Jan/Feb 1981 Volume 1, Number 1 $2.50 (USA) £ 1.20 (UK)
The magazine for Sinclair ZX80 users
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CHEST OF CLASSICS
FOUR CLASSIC COMPUTER GAMES FOR THE MICROACE AND 4-K ROM ZX80.
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The magazine for Sinclair 2X80 users
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January/F ebruary 1981 Volume 1, Number 1 2 Interview With Clive Sinclair....................... Ahl 22 Random Огарћісѕ............................. McGath Past, present and future of Sinclair Research Diagrams and pictures on the ZX80 4 Sinclair 2Х80................................. Tebbutt 24 ZX80 Circuit Diagram and Ѕресѕ...................... An in-depth review of the ZX80 26 Crash Cursor—Origin.......................... Truman 8 Building a MicroAce....................... McLaughlin 30 бекеті Дын Тһе times, they are a changing astie voors...... ЕИН ПЕНЕН orton 4 2 Cyclops, dragons, witches and zombies lll Ier" McLaughlin . Search for the beastie on a 10x 10 grid 32 ciini о e Руст AXE Branch aces, dogs and flowers 1 3 Converting F rom Other Basics.................. Lubar FOR-NEXT loops 34 Dollars & Cents, Pounds & Pence................Gaunt 4 3 Handling decimal numbers on the ZX80 Едпопа!........................................ Lubar 38 LED Load Мопйог........................... Bridges 14 Dealing Out a Conversion....................... Lubar A perfect load and read every time How we converted a program | 4 6 39 New Peripherals for ZX80............................. Acey Писеу.................................... Lubar The popular card game for the ZX80 39 30 Programs for the 7Х80--А Review............ Lubar 18 Nicomacus.......................... Ahl & McLaughlin 40 Linsac’s Game Packs—A Review................. Stein An ancient “boomerang” puzzle 42 Resources for ZX80 and MicroAce................ Staff 1 9 A Weekend With the 2Х80...................... Singer 45 А РРР упс Header ӛшүуеу.................................. 20 The SNYC Сһаепде............................ Stein Can you fit Hammurabi into the ZX80? 46 Glossary of Computer Тегт5...................... Staff Staff Index to Advertisers Volume 1, Number 1 Publisher/Editor-in-Chief David H. Ahl Advertiser Page SYNC is published bi-monthly by SYNC, 39 East Editorial Director George Blank C — А Hanover Ave., Morris Plains, NJ 07950. : : e om er in m Managing Болот Јона ап д. i DONE. Music Pod = Subscriptions in USA: 6 issues $10; 12 issues $18; Associate Editor David Lubar : 9 18 issues $24. UK and foreign airmail subscri Secretary Elizabeth Magin Creative Computing Cover 3 done Gi £10: 12; "us 18 i $2 Production Manager Laura McKenzie K. Macdonald 19 оине T Tean Ann Vok Lamo Lem Cover? Send subscription orders or change of address РМК 22 m T NUM. а 7 (P.O. Form 3575) to SYNC, 39 E. Hanover Ave., Financial Coordinator | William L. Baumann Morris Plains, NJ 07950. Call 800-631-8112 toll- Bookkepper Patricia Kennelly "P as уй Рио = free (in NJ 201-540-0445) to order a subscription Customer Service Patricia Brown Micr oAce Cover 4 | | Order Processing Alan Kelly Sinclair | 17 Controlled circulation pending at New Berlin, Dorian Snipes SYNC Magazine 44 Wisconsin. Joan Swihart SYNC T-Shirts 37
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Jan/Feb 1981
Suzanne Guppy Frances Miskovich Dorothy Staples
Copyright 1981 by Creative Computing. АП rights reserved. Reproduction prohibited in any form. Printed in USA.
Clive Sinclair is the man behind the first mass pocket calculator, the first scientific calculator kit and, now, a mass- market computer. I talked to Clive while in London at the PCW show.
Ahl: How did you get started in the elec- tronics business?
Sinclair: I started in 1962 when I first came to Sinclair Radionics. We were in the kit business with hi fi systems and pocket calculators, (we made the first pocket calculator which is on display in the Museum of Modern Art in New York). From there we went into digital watches and TV sets and for a while we were linked with a government body in the U.K. At this point I left, as this arrangement did not work out too well. I took the same people with me and reformed the company as Sinclair Research Ltd. and launched the personal computer.
Ahl: Does Sinclair Radionics and its products still exist?
Sinclair: Only as a legal entity, but it doesn't trade.
Ahl: So effectively today your main pro- duct is ZX80?
Sinclair: That's right, but it's not our main research program. Our biggest research/ development program is on flat screen television.
Ahl: Have you shown that at all? Or proved its capability?
Sinclair: Yes we have. We are at the stage where we have demonstrated it and will be doing so again later this year. We have pilot production and hope to shortly be at the next stage.
Ahl: What type of technology is used?
Sinclair: It is a flat screen Cathode Ray Tube.
Reprinted with permission from Creative
Computing , December 1980. 2
Interview with
Clive Sinclair
Ahl: Does it have electron guns?
Sinclair: It has a conventional electron gun, but instead of the beam following a straight path, it bends to a right angle and it splits the screen.
Ahl: Is it monochrome or could it be color?
Sinclair: It is monochrome today, but eventually it will be color. We will pursue that.
Ahl: That sounds very interesting. Sharp had shown one about two years ago which provoked much interest in the electronics community but nothing ever came of it. Today it doesn't look like they are any closer to a commercial product than two years ago.
The philosophy of the company is very clear— to lead in technology.
Sinclair: What Sharp showed was an early development model of vertical projection, which, novel as it was, was a long way from a commercial product. But that is not the case with ours. Ours gives a picture which is not simply as good as a con- ventional Cathode Ray Tube, but it is better, and all the snags have been ironed out.
Ahl: Do you anticipate that the price of this will be competitive with the existing technology?
Sinclair: Absolutely. There is no way we would introduce something which cost more than existing technology. Not only does this have more feature advantages, it has price advantages over conventional technology. But in order to achieve this and because conventional tubes are made in such vast numbers, the only way it can be competitive is to have very large scale production. That is why it will take quite some time before the tube emerges.
David Ahl
Ahl: About the ZX80; how long has that been in development?
Sinclair: It started in March 1979 and it was put on the market in February 1980. Ahl: How many people were involved? It seems to be quite a breakthrough on many fronts. Did you have simultaneous projects going on to bring it to fruition? Or was it mainly you, or a small team of people?
Sinclair: There were very few people in- volved really. I had the original idea and some of the system ideas. Then there were about two or three engineers who were in- volved in the detail and design; one engineer in particular did the final design and one wrote the software.
Ahl: Some people look at it and conclude that it is no more than a larger computer scaled down to smaller dimensions, while others will look at it and think of it as one of those language translators with a little more capability. From glancing at the specifications and seeing it at the Con- sumer Electronics Show, I have the im- pression that it has much more capability than that and that it does not seem to be just a scaled down computer. What is your concept? How do you view the machine?
Sinclair: While the 7Х80 is a true com- puter in every sense, without any inherent limitations, it obviously was restricted in performance in its minimum configura- tion. We wanted to sell at as low a price as we possibly could, a computer upon which people could start to learn, really seriously, how to break into computers and how to really learn what computers were about. Now that might be an end in itself for many of them, but these may be executives who want to understand com- puting so when they buy computers for their firms or talk to people about the use of computers in their firms, they do so from a knowledgeable standpoint and they don't feel awed by it. Equally, we see itasa very powerful aid for students wanting to
SYNC Magazine
learn computing. But at the same time it is expandable. We have just announced a Basic for it — which is more of a pro- fessional Basic than the original one and a 16K byte RAM pack for it at a very keen price, (around $100), so that it can be taken from the basic configuration to a really very powerful system at a very low cost. Hence our price will be somewhere around half the conventional competi- tions. I would make the point that in order to do this we have done everything in- house, i.e., in the way of anything having to be specially done we had to write our own Basic because we wanted to achieve performance in the Basic as it wasn’t available on the existing Basics.
Ahl: Is.that Basic compatible with Micro- Soft Basic or some other Basic on the market or has it got a lot of bells and whistles that make it incompatible with others?
Sinclair: It is not compatible. It is our own. We had to take that step in order to achieve the bells and whistles that you
Jan/Feb 1981
mentioned and have those features that we feel are important to our customers. In order to hit our cost goal we had to do a better packing job than had been done be- fore. The ROM in our basic machine is just 4K bytes which contains everything — Basic, operating system, keyboard control and display I/ O. Now there is no way we could have done all that with an off-the- shelf Basic. Furthermore, we then pack data into the RAM at least four times as tightly as апуопе else. We would not have been able to do that unless we had our own Basic. Another thing that we wanted was keyword entries. You may have noticed that by pressing a certain key a keyword is entered. So there is very little for a non-typist to do. A lot of people are put off in the learning stages with having to type PRINT every time and abbreviations can be misleading. We felt this was very crucial and it is not in- cluded in standard Basics, so we had to choose to go away from the existing pat- terns.
Ahl: Pertaining to the marketing of the ZX80, do you anticipate selling it through computer stores, department stores, or other types of outlets or through direct- mail as you have done with some of your other products?
Sinclair: We are going to sell the computer by direct-mail in England and the U.S. There may come a time when store dis- tribution is possible, but you can't really distribute to a store until you have a much better informed public. A very large mail- order campaign may help do that, so it may be possible later to distribute to stores.
Ahl: Many people buying computers to- day, particularly at this price level, are con- cerned with where or whocan they go back to for service, particularly if they buy a machine by direct-mail.
Sinclair: There are two points there: the first involves the product, the second is who to come back to for service. We һауе а
permanent office in the States and we stand behind our product at all times. We haven't seen anything but 196 or under 1% failure rate in the field in the U.K. It is a very reliable product so we haven't got a serious problem. We operate with service contract houses and this is all part of the guarantee of the product.
Ahl: Jumping back to the technical aspect of the 7Х80, it appears that although now that it is designed for a power supply to be plugged into standard power, it could probably be battery operated and com- pletely portable. Is this in your plans?
Sinclair: Yes it is. It hasa very low power consumption and could certainly run fora reasonable time on batteries. Of course you need a battery T.V. set as well.
Ahl: What about other peripherals, floppy disk, mass storage, printers etc.? Are they in the works?
Sinclair: Yes they are, we have a floppy disk coming in about a month; the other items should be out the middle of next year.
Ahl: How do you feel about other alterna- tive forms of mass storage? Some people have said that the bubble memory is coming down in price fast enough that it may in two or three years replace the floppy disk as a mass storage device. Do you think that's likely to happen?
Sinclair: The price projections we see from manufacturers over the next two or three years don't suggest that to me.
Ahl: What else would you like the world to know about you, the product, philos- ophy etc?
Sinclair: The philosophy of the company is very clear — to lead in technology. We've got a good start in this field and we plan to take as good a lead as we can. Some of the things we are developing, such as the flat TV screen, a truly portable sys- tem, etc. are coming along too. Clearly we think these are things we can do. D
3
David Tebbutt
Clive Sinclair has surprised the world with the launch of his attractive, hand-held personal computer. Costing less than $200, and plugging into a TV and cassette re- corder, some now suggest the 7Х80 to represent the thin edge of a mass consumer market wedge.
Introduction
Sinclair Research set out to build a simple to use personal computer running Basic and capable of breaking the psychological price barrier of $200. Well, they succeeded with their ZX80. Why ZX80? No reason really except that it's based on an NEC copy of the Z80 pro- cessor chip... and it sounds nice.
The machine is available by mail order only; there are no plansto sellitinstores — yet. The kit version is only available in the U.K.; in the U.S. the assembled version costs $200 and includes an AC power supply.
The ZX80 is amazingly light, twelve ounces in fact, and easily held in one hand. The low weight is achieved through use of a moulded plastic casing just Imm thick.
It connects quite happily to the tele-
This article has been reprinted with the permis- sion of Personal Computer World, a British publi- cation covering the personal computer field. Since we cannot make frequent trips to England we keep aware of the latest British developments through magazines such as Personal Computer World.
A one-year subscription to PCW costs £8 in the UK or £22 in the USA (via air). Write Per- sonal Computer World, 14 Rathbone Place, London W1P 1DE, England.
4
— а = — mm
vision set and the cassette recorder, although it might take a few minutes to find the optimal settings. Once attached to the TV, it gives a rock steady display (more on that later).
Hardware
I have to say that I think it very pretty (our art director would probably beg to differ) — the casing even has go-faster stripes, which look suspiciously like ventilation slots in black and white photo- graphs (coincidence, Im sure). I would, however, have been happier with some- thing rather more sturdy; ABS plastic might have done the trick, although per- haps at the cost of attractiveness.
The keyboard is most interesting; it's one of those waterproof, chemical proof, completely sealed units and it's stuck on to the main printed circuit board (PCB). Made of a special tough plastic, the under- surface is printed with the key symbols so as to eliminate any rubbing off. Between this keyplate and the PCB containing the metal contact strips (about five per key) is a piece of sticky plastic containing forty holes which line up with the “keys”. This material is about .006" thick and is just suf- ficient to keep the metal underside of the
keyplate away from the contacts, except when touched of course.
Typing gives a sensation of drumming your fingers rather than of doing anything useful. This is a totally mistaken impres- sion because it really works rather well. For those who are interested, I found that a *wiping" action was more successful than the tapping movement usually associated with typing. Typists may be pleased to hear that the keys are in standard QWERTY layout although somewhat compressed compared to, say, the office IBM.
Looking inside the machine, I find that it's controlled by an NEC 780-1 processor chip...acopy ofthe well known and very successful Z80. This CPU, run- ning at 3.25M Hz, does all the work for the ZX80, including driving the TV and the cassette recorder. You'll notice that if any work is taking place, be it calculation, accepting input from the keyboard or driving the cassette, then the TV picture disappears — only to return when the activity is complete. This can be irritating to observers (at a demonstration for example) but I found it positively bene- ficial when keying in programs because it gave me positive feedback whenever a key made successful contact.
SYNC Magazine
The Basic interpreter, operating sys- tem, character set and editor are all held in a 4K Byte ROM. If you are feeling adventurous there's no reason why you shouldn't pop your own ROM (TMS 2532) in its place.
Memory in the basic system com- prises IK static RAM; you can add to it via the expansion port, giving a maximum potential of 16K. The memory expands with the aid of plug in modules, each designed to carry up to 3K in IK in- crements. Thus five modules would be re- quired to give the 16K maximum. At switch-on the machine does a memory check which also tells the system how much memory is on-line. Should you re- configure the memory, then the command NEW will execute the memory check cycle again.
Moving on to the "outside world" connections, there's a cassette interface, IV socket and a hefty edge connector. Тһе cassette interface comprises two 3.5mm jack plug sockets, securely mounted on the main (and only) PCB. Oneconnects to the "ear" socket on the cassette recorder and the other to the “mic” socket. There is no facility for remote control of thecassette motor.
Although I encountered one or two problems at first, once working, the cassette interface proved trouble free. My particular recorder had a nasty habit of recording noises when the CPU was “send- ing out" silence. This caused the system to get its knickers in a twist when reading from cassette because it expected silence just before the file header record. After a couple of hours (what a confession) the culprit was found — the "ear" lead, which acts as a monitor while recording, was setting up some sort of oscillation. Answer — simple — disconnect the “ear” jack when recording. Another tip which ensures trouble free loading is to move the tape into the silent section before issuing your LOAD instruction. Rumor has it that the cassette operates at around 250 baud — I believe it, although it doesn't seem terribly important when you're only loading the ІК that I was.
The television connector is simplicity itself. Plug one end of the cable (supplied) into the ZX80 and the other into the tele- vision aerial socket, tune to channel 2 and you're in business. The display is magic; rock steady and very clear although re- versed characters (white on black) are not so good.
І have already mentioned the bus- iness of the display switching off every time the processor needs to do something else. If this drives you mad then you'll have to forfeit some of the undoubted plea- sures that this machine has to offer. The screen is not memory mapped: it's treated like a serial file — like a printer in fact — which means that fast moving graphics are out of the question. No doubt some clever
Jan/Feb 1981
Technical Specification
CPU: NEC 780C-1 (copy of 780) 3.25 MHz
Memory: IK static RAM, expandable to 16K
Keyboard: — Keyplate, under-surface printed
Screen: Use own television. Pixel graphics 24 lines x 32 chars.
Cassette: Use domestic audio cassette recorder.
Bus: Edge connector with 44 lines — 37 from CPU, 0V, SV, 9V, Clock, External memory indicator and two earths.
Software: 4K ROM containing Basic, Editor and Operating System
Dick out there will take up the challenge and fudge the system, just to prove me wrong. More about the reasons for this in the Software section, but anyone who is hooked on white characters on a black background can suitably modify the PCB, though why they should want to I'll never know. It's a matter of cutting one track and making a small bridge to another.
Do you take your computer camping with you? You'll be pleased to hear that it can run from a car battery, provided that the lead regulates the supply. I believe you can buy a cigarette lighter plug with a built in regulator ...couple that with a portable IV and a battery powered cassette re- corder and you'll be the envy of the camp- site.
The keyboard is most interesting; its one of those waterproof, chemi- cal proof, completely seal- ed units.
Now let's look at the hefty edge con- nector. This is where the memory ex- pansion modules fit in, each one being "piggy backed" on the one previous. Thus there are always 44 contacts available for outside use. There are 37 lines drawn from the CPU plus 3 power lines (at ОУ, 5V and ӘУ); the other lines comprise two grounds, a "clock" signal and an "external memory in use" indicator.
АП in all, the Sinclair ZX80 is a well designed, well produced personal com- puter. Memory addition comes a bit ex- pensive at about $700 for the full ex- pansion but Clive Sinclair tells me bigger RAMs аге on the way — that means cheaper expansion when they appear.
I’m sorry that there are no pictures of the machine's innards. The fact of the matter is that I was given one of the de- velopment machines which had a couple of "Veroboarded" EPROMS and a selector IC floating around on the ends of some pieces of wire which in turn were soldered into the "official" ROM socket. І thought it best to spare Mr. Sinclair's blushes.
Software
The software of the ZX80 comprises the Basic interpreter, the Editor and what- ever it is that does the rest of the work (Operating System seems too grand a title). Rather than looking at each separately, I shall examine them in the order they might be encountered.
First of all the keying in of programs. For two reasons it's an absolute joy! First you don't have to type in many of the Basic instruction codes, one key is sufficient; second you cannot enter anything that is syntactically incorrect. Some Basic in- structions have to be entered the long way (these are listed above te keyboard) but 29 of the instructions may be entered with a single keystroke, while only 8 need to be keyed in full.
As with many small computers most of the instruction codes are stored in a single byte. Normal Z80 machine code can be entered using the POKE statement and executed with the USR instruction. This should keep the buffs happy after they have tired of Basic. Syntax checking is superb — it’s impossible to go wrong. Every character is checked on entry and, if the interpreter thinks that you are going to make a mistake, it signals with a reverse S (for Syntax) at the point it thinks you have gone wrong. If, later in the same line, you correct the error, then the marker dis- appears. What a grown up facility for such a small machine! Incidentally, the pro- gram lines are displayed very clearly with line numbers, instructions, operators and what have you being nicely spaced out.
