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Sinclair ZX80

The Sinclair ZX80 was a home computer brought to market in 1980 by Sinclair Research. It was notable for being the first computer available in the United Kingdom for under a hundred pounds (a pricetag of 99.95, to be exact). It was available in kit form; purchasers had to assemble and solder it together. A ready-built version was also available at a slightly higher cost for those without the skill or inclination to build their own.

The machine was based around the NEC 780C-1 CPU (a Zilog Z80 clone) @ 3.25 MHz, and equipped with 1 KB of static RAM (expandable to 16K), and 4 KB ROM containing the Sinclair BASIC programming language, editor, and "OS". BASIC commands were not entered by spelling them out; instead, the commands were selected rather like they would be on a scientific calculator – each "key" had several different functions, activated by use of several modifier (shift) keys.

The video display generator of the ZX80 used very minimalistic hardware, plus a combination of software to generate a video signal. As a result of this approach the ZX80 could only generate a picture when it was waiting for a key to be pressed. When running a BASIC program the display would black out. This prevented moving graphics etc. The later ZX81 improved on this somewhat because it could run 'slow' while creating a video signal, or 'fast' without generating a video signal (used for lengthy calculations).

The machine was mounted in a tiny white plastic case, with a one-piece blue touch membrane keyboard on the front. The entire system was about the size of two paperback book placed beside each other. It kick-started the 80s home computer craze in the UK and was the precursor to the ZX81 and the very successful ZX Spectrum.