing the character codes 27 STARTING FROM SCRATCH Our regular fe Zxei 29 TOOLKIT ROUTINES In his second article Phil Garrett looks at moro aids for 31 PROGRAM PRINTOUT Another eight pages of great programs from our readers 39 25 99 Stephon Adams reviews this major piece of hardware 43 HARDWARE WORLD Our regular look 45 MIND GAMES Philip Joy and more of the 47 file on the ZX 81 50 MOVIES Jack Knight describes easy ways in which to include moving graphics into 55 INSIDE SINCLAIR Claudia Cooke interviews Rick Dickinson the award winning designer of the ZX 81 and the Spectrum 59 COMPETITION Cricket is the theme for this month s contest for the last of our printers 61 SINCLAIR USER CLUB We speak to the first club member and there are thr special offers for members of our ever growing user club 63 SPECIAL OFFER ZX 81 kits for 29 95 plus postage and packaging A saving of 20 Editorial production assistant Margaret Hawkins Managing director ture on how to begin using your Terry Cartwright Chairman Richard Hease Sinclair User is published monthly by Publications Ltd It is not in rom Data Assette what is new in the peripherals market ames which test your mind ndrew Hewson answers your problems
131. this month about the display If you would like to contribute to Sinclair User please send typed or beautifully hand written articles or programs to Sinclair User ECC Publications 30 31 Islington Green London N1 We will pay 10 for each program printed and 50 for each article which should be approximately 1 000 words long Copyright 1982 Sinclair User ISSN No 0262 5458 Origination by Outline Graphics Printed by Eden Fisher Southend Ltd 66 ADVERTISEMENT INDEX Your guide to the many items advertised in the pages of Sinclair NEXT MONTH Special Education Edition We look at uses for Sinclair machines and the growing amount of software available Distributed by Spotlight Magazine Distribution Ltd 1 Benwell Road Holloway 01 607 6411 SINCLAIRUSER August 1982 3 MELBOURNE HOUSE 228 SPECTRUM Why is this man smiling You d be smiling too if you were Dr lan Logan Dr Logan is shown receiving the Rosetta Stone Award for his perceptive insights into the way the 2 81 ROM operates Melbourne House are proud to be the publishers of Dr Logan s books Melbourne House are Sinclair specialists publishing books that are winners in every category Whether you are a beginner or an experienced programmer you ll need Melbourne House books
132. ts case this can also be fixed inside We will carry out the installation work free of charge if required KEYBOARD LAYOUT All the Sinclair ZX81 keys are duplicated on our layout with extra shift and new line keys The professional momentary action key switches have a guaranteed life of 10 operations The unit is fully built tested and comes complete with a money back guarantee INSTALLATION MOTHERBOARD Simply unscrew the ZX printed circuit board from also manufacture a mother board which allows its case and screw it into the FD Case expansion to the ZX memory and 1 0 facilities WITHIN the case as well as our power supply unit and reset switch Code zxu Price Amount Fuller FD System 42 Keyboard amp case 39 95 FD System Motherboard 15 95 B E FD 16K Memory Module 29 95 i FD 64K Memory Module 7895 83 FD PSU 9 Volts at 2 amp 1295 EL 55 FD Shipping and Handling 2 50 _ 3 to FULLER MICRO SYSTEMS Sos The ZX Centre Sweeting Street Liverpool 2 England U K 2 SAE for more details Enquiries Tel 051 236 6109 X NC 5 City State Zip 28 SINCLAIRUSER August 1982 Phil Garrett looks at routines which can assist in writing tidier systems Basic toolkits can help put polish on programs HEN I discussed reviewing ZX 81 utility programs with the editor he was dis appointed t
133. ved and it saves me plenty of time he said Recently he has devel oped a program to display details and results of motor rallies A friend has built him regulator for converting 12V supply to Sinclair helps in work rest and play N the 9V needed for the Sinclair to be used away from a mains supply It had its first showing towards the end of June in the Cossack Rally in North Humberside At the start it listed details of the com petitors scrolling them up 50 that all of them could be included At the end it pro vided the results It took about 25 minutes to input all the figures but we were able to do it as the cars arrived so the results were ready within two minutes of the last competitor finishing which was the time needed to sort through all the in formation Lown said He first had contact with computers 25 years ago and was a founder member of the Hull and District branch of the British Computer Society In those days he was work ing on a National Elliott machine which though having the same capacity as the ZX 81 was the size of a side of a house Britain Aylesbury ZX Computer Club Ken Knight 22 Mount Street Aylesbury 5181 or 630867 Meetings first Wednesday and third Thursday of tho month Edinburgh ZX Users Club J Palmer 031 661 3183 or Mitchell 031 334 8483 Meetings second Wednesday of the month at Claremont Hotel EZUG Educational ZX 80 81 U