Inside the memory, however, there’s a completely different story. The lines of code are held as compactly as possible with most of the commands and operators occupying one byte each. The spaces are removed and there are very few extra bytes needed — for instance the new line code is one byte, although I did notice that the “=" operator needed one extra for some reason. I'm sure there are others, but l'm equally sure they are very few and far between. An example of the storage requirement is as follows:
10 FOR A- 16424 TO 17424 18 Bytes 20 PRINT PEEK(A); 12 Bytes 30 NEXT A 5 Bytes 40 STOP 4 Bytes
5.
So you see, the storage for that program (displaying the IK memory) is 39 bytes long — an average of 10 bytes per in- struction. I'll leave you to work out what sort of program you can ве in ІК, Perhaps І should mention that the screen buffer uses part of the IK, as does the stack and system controlarea. The stack is held at the top of memory and "grows" down; I put 327 entries on it before it stopped accept- ing them.
The program and variables “grow” up into the screen buffer thus reducing the amount of data on display. Eventually it's possible for the program or variables to grow so large that there's nothing left on display. It was while experimenting with this interesting feature that I crashed the system. It seems the software couldn't cope with someone entering a string 868 bytes long! After about 424 bytes of input the screen removed another character every time I keyed in a new one — it was most odd to watch.
Another way of crashing the system, in fact the only other way I could find, is to hit the EDIT key while in the middle of an INPUT loop. This returns the current program line with a syntax error which is impossible to clear. For those who are feeling unhappy about all this talk of crashing systems, don't worry, it's not as bad as it sounds. In the first place you have to enter forty characters after the screen has gone blank, and in the second place you can only hit EDIT when you are also holding the SHIFT key down.
Now it may be that, having loaded your program, you wish to edit it. Well once again there is some rather excellent software to help you. The Editor enables you to move a "current line marker" up and down the program text. Wherever it is you will always be able to see the marked line and at least some of its neighbors (it's called getting it in context). Pressing the HOME key causes the marker to disappear — it has in fact gone to an imaginary posi- tion, one above the first program line. Having reached the line to be edited press the EDIT key and the line will be pre- sented at the bottom of the screen ready for you to do your worst. From now on it isas if you areentering the line for the first time.
The benchmark* timings show the ZX-80 to be very fast, even though I had to introduce some extra code to make some of the instructions work. Specifically I had to bracket expressions like LET A=(K/ K)* K)+K—K ... if I hadn't, the expression would have exceeded the 7Х80% capacity. The machine can only operate on integers and these must have values from — 32768 to 32767. 1 couldn't execute Benchmark 8 because the machine has по logarithmic or trigonometrical functions built in.
*PCW uses 8 Benchmark programs to compare computers.
6
Basic
String Expressions
СНЕЗ(п) TLS(s) Integer Expressions
PEEK(n) CODE(s) ABS(n)
Statements
NEW LOAD RUN CONTINUE INPUT dest PRINT STOP DIM (n) POKEn,n RANDOMIZE n CLS GOSUB n Operations
n**n —n
n+n n—n
n< n SES
NOT n n ANDn
n = number s = string ** = to the power of
Finally, it's possible to save programs and any variables associated with them. If you want to make use of those same variables when reloading the program, use GOTO rather than RUN. Although it's possible to SAVE programs in this way, no provision has been made to save files — yet.
Every character is checked on entry.
That's about it for the software; once again, considering the size of machine and price, I think that it's not at all bad.
Basic
The 7Х80 Basic has been well thought-out and, while it lacks some of the elegance and sophistication of the bigger machines, it’s a very usable version of the language.
The main limitations relate to file handling and mathematical functions. File handling facilities don't exist, except by SAVEing the whole of memory (which is probably not as daft as it sounds). It does mean that you can save a program with all its variables, reload it the next day, remember to kick off with a GOTO rather than RUN, and carry on from where you left off. On the small memory machine it doesn't seem that important, but on the larger memory machines it means you can hold some reasonable sized files together with your program.
Benchmark timings (in seconds)
BMI 1.46 BM2 4.69 BM3 9.18 ВМ4 8.95 ВМ5 12.7 ВМ6 25.9 BM7 39.2
BMS not performed (see text)
STRS(n)
RND(n) USR(n) SAVE RUN n REM IF n THEN stmnt LIST n LIST FOR -n TOn GOTO n RANDOMIZE CLEAR RETURN NEXT n*n n/n n-n n»n
5 > s S< 6
п ОК п
The mathematical limitations аге possibly more serious. The fact is the Basic can only handle integers in the range — 327168 to 32767, no decimals, hence the programmer must write a little routine for each mathematical function that requires decimals to be used. This should pose few problems for those with the larger memory machines but it will undoubtedly occupy a fair chunk of the basic ІК system.
So much for bad news; now here are some of the good features of the language.
Taking numeric functions first, the Basic offers up to 26 single dimension numeric arrays of any length. It also allows three Boolean operations — AND, OR and NOT.
The randomizing functions are worth a mention. RANDOMIZE n sets a seed value, while RND(n) gives a random number in the range І to n. PEEK and POKE are both available so it's possible to read or modify memory contents; coupled with the USR function, this means that Z80 machine code routines can be ex- ecuted.
Ор to 26 FOR ... NEXT loops can be nested and the number of nestable sub- routine calls seem to be dictated by the amount of memory available to the stack. On the IK machine with a short (4 line) program, I ws able to get 327 subroutine calls in before needing to RETURN.
String functions, while adequate, could definitely be improved. Тһе absence of a DATA statement and the lack of string arrays caused particular frustra- tion. Although there are ways around these problems, they can be time con- suming and messy.
The functions which are available, and which form the building blocks of string handling subroutines, are 5ТК8, TL$, CODE, CHR$and INPUT. STRS(n) returns a string of 1 to 6 characters repre- senting the signed, decimal value of n. TL$ returns a string minus its first character, while CODE returns the code for the first
SYNC Magazine
character in a string. CHR§(n) represents the character whose value is n and INPUT allows the operator to input numeric or alphanumeric information. A nice touch is that if the destination of input is a string variable, then the Basic kindly provides a pair of quotes which act not only as a prompt, they also save a little bit of keying.
There is one trap here for the unwary, and I fell into it. I had this nice little loop going and after a while I got fed up with it. Could I get out of the system — could I heck! I hit everything in sight but all I managed to do was crash the system (see earlier). The trick is that if you are in an input string loop, remove the quotes and then put in an arithmetic expression which will resolve outside the range — 32768 to 32767.
So, that's the Basic — I reckon that it's pretty good under the circumstances and in some respects I prefer it to the Basics that do all your thinking for you.
Documentation
This comprises a programming cum operating manual. It's very well pre- sented, being written by Hugo Davenport of Cambridge Consultants, with ар- pendices by the mystery man from Cambridge who wrote the Basic in- terpreter. There are a few small mistakes in the manual — none of themterribly serious and all of them being dealt with before the next reprint. It's probably good enough to
learn to program from it and my only real criticisms like in the area of what it does (or rather, doesnt do) for the raw beginner. I lent the machine to one such person for a few hours and here in his reply regarding the documentation:
"[ read Chapter 2 (Getting Started) and got completely lost by the third page. One minute it's telling me how to wire everything up, the next there's something incomprehensible about storing programs on tape. I couldn't find an ‘Idiot’s Guide to getting started' anywhere."
Maybe the Operating Manual wasn't designed with such a person in mind — even so, novices like him must surely repre- sent a good sized chunk of the ZX80’s ownership potential."
Future Plans
A new ROM is being developed which will overcome most of the shortcomings of the existing system. Being 8K instead of 4K means that file handling routines will enable us to read and write tapes — even discs! This new ROM will also in- clude the missing trigonometrical, logarithmic and floating point arithmetic functions.
Another area of development is on the memory front. A 16K plug in dynamic RAM is a distinct possibility; this will be considerably cheaper than taking the present $700 expansion route. A printer is also likely to appear in due course.
Jan/Feb 1981
Potential Use
In its present form the ZX80 offers an ideal introduction to computing. It makes Basic easy to learn, it’s small enough for it not to be intimidating and it’s cheap enough that, should you decide computing is not for you, you can give it away, sell it or whatever. Indeed it’s probably cheaper to learn Basic this way than to pay for many of the courses around.
Teachers might buy it for their students’ use because at the price there is no need to go through a complicated rigmarole to get the money. The IK ver- sion can be used for fairly simple games and activities, although it’s likely you will want to expand it before very long. Later, when the file handling facilities are intro- duced together with floating point arith- metic, I think the machine will become really useful, though still very much at the personal level. Home accounts and en- gineering calculations spring to mind im- mediately — don’t ask me why! Suddenly the machine becomes something more than a teaching machine or toy: it starts to become a real computer.
Conclusion
Having just read Science of Cambridge’s claims for the machine again, I have to say І agree with most of them. The only point I would question is that it offers high resolution graphics. OK, OK, so they are playing the same game as
everyone else . . . all the same I feel that it should be explained. Just lately, people have taken to calling pixel graphics, high resolution graphics. Accordingly, what used to be called high resolution graphics now has to be called ultra high resolution graphics. To put it another way, the ZX80 offers a graphics resolution of one quarter of one character, plus you must write your own software to be able to use it. PET is in exactly the same boat, unless you want to buy the high resolution add-on at about $600.
The ZX80 appears to be a well thought out machine both in terms of hardware and software. It has an excellent editor and interpreter which between them help you avoid all sorts of nasty pitfalls. The Basic instruction set lacks one or two fairly important facilities — namely file handling and floating point calculations. Despite this, it’s still a fine machine on which to learn about com- puting. The new ROM expected later this year will overcome the prime limitations leaving me very little to say except that | hope Mr. Sinclair and his merry men of Cambridge can cope with the expected flood of orders and, perhaps more im- portantly, the after sales service which is vital in this sort of operation. []
Our thanks go to Clive Sinclair for lending us the machine, and to Jim Westwood (its designer) for patiently answering so тапу questions.
LINSAC
THE ZX80 COMPANION
68 Barker Road Middlesbrough TS5 5ES
THE ZX80 COMPANION
(Second Edition)
ISBN 0 907211 00 5. Price £10.00 incl. UK postage.
This best-selling manual on the Sinclair ZX80 covers ZX80 BASIC, hardware and programs and has a detailed explanation of the ZX80 Monitor, routines and entry points.
Ch.l - Operating the ZX80.
Ch.2 - Theory of Computers Ch.3 - ZX80 BASIC.
Ch.4 - The ZX80 Monitor.
Ch.5 - Construction and Hardware
Ch.6 - ZX80 Programs.
App.l - Comparison of Z-80 Opcodes and ZX80 Characters. App.2 - The 8K ROM.
For a cassetté of ten programs from the Companion add £4.95.
Cassette Software
All LINSAC program packs come on single C12 cassettes with printed run instructions. АП apart from Games Раск 3 are designed for 1K 2Х805. Price £10.00 per pack
including ОК postage.
Games Раск 1 - Three Towers, Number Guessing, Mastermind, Sketcher, Hurkle,
Nim, Symbol Simon.
Games Pack 2 - Nine Lives, The Maze Game, Plain Sailing, Noughts and Crosses, Chinese Puzzle, Tower of Hanoi, Battleships.
Games Pack 3 (for 2 - АК 7Х805) - Fruit Machine, Four-in-a-Line, Zombies.
Education Pack 1 - Maths Drill, Dot Recognition, Musical Notes, Spelling Quiz, Day Finder.
Education Pack 2 - Graph Plotter, Prime Factors, Number Bases, Bar Charts, Statistics.
Utility Pack 1 - Memory Display, Hex Code Monitor, Renumber, Memory Search.
The above ZX80 products are distributed by IMAGE COMPUTING in the United
States
The Times
They are a' Changing: The Building of
a MicroAce
Laura L. McLaughlin
Back in the beginnings of the personal computer industry, I built my first “very own” computer with a friend. That was in January of 1976 (less than 5 years ago). It was one of the first IMSAI computers (remember them?— they’re one of many companies that are no longer). The box was about 19 1/2“ X 17“ X 7“, weighed in excess of 40 pounds and contained a fromt panel, fan, power supply and a mother- board which would hold up to 22 S-100 boards. Initially we built 7 boards; a pro- cessor, four 4K RAM cards, a cassette interface and a serial interface. This was а many man-hours project — if my memory serves me correctly, Га say about 80 man- hours— no small task. And at that point our only I/O on the system consisted of 8 switches on the front panel for entering one byte (character) at a time and 8 lights for output of byte. Of course we had a serial interface to drive a printer or ter- minal (maybe even with a keyboard), but that would have to wait until we could afford it. We could save a program, once loaded in through the switches, onto a cassette and then load it into memory from the cassette - but to do that we had to use the switches to load the program that could read the cassette. Please note that at this point we had invested approxi- mately $2000.00 in our system.
8
A q
-о == ==»
Bway VANE
2% / les ti)
pe
г; i
bu
d
Rc
=> < =
--Ф -s
NEW LOAD SAVE
RUN
INPUT РАМТ
LIST STOP DIM
FOR GOTO LET
CLEAR
CLS
GOSUB RET
Now consider this. Today I sat down to build another personal computer, a MicroAce that retails for $169.00 (less than 9% of the cost of the IMSAI), and takes approximately 7 hours (less than 10% of the time) to build. It measures about 8-1/2” X 7" X 1-1/2” and weighs in at 13 ounces.
But what do I get with the MicroAce? Well, let's look at that for a moment. It comes with processor, cassette interface, pressure-sensitive keyboard, video inter- face (with built in UHF modulator so that it connects directly to the antenna leads on a standard TV set), power supply (an AC adaptor just like the one you use on your calculator that plugs into a regular 110 volt wall outlet), 2K of RAM memory and a 4K Basic in ROM. Basic? When we first built the IMSAI we couldn't even buy a Basic that would run on it! The IMSAI had more memory and certainly more potential to expand (and, in fact, was eventually developed into an extremely powerful system), but in comparing what is available today versus what there was back in the "early" days of home com- puters, there is no question that the MicroAce is amazing.
I should mention that my background is in software; I am not a hardware person. Extensive exposure to the equipment has given me a reasonable understanding of how it works, but I am not an expert. The only experience I have had with building electronic kits is that with the IMSAI.
Okay, now that we've set the scene, let's get down to the discussion of what it took to build this machine. The first phase of the project was to read through the manual. Upon opening the booklet I first saw a xeroxed sheet with a heading that said "Important — Read this and the last page in the manual first."
Alright, this is a newly released product so I guess errata sheets are to be expected. The best way to handle an errata sheet is to transfer the corrections directly into the manual with a colored pen. Don't be afraid to write in the book — remember, it is yours. This way you will not forget (or lose) the changes. One of the changes involved installing two jumper wires on the back of the printed curcuit card (PCB), but nowhere did it say when this should be done. Since they would likely be in the way during normal assembly, I noted in the instructions (on page 11) that this should be done just prior to inserting the integrated circuits (ICs).
SYNC Magazine
Now to the assembly instructions them- selves. Note that the manual is sub-titled “Тһе Teach-Yourself BASIC Manual." This is not particularly misleading. Of the 66 pages, the chapter on assembly takes 10; and that contains 4 pages on tips and component identification, 2 on board dia- grams and 1 on a parts list. Much of the remaining 3 pages are either diagrams or precautions. The actual assembly instruc- tions basically just say:
1. Install sockets
2. Install small discreet components
3. Install tape and power sockets, voltage regulator and modulator
4. Make tape and video cables (if necessary)
5. Insert ICs
These are indeed sparse assembly in- structions. Now, I fully admit that the rest of the manual goes on to explain Basic to the novice in a very reasonable fashion, but it seems to me that a little more detail on the actual construction is called for (maybe even just a checklist by compo- nent type?). In any case, they do provide
Photo 1 Checking for all of the parts
Jan/Feb 1981
Photo 2 The solder side of the MicroAce
you with some very good information on both component identification and on many of the precautions that should be taken in the process of putting together the MicroAce (or any other digital elec- tronic circuit board kit), including such things as how to avoid destroying static sensitive chips. I do hope you have some familiarity with the terminology, other- wise you may find the instructions con- fusing.
Having become familiar with the in- strictions, I proceeded to compare the parts supplied against those in the com- ponent list. This was a relatively straight- forward task since they provide an excel- lent section on parts identification, including a complete list of resistors, by number, with their color codes. Checking the parts off as I went along, and noting any discrepancies, I found I had 1 extra resistor, 1 extra socket and 2 missing diodes. Well the extras would obviously not be a problem, but the elusive diodes might.
Since the next step was to locate the positions of all the parts on the board (using theccomponent layout on page 7 of the manual), I decided to look first for where the diodes were located. Low and behold, I saw markings for only 9 of them, instead of the 11 indicated in the parts list. Encouraging. Maybe I wasn't missing any- thing afterall. As a double check, I went to the schematic (pages 34-35) and once again could see only 9 diodes. It seemed safe to assume that the component list was wrong.
I found the rest of the parts easily. There was just one confusing marking on the board layout. Since this is a new re- lease, it did not surprise me to find extra screenings on the board for parts no longer necessary. These were all clearly noted in the list of components. However, I noticed a symbol for a transistor (TR1) on the upper righthand corner. Once again I went to the schematic, but could find no indication of any transistors. With none supplied and no other mention of it to be found, I assumed it to be one more unused part, so I indicated that on my component list.
Now install the voltage regulator following the diagram below exactly.
Bend the regulators leads as shown (not too close to the plastic) and bolt it down firmly to the board before soldering the 3 wires.
Lastly install the modulator again bending the leads so that they fit through the holes in the board.
| | MICROACE isu o0. ӨӨ @8 е
Sample page from assembly manual.
Photo 3 Beginning the assembly
Photo 4 Progress continues
10
Now I was ready to turn on my solder- ing iron and begin. Following the instruc- tions, I started with the sockets. This practice works well not only for efficiency of construction, but also because it means initial soldering is done on things that are not damaged when overheated. I found this reassuring since I was afraid I'd be a little rusty in this department. All went well. I was pleased to see that they had been very careful in the placement of markings on the board. Although things were somewhat tight in places, nothing was hidden as I put in the sockets.
The next task, according to the manual, was to install the discreet components. With no detailed instructions or checklist, I decided to follow the component list, checking off the parts as I put them on the board. Once again the component identi- fication write-up turned out to be very useful, as it showed orientation markings for those parts that had to be inserted in a particular direction (the two electrolytic capacitors and the nine diodes). First I put in all the resistors (R1-R36), double checked their positioning, soldered them in place, clipped their leads and inspected the solder joints. I then did the same with the capacitors (C1-C16), then the diodes (D1-D9) and the crystal (X1).
The instructions then call for installing the 3 tape and power sockets (not men- tioned in the component list), the voltage regulator (U25) and the UHF modulator, in that order. Following the excellent dia- grams in the manual, this was done with no problem. Then came the tape and video cables. The manual states that if you're lucky (based on availability) they will come pre-assembled. I was not lucky. But since I had cables available from other equipment, I postponed this task for later. I do feel that if they are going to send unassembled cables, they should at least provide a diagram for their construction.
