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Rich [soylentnews.org] writes:

Youtuber Patrick Craenen, on his Happy Little Diodes channel (https://www.youtube.com/watch?v=jiW3P1rJRMc [youtube.com]), has announced that he was able to obtain a stash of development documents from former UK electronics company Ferranti. These documents contain a vast treasure of information about the custom ULA (Uncommited Logic Array) chips used in the ZX81 and Spectrum computers that defined much of the 1980's UK computing scene. Starting with the ZX81, a ULA replaced great numbers of individual logic ICs, reducing the chip count to a fraction and enabling a two-figure price for the machine. On the Spectrum, they enabled colour graphics with the lower development effort for a gate array, where US competitors Commodore and Atari were using full custom layout ICs, and Apple was using none, relying on NTSC artifacts until the Mac II.

The Ferranti Files contain detailed schematics for many of the ULA revisions, which will be of great interest to computer historians. As Ferranti is no longer existent, and the Sinclair rights have, via Amstrad, gone to Sky, Craenen cleared the release with their lawyers, who agreed under the condition that personal information is redacted.

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