“The year is 2582 and the people of Earth are in the midst of battle against the Robots.” So begins Robot Missile, the first of thirteen games in Computer Battlegames. A missile has landed, and you have four guesses at the secret letter that defuses it. After each guess the computer says only “LATER” or “EARLIER” in the alphabet. The whole program is 23 lines of BASIC, and beside every line the book explains what it does.
Usborne, a London publisher of illustrated children’s books, brought out Computer Battlegames in 1982 with its companion, Computer Spacegames. Both were by Daniel Isaaman and Jenny Tyler. The book’s trick was to print each game once, as a listing for the Sinclair ZX81, and to mark every line that had to change on another computer with that machine’s symbol, with the replacement printed underneath. One 48-page paperback served the ZX81, ZX Spectrum, BBC Micro, VIC-20, Pet, TRS-80 and Apple, and many of its games were short enough for the ZX81’s 1K of memory.
Fast facts
- Authors: Daniel Isaaman and Jenny Tyler; the Robot Invaders program is credited to Bob Merry.
- Pictures: illustrated by Rex Archer, Jim Bamber, Tony Baskeyfield, Martin Newton and Graham Round; designed by Graham Round and Roger Priddy.
- Publisher: Usborne Publishing, 20 Garrick Street, London, 1982; published in the United States by Hayes Books and in Canada by Hayes Publishing.
- Length: 48 pages, with thirteen games.
- Machines: ZX81 (the main listings), ZX Spectrum, BBC Micro and Acorn Electron, VIC-20 and Pet, TRS-80 and Apple. A later printing replaced the Pet with the Commodore 64 in the symbol key.
- Price: £1.99 in January 1983; by December 1984, £2.25 in paperback and £4.50 in hardback. The American edition cost $5.95 in paperback.
- Free download: one of fifteen Usborne computer books made free as PDFs in February 2016.
The games
Most of the games belong to one story, a war between Earth and the robots of the U.R.S., the United Robot States. In The Vital Message you are a laser communications operator who must memorise a code that flashes up for a moment. Desert Tank Battle gives you five missiles to fire at a robot stronghold hidden in castle ruins, aimed by direction and elevation. In Secret Weapon you guess the coordinates of an underground robot spare-parts store. Escape! has you tuning a sonar wristwatch to the resonant frequency of your robot guards, so that they shake themselves to pieces. Supersonic Bomber shows five bar charts of robot population and gives you a moment to bomb the biggest.
Others leave the robots behind. Shootout is a Wild West duel: the computer counts ten paces, pauses for a random time, prints “HE DRAWS…” and gives you a moment to press a key before he fires. In Battle at Traitor’s Castle you are one of the King’s bowmen, shooting at the Baron’s men as they pop up on the battlements. In Iceberg you steer a damaged ship across a grid and try to lure a pursuing enemy into the ice, and in The Wall you fling boulders at a moving wall built by a wizard. The book ends with Missile!, in which you fire three missiles at passing planes.
Each game was chosen to show something. Robot Missile compares strings, so the computer can tell whether your letter comes before or after its own. The Vital Message builds a random code one letter at a time with CHR$. Desert Tank Battle uses SIN to work out how far a missile travels from its elevation angle, and ABS to judge whether it landed close enough. Shootout checks the keyboard inside a FOR loop, and the book explains why: “computers work so quickly, you wouldn’t have a chance of pressing a key in the time it takes the computer to do one check”. Battle at Traitor’s Castle adds a score, and the book suggests copying its two scoring lines into other programs. Supersonic Bomber introduces an array, and Iceberg uses a two-dimensional one as the map of the sea.
Missile! is different because it uses graphics, and the machines drew pictures in such different ways that one listing with changes would not do. The book prints it in six complete versions, for the TRS-80, BBC, ZX Spectrum, VIC-20, Apple and ZX81, on a page each.
One book, several BASICs
The introduction is frank about the cost of the method: “The fact that the programs are written for several micros means that they do not make full use of each one’s facilities. You could try finding ways of making the programs shorter and neater for your micro.” The differences show up even in short games. In Shootout the ZX81, Spectrum, BBC and TRS-80 read the keyboard with INKEY$, the VIC-20 uses GET, and the Apple has to PEEK a memory location, and the book points this out beside the listing.
The book expects mistakes and tells you how to find them. Its checklist runs from “Line missed out” to “Letter ‘O’ confused with zero”, and it reminds ZX81 and Spectrum owners to type each keyword with its own key, not letter by letter. It also tells nervous beginners: “You can’t damage the computer and you can always change back to the original if the changes don’t work.” Every game has suggestions for changing it, from adjusting the speed to adding a second kind of target, and a “Puzzle corner” whose answers are at the back.
The last pages turn from typing to writing. “Writing your own programs” advises planning a game in English before writing any BASIC, and gives a seven-step plan for a simple shooting game. It is realistic about what follows: “Remember that debugging programs is a long, tedious process even for expert programmers, so don’t expect to get yours right first time.” A summary of BASIC and a conversion chart for adapting listings from magazines and other books complete the book.
Reception
Sinclair User noticed the first four Usborne computer books in January 1983. It liked the single listings with symbols “at the side” pointing readers to the conversion notes, and thought the books, “full of colourful drawings”, were “a good idea, for they will coax children into work with computers”. In America, Family Computing recommended Computer Battlegames and Computer Spacegames in January 1984 for readers aged nine and up, praising their “superb illustrations” and “fairly short game programs, with explanations of each program and suggestions for improving programs”. It added that they were “not really a BASIC manual, but good instructional material”. In the American edition the main listings were described as programs for the Timex Sinclair 1000, the American version of the ZX81.
TV Gamer still counted the two books among its favourites in December 1984, calling them “an excellent introduction to programming your own games”. By then they listed the Commodore 64 and Electron among their machines. In February 2016 Usborne put Computer Battlegames online as a free PDF, with fourteen other computer books from the 1980s. See Usborne computing books for the whole range.
Sources
- Daniel Isaaman and Jenny Tyler, Computer Battlegames (Usborne, 1982): contents and credits page; “About this book”, “Typing in the programs”, “Points to remember”, “Debugging programs” and “Experimenting with the games” (pp. 2–3); Robot Missile (pp. 4–5); The Vital Message (pp. 6–7); Shootout (pp. 8–9); Desert Tank Battle (pp. 10–11); Battle at Traitor’s Castle (pp. 12–13); Secret Weapon to The Wall (pp. 16–27); Missile! and its six versions (pp. 28–35); “Writing your own programs” (pp. 38–39); “Summary of BASIC” (pp. 40–45, the
INKEY$andGETentries); back cover (the Hayes editions and ISBN 0 86020 685 8). A later printing (legal deposit 1984) has the same contents with the VIC and Commodore 64 sharing a symbol. - Sinclair User issue 10, January 1983, p. 41: John Gilbert’s books column (the four Usborne books, £1.99 each).
- Ed Hoornaert, “BASIC Book Buying”, Family Computing vol. 2 no. 1, January 1984, p. 146: the American edition (ages nine and up, 48 pages, $5.95 softcover and $8.95 hardcover, Timex Sinclair 1000 listings, the reviewer’s comments).
- TV Gamer, December 1984: book recommendations (Computer Space Games and Computer Battle Games, prices and machines).
- Shaun Nichols, “Ready for a nostalgia kick? Usborne has put its old computer books on the web for free”, The Register, 9 February 2016 (web, secondary): Computer Battle Games among the fifteen titles. https://www.theregister.com/2016/02/09/usborne_programming_books_now_free/