In any case, all I had left to do was the insertion of the ICs. Or did I? No, I had noted in my manual that this was the best time to install the two jumpers called for by the errata sheet. After doing that, I inserted the 24 ICs, being careful to follow all the precautions and tips mentioned in the instructions (except for earthing my- self on a cold water tap; I discovered 5 years ago that working barefoot on a tiled floor eliminated the risk of static).
I now had a completed MicroAce com- puter. It seemed sensible to test it before putting it into its case, so the crucial moment had arrived. I hooked it up to my TV, plugged it in and there it was— a blank screen with a K in the bottom left corner. So far, so good.
Then I pressed a key. Nothing hap- pened. Nothing. Well, it was time to start checking and re-checking the board. After spending quite some time doing just that, looking for misplaced or incorrectly oriented components, bad solder joints or bent under pins, I was getting quite dis- couraged. Yet I was determined to have a working computer. Sure, the kit comes
with a terrific guarantee — for a flat fee of-
$20 you can return it to the company and they will repair it and send it back in per- fect working order. But that might take a couple of weeks. I wanted to start using it immediately.
SYNC Magazine
As I said before, I am not a hardware person, but I decided to look at the sche- matic anyway to see if I could pin-point, or at least isolate, the problem. I noticed immediately that the 8 diodes along the bottom of the board were a direct inter- face between the keyboard and the rest of the circuitry (going specifically to U11). I had checked those diodes a number of times already and was sure they were in- stalled correctly. Checking them again reassured me that I was right.
I won't go through the whole frustrating story of the next few hours trying to track down the problem with a friend (who is a hardware person and who also checked the diodes). Needless to say, in the end we discovered that the diodes were in back- wards. What had appeared to be a yellow diode with a green band on one end, was in reality a clear diode with a narrow green band on one end and a very wide yellow one on the other. What can I say but that I hope someone can benefit from my mistake.
Anyway, at that point (about midnight), it didn't matter. My MicroAce worked — that was exciting. Forgetting all the earlier frustration, I put itin its case and sat down to a couple of hours of joyous program- ming.
Jan/Feb 1981
Photo 5 Almost done
Photo 6 Trying to locate the reversed diodes
Photo 7 The finished product
11
Hurkle
ГІМЕСІ EZ s wast
4...
Сам - tees
420) Fo) us a0 510 ATO ASO e640 ADO 560 570 (St e 700 710
20)
Fecit
12
д \ lo ` у | DN ; š Nm "n! \ Р - | 4 is E W, " e A EX Z 1148) -- А f - Ш
| by fi Ç N | UE S SIR. па ws
FRINT "А HURELE IS HIDING IN ñ 10 BY 10 GRID." FRINT "TRY TO GUESS THE LOCATION OF THE НИКЕГЕ." PRINT "YOU GET 5 TRIES."
PRINT "AFTER EACH TRY, I WILL TELL You"
FRINT "THE DIRECTION TO GO TO FIND HIM."
FRINT "HIT NEWLINE TO START."
INPUT АФ
LS RANDOM I SE LET A-«RNLIC10)
^ LET ВЕКМК1О)
FOR К=1 TO 5
PRINT "GUESS NUMBER "ЗЕ
PRINT "X COORDINATE?"
INFLIT X
PRINT "Y COORDINATE?"
INFLIT Y
IF ABS (X-A)-ABZS(Y-B)-O0 THEN GO Tü 500
ГІШ
PRINT "Ха": Xš "Үл" у: О";
GH SUB 610
NEXT E |
PRINT "SORRY. THAT IS 5 GUESSES"
PRINT "THE HURELE IS HIDING AT "ЗА", "Б PRINT
PRINT "PLAY AGAIN?"
INPLUT A$
IF NOT CODE САФ) =42 THEN STOF
GO TO 222 lo PRINT 9 PRINT "YOU FOUND HIM IN "sks" GUESSES. '
GO To 440 8 PRINT "GO "; 4 IF Y=B THEN GO TO 470
IF YZE THEN GC TO 440 о PRINT "SOUTH"; N
GO TO &70 7 PRINT "NORTH": 4. IF Х-А THEN GO TO 720 5 ТЕ Х<А THEN GO TO 710
PRINT "WEST" w E 2 GG To 7z0 | PRINT "EAST"
PRINT | о RETURN S
A Hurkle is a happy beast and lives in another galaxy on a planet named Lirht that has three moons. Hurkle are favorite pets of the Gwik, the dominant race of Lirht and . . .well, to find out more, read "The Hurkle is a Happy Beast," in the book A Way Home, by Theodore Sturgeon.
In this program a shy Hurkle is hiding on a 10 by 10 grid. Homebase is point 0,0 in the southwest corner. Your guess as to the gridpoint where the Hurkle is hiding should be a pair of whole numbers. After each try the computer will tell you the approximate direction to go look for the Hurkle. You get five guesses to find him.
This program was written by Bob Albrecht of People's Computer Company, and was translated by Laura McLauglin.
THIS 15 GRIO- PONT 3,7
SYNC Magazine
Converting From Other Basics
David Lubar
While Basic is a distinct computer language, it exists in many forms. Thus, a program written for another machine might have to be converted before it will work with the Sinclair. This series will deal with conversion techniques, in hopes of allowing you to get as many programs as possible running.
A command found in many Basics is STEP. This is used in FOR-NEXT loops when an increment other than one is desired. For example:
10 FOR - 1 TO9 STEP2 20 PRINTI 30 NEXT I
This program will print the odd numbers from one to nine. At each pass through the loop, the variable I will increased by two. STEP can also be negative:
10 FOR I — 10 TO 1 STEP -1 20 PRINT I 30 NEXT I
In this case, I will decrease by one on each pass through the loop.
There is no STEP command in Sinclair Basic. Fortunately, there is an easy way around this. Loops are convenient, but they can always be replaced with IF-THEN statements. This is done by using a variable for a counter, and checking to see whether it is still in the desired range. If it is, the program portion is repeated. A simple loop such as
10 FOR I = 1 TO 10 20 PRINT І 30 NEXT I
could be replaced with 10 LET I =1 20 PRINT I 30 LETI=I1+ 1 40 IF I < 11 THEN GOTO 20
Jan/Feb 1981
Line 10 initializes the variable. After the desired action is performed by line 20, line 30 increases the variable. Then, at line 40, the variable is checked to determine whether it is still within the set limits. A value of 11 was used since we want the action to be performed ten times. The variable is increased and checked after the action since this is the way it is done when using FOR-NEXT loops. As might be obvious now, the STEP command is equivalent to the actions performed by line 30. In this case, the STEP was one. For other steps, all that is needed is a change of the values used. For instance, the first example could be rewritten as:
10 LETI=1
20 PRINT I
30 LETI=I+2 .
40 IFI < 10 THEN GOTO 20
For the second example, with a negative STEP, you would use
10 LET I =I 20 PRINT I ЗО ШЕТІ = 1-1
40 IFI > 0 THEN GO TO 20
Notice that when replacing the negative STEP, a > was used, while а < is used in positive STEPS. In either case, you have to check to see if the value has gone beyond the desired range.
Some programs use fractional values for STEP. In some cases you can get around this by multiplying everything by a constant that will make the STEP value an integer. In other cases, where the decimal value is essential, this won't work.
Future articles will cover other conver- sion techniques, showing how to get those strange looking programs to run on the ZX-80.
Editorial
by David Lubar
The Sinclair ZX80 is the new kid in town; a short-lived position in this rapidly changing field. In the past few years, several dozen personal computers have made an appearance. Some are thriving, others have fallen into the obscurity of bargain sales. We believe that the Sinclair is going to be one of the winners; otherwise, there would be no sense in starting this magazine. So, what are our plans? We aim to cover many levels, with articles that will help beginners, as well as features for pros.
The Sinclair is an exciting machine with a lot of potential, and we hope to reflect this in the programs and articles we publish. There will be plenty of games, both new ones and conversions of classics. As new aspects or hidden capabilities of the Sinclair are discovered, we'll pass the information on to you. As you make discoveries, we hope you'll take the time to write articles for us.
There is another question tied in with this: what happens when Sinclair owners begin to get extended Basic and expanded memory? Inevitably, there will be a time when our readers cover the full spectrum from those with minimal systems to those with fully expanded ones. This might seem to pose a problem, but the problem is not unique. Several of the popular home com- puters started out as very small systems with little memory and modest Basics. As memory became less expensive, most own- ers expanded their systems. For a time, computer magazines dealt mostly with the original configurations, and occasionally ran an article or program aimed at expaned systems. Later, the coverage shifted, but the smaller systems were not ignored.
This will probably be the case with SYNC. We'll stick to the ІК RAM 4K Basic machine now, while running a few pieces designed for other configura- tions. Later, there will most likely be more attention given to expanded systems, but plenty of coverage will still be dedicated to the original model. In a way, this will be determined by you. Much of our material will come from free-lance sub- missions. As more writers expand their Sinclairs, we will receive more articles and programs aimed at larger systems. But it must be stressed that SYNC will never ignore those pioneers who own the original model.
13
ИА ЕЕЕ СОС ЕИ ЕС СКС ЈО буе айе
Dealing Out a Conversion
David Lubar
Sinclair owners will probably spend a fair amount of time converting programs from other Basics. This can be a rewarding and educational practice or an exercise in frustration, depending on how you go about it. To pass on a few tips and tricks for translating, ГІ explain the techniques used in getting Acey Deucy running on the ZX 80.
The first step in any translation is to get a good idea of the functions being performed by the program, and of the logic flow behind these functions. Let's go through the original listing, examine what each part does, and see how the functions can be duplicated on the Sinclair. Basically, the program does the following; it deals two cards, accepts а bet, deals a third card, checks for a win or loss, adjusts the player's total, and checks to see if he is broke. The first portion of the program prints the instructions. In the interest of saving memory, these lines were not included in the translation. If there is room, they can always be added later.
In lines 100 and 110, variables are defined. "N" is not used later in the program, so it isn't included in the translation. The original programmer probably had plans to use it in some later version of the game and didn't bother to remove it from the listing. "0" holds the amount of money the player has. The next section, lines 120 and 130, print the player's total and then print a blank line. While the extra PRINT statement adds readability, it also uses memory. Like the instructions, it can always be added later. The program then jumps to the section from 260 to 650 where the cards are selected and displayed. This is where the real changes begin to occur.
14
PRINT TAB(268);"ACEY DUCEY CARD GAME"
PRINT ТАВ(15); "CREATIVE COMPUTING MORRISTOWN, NEU JERSEY"
PRINT PRINT . PRINT
PRINT"ACEY-DUCEY IS PLAYED IN THE FOLLOWING MANNER " PRINT"THE DEALER (COMPUTER) DEALS TUO CARDS FACE UP" PRINT"YOU HAVE AN OPTION TO BET OR NOT BET DEPENDING" PRINT"ON UHETHER OR NOR YOU FEEL THE CARD UILL HAVE"
PRINT"A VALUE BETUEEN THE FIRST TUO." PRINT"IF YOU DO NOT WANT TO BET, INPUT A 0" N=100 08-100
PRINT"YOU NOU HAVE ";0;" DOLLARS" PRINT
GOTO 260
Ra as 660 INPUT"UHAT IS YOUR BET";M
0-0-М 670 ТЕ M<>0 THEN 680
GOTO 120 675 PRINT"CHICKEN!I"
PRINT"HERE ARE YOUR NEXT TUO CaRps “ 978 PRINT
As INTCIASRNDCOD )+2 677 GOTO 260
IF 4<2 THEN 270 680 IF M<=@ THEN 730 | IF 4214 THEN 270 690 PRINT"SORRY, MY FRIEND BUT YOU BET TOO MUCH B=INT(14*RND(1))+2 700 PRINT"YOU HAVE ONLY ";Q;" DOLLARS TO BET IF 8<2 THEN 300 710 GOTO 650
ТЕ B>14 THEN 300 730 CsINT(IASRNDCD )+2
IF А>=В THEN 270 740 IF C«2 THEN 730
IF А<11 THEN 400 250 IF C>14 THEN 730
IF A=11 THEN 420 760 IF С<11 THEN 810
IF 4=12 THEN 440 770 IF C=11 THEN 830
IF 4:13 THEN 460 280 IF C=12 THEN 850
IF 4:14 THEN 480 790 IF C=13 THEN 870
PRINT A 800 IF C=14 THEN 890
6070 500 810 PRINT C
PRINT"JACK" 820 GOTO 910
GOTO 500 830 PRINT"JACK"
PRINT"QUEEN" 840 GOTO 910
GOTO 500 850 PRINT"QUEEN"
PRINT"KING" 860 GOTO 910
8070 500 870 PRINT"KING"
PRINT"ACE" 880 GOTO 910
IF B<11 THEN 550 890 PRINT "ACE"
IF B=11 THEN 570 900 PRINT
IF B=12 THEN 590 910 IF C>A THEN 930
IF Bz13 THEN 410 920 GOTO 970
IF В=14 THEN 630 930 IF C>=B THEN 970
PRINT B 950 PRINT*YOU UIN!!!"
GOTO 650 960 GOTO 210
PRINT“ JACK" 970 PRINT"SORRY, YOU LOSE”
GOTO 650 980 IF М<0 THEN 240
PRINT "QUEEN" 990 PRINT
GOTO 650 1000 PRINT
PRINT"KING" 1010 PRINT"SORRY, FRIEND BUT YOU BLEU YOUR WAD" GOTO 450 1020 INPUT"TRY AGAIN (YES OR МО)";4% PRINT"ACE" 1030 IF A$z"YES" THEN 110
PRINT 1040 PRINT"OK HOPE YOU HAD FUN" PRINT 1050 END
Listing of Acey Ducey from Basic Computer Games. Copyright 1976 by Creative Computing. Reprinted with permission.
SYNC Magazine
ACEY DUCEY CARD GAME CREATIVE COMPUTING MORRISTOUN, NEU JERSEY
ACEY-DUCEY IS PLAYED IN THE FOLLOUING MANNER THE DEALER (COMPUTER) DEALS TUO CARDS FACE UP
YOU HAVE AN OPTION TO BET OR NOT BET DEPENDING
QN UHETHER OR NOR YOU FEEL THE CARD UILL HAVE А VALUE BETUEEN THE FIRST TUO.
IF YOU DO NOT UANT TO BET, INPUT А 0
YOU WOU HAVE 100 DOLLARS
HERE ARE YOUR NEXT TUO CARDS 2 ?
WHAT IS YOUR BET? 25 QUEEN
SORRY, YOU LOSE
YOU NOU HAVE 25 DOLLARS
HERE ARE YOUR NEXT TUO CARDS 4 10
UHAT IS YOUR BET? 25 10
SORRY, YOU LOSE
YOU NOU HAVE 50 DOLLARS
HERE ARE YOUR NEXT TUO CARDS 8 QUEEN
UHAT IS YOUR ВЕТ? 0 CHICKEN! !
HERE ARE YOUR NEXT TUO CARDS 6 10
UHAT IS YOUR BET? 20 10 SORRY, YOU LOSE YOU NOU HAVE 20 DOLLARS
sample run from original Acey Ducey game in Basic Computer Games.
Jan/Feb 1981
Several things are happening here. First, a value from two to fourteen is chosen. By using fourteen as the value of an ace (aces are high), the cards can be compared easily. In the original program, the first card (variable A) had to be lower in value than the second card (variable B). If this wasn't the case, new values had to be used. In the conversion, it doesn't matter which of the two is higher. The program only checks to see if they are the same. In this case, since the player can't win, new values are selected (see line 300 of the translation). Next, the values are printed. If the value is below eleven, a number is used. For a higher value, the name of the card is needed. In the original, this is done separately for each card. To save space in the conversion, this function was put into a subroutine which could be used for all three cards. The subroutine uses the variable *C". In line 320 of the conversion, C is made equal to A. Thus the subroutine prints the name of the card if A is greater than ten.
At line 660 of the original, the bet is taken. Line 670 shows a common operation used in many programs: an inequality where more than one operator is used. The symbols =, <, and > are often used in pairs. In this case, the symbols “< >" mean “not equal to." This can be translated using the NOT operator. Whenever a program has two symbols (such as >=, which means "greater than or equal to,") the line can be translated using NOT and the unused symbol of the trio <, > апа =. So a line such as 10 IF X >= 10 THEN GO TO 50 can be translated as 10 IF NOT X € 10 THEN GO TO 50
Getting back to the program, line 680 checks to see if the player bet more than he has in his winnings. This line could have been translated using the trick just mentioned. For variety, another method was used. In this instance, the two symbols were used, separated by a logical OR (see line 410 of the translation). Lines 730 through 890 select and print the third card. In the translation, this is replaced with 450 through 465. Note that the lines in the original, such as 740, that check for values less than two or greater than fourteen aren't needed. The RND function won't return a value outside the desired range.
After the third card is displayed, the values must be compared to see whether there is a win or a loss. In the original, since A was always less than B, the program only had to determine whether D was greater than A and less than B. This is done in the series of lines from 910 to 970. In the translation, we have to see whether D is between A and B, regardless of whether A or B is the higher of the original pair. This is done in line 600. D must either be greater than A and less than B or greater than B and less than A. Otherwise, the player loses.
Once a win or loss has been determined, the program must adjust the player's total. In the original, different routines were used for win and loss. This is the section from 210 to 240. To save space, just one routine was used in the translation. This is done in line 215. If the player lost, M will have a negative value (see line 630) and the bet will actually be subtracted from the total.
Line 620 of the translation checks to see if the player is broke. If he is, the program goes on to line 900 where the player is offered another chance.
That about covers the translation. Note that on each pass through the game, the player must hit NEWLINE to continue (line 210). This serves two purposes. The input stops the program temporarily, allowing the printout to appear, and it also gives the player a chance to read everything before the CLS is encountered. Also, commas are used in the print routines so the cards will be printed on one line.
Those who are interested might try adding some improvements to the game. For example, in some versions of Acey Deucy, the player loses $5 whenever a pair is dealt. Also, in the real version, the player has a choice of letting an ace be either high or low if it is the first card of the two dealt on any hand. These features could probably be added to the existing program with little difficulty.
15
Acey Ducey
у)
16
= RANDOMISE
= LET маше
r >
LET &G-100
FRINT "ҮСІП HAVE "sus" DOLLARS" GO TUO 240
FRINT "HIT NEWLINE TÜ CONTINUE” INFLIT &$
CL
GG Ті 120
PRINT "НЕКЕ ARE THE NEXT ТЫП CARDS" LET ВЕКМЦИ 1:23) +1
LET Е-КМП(12)-41
IF &à-B THEN GO TÜ 270 IF 6411 THEN РКІМТ ñ; LET С=а
GO SUB 500
IF Е<11 THEN FRINT В: LET C-HR
GO SUB 500
РКІМТ
FRINT “YOUR БЕТ?"
INFLIT М
IF NOT M=0 THEN GO TO 410 CL
PRINT “CAUTTIOLES"
GO ТО 2930 IF Меп OR Met! THEN GO TO 450
ши"
PRINT "SORRY. YOU ONLY HAVE "sos" DOLLARS TO BET."
