1981 · Four-Chip Membrane Computer · Work 977 of 1,871
The test line of an electronics factory in Dundee in Scotland on an early spring morning, along a steel bench a belt carrying a row of identical small flat computers, each a nearly square case of matt black finely grained plastic sixteen by twenty-one centimetres and four centimetres high, a shallow horizontal groove across it, below it a flat pale grey membrane keypad of forty square pads, every pad plain, smooth and unmarked, a woman's hands in pale blue overall sleeves lifting one from the belt, its thin cable running to one of a row of small portable television sets on a shelf above, each glowing soft even grey, high windows.
What it was used for
A Sinclair home computer, launched on 5 March 1981 as successor to the ZX80, at 49.95 pounds as a kit and 69.95 pounds ready built. It had 1 KB of working memory, expandable to 16 KB by a plug-on RAM pack. It was manufactured by Timex in Dundee. The Centre for Computing History calls it the first mass-market home computer sold in high street chains such as W. H. Smith, and gives over 1.5 million units sold in all.
What was new
What stands out is the reduction in parts: the ZX80 used about 21 chips, the ZX81 4. Sinclair stated that a Ferranti custom chip replaced 18 of the predecessor's chips. Sinclair's advertising credited the low price to this design. It was paid for elsewhere: 1 KB of working memory, and anyone expanding beyond 16 KB replaced the built-in memory rather than adding to it, according to the Centre for Computing History. An article in Electronics Times of February 1982, cited on the same page, gives 60,000 machines a month, two thirds of them for export.
What the sources leave open: The production figures - one machine every 10 seconds, 60,000 a month, more than 300,000 by February 1982 - come from an article in Electronics Times of February 1982 cited by the Centre for Computing History; I did not see the original article. The total of over 1.5 million appears on the same page with no cut-off date and no source.