ZX Spectrum 16K / 48K

After the black-and-white ZX80 and ZX81, Clive Sinclair's Sinclair Research wanted a colour computer that cost little. The ZX Spectrum was unveiled on 23 April 1982, in two versions: 16 KB for £125 and 48 KB for £175. The name comes from the colour spectrum, which is also where the rainbow stripe in the corner comes from.

The hardware was designed by Richard Altwasser, the ROM with Sinclair BASIC was written by Steve Vickers of Nine Tiles, and the black case with rubber keys is by Rick Dickinson. It was manufactured by Timex, in Dundee, Scotland.

The processor is a Zilog Z80A at 3.5 MHz. Almost everything else is in a single chip, the ULA (Uncommitted Logic Array) made by Ferranti, which generates the picture, reads the keyboard, handles the cassette and produces the sound.

The picture is 256 × 192 pixels, but colour is set in 8 × 8 blocks: each block can only have two colours, ink and paper. When two characters of different colours cross, the colours "bleed" into each other, the famous attribute clash. There are eight colours, each with a normal and a bright version, and black does not change, which gives 15 distinct colours.

The sound is a 1-bit beeper, which programmers managed to make play two and three voices through sheer ingenuity. Programs load from cassette at about 1,500 bits per second, with coloured stripes in the screen border showing the data going by.

The Spectrum was the computer of a generation in the UK and across much of Europe. In Portugal it had a special presence because of Timex, which had a factory in the country and made the Spectrum-compatible Timex Computer 2048 and 2068 there.

There were clones all over the place: the TK90X in Brazil, dozens of models in the Soviet Union and Eastern Europe. Games such as Manic Miner, Jet Set Willy and Knight Lore came out of bedrooms and garages and founded studios that still exist today.