GO TO 270
LET пекми 12) +1
IF [6211] THEN PRINT П
LET С-П
Гиз SUB SOO
GO To 400
IF C-11 THEN FRINT "JACK", IF C-i1z THEM PRINT "QUEEN", IF C123 THEN FRINT "KING", IF С=14 THEN FRINT "ACE", RE TURN
IF DL AND DB OR ТЕА AND DB THEN GO Tü 700
PRINT "SORRY, YOU LOSE"
IF Mot! OR M= THEN GO TO 700
LET Mz-M
GO TO 210
PRINT "YOu WIN"
GO TO 210
FRINT "YOU ARE ТАРРЕП OUT. FLAY AGAIN?" INFLIT AS
IF NOT CODE (A$)=42 THEN STOF
Gl TO 110
This simulation of the Acey Ducey card game. In the game, the dealer (the com- puter), deals two cards face up. You have an option to bet or not to bet depending whether or not you feel the next card dealt will have a value between the first two.
Your initial money is set at $100. The game keeps going until you lose all your money, or interrupt the program.
The original program author was Bill Palmby of Prairie View, Illinois, and David Lubar translated for the ZX-80.
SYNC Magazine
The first personal computer
. for under
The Sinclair ZX80. A complete computer—
only $199. 95 plus $5.00 shipping.
Now, for just $199.95, you can get a complete, powerful, full-function computer, matching or surpassing other personal computers costing several times more.
It’s the Sinclair ZX80. The computer that “Personal Computer World” gave 5 stars for ‘excellent value.’
The ZX80 cuts away computer jargon and mystique. It takes you straight into BASIC, the most common, easy-to-use _ computer language.
You simply take it out of the box, con- nect it to your TV, and turn it on. And if you want, you can use an ordinary cassette recorder to store programs. With the man- ual in your hand, you'll be running programs in an hour. Within a week, you'll be writing complex programs with confidence.
All for under $200.
Sophisticated design makes the ZX80 easy to learn, easy to use.
We've packed the conventional computer onto fewer, more powerful LSI chips— including the Z80A microprocessor, the faster version of the famous Z80. This makes the ZX80 the world's first truly port- able computer (612" x 812" x 112" and a mere 12 oz.). The ZX80 also features a touch sensitive, wipe-clean keyboard and a 32-character by 24-line display.
Yet, with all this power, the ZX80 is easy to use, even for beginners.
Q
Кш
Your course in computing.
` The ZX80 comes complete with its own 128-page guide to computing. The manual is perfect for both novice and expert. For every chapter of theory, there's a chapter of practice. So you learn by doing— not just by reading. It makes learning easy, exciting and enjoyable.
You'll also receive a catalog packed with items that can make your ZX80 even more useful. Including 27 program cassettes, from games and home budgeting for just
$6.95, to Sinclair's unique Computer Learning
Lab. And books, hardware options and other accessories.
ZX80’s advanced design features. Sinclair's 4K integer BASIC has perfor-
mance features you'd expect only on much
larger and more expensive computers.
B Unique 'one touch' entry. Key words (RUN, PRINT, LIST, etc.) have their own single-key entry to reduce typing and save memory space.
$200.
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B Automatic error detection.
A cursor identifies errors
immediately to prevent entering
programs with faults.
= Powerful text editing facilities.
m Also programmable in machine code.
B Excellent string handling capability —up to 26 string variables of any length.
= Graphics, with 22 standard symbols.
m Built-in random number generator for games and simulations.
Sinclair’s BASIC places no arbitrary re- strictions on you—with many other flexible features, such as variable names of any length.
And the computer that can do so much for you now will do even more in the fu- ture. Options will include expansion of 1K user memory to 16K, a plug-in 8K floating- point BASIC chip, applications software, and other peripherals.
Order your ZX80 now!
The ZX80 15 available only by mail from Sinclair, a leading manufacturer of con- sumer electronics worldwide.
To order by mail, use the coupon below. But for fastest delivery, order by phone
and charge to your Master Charge or VISA.
Тһе ZX80 is backed by a 30-day money- back guarantee, a 90-day limited warranty with a national service-by-mail facility, and extended service contracts are available for a minimal charge.
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4.
Price includes TV and cassette connectors, AC adaptor, and 128-page manual.
All you need to use your ZX80 is a standard TV (color or black and white). The ZX80 comes complete with connectors that easily hook up to the antenna terminals of your TV. Also included is a connector for a portable cassette recorder, if you choose to store programs. (You use an ordinary blank cassette.)
he ZX80 is a family аеру aid. Children 10 and above will quickly understand the principles of computing — and have fun learning. Master Charge or VISA orders call: (203) 265-9171. We'll refund the cost of your call. Information: General and technical — (617) 367-1988, 367-1909, 367-1898, 367-2555. Phones open Monday-Friday from 8 AM to 8 PM EST.
Sinclair Research Ltd., 475 Main St., P.O. Box 3027, Wallingford, CT 06492.
Please send me. 02 shipping. (Your ZX80 may be tax deductible.)
Name Address City cn ае
Occupation: Intended use of ZX80:
---
ч Sinclair Research Ltd., 475 Main St., P.O. Box 3027, Wallingford, СТ 06492. ZX80 personal computer(s) at $199.95* each (US dollars), plus $5
I enclose a check/money order payable to Sinclair Research Ltd. for $
Have you ever used a computer? O Yes O No. Do you own another personal computer? [0 Yes [0 No.
Zip Age:
*For Conn. deliveries, add sales tax.
SY-1-1 | mS GES OL (SEE EES GE SSS SSE —— LÀ —— M ——aM — SEE u- —- — —
Nicomacus
One of the most ancient forms of arith- metical puzzle is sometimes referred to as a "boomerang." At some time, everyone has been asked to "think of a number," and, after going through some process of private calculation, to state the result, after which the questioner promptly tells you the number you originally thought of. There are hundreds of varieties of the puzzle.
The oldest recorded example appears to be that given in Arithmetica of Nicomachus, who died about the year 120. He tells you to think of any whole number between 1 and 100 and divide it successively
30 FRINT 40 PRINT 45 INFLUT А a0 FRINT за INPUT В
25 ІМРІТ C 70 FRINT GO FRINT
60 PRINT "YOUR NUMBER DIVIDED BY 7 HAS A REMAINDER DF" | |
110 120 LET D=D-10% 130 GO TO 110 140 РКІМТ 160 INPUT АФ
170 IF CODE (A#)=42 THEN
190 FRINT 200 GO TÜ 220 PRINT 2:20 GO TO 250 240 PRINT ао PRINT 260 PRINT 270
160
INFLIT At
"THINK ОР A NUMBER BETWEEN 1 ANT 100, " "YOUR NUMBER DIVIDED BY THREE HAS A REMAINDER =
"YOUR NUMBER DIVIDED BY % HAS A REMAINDER ПЕ"
"LET ME THINE A MOMENT..." 100 LET Пп=70о%8+21%8+12+С
IF NOT D2105 THEN GO TO 140
"YOUR NUMBER WAS GO TO 220
120 IF СОПЕСАФ)==1 THEN GO "I DO NOT UNDERSTAND
"І THINE YOUR ARITHMETIC IS
ANTES
by 3, 5, and 7, teling hin the remainder in each case. On receiving this information, he promptly discloses the number you thought of.
Can you discover a simple method of mentally performing this feat? If not you can see how the ancient mathematician did it by looking at lines 100-120 within the program.
The game was originally programmed by David Ahl and it appeared in his book, Basic Computer Games. This version was translated for the ZX-80 by Laura McLaughlin.
ce Ns / eA АД, (rk TAP ДУ ы “" e Pau - ууу дах АУА) 1", ix
АМА SAY
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М AN
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NN N
wW) NN У
NN NN
NN SN
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На a i! BUE ?
RIGHT?"
TÜ 240
"SASS". TRY YES OR NO,"
"HOW ABOUT THAT."
IN ERROR."
"WANT TO TRY АМОТНЕК?"
230 IF NOT CODE(CA$)=42 THEN STOF
270 CLS
300 GO TO зо
18
SYNC Magazine
A Weekend With the ZX-80
Joshua Singer
I have always been intimidated by com- puters, and mathematics in general. One look at the Sinclair ZX-80, and I was con- fused. It wasn't what I had expected; there were no blinking lights, or humming, and no rows of ceiling high, pulsing units. It looked nothing like my 1950's science fic- tion concept of a computer. The ZX-80 was a pleasant suprise. It didn't look intim- idating. In fact, it looked like a machine I might even be able to operate. Another suprise: I lifted the computer and found that it weighed only a few ounces.
I borrowed the computer from a friend, took it home and immediately connected it to my battered, portable television, which showed the clearest picture ever to grace the screen. With the Sinclair, the T.V., and the owner's manual in front of me, I began my first lesson in program- ming. The manual tells you everything you need to know, in clear, concise, often amusing language. The manual was so interesting that I lost track of time, some- thing I rarely do when dealing with numbers and other non-literary subjects.
The book is extremely logical, begin- ning with instructions on how to connect the Sinclair to your television set. The same section also explains using a cassette recorder to store programs. The introduc- tory portion of the manual even includes an explanation of computer languages, ending with a discussion of the Basic used with the ZX-80. As a complete beginner, I related to the way in which the booklet explained Basic as a simplified English dialect. It made sense, maing me realize that to give the computer commands, I merely had to be concise, as well as careful in choosing my words. The book suggested the machine was stupid, and therefore, that one had to be careful about the manner in which it was address- ed. I liked that attitude because it made me feel brighter than the computer.
The manual continued by explaining general programming procedures, and several computer terms. I was unable to work my way through the entire manual, but that was only because of my own time limitations. By the end of the first session I
Jan/Feb 1981
could program and run addition, multipli- cation, and division problems. Most of these were simple enough to do by hand, but were a good foundation for learning programming. The book eventally en- ables the user/reader to execute games and provides enough information for the Sinclair owner to continue the learning process individually.
With just two weekends of not terrribly intensive study, I can now run just about any pre-programmed cassette, as well as doing some of my own programming. I am no programmer, but I do find that I can have a lot of fun playing games or learning on the Z X-80. It is such an easy machine to learn, that I have no doubts that ГЇЇ be writing my own programs in the near future.
C Z⁄ ФА
Cra «еса ni (
Poke to memory mapped screen - use your ZX80 as a
sketehing pad. Character and direction control.
Music
(#15)
Tunes to your cassette recorder, with selectable
octaves, semitones and duration from а wide range of notes. Your tune will repeat itself continuously. For the best results, memory ІК is necessary.
doce emi ( #5)
Hex. Loader - this routine provides а simple means
for machine code programming in Hexadecimal notation. A 'String Rotate' demonstration program is included. Hex. Display - this routine allows you to inspect
the contents of memory in 64 byte blocks - just
enter the decimal address.
е Display ; ( #20)
Write your own games or use the ZX80 for continuous
data monitoring. You decide how long а dísplay will hold before your program continues (1/60th second to approx. 16 mins.). A Hex. Loader and a 'top row' keyboard scanning routine is included with a demo.
usu: ( 220 )
Try your skill а% knocking а11 the bricks from the
wall before your final ball is lost. The ball starts at '9' and decrements each time it is lost until the game is over. The paddle moves swiftly under your control - the game restarts automatically.
» >
( #15 )
Pictures of your own creation (7x8 characters) are
displayed in rapid rotation giving animation effect. For the best results, memory ІК is necessary.
Space po hails Pi ( #25 )
А simplified version of the famous arcade game.
Zap the intruders as they attempt to land. The impulse to beat your last score is paramount. Requires 2K memory.
No modifications to hardware whatsoever. All software is thoroughly tested and claimed to be the most advanced developed so far.
Games are written in machine code to make maximum use of memory and provide continuous live action without loss of T.V. synchronisation. All programs run іп ІК memory unless stated otherwise.
Inelusive prices for program listing, details and Air Mail postage, (Send only $90 total if all the software listed is ordered together). Cheques (ог S.A.E. for U.K. price list and details) to:- K.Macdonald, 26 Spiers Close, Knowle, Solihull, West Midlands, B95 9ES, ENGLAND.
19
|
The SYNC Challenge
The editor wants you to prove your programming skills. We at SYNC have chosen Hammurabi from Creative Com- puting's Basic Computer Games as the challenge program because it is a com- plex and refined game. We challenge you to fit this complex game into the 1K memory of a ZX-80.
In the conversion we are seeking to preserve as much of the original game as possible. Therefore, the primary factor in our evaluation of your conversion will be the preservation of as many facets of the game as possible. Judging will also be based on the ease of operation and the demonstration of good programming tech- nique.
АП programs must be submitted on cas- sette, with a letter of explanation. Both the cassette and the letter must be clearly marked with the participant's name, address and phone number. Entries received by March 15, 1981 will be judged in time for publication in the May/June issue.
HAMURABI
CREATIVE COMPUTING MORRISTOUN, NEU JERSEY
When Hammurabi is converted for the ZX-80, the program must be substantially shortened. Such things as the initial direc- tions, copyright information, and REM statements may be eliminated completely. The ten year results may also be deleted. Many statements may be combined, espe- cially those referring to the same line. In
general, the program must be streamlined
to fit the ZX-80. Prizes
Ist —A one year subscription or renewal to SYNC, and a SYNC T shirt.
2nd —A one year subscription or renewal to SYNC.
3rd — A SYNC T shirt.
Send all entries to: The SYNC Challenge 39 East Hanover Avenue Morris Plains, New Jersey 07950
—,əə— v N — —— nF n
In this game you direct the ad- ministrator of Sumeria, Hammurabi, how to manage the city. The city initiallyhas 1,000 acres, 100 people and 3,000 bushels of grain in storage.
You may buy and sell land with your neighboring city-states for bushels of grain — the price will vary between 17 and 26 bushels per acre. You also must use grain to feed your people and as seed to plant the next year's crop.
You will quickly find that a certain number of people can only tend a certain amount of land and that people starve if they are not fed enough. You also have the unexpected to contend with such as a plague, rats destroying stored grain, and variable harvests.
You will also find that managing just the few resources in this game is nota trivial job over a period of say ten years. Thecrisis of population density rears its head very rapidly.
HAMURABI: І BEG TO REPORT TO YOU, IN YEAR 3 , 5 PEOPLE STARVED, 5 CAME TO THE CITY,
А HORRIBLE PLAGUE STRUCK!
POPULATION IS NOU 52
HALF THE PEOPLE DIED.
THE CITY NOW OWNS 1035 ACRES. YOU HARVESTED 1 BUSHELS PER ACRE.
RATS ATE 0 BUSHELS.
YOU NOW HAVE 744 BUSHELS IN STORE.
TRY YOUR HAND AT GOVERNING ANCIENT SUMERIA
FOR A TEN-YEAR TERM OF OFFICE.
HAMURABI: I BEG TO REPORT TO YOU, IN YEAR | , 0 PEOPLE STARVED, 5 САМЕ TO THE CITY,
POPULATION IS NOW 100
THE CITY NOW OWNS 1000 ACRES.
YOU HARVESTED 3 BUSHELS PER ACRE. RATS ATE 200 BUSHELS.
YOU NOU HAVE 2800 BUSHELS IN STORE.
LAND IS TRADING AT 17 BUSHELS PER ACRE. HOU MANY ACRES DO YOU WISH TO BUY? 0
HOW MANY ACRES DO YOU WISH TO SELL? 25
HOW MANY BUSHELS DO YOU WISH TO FEED YOUR PEOPLE? 1000
HOW MANY ACRES DO YOU WISH TO PLANT WITH SEED? 500
HAMURABI: THINK AGAIN. 169 BUSHELS OF GRAIN.
YOU HAVE ONLY NOU THEN,
HOW HANY ACRES DO YOU WISH TO PLANT WITH SEED? 300
LAND IS TRADING АТ 24 BUSHELS PER ACRE. HOW MANY ACRES DO YOU WISH TO BUY? 10
HOW MANY BUSHELS DO YOU WISH TO FEED YOUR PEOPLE? 2000
HOW MANY ACRES DO YOU WISH TO PLANT WITH SEED? 990
HAMURABI: I BEG TO REPORT TO YOU, IN YEAR 2 , 0 PEOPLE STARVED, 5 САМЕ TO THE CITY,
POPULATION IS NOW 105
THE CITY NOW OWNS 1010 ACRES.
YOU HARVESTED 3 BUSHELS PER ACRE. RATS ATE 16 BUSHELS.
ХОЏ NOU HAVE 3019 BUSHELS IN STORE.
HAMURABI: I BEG TO REPORT TO YOU,
POPULATION IS NOW 62
IN YEAR 4 , 2 PEOPLE STARVED, 12 САМЕ TO THE CITY,
THE CITY NOU OUNS 1010 ACRES.
YOU HARVESTED 1 BUSHELS PER ACRE.
RATS ATE 0 BUSHELS.
YOU NOU HAVE 319 BUSHELS IN STORE.
LAND IS TRADING AT 23 BUSHELS PER ACRE. HOW MANY ACRES DO YOU WISH TO BUY? 0 HOW MANY ACRES DO YOU WISH TO SELL? 500
HOW HAWY BUSHELS DO YOU WISH TO FEED YOUR PEOPLE? 500
LAND IS TRADING AT 21 BUSHELS PER ACRE.
HOW MANY ACRES DO YOU WISH TO BUY? 25 HOW MANY BUSHELS DO YOU WISH TO FEED YOUR PEOPLE? 2000
HOW MANY ACRES DO YOU WISH TO PLANT WITH SEED? 1000 HAMURABI: THINK AGAIN. YOU HAVE ONLY
494 BUSHELS OF GRAIN. NOW THEN, HOW MANY ACRES DO YOU WISH TO PLANT WITH SEED? 500
20
HOW MANY ACRES DO YOU WISH TO PLANT WITH SEED? 230
YOU STARVED 37 PEOPLE IN ONE YEAR!!!
DUE TO THIS EXTREME MISMANAGEMENT YOU HAVE NOT ONLY
SO LONG FOR NOU.
BEEN IMPEACHED AND THROWN OUT OF OFFICE BUT YOU HAVE ALSO BEEN DECLARED NATIONAL FINK! !!!
SYNC Magazine
Nac: <. (У
72
£ | a А AF S M.
n rt f, ` оф 5 S ih:
` \ \
4&0 PRINT "BUT YOU HAVE ONLY";P;"PEOPLE TO TEND THE FIELDS! NOW THEN,"
10 PRINT TAB(32) ; "HAMURABI" k 470 GOTO 440
20 PRINT TAB(15);"CREATIVE COMPUTING MORRISTOUN, NEW JERSEY" 510 S=S-INT(D/2)
30 PRINT:PRINT:PRINT 511 GOSUB 800
80 PRINT "TRY YOUR HAND AT GOVERNING ANCIENT SUMERIA" 512 REM *** A BOUNTIFUL HARVEST!
90 PRINT "FOR А TEN-YEAR TERM ОҒ OFFICE.":PRINT 515 YC: HsDsY: Е=0
95 р1=0: P1=0 521 GOSUB 800
100 1:0: Р=95:5=2800: Н=3000: E=H-S 522 IF INT(C/2) O C/2 THEN 530
110 Үз3: А=Н/Ү: 125: 021 523 REM +++ RATS ARE RUNNING WILD!!
