Sir Clive Sinclair is fifty this year, and it was ten years ago he launched the first computer branded Sinclair ZX. The ZX80 was followed by the ZX81 and then the ZX Spectrum. Six ZX incarnations later the Speccy is still the favorite! CRASH reveals the story of Britain’s most popular computer...
The SPECTRUM is the best and most famous ZX computer. But it’s worth remembering the other computers that Sir Clive Sinclair had a hand in designing before the ZX range was conceived.
By the late 70s Sinclair was running out of road. He’d hit trouble selling calculators and digital watches, and had been trying to make and sell a pocket-sized TV set since the 60s. At last he’d produced one, but it was costly, unreliable and difficult to make.
One plan to raise money for the TV project involved a computer, the NewBrain. Britain’s Labour Government bought a large stake in Sinclair’s firm, Sinclair Radionics, to try to keep things going — but lost confidence after a while. Radionics was split up and Sinclair left to run a new firm, Science Of Cambridge.
The NewBrain was sold to Newbury Labs, then to Grundy; at one time it was going to be the official BBC micro, but it reached the market too late and didn’t catch on.
Over at Science Of Cambridge, Sinclair and on engineer called Chris Curry pooled their experience and invented a horrid wrist calculator, with keys you could press in three different directions for various functions — a sign of things to come!
Then they dreamed up a computer system which has never been beaten on price or uselessness — the MK-14. It used an obscure processor called an SC/MP, mainly because the firm that made it offered to design the computer for nothing as long as Sinclair used its chip.
The MK-14 had a calculator display and keyboard, 0.25K of memory, and no box. Sinclair sold 10,000, and decided that computers were a good way to raise money. Science Of Cambridge changed its name to Sinclair Research. And after moonlighting for a while, Chris Curry left, to set up Acorn Computers.
In 1980 the first ZX computer was produced — the ZX-80 designed by Jim Westwood and with software by John Grant. The ZX-80 looked very much like a real computer, though it was made of bendy plastic, had no keys and was less than a quarter of the size it appeared in the glossy adverts.
You could program it in BASIC, using a TV display, and save programs on cassette. But lots of improvements were needed. The ZX-80 contained only 1K of memory, and it could only work with whole numbers between -32768 and 32767. Worst of all, the screen went blank when you pressed a key or ran a program!
Still, the ZX-80 was a success, and even spawned a clone — the CompShop Micro Ace. A 16K RAM pack — prone to fall off at inconvenient moments — was produced, and various ingenious tricks were used to stop the machine overheating.
Within a year the ZX-80 had been redesigned, with a custom chip in it to make copying more difficult, and with a much-improved display that allowed programs to run while the screen display was visible — albeit at about a quarter of the ZX-80’s speed. And ZX BASIC was souped up to handle text and floating-point mathematics, though square roots didn’t work properly at first.
The result was the ZX-81: a big improvement, launched in March 1981 at a price that undercut the ZX-80 by £30! The cloned Micro Ace disappeared, but Acorn Computers, founded by Sinclair’s former colleague Chris Curry, got the BBC contract — the ZX-81 had only a black-and-white display.
The ZX-80 had been assembled for Sinclair by part-time home workers, but the ZX-81 was obviously going to sell too many for this arrangement to work. So Sinclair did a deal with Timex, which owned a big factory in Scotland. In return for building the ZX-81 Timex was allowed to sell it in the USA, paying Sinclair a 5% royalty.
The ZX-81 sold well — as did the US version, the TMS-1000, when it popped up in 1982. But Sinclair was still after the BBC contract, and in the summer of 1982 he announced the ZX Spectrum — a colour computer aimed at would-be programmers, with 16K or 48K memory. The extra 32K was fitted on an extra board inside the computer, so it couldn’t fall off.
The turning point for home computers was about to be reached! Isn’t history fascinating!
DON’T MISS THE NEXT INSTALMENT OF SINCLAIR: A STORY OF SURVIVAL IN THE NEXT ISSUE OF CRASH!
£100, 4K ROM, 1K RAM; whole numbers only; very limited black-and-white graphics but basic 32 * 24 screen established. Total sales about 50,000.
£80. 2K RAM; ZX-80 kit copy
£70, £150; 8K ROM, 1K RAM; floating-point maths; slow but continuous black-and-white display. 500,000 sold in the first year
$100; licensed ZX-81 — a big hit for Timex in the USA
£125 (16K), £175 (48K); 16K ROM, 16K/48K RAM; colour graphics and much-improved display circuitry. 60,000 issue 1 Spectrums sold; grey keys; add-on 32K, ‘dead cockroach’ bodge.
ZX-81 price cut to £50
TMS-1000 price cut to $40