134. y dis played and it is the job of the LIST routine to copy the appropriate part of the program area into the display file so that it appears on the TV screen The address of the beginning of the display file varies with the length of the program and so it is held in the D FILE system variable and can be PRINTed by entering PRINT PEEK 16396 256 PEEK 16397 SINCLAIRUSER August 1982 Similarly the address of the end of the display is held in VARS or more correctly is one less than the value in VARS and can be PRINTed by entering PRINT PEEK 16400 256 PEEK 16401 1 Each line displayed on the screen is terminated by a byte containing decimal 118 and there is one more byte at the beginning of the file also containing 118 As there are 24 lines in the display there are 25 bytes containing 118 and it essential to the correct functioning of the dis play software that all 25 bytes are present If one or more is absent the ZX 81 will almost certainly crash With an unexpanded ZX 8i the display file consists of those 25 bytes and no more unless a LIST PRINT or PLOT command has been executed since the last CLS or RUN command That is a device to keep the display file as small as possible thereby saving valuable space in RAM With a memory expansion pack of 4K or more the ZX 81 pads out the display file with 32 bytes per line each containing zero i e blanks That mechanism creates an immediate pr
135. y spent some time working for Clive Sinclair while he was studying for his degree and it was not long before he was absorbed as a full time member of staff and the company s sole industrial designer He is responsible for the appearance of Sinclair products down to the layout of the components inside and the pattern of information on the keyboards His membrane keyboard for theZX 81 was revolutionary and largely responsible for the low retail price of the product Dickinson has learned that price is the ultimate justification and on all his designs he has to bear in mind the cost factor as well as the straightforward appearance of any item The membrane keyboard was continued on page 56 55 continued from page 55 great success and Sinclair has had to cope with numerous pirate copies since its inception but as with everything it had its disadvantages Its main disadvantage was its in ability to register touch To ensure you have a response it is necessary to look at the screen there is no re assuring click when you touch each key For the Spectrum Dickinson has returned to a raised keyboard but again he has produced a first by making it from rubber He says I like the Spectrum much more than the ZX 81 was much quicker to design but much more complicated It is a step up market and 1 was really trying hard for a super smart machine It is not for quite the same amateur market The process
136. you ve forgotten them Where gives the address where a Basic line starts i ment of specified length Check generates a check number toensure a program has loaded correctly In addition it has Renumber which highlights computed and non existent line GOTOs Copy Move Extract place above RAMTOP and merge blocks of Basic ZXTK costs 6 Hewson Consultants 7 Grahame Close Blewbury Didcot Oxon 0X11 9QE JRS Software 19 Wayside Avenue Worthing Sussex BN13 3JU ACS Software 7 Lidgett Crescent Roundhay Leeds 158 1HN dK tronics 23 Sussex Road Gorleston Great Yarmouth Norfolk Rd DEI TR Aper OM Wall Street Liverpool L3 SINCLAIRUSER August 1982 NE ROGRA RINTOU programs ANOEUVRE your Bazooka with keys 1 and Q and fire at the oncoming tank withO before it can nail you with its own weapon A simple but effective game submitted by A S Gale of Exeter Perhaps its most distinctive feature is that it manages to produce both flicker free graphics and an enemy which fights back and that on a 1K ZX 81 Graphics notes 40 Graphic A 128 Inverse minus Inverse 0 graphic 5 space 150 Inver ifted M 190 Graphic 4 graphic 2 199 Inverse space 200 Space shifted M 240 Inverse shifted 400 Asterisk O graphic A 500 Shifted H 600 Inverse BOOM SINCLAIRUS

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