210 D=0 525 E=INT(S/C)
215 PRINT:PRINT:PRINT "HAMURABI: I BEG TO REPORT ТО YOU,": Z=Z+1 530 S=S-E+H
217 PRINT "IN YEAR"; 25;",";D; "PEOPLE STARVED,";1;"CANE TO THE CITY," 531 GOSUB 800
218 P=P+I 532 REM *** LET/S HAVE SOME BABIES
227 ТЕ 020 THEN 230 533 1-ІНТ(С%(20ы4%5)/Р/100%1)
228 P=INT(P/2) 539 REM *** HOW MANY PEOPLE HAD FULL TUMMIES?
229 PRINT "A HORRIBLE PLAGUE STRUCK! HALF THE PEOPLE DIED." 540 C=INT(Q/20)
230 PRINT "POPULATION IS NOU";P 541 REM *** HORROR, А 15X CHANCE OF PLAGUE
232 PRINT "THE CITY NOW OUNS";A; "ACRES." 542 Q=INT(10#(2#RND(1)-.3))
235 PRINT "YOU HARVESTED"; Y; "BUSHELS PER ACRE." 550 IF P<C THEN 210
250 PRINT "RATS ATE";E;"BUSHELS. " 551 REM *** STARVE ENOUGH FOR IMPEACHMENT?
260 PRINT "YOU NOU HAVE";S;"BUSHELS IN STORE.": PRINT 552 D=P-C: IF D».45*P THEN 560
270 IF Z=11 THEN 860 553 Рі-((17-1)%Р1%0%100/Р)/7
310 C=INT(10*#RND(1)): Ү=С+17 555 PsC: D1=D1+D: GOTO 215
312 PRINT "LAND IS TRADING AT";Y;"BUSHELS PER ACRE." 540 PRINT: PRINT "YOU STARVED";D;"PEOPLE IN ONE YEAR!!!"
320 PRINT "HOW MANY ACRES DO YOU WISH TO BUY"; 565 PRINT "DUE TO THIS EXTREME MISMANAGEMENT YOU HAVE NOT ONLY"
321 INPUT 0: IF 0<0 THEN 850 566 PRINT "BEEN IMPEACHED AND THROWN QUT OF OFFICE BUT YOU HAVE" 322 IF Y#Q<=S THEN 330 567 PRINT "ALSO BEEN DECLARED NATIONAL FINK!!!!": GOTO 990
323 GOSUB 710 710 PRINT "HAMURABI: THINK AGAIN. YOU HAVE ONLY"
324 GOTO 320 711 PRINT S;"BUSHELS OF GRAIN. NOW THEN,"
330 IF 0=0 THEN 340 712 RETURN
331 А=4+0: 5=5-Үз0: C=0 220 PRINT "HAMURABI: THINK AGAIN. YOU OWN ONLY";A;"ACRES. NOW THEN," 334 GOTO 400 230 RETURN
340 PRINT "HOW MANY ACRES DO YOU WISH TO SELL"; 800 C=INT(RND(1)#5)+1
341 INPUT 0: IF Q«0 THEN 850 801 RETURN
342 IF Q<A THEN 350 850 PRINT: PRINT "HAMURABI: I CANNOT DO WHAT YOU WISH."
343 GOSUB 720 855 PRINT "GET YOURSELF ANOTHER STEWARD! ! 11!"
344 GOTO 340 857 GOTO 990
350 A=A-Q: S=S+Y#0: C=0 860 PRINT "IN YOUR 10-YEAR TERM OF OFFICE,“;P1;"PERCENT OF THE"
400 PRINT 862 PRINT “POPULATION STARVED PER YEAR ON THE AVERAGE, I.E. A TOTAL OF" 410 PRINT “HOW MANY BUSHELS DO YOU WISH TO FEED YOUR PEOPLE"; 865 PRINT DI;"PEOPLE DIED!!": L=A/P.
411 INPUT Q 870 PRINT “YOU STARTED WITH 10 ACRES PER PERSON AND ENDED WITH"
412 IF 0<0 THEN 850 875 PRINT L;"ACRES PER PERSON.": PRINT
418 REM *** TRYING TO USE MORE GRAIN THAN IS IN SILOS? 880 IF P1>33 THEN 565
420 IF 0<=5 THEN 430 885 IF 1<7 THEN 565
421 GOSUB 710 890 IF P1>10 THEN 940
422 GOTO 410 892 IF L<? THEN 940
430 S=S-Q: С=1: PRINT 895 IF IF P153 THEN 960
440 PRINT "HOU MANY ACRES DO YOU UISH TO PLANT UITH SEED"; 896 IF L<10 THEN 960
441 INPUT D: IF 2-0 THEN 511 900 PRINT "A FANTASTIC PERFORMANCE!!! CHARLEMAGNE, DISRAELI, AND" 442 IF D«0 THEN 850 905 PRINT "JEFFERSON COMBINED COULD NOT HAVE DONE BETTER!":GOTO 990 444 REM *** TRYING TO PLANT MORE ACRES THAN YOU ОШМ? 940 PRINT "YOUR HEAVY-HANDED PERFORMANCE SMACKS OF NERO AND IVAN IV." 445 IF D<=A THEN 450 945 PRINT "THE PEOPLE (REMAINING) FIND YOU AN UNPLEASANT RULER, AND," 446 GOSUB 720 950 PRINT “FRANKLY, HATE YOUR GUTSI!":GÜTO 990
447 GOTO 440 960 PRINT "YOUR PERFORMANCE COULD HAVE BEEN SOMEWHAT BETTER, BUT" 449 REM *** ENOUGH GRAIN FOR SEED? 965 PRINT "REALLY UASN^T TOO BAD AT ALL. ";¿INT(P*.8*#RND(1)); "PEOPLE" 450 IF INT(D/2)<=S THEN 455 970 PRINT "DEARLY LIKE TO SEE YOU ASSASSINATED BUT WE ALL HAVE OUR" 452 GOSUB 710 975 PRINT “TRIVIAL PROBLEMS."
453 GOTO 440 990 PRINT: FOR N=1 TO 10: PRINT CHR$(2);: NEXT N
454 REM *** ENQUGH PEOPLE Т0 TEND THE CROPS? 995 PRINT "SO LONG FOR NOW.": PRINT
455 IF 0<10%Р THEN 510 999 END 21
Random Graphics
Gary McGath
160 170 10 ІУО 200
210
22
FOR I=1 TO ЕГІН zi ТП PRINT " "; NEXT м PRINT
NEXT I
LET Же LET Y=1
vem, um “(1 С
NC »
A large part of the fun of having a home computer is being able to put pictures up on the display screen. This can be done on the ZX80, thanks to the graphics characters. You simply have to PRINT as many lines of the appropriate characters as you want. These characters can be generated one at a time, using the state- ment
PRINT CHR§(N); with appropriate values of N.
So you write your program, putting up as much as twenty-four rows of thirty-two characters; you run it, and in a rather large fraction of a minute, you have your picture.
LET F=xtalecy-13
РОКЕ PEEK INFLIT ХФ IF X$z"" T РОКЕ РЕЕК LET Y$=TL# IF уф= "R" IF Y$z"L" IF Y$z"D" IF Үфшы" Go TO i20
(14396) + 2S64PEEK (16397) +P, 141 НЕМ STOF
(16296) -256PEEkK (16397) +P, CODE
(Аф)
АМО ХО THEN LET X=X+1
АМО X21 THEN LET XzX-1
AND YIZO THEN LET Y=V+1
АМО Ү>1 THEN LET YzsY-1
Figure 1. The cursor can be moved around the screen to put up entertaining diagrams and pictures.
Fine. But now, suppose you want to make a small change in the picture in response to an input. You have to clear the screen and do the display all over, taking another large chunk of a minute. Having to redo the whole screen for every change can get tedious, to say nothing of making the programming difficult.
But it is possible to do better. Appendix III of the ZX80 Operating Manual tells us the location of system variables in memory. At location 16396 we find a variable called D FILE, which contains the address of the beginning of the display buffer. We can get this address by taking PEEK (16396) + 256*PEEK (16397). By doing POKEs at offsets from this address, we can manipulate individual characters at random without disturbing the rest of the display. This random access technique allows much faster small changes to what you see on the screen.
Gary McGath, 5 Ames Rd., RFD 3, Milford, NH 03055.
(ХФ)
SYNC Magazine
The first step in doing random-access graphics is to give yourself some screen memory to play with. The simplest way to do this is by PRINTing a number of lines of equal length. For example, to do 10 rows of 20 characters:
10 FOR I-1 TO 10 20 FOR J=1 TO 20 30 PRINT “”; 40 МЕХТЈ 50 PRINT 60 NEXTI You can now address specific characters in the display with some simple arithmetic. Remember that the first character in the display is always in a Newline code, and that there's a Newline code after every line. This means that if your lines are 20 characters long, each line really takes up 21 bytes of storage. Thus, the offset into the display area for row Y and column X (for a 10x20 display) is X —21*(Y-1). Since the ZX80 treats memory dynam- ically, moving things from one address to another in unexpected ways, you should POKE screen locations in the same state- ment that contains the PEEK to obtain the screen address. You can't just PEEK once to find out where the display start and assume it will stay there ever after. So, to put the character CHRS(C) at row Y and column X, the necessary statements are:
LET P = X+21*(Y-1) POKE РЕЕК (16396) + 256*PEEK (16397) TPC
This is still assuming 20-character lines.
You can do INPUTS at the bottom of the screen while playing with the display in this manner. This lets you enter com- mands to manipulate the display.
The program in Figure 1 lets you move a cursor around the screen and put graphics up where the cursor is. You operate the program as follows:
The required input is a two-character string. The first character gets displayed where the cursor (an inverted dollar sign) is; the second character, which must be L, R, U, or D, tells the cursor which way to move (left, right, up, or down). To exit from the program type a null string (just Newline).
A word of caution is necessary; Since you're doing PEEKs and POKEs, errors in random graphics programs can easily crash the ZX80. If this happens, just unplug it for a moment and try again. This will, of course, wipe out the program in memory, so you might consider saving it on cassette before testing it. It's worth the extra difficulty, though, since this technique lets you do things that never seemed possible before on the Z X80's display.
Jan/Feb 1981
The most complex computer circuit can be explained with just nine cents
The "penny switch." It sounds strange. But it's not.
Joe Weisbecker, the designer of the RCA 1802 microcomputer, was trying to explain to some children just how a computer works. He wasn't having much success.
Computers Aren't Magic
Joe's hobby is magic. He thought, “таубе | can use some kind of illusion to Show how a computer works.” But he didn't really want to use an illusion. He didn't want the chil- dren to think of a computer as magic.
So he hit upon the idea of a simple flip- flop switch (the most common circuit in a computer) represented by the head or tail of a penny. This flip-flop circuit uses just one penny. Every time it receives an impulse it changes from head to tail or tail to head. Simple.
But then Joe went on and put two of these simple flip flops together to make a circuit that adds two numbers together. And another that subtracts numbers. Kids loved these circuits and played with them like games.
Games With Pennies
Before long, Joe devised circuits to play more complicated games like Tic Tac Toe,
T
"Heads Up Game." Starting with tails in all positions, how many times through to get all four pennies heads up?
Guess A Number and Create A Pattern. Pretty soon he had 30 circuits (or games) that explained everything about computers froma basic adder to complex error correc- tion. The most complex circuit uses just nine pennies (or dimes for the big spender).
These circuits, each one with a full size playing diagram, have been collected to- gether in a book called Computer Coin Games. With this book children or adults can easily understand the workings of even the most complex computer circuits.
Games Magazine said, "whether or not you have any experience with computer technology, you'll be both amazed and de- lighted with the simplicity of the format and the complexity of the play. All you need is some common cents."
Dr. Dobbs Journal agreed, saying, “Сот- puter Coin Games is a simple approach to a complicated concept. The book is liberally sprinkled with clever illustrations and dia- grams, and provides a relatively painless route to understanding how computer cir- cuits function."
Money back Guarantee
We're convinced that you'll understand the inner workings of a computer after playing these 30 games. If you don't, send the book back and we'll refund the complete price plus your postage to send it back.
To order your copy of Computer Coin Games, just send $3.95 plus $1.00 shipping and handling to Creative Computing Press, Morris Plains, NJ 07950. Visa, MasterCard and American Express orders may be called toll free to 800-631-8112 (in NJ, 201-540- 0445).
With its wonderful illustrations by Sunstone Graphics, Computer Coin Games makes an ideal gift. The Association for Educational Data Systems calls the book "an ideal intro- duction to the concepts of computer circuitry."
Order your copy today.
creabive competing
Morris Plains, NJ 07950 Toll-free 800-631-8112 (In NJ 201-540-0445)
23
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SYNC Magazine
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Jan/Feb 1981
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“ATTACK or tHe GUTCHOIUZ^ d
A one-hour LP record of eight synthesizers may
change your views about computer music forever наннан анны а 2-2... ............ -------------- МИ TS
Binary Beatles
by David Ahl
Computer music. Who needs it? It's mostly boring beep, beep, beeps or wildly modern stuff. Its certainly nothing you'd want to listen to more than once. That's what | thought about computer music and most of my friends agreed.
In 1978 | entered Yankee Doodle Dandy into my Software Technology system just to be different. Dick Moberg heard of itand asked me to perform in the Philadelphia Computer Music Festival. І agreed expecting to be the only one with something out of the ordinary. | was wrong.
Computer Accompanist
Nine individuals and groups performed in the festival. There were the usual Bach pieces but even they were different. Gooitzen van der Wal performed the last movement of the 2nd Bach Suite in à unique way. He played the flute solo while using the computer as accompaniment.
Then Dorothy Siegel did the same thing, playing the clarinet solo part of Wanhal's Sonata in b flat. The audience went wild.
Hal Chamberlin played Bach's Tocatta and Fugue in d minor. Butalso with a differ- ence. He used a large computer before hand to "compute" the waveform of every
instrument playing every note. It took one hour of computation time for each two min- utes of playback time. The result could hardly be distinguished from the organ in the Hapsburg Cathedral.
Don Schertz had a home brewed synthe- sizer truly mounted on a breadboard that allowed him to control 25 parameters of each note. It produced spectacular sounds in his arrangement of Red Wing.
Singing Computer
In 1962, D.H. Van Lenten at Bell Labora- tories produced the first talking computer. Bell engineers taught it to recite the soliloquy from Hamlet. Then they went one step further and taught it to sing Daisy both alone and accompanied by another computer. This was also performed at the festival.
Yes, the Beatles were represented. Andrew Molda played Hey Jude on his COSMAC VIP system with a program called PIN-8 (Play it Now).
Superb Quality Recording
All these pieces and twelve others were recorded with broadcast quality equipment. Because of audience noise, eight were re- recorded later in a studio. We then took these tapes to Tru-Tone, a top recording
“This Book is Excellent!"
— Clive Sinclair
The unique book contains 30 programs all designed to fit in the basic 1K version of
the SINCLAIR ZX80!!
With this book you will realise that the ZX80 is more powerful than you ever imagined!
112 pages packed full of solid information!
BLACKJACK — actually contains a full pack of cards, shuffles them, keeps track of the dealer and player totals, and the money bets, all within 1K. Dr. ZX-80 — a truly conversational program: DR. ZX-80 is your personal computer
analyst.
LINE RENUMBER - an invaluable program which automatically renumbers lines
and puts order to your programs.
MEMORY LEFT — an incredible routine especially useful with only 1K, which lets you know to the byte how much memory is left. This also illustrates USR routines.
GOMOKU - the computer challenges you to this complex Japanese game, incredibly this program including display of the 7 x7 board fits into 1K — it only does so because
it uses the display as memory!
Other programs included are HORSE RACE, LUNAR LANDER (with moving spaceship display, NOUGHTS AND CROSSES, NIM, SIMPLE SIMON, HANGMAN, LIFE:
MASTERMIND, PINCH and 16 others!
available $ 1 4 95 Other шыңы ° include:
by mail нбр insane 2Х80 Machine Language
order only and handling) ны
studio and cut а lacquer master. It was а long session since the recording engineers insisted upon analyzing the sound from every source and setting up the equilization curves accordingly. It took over 12 hours to produce a one-hour lacquer master.
Finished recordings were then pressed on top-quality vinyl and inserted into liners and record jackets. These were then shrink wrapped in plastic for maximum protection. We guaranteee that every LP record is free from defects or we will replace it free of charge.
The extensive descriptions of each of the eight synthesizers and the festival would not all fit on the jacket so we've included ап extra sheet with each record. This entire package is mailed ina protective corrugated package to insure that it reaches you in mint condition. The cost is a modest $6.00 postpaid in the U.S. and $7.00 foreign. Send order with payment or Visa, MasterCard or American Express number to Creative Com- puting, Morris Plains, NJ 07950.
This LP record contains one hour of eight computer music synthesizers that you'll listen to over and over again. Send in your order today at no risk whatsoever.
creative competing
Morris Plains, NJ 07950 Toll-free 800-631-8112 (In NJ 201-540-0445)
MELBOURNE HOUSE
Orders 10: IMAGE COMPUTER PRODUCTS
PUBLISHERS 615 Academy Drive, Northbrook, ІІ. 60062. Please send me copy/ies of '30 Programs for the ZX-80: 1K NAME ADDRESS
Jan/Feb 1981
Please encolse Check or Money Order for $15.95
29
Castle Doors
Weldon J. Horton Ph.D
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| FRINT z FRINT
а PRINT "WELCOME ТО CASTLE DOORS" & PRINT
о LET EzRND (200) --Wizard’s strensth--
10 LET CzRND 620) ——Ztartins strength af Plaver-- 12 PRINT
14 ЕКІМТ
16 FRINT “YOUR STRENGTH IS "ee
18 PRINT
20 РКІМТ
27 PRINT "PRESS 4 TO ОРЕМ à DOOR, PRESS Š Tü FIGHT THE WIZARD" 24 RANDCOMIZE
z6 LET D=RNO 62) --Поог selector--
we LET Ao -—Initializes monster strensth--—
30 LET E=RND (20) --Шіге of acceptable bribe--
лр LET F-RND (100) --ПСрапсе af settins caught an run option 34 LET G=RND C232) ——(Gain in strenath on шіп over manster-— ло LET HRNO C132) ——Lass ӘЖ strensth an гып aption--
= INPUT 0 40 ELS | THEN GOTO 176
42 IF (шшщ
44 IF П=1 THEN LET A=RND (20) ——Ztrenseth of monster in line belaou-- & IF П-і THEN LET A$=" CYCLOPS" -——-Manster name--
Ай IF Пе? THEN ñ=RND (20)
О IF Пе? THEN LET Aa$-"WITCH" usaba . "ез e = = - E - astle doors is an adventure game tha ija IF ii THEN LET ñ bese ( 49 Қ presents a new challenge with each play- 24 IF D=% THEN LET A$= DRAGCUN ing, and the opportunity for easy adjust- “5 IF D4 THEN LET А= (50) ment of difficulty if the Wizard is winning So IF D-4 THEN LET A$-"GAaRGÜYLE'" too much, or too little of the time.
40 IF [i= THEN LET A=(40) You, the player, have the ultimate task 1n оше qu EM + | Meroe ‘eh of defeating the evil Wizard, but first you isa МЕ Li THEN bET po TE — - must gain strength and experience by 54 IF D-& OR Пе7 OR Des THEN GOTO 160 confronting the strange denizens of the һо PRINT Wizard's enchanted castle. Behind each а PRINT door of the castle lies a new adventure. 70 PRINT “YOUR OFFÜNENT IS He АФ Some of the castle dwellers are friendly,
м PRINT (like the Fairy, who gives you a magic
otion that doubles your strength) but 74 PRINT ú T gth)
76 PRINT ^ YOUR STRENGTH IS "#0 Weldon J. Horton, 3215 W. Degan, Midland, TX c PRINT 79701.
30 SYNC Magazine
&0 PRINT
22 PRINT "YOU MAY: FIGHT=1 BRIBE=2 RUN-3" 84 ІМРЫТ М
CL
IF Nez THEN GOTO 124
e
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IF Мез THEN GOTO 142 У: IF C«à THEN GOTO 174 74 FRINT v6 PRINT
"ui
: PRINT "YOUR STRENGTH IS "sc
100 РКІМТ
102 PRINT
104 PRINT "HOW MUCH STRENGTH Ші YOU WANT ТО FIGHT WITH?"
106 INPUT É
108 CLS 107 РКІМТ 110 РКІМТ 112 IF QC THEN GoTo 74 114 IF Ш>А OR Gà THEN LET GCzC-G 116 IF QLA OR ü= THEN PRINT "YOu WIN BRAVE ALDVENTLURER " 112 IF Cñ THEN LET C=t-—nm 120 IF ОА THEN FRINT “You LOSE ТО THE "АФ 122 GOTO 12 124 PRINT lz6 PRINT 122 PRINT "YOGUR STRENGTH IS "sc 130 FRINT Ize FRINT "HOW BIG A BRIBE ПП you WANT та OFFER?" 134 INPUT F 136 CLS 138 IF PLE ПК Р-Е THEN LET C=C—F+6 140 IF FE OR FzE THEN FRINT"BRIBE ACCEPTED"
142 IF PE THEN FRINT "BRIBE REFUSED" 144 IF Р<Е THEN GOTO 44
146 GOTO 12
145 FRINT
150 РКІМТ
Jae IF Е-50 THEN GOTO 174
1534 PRINT "You GOT AWAY FROM THE MONSTER" 156 LET C=C—-H
138 GOTO 12
160 PRINT
162 FRINT
most offer you only of of three alterna- tives: fight the monster and pass through the door, bribe the monster to let you Pass, or you can run away from the monster.
After chosing to fight the monster, you must decide how much strength to fight with. If you lose, you lose the strength you fought with; if you win, you win addi- tional strength. If your total strength is less than the strength of the monster whom you are fighting, you lose the game.
If you chose to bribe the monster to let you pass, it may refuse your bribe, and you must decide what to do next: fight, offer a bigger bribe, or run away. If your bribe is accepted you lose the bribe and gain the same amount of strength points you would have had if you had fought the monster and won. Be warned, however, that a successful bribe can easily result in an overall loss of points.
If you chose to run away you will, natu- ralli, lose some strength. Also, the monster has a one in one-hundred chance of catching you and ending the game.
When you feel that you are ready, you may chose to fight the evil Wizard. The battle is short, fierce, and has the imme- diate outcome of either total victory or defeat.
This program is written in such a manner as to make the adjustment of all strength and penalty values quite easy. Messages printed in the course of the program run have been adjusted to print correctly on the screen by the addition or delection of internal spaces. Comments have been added to the program listing in order to identify those values that you might want to change as you become more familiar with the program, in order to customize it to your preferences. You will note, that even if you are called upon to fight the same type of monster twice in a row, that each individual monster with- in a type posesses individual character- istics, withing the set limits. Only the power of the evil Wizard remains con- stant during each game.
164 IF L-& THEN FRINT "SAVE А FRINCESS AND GAIN. 50 POINTS"
166 IF D=4 THEN LET CzC-50
16е IF D=7 THEN FRINT "FAIRY GIVES YoU А MAGIC
THAT DOUBLES YOU STRENGTH" 170 IF D=7 THEN LET C=C#2
FT TON
172 IF D=& THEN PRINT "А GIANT BAT CARRIES YOU TO ANOTHER DOR:
174 GOTO 12 17& PRINT 178 FRINT
150 IF СОВ OR C-B THEN FRINT "THE WIZARD IS DEFEATED-YOU WIN" cz IF CCR OR CJA ОК F=50 THEN PRINT "YOu FOUGHT BRAVELY,
BLUT WERE DEFEATED-GAME OVER" 124 STOP
Jan/Feb 1981
Draw a Picture
Howard Branch
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A new house. A new neighborhood. We've all been through it. Last time, I remembered, it took me two or three years before I met most of the people on my block. This move, I was determined that would not happen.
My solution? An open house a few weeks after I moved in. It forced me to get settled fast; I didn't want my neighbors climbing over packing cartons.
I didn't know how many people to expect and whether I'd be able to entertain them all at once, so I set up two computers (borrowed from work) on the lower floor. One was an Apple, the other a ZX-80.
Naturally the Apple equipped with two ALF music synthesizers playing stereo music (accompanied by spectacular color graphics of the notes being played attracted the most initial attention).
But then some people discovered the Sinclair in the other room. “What's this?" and "It can't be a real computer" were the typical comments.
I had seven or eight games on tapes, some of which I loaded in and demon- strated. Some people were interested. Others started drifting back to the wine and cheese. Then I loaded in Draw a Picture.
This was the first program I had ever keyed into the ZX-80. I was looking for a short program to try out the machine, and I was interested in the graphics. This seemed ideal. And so it was.
Within 15 minutes I had made a face. (Why is the first thing one usually drawas with paint, computer or charred stick usually a smiling face?) I changed the expression, ears, nose, eyebrows and all the other features at least five times. What fun [| think I skipped lunch that day.
My guests also made faces on the ZX- 80. First a happy face. "Oh, let me try" said one previously timid woman. She made a face with a large beard. Another woman felt that a squarish, robot-type face was more appropriate.
SYNC Magazine
At this point I broke through the crowd and quickly “drew” a small dog. After all, I reasoned, computers can do more than draw faces. But alas, they would have none of it, and I was unceremoniously elbowed aside for yet another face.
As the guests drifted out, I noticed that the computer crowd downstairs was show- ing no such inclination. Interestingly enough, this time the Apple had been deserted and the crowd was around the ZX-80 with Draw a Picture.
You too can draw faces with your ZX- 80. You can draw small dogs, or even other things like boats, flowers and space ships. But don't try to do it with a crowd standing around; all they want are faces.
Draw a Picture is from 30 Programs for the ZX-80, published by Melbourne House, Glebe Cottage, Gleebe House, Station Road, Cheddington, Leighton Buzzard, Bedfordshire, England, and costs $14.95 in the U.S. or £ 7.45in the U.K.
11 12 13 14 16 16 T1 GV 62 63 64 bG be 67 21 52 93 94 55 5b 51 41 42 43 44 45 44 47 31 32 33 34 35 36 37 21 22 23 24 29 2b 27 1 12 13 14 15 te 17
When the program says "ENTER COORD,” enter a single number from the grid numbering diagram. If you enter 0, the program will give you a summary of what codes you used at each location. When the program says “ENTER CHAR CODE," enter the code of the graphics character you want to appear on the screen. If you want to erase a previous character, enter 0.
Jan/Feb 1981
AVAILABLE FROM THE KEYBOARD:
2 5
10
S NEM Bim inl
Ж
NOT AVAILABLE FROM THE KEYBOARD:
128 am 129 E 130 ú 131 на 1% m 152 L 134 = 135 gm 136 a 142 B
QTHER USEFUL ‘GRAPHIC’ SYMBOLS: 6 £ 18 - 19 +
20 * 25 у 24 <
33
|. Pounds and Pence, Dollars and Cents
Leonard Gaunt There are ways of getting round the problems. A useful educational program, for example, is to teach kids to add up
dollars and cents, or what have you. That can be done in a relatively simple manner, as Program 1 demonstrates. This is
The new ROM for the ZX80 may be available before these a program that goes on indefinitely setting new sums. words are in print. It remedies a lot of the defects of the This program is self-explanatory; It asks you to add four original ROM. It gives floating point facilities, trigonometric randomly produced amounts from 1.01 to 99.99. functions, keyboard access to reversed characters and many It asks you to print the answer using Newline instead of the other useful functions. decimal point. Subroutines line up the decimal point, produce the 0 after For those who still have the old ROM, there is no way of the decimal point where required and add the whole numbers dealing with pounds and pence, or dollars and cents, is there? and the decimals separately. Your answer and the correct | answer are printed and you аге told whether you are right or As a matter of fact, the answers are ‘yes’. wrong. —C————————————À You are then invited to press Newline for another sum or S Leonard Gaunt, 44 Hatherop Rd., Hampton, for you Score. Middlesex, TW12 2RF. The program produces new sums indefinitely. 1 LET . = © = LET F = б 2000 INFLT ñ = PRINT "ADD" 2005 PRINT ыз “езен а 10 LET T = Q SOLO PRINT » 2 Аз"; сә LET T2 = 0 лого INPUT E ea FOR Mo d TU 4 лога IF B < 10 THEN PRINT "O"sE a0 LET ñ x ЕМО 3026 IF NOT B < 10 THEN РКІМТ В 404 LET AS = КМОСУУ) 3031 PRINT го LET X = а 3032 PRINT &O LET Y = AZ 2028 PRINT "THE ANSWER IS "3 75 LET T = T+A 3040 GOSUR 2000 шо LET Tz = ТЕ + ñz лоо PRINT 70 GOSUE 2000 3070 IF à = X AND Е = Y THEN GOTO 4000 100 NEXT М 3100 PRINT "ҮШІ WERE WRONG" шо LET X = T 3110 LET F = FE + 1 311 LET Y = Т2 3120 GOTO 4040 clo FRINF | 320 PRINT 4000 PRINT "THAT IS RIGHT"
371 PRINT "PRINT YOUR ANSWER" 4010 LET J= J 1 327 PRINT 323 PRINT “PRESS NEWLINE INSTEAD OF" 7 4040 PRINT | зге PRINT "THE DECIMAL FOINT" 4050 PRINT "PRESS NEWLINE FOR ANOTHER ум" USO Glee SOOO 4055 PRINT 4054 PRINT "OR 5 FOR YOUR SCORE" 2000 IF Y < 100 THEN GOTO 2035 gang INPUT 7% a age M _ ш 4055 CLS et NS 4070 IF 7% = "" THEN GOTO 5 UO. Mis eue 4080 IF 7% = "S" THEN PRINT "YOU GOT "sd:
E Q 73 72: F : I N T .. eoe .. ші n. 2033 FR " RIGHT AND ": Es" WRONG" 2... IGHT AND ": Ks" WR
2038 IF X « 10 AND Y <= 10 THEN FRINT » + " "3X3" , О"; 2040 IF X < 10 AND NOT Y < 10 THEN PRINT » > " "$XS"."3 2050 IF NOT X < 10 AND NOT Y < 10 THEN FRINT , ə X5"."3 2060 IF NOT X < 10 AND Y = 10 THEN FRINT » + Xs:".0"5 Y 2070 RETURN
СИ eee “owe” “sae
<<<
34 SYNC Magazine
10
ж
FRINT INFLIT DLE
LET X FRINT РКІМТ FRINT РКІМТ ІМРІШТ
"WHAT Іс YOUR МАМЕ?"
АФ
= (Q
"ТИТ YOU WANT EASY, ñ LITTLE HARDER, OR DIFFICULT MURS TIONS?"
"TYPE E FOR EASY; H OR D
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г.“ +. = а ^ € . . e * . Ж а Тор ht Та tt ii 137
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400 410 qzO qo 440 430 4) 470 4330 auo mOO alo an MIN 40 ы)
a t Q
CLS
PRINT РКІМТ РКІМТ РОК 2
"OK, "A$
"HERE ARE 10 GUEZTIUNZ" 1 TO 10
LET à RND CIO)
LET В RNDC 103
IF A < 2 OR E <= 3 THEN GoTo IF BS "п" THEN LET A = AHS IF BẸ "о" OF BS = "HR" PRINT
FRINT
FRINT "ИНАТ IS "jA" INFLIT T
l H d
H H
LIMES
IF T = А#Б THEN GOTO 240 DOLIO GEO MENT
FRINT РКІМТ LET X = X + 1 NEXT Z
GOTO B40 CLS FRINT “WRONG, FRINT ". PAF” FRINT NEXT Z FRINT ЕКІМТ FRINT FRINT PRINT FRINT FRINT PRINT FRINT РКІМТ “ТҮРЕ Y FOR YES I М INFUT ПФ IF D = CLE РКІМТ РКІМТ РКІМТ FRINT РКІМТ ЕКІМТ FRINT FRINT ;
“RIGHT”
"ТАФ TIMES
"THAT IS ALL. "SA
"VOLE ШГПЕЕП
"Ха"
"ПО YOU WANT
"Y" THEN GO TO 30
"THANE YOU, "SAS
"GOODBYE FOR NOW"
Jan/Feb 1981
1 50
THEN LET
"SB
E AKE
CIT ПЕ 10" ANOTHER 107"
FUR МП"
"GUT PLEASE СОМЕ ВАСЕ"
E = Es
Multiplication tables
I haven't yet got round to making the ZX80 multiply and divide decimals but Program 2 is a simple ‘multiplication table’ teacher. It is a ‘talkative’ program offering three grades of difficulty, setting ten questions, giving the score and inviting further participation.
g l|
| «
— | —
"When you're through Dad, I want to write a | program to experiment with the effect ој а different coefficient on a plot of a polynomial of the form Y (X( = A*X + B*X + С.”
35
le Ж |. L. == 10
i W = L. GL 4 L.
DG
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= . ~ 4 et £ + £ 2 ~ > °
E e.
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— С - "m. >
2
110 10 12203 140 130
4. 1527 140 170 195 QOO <10 zi 27 290
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Ea Pai fai і
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Vo oM D 3
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e = к
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36
ET ll = Q
ЕТ Joco
ET H = б
ET Hz = (о
ET G = б
ET Gl = 0
ET K = Q
ЕТ Hzc ©
ET L = Q
LET Le = ©
LET M = Q
LET МЕ = 0
LET Z = ©
LET 22 = 0
FRINT "ACUCLULINT еР
GCSB 500
ЇМЇТ A$
IF А5 = "T" OR A$ = "TC INFUT EB
INPUT Bi
IF E <= О THEN LET Ez = - INFLIT C
PRINT AS:
LET I = 13 LET X = B
LET Y = Би GÜUSLUB 2000 ПЫН 1000 OSB SOR LET Z = Z + B LET 22 = ZZ + Бу LET I = 22 PRINT L
ИС MOCNO GETO Eo
GOSLIB AQ FRINT "TOTALS S$ LET I = 13 LET X = Z
LET Y = 22 BOSIB SOOO GOSIER 2000 nostis 1000 GESIE ZOSO0
At GUTE & PRINT PRINT PRINT LET X LET Y GOSE PRINT LET X LET Y lis Lis
PRINT LET X LET Y
= " T e ti Q0
"CATEGORY CITTA
= H
= На
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TOTALS"
CATEGORY"
" THEN
3495
СЕЕ
Basic Accounting With Decimal Currencies
Program 3 is very complicated. It keeps accounts, in a way. It prints out the account name or number, adds and subtracts cash amounts, splits them into categories or groups, gives one grand total and six sub-totals. Of course, it is rather limited by the availability of display space. The ‘Continue’ facility can be used but it really needs a printer.
This program allows the entry of account number, name, etc., plus a column of pounds and pence, or dollars and cents, and a category column.
The amounts can then be totalled in one grand total and six subtotals by category number.
a 20
Data entry is in the form: 1 Account number, name, etc. (any string) —пем пе
2 Pounds/dollars — newline — pence/cents — newline
3 Category of account (any number, normally 1 to 6) —new-
line
Note that the decimal point is not used but that .50 must be entered as 50 and not 5 as in calculator usage. The entry of a single figure after the decimal point is treated as one-
hundredth part, i.e. 5 is treated as 05.
Debits (minus figures) are entered in the normal way e.g. -2566 newline 09. There is no need to put the minus sign before the decimal entry.
After the entry of the category number, the details in 1,2 and 3 are printed. Repeat for as many entries as required.
When all entries have been made, enter: T newline to obtain main total only OR TC newline to obtain main total and subtotals
If further entries or corrections are necessary, enter
C newline
and repeat 1,2,3,T or TC. The amounts entered are added to the previous totals.
The program uses several subroutines for tabulation, to persaude the ZX80 to add and subtract decimals and to ensure that the results are printed correctly.
400 404 доз az 430 440 450 450 aeu OO 305 210 GO
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=
PRINT LET X LET Y PRINT LET А LIST Y GUSLIB FRINT DOSJE ІМРІШТ РКІМТ IF Еф
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SYNC Magazine
600 FOR N = 1 TU SF 610 PRINT "=";
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1000 1010
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£ 87%
RETURN FRINT
IF I + РЕЕК(16420) THEN IF PEER
о... 559
IF I Q GOTO 1040 ІР Y < 10 LET Y = Y
LET X = X HOTO zOOO
RETURN ЈЕ Y < IF Y < IF Y > IF МОТ RETURN
10 way ш Y
IF С = 1 ЈЕ С = 1 IF Ü = Z IF С = p ЈЕ С = 3 ІК C d ЈЕ £ = 4 ЈЕ С = 4 IF £ = m ЇР C = Б IF С = 4 IF C = 6
RETURN
IF Y > -1
LET Y = Y LET X = X
Фе. |. 22.
DOTÉ 4000 RETLIRN ` Y
LET Y = LET X = X
СТО YOO
LET X = X LET Y = Y GOTO VOTO
Gis Lis GOSE GEJE RE TURN
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+ 1
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THEN 100
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29 4-2 1 о 5. 3
3 THEN 16420) < 2
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Y < Q THEN FRINT
THEN FRINT X:"."sY&-1
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THEN THEN THEN
. THEN
THEN THEN THEN THEN THEN THEN THEN THEN QQ
+
о
1
1
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2000
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IF Y < о AND X
IF X 2 IF X < RETURN
[)
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Jan/Feb 1981
AND AND
Y Y
ү THE
LET LET LET LET LET LET LET LET LET LET LET RET
THEN 100
100
100
a - ке *-
Q THEN PRINT X PRINT Xs"'","sYs
N
G = G Б G2 = G? + ва H =H + B
2 = He + B2 oc | + E da = d7 «ОР? К = K + B орош KE + ВІ L = L + B
п Lae p3 М = M + B М2 = M2 + ВІ
Gara 6040
Q THEN GOSUB 4000 QO THEN GOTO 6300
О ТНЕМ BOT 700
RETURN THEN RETURN
APUQ YG
2.0: YS]
T-SHIRTS! Proclaim the computer of your choice on your chest with our own Crash Cursor and Sync.
Design is silver on dark blue shirt for a striking effect. Available in adult S,M,L and XL. $6.00
postpaid in U.S.A.; 3.00 postpaid in U.K. Send U.S. orders to SYNC, 39 East Hanover Ave., Morris Plains, NJ 07950. Send U.K. orders to SYNC, 27 Andrew Close, Stoke Golding, Nuneaton CV13 6EL.
Adding an LED Load Monitor to the 7Х80
Cecil Bridges
The input signal level is critical when loading a program from cassette tape. Save and Load operations can be done with the computer as it exists: One estab- lishes the correct volume control setting on the tape recorder by trial and error. One then secures the volume control in the correct position with sticky tape, or makes a couple of index marks which allow the recorder to be set properly. If one's tape recorder batteries age, or if one tries to load a program recorded by someone else, then a new level has to be re-established by trial and error.
An alternative is to use a load monitor to show when a program to be loaded is at the correct level. Initially, I dedicated an oscilloscipe as a load monitor, but this seemed like overkill, particularly in view of the size discrepancy between the 'scope and the computer. I then added a single LED (light emitting diode) to the tape "ear" input of the computer. The voltage for lighting the LED is just right for loading a program from the cassette tape.
In order to add the LED, it was neces- sary to get the top off the computer. This was no problem for me because I had already destroyed the plastic rivets in attempting to assemble my Microace, and had substituted small screws. You may want to add the Microace 2K RAM option at a later date, and screws look better than the rivets anyway, so very carefully drill out the five rivets around the outside of the top cover, taking special care not to damage the printed circuit board. Get out your soldering pencil and thin rosin core solder. The LED can be soldered into the printed circuit board from the top if you want to
Cecil Bridges, 1248 N. Denver, Tulsa, OK 74106.
38
avoid taking out the rivets holding the board to the bottom of the case. The short lead on the LED is attached just below the input (“ear”) jack at the point marked X in the illustration and the long lead attaches at the point marked Y. You will probably have to extend the leads of the LED with fine insulated wire. Drill a hole in the top of the case where the LED will stick through. Use insulating tape on the bare lead wires of the LED and assemble the case.
To minimize any interaction with the input circuit, use small LEDs which draw less current and have less capacitance than the large ones. I found mine, red, about 2mm in diameter, at Radio Shack. Be careful when bending the leads of these little LEDs; any strain on them will break their little red plastic cases.
In use, the LED will just light up when the tape recorded program is coming in at the correct level, and will remain dark or barely flicker when it is too low for the computer to accept.
I used the single LED load monitor for a while, but later added two additional components to make a more elegant monitor. A second LED was added in parallel with the first, with a silicon diode in series with it to drop the voltage slightly. See the wiring diagram in the illustration. The second LED then acts as an over-voltage indicator when it is lit. The 3/4 volt forward conduction voltage drop across the silicon diode makes a fairly precise bracket for the input volt- age. Solder the second LED and the sili- con diode to the lead extensions of the first LED, not to the printed circuit board.
Setting the correct tape recorder volume level for loading is now simple. Given a taped program recorded at some unknown level, the volume level is in- creased (while the tape recorder is play- ing back the recorded program) until the first LED lights up and the second re- mains dark. Rewind the tape and it should then load successfully.
Y
SYNC Magazine
30 Programs for the Sinclair ZX-80 —
New Peripherals from Sinclair |a Review
Printer
"Extremely low cost." That's the answer I got when I asked Nigel Searle about the forthcoming Sinclair printer. Relentlessly, I pressed for more.
It is a line-at-a-time printer and only prints a line when the user hits NEWLINE. "Seems awkward," said I. "Extremely low cost," said Nigel.
It has a 32-character line, the same as the display. "That means non-standard paper,” said I. “Extremely low cost," said Nigel.
The printer uses a dot matrix and prints the complete ZX80 graphics character set. "Very nice," said I. "Yes," agreed Nigel.
Flat Screen Display
When I interviewed Clive Sinclair last fall, he indicated that the major research program at that point was flat screen television. Nigel Searle informs us that working prototypes have been produced and that a factory is now being built to produce the units. Production units are expected by December 1981.
The CRT measures 3 inches across the diagonal. Sinclair is currently considering a projection device to increase the effective picture size to 5 inches. The CRT tube is an astonishing 3/8" thick.
A standard, but miniature, projection gun shoots the beam parallel to the surface of the screen and it is then bent. The principal itself is not new, however, this is the first time it has been successfully executed.
Clive Sinclair was emphatic that the company would not introduce anything that was not price competitive with existing technology. However, he would not elaborate on the price of the flat screen TV in September when we talked. Now, with four months of additional experience with the unit, Nigel tells us that the original retail target price was $125 ог £ 50. This was for a broadcast TV receiver. (Existing conventional 3" units now on the market carry retail prices of $200 and up.) How- ever, more good news. It appears Бу employing a highly automated production line, the original target price can be beaten down some 40% to $75 ог £ 30.
Jan/Feb 1981
Sinclair Withdraws 8K Basic ROM
We read with interest іп Computer Weekly that Clive Sinclair has withdrawn the 8K Basic ROM chip for the ZX-80 until the first quarter of 1981. This occurred only a month after it was announced to the world (September 11, 1980). He denies rumors that software bugs are the cause and blames the delay instead on the incorporation of extra functions.
The 8K ROM chip is supposed to directly replace the original 4K ROM even though there is no upward compatability between the two slightly different Basics. When it eventually appears, the ВК ROM will enable the ZX-80 to work in floating point arithmetic to 9-digit accuracy.
The extra functions now being incor- porated in the chip mainly consist of a printer driver. The printer is planned for introduction in the first half of 1981.
In explaining the product announcement and subsequent withdrawl, Sinclair stated, “We were caught out. We wanted to bring out the 8K as soon as possible, but on the other hand we did not want to be severely critisized at a later stage when we would have to bring out another version."
8K Basic ROM
Originally announced in September 1980 and then withdrawn, the 8K Basic will probably be out by the time this is printed.
The new one differs from the original in that it incorporates a printer driver routine and one other new feature about which Sinclair is being quite secretive. Some minor functions were cut out of the first version to make way for these two new features.
Sinclair either doesn't know or isn't saying whether the 8K Basic will work in the MicroAce. Apparently there is no love lost between the two companies even though they have a rather close business licensing arrangement. Reputable sources tell us that, indeed, the 8K ROM will work in the MicroAce.
David Lubar
30 Programs for the Sinclair ZX-80, by Melbourne House, Glebe Cottage, Glebe House, Station Road, Cheddington, Leighton Buzzard, Bedfordshire, England, distributed in the United States by Image Computer products, 615 Academy Drive, Northbrook, IL 60062, 111 pages, paper- back $14.95. 1980.
30 Programs for the Sinclair ZX 80 published by Melbourne House, contains games and utilities that will run in 1K of memory. But the book is more than just a collection of programs; it is a storehouse of valuable techniques and tricks. While many of the programs are entered in the usual way, some are entered in ways that expand the capabilities of the Sinclair. For example, several of the programs come in two parts. The first part accepts inputs which are stored as data for the second part. In "Lunar Lander," these data are used to draw the rocket ship. In "Dr. ZX- 80" (see Creative Computing's More Basic Computer Games for the original Dr. Z), the data are used to store strings in memory.
These techniques alone make the book worthwhile. Add to this the fun of the games themselves, from a simple "Leap Frog" to the complex programming of “Gomoku,” and you have a bargain that should be a part of every Sinclair owner's library.
The listings are presented in clear, large type. The numbers are larger than the letters, thus avoiding confusion be- tween zero and the letter O, as well as one and the letter I. Each program is preceeded by a description which covers any special techniques used. The only shortcoming is the lack of sample runs. It is always nice to see what a program does before going to the touble to enter the whole thing. Also, sample runs can help show where you went wrong if there is an error in your typing. Despite this, the book is highly recommended.
You will find two programs from the book reprinted in this issue of SYNC. "Life" and "Draw a Picture" were re- printed courtesy of Melbourne House Publishers. |
39
Linsac' s Game Programs 1 and 2
А Review
Jonathan A. Stein
Linsac of England is now producing software for the Sinclair ZX-80. In addi- tion to publishing the book, The ZX-80 Companion, they are marketing a series of educational and game cassettes, all of which are reaching The United States through Image Computer Products, 615 Academy Drive, Northbrook, Illinois 60062. In the U.K. they are available di- rectly from Linsac, 68 Barker Road, Middlebrough TS5 5ES, England.
Although there are five games cas- settes packages, we chose to look at the two for the 1K computer, since this is the most common version of the machine. We will reserve reviewing the educa- tional cassettes and the games for the 2K version until a later date. Games Pack One includes Three Towers, Number Guessing, Mastermind, Sketches, Hurkle, Nim, and Simple Simon.
Three Towers is a version of the game Tower of Hanoi, in which the object is to take six graduated rings and move them from the first of three rods to the third, without ever placing a larger ring on top of a smaller one. The game is difficult until one figures out the system needed to make it work, although it continues to be time consuming. If, however, you make an improper entry, the program is unfor- giving, sometimes forcing you to begin again.
The second game on the cassette is Guess a Number, which has the player deduce a number between 1 and 100 based on hints offered by the program, which tell the player whether his or her guess is above or below the value of the number trying to be guessed. This game should be particularly interesting to a child, but for an adult it is a bit limited.
40
Mastermind is a version of the popular board game of the same name. The ma- chine selects a four digit code which you try to solve. After you enter your guess, the computer responds, letting you know how many digits are correct and in the right location, and how many are correct, but improperly situated. The game is ex- tremely challenging, and made more dif- ficult by the way in which it treats dupli- cated digits. For example: if the code contains two zeros, and you only have one in your guess, the machine will tell you that you have one digit in the right place and one in the wrong place.
In Sketcher, an introductory program for computer graphics. The player is given a 31 x 16 grid, on which he can enter designs. As a first encounter with compu- ter drawing, the program is very good, and can be a delight to small children and of interest to adults.
Linsac’s version of Hurkle is a pleasure to play. The player is given a 15 x 15 grid in which a Hurkle is hiding. To find the Hurkle one must pick X and Y values corresponding to the location of the beast. With only five guesses, you must quickly follow the hints provided by the computer. To keep track of your path, I would recommend writing down both your guesses and the computer hints.
Nim is another game on this cassette, in which the player competes against the computer by taking stones away from several piles. The object is to be the last player to take a stone. The human player has the option to establish the number of piles, and the number of stones in those piles. The game is pleasant, and can often be challenging.
Symbol Simon is the final game in this series. The computer establishes a pat- tern of letters, numbers, ог graphics,- depending upon your selection. The game is fairly easy, because it just entails repeating what the program presents.
The second Linsac game package offers several more challenging games and exercises than does the first selection of games. It includes Nine Lives, The Maze Game, Plain Sailing, Noughts and Crosses, Chinese Puzzle, Tower of Hanoi, and Battleships.
The first game is Nine Lives, a version of the children's game Hangman. Two people play, using the machine as both the paper and the scorer. The first player enters a word, and the computer tells the second person the number of letters in that word by displaying a dash for each character. With each incorrect letter entry, one of nine lives is lost. The game continues until the word is completed, or until all of the lives are gone.
The Maze Game, the second game on the tape,is one of the better Linsac games I sampled. The object is for the player to find his way through a constantly chang-. ing maze to a treasure. Quite often the maze closes in to make reaching the booty impossible. After the game ends, either by winning the treasure, or by con- ceding defeat (by entering 0), the compu- ter posts the score out of a possible 18.
Plain Sailing is the third “game” on the cassette. Actually more a mathematical exercise than a game, it entails sailing a dinghy, with a top speed of six knots through a chanel four miles long and two miles wide. The sailor selects the wind speed and direction, as well as the tidal force and direction. After entering this information the player must determine the length of time and number of tacks needed for the journey. The computer then posts the actual number of minutes and tacks required. Although this is really not a game as such, it is extremely interesting, requiring a good deal of thought and attention.
SYNC Magazine
The fourth game, Noughts and Crosses, commonly known as Tick Tac Toe, offers the player more of a chal- lenge than one usually expects from this game. The ZX-80 version of this old fa- vorite requires a different kind of strategy than when the game is played against a human opponent, because the machine is so consistent. For instance: If your first move is in the center square, the ZX-80 will always play the lower right square. If however, you choose any square but the center, the machine takes the center position. The machine will consistently win unless you take a radical plan to keep you moves on the offensive. Once you are forced into a defensive position, the machine will win, or you will draw.
The next game, Chinese Puzzle, is a challenging game requiring a great amount of patience. The object is to slide the alphabet squares around until they are in proper order. Considering there is just one vacant place on the board, this becomes a major task. The game easily becomes frustrating, because it seems that you can never really gain ground, you just switch around the squares which are in the proper positions. The game is fairly good if you are long on patience and endurance.
Tower of Hanoi is virtually identical to the Three Towers game already re- viewed in this article. The primary differ- ences are the way in which the entries are made, and that in this game the game is won by setting up all of the rings on either the second or third rod, rather than just on the third column as in the Three Towers game. The game is moderately challenging, but one version is enough.
The final game on the cassette is Battleships, which is basically a compu- terized version of the old board game Battleship, in which the object is to sink the enemy ships on a grid marked with X and Y coordinates. The main difference between the ZX-80 version and the board version is that the player does not have a fleet of his own. This game is based totally on trial and error, as one ran- domly picks X and Y coordinates to fire torpedoes into the enemy waters. The game easily becomes tiresome, because it requires no skill or cunning, just the methodical entering of coordinates.
Both of the Linsac tape packages offer some intersting games and exercises, of which my favorites are: Hurkle, The Maze Game, Plain Sailing, and one of the Tower games. Most of the games are made a little eaiser if you use pencil and paper to record your moves. The games packages are definately worth having al- though several of the games are not terribly challenging.
Jan/Feb 1981
Sourcebook of Ideas
Many mathematics ideas can be better illustrated with a computer than with a text book.
à; А = < AR
Creative Computing Press
Consider Baseball cards. If there are 50 cards in a set, how many packs of bubble gum mustbe purchased to obtain a complete set of players? Many students will guess over 1 million packs yet on average it's only 329.
The formula to solve this problem is not easy. The computer simulation is. Yet you as a teacher probably don't have time to devise programs to illustrate concepts like this.
Between grades 1 and 12 there are 142 mathematical concepts in which the com- puter can play an important role. Things like arithmetic practice, X-Y coordinates, proving geometic theorems, probability, compounding and computation of pi by inscribed polygons.
Endorsed by NCTM
The National Council of Teachers of Mathematics has strongly endorsed the use of computers in the classroom. Unfortunately most textbooks have not yet responded to this endorsement and do not include pro- grams or computer teaching techniques. You probably don't have the time to develop all these ideas either. What to do?
For the past six years, Creative Computing magazine has been running two or three articles per issue written by math teachers. These are classroom proven, tested ideas complete with flowcharts, programs and sample runs.
Teachers have been ordering back issues with those applications for years. However,
many of these issues are now sold out or in very short supply.
So we took the most popular 134 articles and applications and reprinted them in a giant 224-page book called Computers in Mathematics: А Sourcebook of Ideas.
Ready-to-use-material
This book contains pragmatic, ready to use, classroom tested ideas on everything from simply binary counting to advanced techniques like multiple regression analysis and differential equations.
The book includes many activities that don't require a computer. And if you're considering expanding your computer facilities, you'll find a section on how to select a computer complete with an invalu- able microcomputer comparison chart.
Another section presents over 250 problems, puzzles, and programming ideas, more than are found in most "problem collec- tion" books.
Computers in Mathematics: A Sourcebook of Ideas is edited by David Ahl, one of the pioneers in computer education and the founder of Creative Computing.
The book is not cheap. It costs $15.95. Howeverif you were to order just half of the back issues from which articles were drawn, they would cost you over $30.
Satisfaction Guaranteed
If you are teaching mathematics in any grade between 1 and 12, we're convinced you'll find this book of tremendous value. If, after receiving it and using it for 30 days you do not agree, you may return it for a full refund plus your return postage.
To order, send your check for $15.95 plus $1.00 postage and handling to Creative Computing Press, Morris Plains, NJ 07950. Visa, MasterCard, and American Express orders may be called in toll-free to 800- 631-8112 (in NJ 201-540-0445). School purchase orders should add an additional $1.00 billing fee for a total of $17.95.
Don't putit off. Order this valuable source- book today.
creabive competing
Morris Plains, NJ 07950 Toll-free 800-631-8112 (In NJ 201-540-0445)
41
Resources for the ZX-80
and MicroAce
42
Presented below is a list of currently available products related to the Sinclair ZX-80. Such a list can never be complete, of course. We intend to run this as an ongoing column and in addition, we intend to expand the entries to include a description of each product. In this and other issues you will find in-depth evaluations and reviews of many of these products.
We welcome entries from manufacturers and readers for the resources column. Please include the name of the item, a brief description, price, and complete data on how to obtain it. Send contributions to SYNC Resources, 39 East Hanover Avenue, Morris Plains, New Jersey 07950.
Computers
Sinclair ZX-80 (Great Britain): ІК assembled — f 100.00 ІК kit without power source — £ 80.00
Science of Cambridge
6 Kings Parade
Cambridge, Cambs CB2 1SN England
Sinclair ZX-80 (United States): 1K assembled — $200.00
Sinclair Research Limited 50 Staniford Street Boston, MA 02114
MicroAce Computer: ІК kit — $149.00 2K kit — $169.00
MicroAce 1348 East Edinger Santa Ana, CA 92075
Hardware
Plug in RAM chips for the ZX-80. IK — £ 20, 2K — £ 30, ЗК — £ 40
Quicksilva
56 Bedíord Place South Hampton, Hants England
Software and Books
Games and technical information for the Sinclair ZX-80.
Bobker
29 Chedderton Drive
Unsworth, Bury, Lancs
England
Four cassette tapes — Е 3 each:
1. Moon-landing, Hangman, Code breaker, Inter- cept
2. Bio-rhythm, Solitaire, Battleship, Dice
3. Bingo, Minefield, Remcard, Sequences
4. Five Mathematics Programs
Bug-Byte
251 Henley Road Coventry CV2 1BX England
IK Games for the ZX-80:
Mastermind, Hangman, Simon, Computamath — £ 2 each, four for £ 5.50 incl.
АК Element Math Package - £ 7.50 incl.
Bush Green Enterprises Limited 80 Dumont Avenue
Point Clear, Essex CO16 8JR England
ZX-80 Software (games and educational): Dicethrow, Mastermind, DIV Package, Electro Bandit, Math Programs, and Word Puzzles — £ 5.00 each, three for £ 12.00
CDS Micro Systems
10 Westfield Close, Tickhill Doncaster DN 11 9LA England
Software on cassette for 1K ZX-80:
Simon, Mind Bender, Destroyer, Fruit Machine — Е 5.00, and a general mathematics program for £ 5.00
Econo Soft
4 The Loont Winsford,Cheshire CW 7 1EU England
Software for the 2 Х-80
Tim Hartnell
44-46 Earls Court Road London W8
England
SYNC Magazine
Software Cont.
ZX-80 game for 1 or 2 players — £ 1.50 in UK
R. Hindle
139 Penrhyn Road Sheffield, S11 80Р England
Offers an extensive line of ZX-80 Software. Includes Computer Learning Lab book and tape package — $49.95, a wide selection of game programs, as well as Software produced by Linsac, Melbourne House, and Creative Computing.
Image Computer Products 615 Academy Drive Northbrook, IL 60062
Games package for 1K ZX-80: K Treck, Life, Mind Master, Lunar Lander, four for $9.95, and an Introductory tape for $2.99
Lamo-Lem 712 Pidgeon Street San Diego, CA 92114
The ZX-80 Companion — $19.95, and nine programmed cassettes, of both educational material and games — $6.95 each.
Linsac
68 Barker Road Middlebrough TS5 5ES England
ZX-80 Active Display — Ғ 5.00, and software.
K. Macdonald
26 Spiers Close
Knowle, Solihull B93 9ES England
30 Programs for the ZX-80 — £ 7.45 in the UK, £ 7.95 outside the UK
Melbourne House Publishers Glebe Cottage, Glebe House Station Road, Cheddington Leighton Buzzard, Bedfordshire England
Software Packages for the ZX-80
The Software House 146 Oxford Street London W1 England
Games for the ZX-80, three cassette packages — £ 4.95 each
Syntax Software
96 Collingwood Gardens Giants Hill
Ilford, Essex
England
Jan/Feb 1981
ZX-80 Magic Book — £ 4.75, and ZX-80 memory and I/O boards
Timedata Limited 57 Swallowdale Basildon, Essex England
ZX-80 Teaching Aids: 2X to 10X times tables on cassette — £ 5.00 Higher level teaching programs — Ғ 5.00
Turner Consultants
Falconsbeck
Holbeck Lane, Windmere, Cumbria England
20 ZX-80 Programs, a book for £ 5.25 cassette and book for £ 11.00
Zipprint
11 Romsey Road Winchester, Hants England
Users Groups and Newsletters
Publishes Syntax Z X-80
12 month subscription — $25.00 in The United States, $39.00 in Western Europe, and $30.00 in Canada.
The Harvard Group RD 2 Box 457 Bolton Road Harvard, MA 01451
Bi-monthly newsletter, low cost software, sub- scription — £ 6.00 in UK, £10.00 overseas
ZX-80 User's Club
c/o D. Blagden
P.O. Box 159
Kingston Upon Thames, Surrey KT2 5UQ
England
Seeks to create and share software for the 1K ZX-80. Membership is free (enclose postage). Publishes the newsletter, Interface.
ZX-80 User's Club с/0 Tim Hartnell
93 Coningham Road London W12 England
SYNC cannot vouch for any of the sources listed above. We welcome objec-
tive, in-depth reviews of any of these items and others related to the Z X80.
43
| | | | |
The Sinclair ZX80 is innovative and powerful. Now there's a magazine to help you get
the most out of it.
SYNC magazine is different from other personal computing magazines. Not just different because it is about a unique computer, the Sinclair ZX80 (and kit ver- sion, the MicroAce). But different be- cause of the creative and innovative phi- losophy of the editors.
A Fascinating Computer
The ZX80 doesn't have memory map- ped video. Thus the screen goes blank when a key is pressed. To some review- ers this is a disadvantage. To our editors this is a challenge. One suggested that games could be written to take advan- tage of the screen blanking. For exam- ple, how about a game where characters and graphic symbols move around the screen while it is blanked? The object would be to crack the secret code gov- erning the movements. Voila! A new game like Mastermind or Black Box uniquely for the ZX80.
We made some interesting discoveries soon after setting up the machine. For instance, the CHR$ function is not limit- ed to a value between O and 255, but cycles repeatedly through the code. CHR$ (9) and CHR$ (265) will produce identical values. In other words, CHR$ operates in a MOD 256 fashion. We found that the “-” sign can be used se- veral times on a single line, allowing the logical evaluation of variables. In the Sinclair, LET X=Y=Z=W is a valid ex- pression.
Or consider the TL$ function which strips a string of its initial character. At first, we wondered what practical value it had. Then someone suggested it would be perfect for removing the dollar sign from numerical inputs.
Breakthroughs? Hardly. But indicative of the hints and kinds you'll find in every issue of SYNC. We intend to take the Sinclair to its limits and then push be- yond, finding new tricks and tips, new applications, new ways to do what couldn't be done before. SYNC functions on many levels, with tutorials for the be- ginner and concepts that will keep the pros coming back for more. We'll show
you how to duplicate commands avail- able in other Basics. And, perhaps, how
to do things that cant be done on other machines.
Many computer applications require that data be sorted. But did you realize there are over ten fundamentally differ- ent sorting algorithms? Many people settle for a simple bubble sort perhaps because it's described in so many pro- gramming manuals or because they've seen it in another program. However, sort routines such as heapsort or Shell- Metzner are over 100 times as fast as a bubble sort and may actually use less memory. Sure, 1K of memory isn't a lot to work with, but it can be stretched much further by using innovative, clever coding. You'll find this type of help in SYNC.
Lots of Games and Applications
Applications and software are the meat of SYNC. We recognize that along with useful, pragmatic applications, like finan- cial analysis and graphing, you'll want games that are fun and challenging. In the charter issue of SYNC you'll find se- veral games. Acey Ducey is a card game in which the dealer (the computer) deals two cards face up. You then have an op- tion to bet depending upon whether you feel the next card dealt will have a value between the first two.
In Hurkle, another game in the charter issue, you have to find a happy little Hurkle who is hiding on a 10 X 10 grid. In response to your guesses, the Hurkle sends our a clue telling you in which direction to look next.
One of the most ancient forms of arith- metical puzzle is called a “boomerang.” The oldest recorded example is that set down by Nicomachus in his Arithmetica around 100 A.D. Youll find a computer version of this puzzle in SYNC.
Hard-Hitting, Objective Evaluations
By selecting the ZX80 or MicroAce as your personal computer you've shown that you are an astute buyer looking for good performance, an innovative design and economical price. However, select- ing software will not be easy. That's where SYNC comes in. SYNC evaluates software packages and other peripherals
and doesnt just publish manufacturer descriptions. We put each package through its paces and give you an in- depth, objective report of its strengths and weaknesses.
SYNC is a Creative Computing pub- lication. Creative Computing is the num- ber 1 magazine of software and applica- tions with nearly 100,000 circulation. The two most popular computer games books in the world, Basic Computer Games and More Basic Computer Games (combined sales over 500,000) are published by Creative Computing. Creative Computing Software manufac- tures over 150 software packages for six different personal computers.
Creative Computing, founded in 1974 by David Ahl, is a well-established firm committed to the future of personal com- puting. We expect the Sinclair ZX80 to be a highly successful computer and correspondingly, SYNC to be a respect- ed and successful magazine.
Order SYNC Today
To order your subscription to SYNC, in the USA send $10 for one year (6 issues), $18 for two years (12 issues) or $24 for three years (18 issues). Send order and payment to the address below or call MasterCard, Visa or American Ex- press orders to our toll-free number.
Subscriptions in the UK are mailed by air and cost Е 10 for one year, Е 18 for two years or £ 25 for three years. Send order and payment to the UK address below.
Canadian and other foreign surface subscriptions cost $15 per year or $27 for two years and should be sent to the USA address.
We guarantee your satisfaction or we will refund your entire subscription price.
Needless to say, we cant fill up all the pages without your help. So send in your programs, articles, hints апа tips. Remember, illustrations and screen photos make a piece much more inter- esting. Send in your reviews of peripher- als and software too—but be warned: re- views must be in-depth and objective. We want you to respect what you read on the pages of SYNC so be honest and forthright in the material you send us. Of course we pay for contributions— just don't expect to retire on it.
The exploration has begun. Join us.
The magazine for Sinclair ZX80 users
r ==
39 East Hanover Avenue Morris Plains, NJ 07950, USA Toll free 800-631-8112 (In NJ 201-540-0445)
27 Andrew Close, Stoke Golding Nuneaton CV13 6EL, England
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SYNC Reader Survey
We at SYNC would like to know more about you. That way, we can determine what kinds of material to run in the magazine that will best meet your needs.
In Sync, I would like to see:
very much Hardware Tutorials Software Tutorials Games Simulations Educational Software Mathematics Software Graphics Software Business Software Device Control Software Programming Tips Interfacing Techniques New Products Information Hardware Evaluations Software Evaluations Fiction Puzzles and Problems Advertising
жии ш иик нж їнїн їшїн өш
About Software: []Ilike to mainly write my own
ОШ I mainly use software from other sources
(ЈА bit of both
okay
[] [] = = О ж О = = [] [] О О О О [] О
Which of the following peripherals do you intend to purchase for your ZX80 (assuming they become available)?
forget it
a (1 Additional memory [0 Graphics Tablet rj [0 Floppy Disk [] Modem
= [0 Small Printer (1 Music Synthesizer = О Letter Quality Printer [0 Other
= |
= What other computer magazines do you regularly read? []
[]
[]
O
0 Age: О Under 20 [0 41-50
[J LJ 21-30 [0 51-60
go [0 31-40 O Over 60
Г]
E Sex: L] Male [0 Female
[]
О What was the main reason you bought a ZX 80 or MicroAce?
Comments:
Is the ZX 80 or MicroAce your only computer?
[0 Yes Г] No, I also have а.
I utilize a computer at (check all that apply)
[] Home O Other
[] Work Г] School
Name
Address
Return to SYNC, 39 East Hanover Avenue, Morris Plains, N.J. 07950
If not, you should be. We would like any programs, translations of existing pro- grams, games or tips which you have to pass on to fellow Sinclair ZX-80 or Micro- Ace owners. Articles are much more lively if accompained by photos (black and white), diagrams, and illustrations. If you do not have an output printer, please type program listings and carefully check them against the listing on the screen.
Jan/Feb 1981
Sample runs should be included with pro- grams rather than just a description of what the program does. Articles should be typed, double space. Your name and address, with phone number should be on first page; all other pages should be num- bered. All submissions should include re- turn postage. Payment ranges from $15 to $40 per printed page. Please send all submissions to:
SYNC
39 E. Hanover Avenue
Morris Plains, New Jersey 07950
Are you in SYNC?
Find 7Х-80 Owners
Advertise in SYNC, the magazine ex- clusively dedicated to the Sinclair ZX-80 and The MicroAce. Call or write for de- tails and a rate card. Let SYNC readers know who you are.
SYNC 39 E. Hanover Ave. Morris Plains, New Jersey 07950
45
Glossary of Computer Terms
Access Time
The interval of time between the calling for information from a storage address and the delivery of that information. In
general, tape has a longer access time than disk.
Address
A label (name or number) that desig- nates a location where information is stored in memory device.
Alphanumeric
A set of symbols. Can be letters (A-Z),
and/or special punctuation, mathmatical, or graphic symbols.
Architecture
The internal, preset arrangement or organization of a computer which deter- mines how the computer operates. The interconnections of registers, logic units, control logic, etc. that which makes one microprocessor different from another.
Basic
An acronym for Beginners АП Purpose Symbolic Instruction Code. A high-level conversational, interpretive, program- ming language in wide use. Basic was in- vented by Kemeny and Kurtz at Dartmouth college in 1963. It permits the use of simple English words and common mathmatical symbols to perform the nec- essary arithmetic and logical operations to solve problems.
Bit The smallest amount of information
that can exist: equivalent to yes/no, on/off, +/-, or 0/1.
Byte
A collection of bits, usually eight of them.
46
Code
The relationship between bits and a set of characters. Microcomputers deal only with bits when executing a program. Therefore, letters, numbers, and other human understandable characters must be translated into bits. Each character has a bit code representation.
Coding
Preparing a set of computer instruc- tions.
Ccmmand
An instruction given to the system through an input device or peripheral. It is executed as soon as it has been received.
Compatibility
There are two types of compatibility: Program and hardware. Program compat- ibility refers to the ability to run programs on a variety of computers without change the program language. Hardware compat- ibility means that various components (printers, disks, keyboards, etc.) may be connected directly without intervening electronic devices.
Console
The operating portion of a unit.
Courseware
A combination of content, instructional design, and the software which causes a computer to implement instructions.
CPS Cycles Per Second
CPU
Central processing unit. The heart of the computer, controlling what the com- puter does. It includes three main sec- tions: arithmetic, control, and logic ele- ments. It performs computations and di- rects functions of the system.
Creative Computing
The second best source of Sinclair ZX- 80 information.
Crunch
To make information fit into a smaller place.
CRT
Acronym for Cathode Ray Tube. Simi- lar in appearance to a television screen. Information in the form of characters and graphic designs may be displayed on CRTs at а rapid rate. А CRT terminal usually comes with a keyboard for enter- ing information into the computer.
Cursor
Movable indicator on CRT to indicate a specific character or space that is being displayed. The cursor generally lets the user know where the next character to be typed will appear.
Data
The information given to or received from a computer.
Debug
Process of finding, locating, and cor- recting mistakes or errors in a program that might create problems or provide in- accurate information.
Digit
Either a zero or a one in the binary number system.
Direct Memory Access (DMA)
A technique for rapidly moving data from the microprocessor to a storage de- vice such as a disk. DMA is a accom- plished at the direction of a program. Not all microcomputers permit DMA.
SYNC Magazine
Document
A written description of a piece of soft- ware or hardware. It can also be used asa verb which is the process of producing such a description. Driver
Small program which controls periph-
eral devices and their interface with the CPU.
Editor
A program which allows changing, modification, or movement of program- ming statements. It allows the pro- grammer to write and modify instructions
using the microprocessor and a terminal as a very sophisticated typewriter.
Error Difference in value between actual re- sponse and desired response in the per-
formance of a controlled machine, system, or process.
Execute
The running of a computer program. External Storage
Auxiliary storage such as tape or disk. File
Collection of related data. File Name
Number/letter of characters that iden- tify a file.
Flow Charting A programming technique of using
shaped blocks to indicate the sequence of operations in a program.
Frequency Rate at which anything recurs. GIGO Garbage in Garbage Out. Implies that
misinformation applied to the CPU will result in misinformation output.
Glitch
An intermittent bug
Jan/Feb 1981
Graphics
Characters that can be used to form figures, shapes, and forms on the CRT or printer. In addition to letters and num- bers, a computer may have a graphic set, so arrange that they can be combined to form almost any desired figure.
Hard Copy
Data or information printed on paper. Used to distinguish between printed infor-
mation and the temporary image found on the CRT.
Hardware
Mechanical, magnetic, electrical, and electronic devices which make up a com- puter. The physical equipment that goes into a computer system, consisting of the central processing unit plus all periph- erals. |
IC
Integrated Circuit. A plastic or ceramic body five cm long, two cm wide, and three mm thick, with up to 40 leads extending from it. Inside the body is a chip. The body protects the chip, and the leads allow electrical connection of the chip to other components. The word “chip” is not used to refer to the entire IC.
Input
Information going into the computer or into a peripheral. The same data may be output from one part of the computer and input to some other part of the computer. When using this word, specify what the data are input to or output from.
Instruction
A set of bits, or a command, which will cause a computer to perform certain pre- scribed operations.
Interactive
System capable of two-way communi- cations with a user during operation. A system is interactive if it responds to the user quickly — usually less than a second. All personal computer systems are inter- active.
Interface
An electronic circuit used to connect one electrical device to another electrical or mechanical device to allow the flow of data between units. It refers to the match- ing or interconnecting of systems or de- vices having different functions.
Internal Storage
Memory system which is part of the computer, as opposed to external tape or disk storage.
Interpreter
A program used to translate languages at the time of processing.
/О
Input/output of information in а com- puter system. Examples of I/O devices are a keyboard, a floppy disk drive, and a printer.
Language
A format by which a programmer can communicate more efficiently with a computer where predetermined com- mands will yield requested actions. Basic is one of the most popular languages.
Low Resolution
Graphics composed of coarse blocks.
Macro-instruction
An instruction which causes the com- puter to execute one or more other in- structions. These "other instructions" are called micro-instructions.
Main Memory
That memory which is directly accessi- ble to the computer. It contains the oper- ating system, programs, and data being processed. In a microcomputer, main memory is referred to as RAM or ROM.
Memory
The integrated circuits of a computer which store information in a micro- computer, these are referred to as RAM and ROM.
Memory Chip
A chip which stores data in the form of electrical charges.
Microprocessor
An integrated circuit that can execute instructions. It is one component of a microcomputer. It is the brains of the cen- tral processing unit (CPU).
47
Microcomputer
A hardware configuration usually ac- quired in one of three ways: 1) by con- structing several components from indi- vidual electronic parts (as in building a stereo system from a kit); 2) by connect- ing several already constructed compo- nents (as in purchasing a separate amplifier, speaker and turntable); or 3) by purchasing a unit with built in compo- nents (as in buying a complete stereo system in one package, plugging it in, and using it immediately). The end-product of the microcomputer is information. It re- cords this information, puts it into mean- ingful terms, communicates it, stores it, and retrieves it when needed. It usually includes the microprocessing unit, a key- board for entering data, and a cassette tape recorder or a disk for storing pro- grams, and a T.V .-like screen for display- ing results.
Modulator
An electronic device that allows a nor- mal television set to be used as the video display unit (CPU).
Monitor
1) A video display unit which uses a cathode ray tube to generate characters. It looks much like a normal TV set; how- ever, the monitor has a much higher de- gree of resolution, which permits a clear formation of very small characters on the screen.
2) A program which oversees the opera- tion of other programs.
Noise
Refers to inaccurate data transmission. This causes typographical errors in out- put.
Output
Information emanating from a display unit such as a CRT or printer.
Peripheral Device
A device, such as a printer, mass stor- age unit, or keyboard, which is an acces- sory to a microprocessor and which trans- fers information to and from the micro- processor.
Personal Computer А microcomputer designed for use by
an individual for entertainment, instruc- tion, and book keeping chores.
48
Printer
A peripheral device which accepts out- put data from the microprocessor and prints characters on paper. Printers are
defined as impact or non-impact depend-
ing on the means by which a character is formed on the paper. Impact printers strike the paper through a ribbon in a manner similar to a typewriter. Non- impact printers form characters by vari- ous means such as heat, electrical charges, or spraying ink.
Program
A series of instructions to a computer which cause the computer to solve a prob- lem or perform a task.
RAM
An acronym for Random Access Mem- ory. Any memory which can be written on or read from by a program in which the memory locations can be accessed in ran- dom sequence. RAM can be erased and reprogrammed by the programmer as fre- quently as necessary. RAM size is ex- pressed as a quantity of bytes, such as 4K (4,000 bytes). RAM may be expaned by adding memory chips or memory boards.
Register
A temporary storage device located in the microprocessor which can hold com- puter bits or words.
Response Time
The interval of time required for the microprocessor to respond to an instruc- tion or an input from a peripheral such as the keyboard. In an educational environ- ment, the time interval from the activa- tion of the keyboard to a display on the CRT should be less than three seconds.
RF Modulator
See Modulator
" Back up..what back up?"
Run
Jargon for execute, (There is a run key on the ZX-80).
Software
Refers to programs and accompanying documentation. Software is stored on tape cassettes or disks when not being used by the computer. The computer reads the software into its memory in order to use the programs.
Storage Capacity
The quantity of bytes a storage device can hold. It is usually expressed in kilo- bytes (1024 bytes), which is abbreviated K. Thus, a disk is said to have a storage capacity of 400K (400,000 bytes). This can be understood as 400,000 characters or letters, numbers, spaces, etc.
Storage device
A peripheral device which holds infor- mation. This includes tapes and disks.
Store
This term refers to the process of plac- ing data onto some type of storage device. Usually the data