Scientific programmable Calculator
- Released 1975
- 9V Alkaline battery or mains adaptor
- 9 digit 7-segment green vacuum fluorescent display
- 5 digit precision
- Reverse polish data entry
- Sine, cosine, arc-tangent, antilog, log, reciprocal, square and square root
This is a very basic programmable calculator with many shortcomings. Although there is a 9 digit display, the precision is limited to 5 digits because 3 are reserved for the exponent. There is no "power of" function. The reverse polish entry is limited by a two level stack, which is destroyed whenever a scientific function is used. The programming model is wasteful, for example constants require a start and end quote. Constants in programs must be integers.
ZX81
- Released 1981
- CPU Z80 at 3.58MHz
- RAM 1k (expandable to 32k)
- ROM 8k
- Text 32x15 (black & white)
- Graphics 64x44 (black & white)
- Tape storage
Successor to the ZX-80, this computer replaced much of the discrete logic with a ULA. Further cost reductions were the membrane keyboard and a TV interface directly driven by the CPU (and shared with the tape interface, which produced some nice patterns when loading and saving). A dedicated electrostatic printer was available which printed on "silver toilet roll". This machine was really the start of the "home computer revolution".
Spectrum 48
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Released 1982
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CPU Z80A at 3.5MHz
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RAM 48k
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ROM 16k
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Text 32x24 (16 colours)
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Graphics 256x192 (16 colours)
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1 channel sound
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Tape and Microdrive
Very popular machine with a large software base. Several variations were made, a 16k Spectrum 16, Spectrum+ with a better case and keyboard (similar to the QL) and Spectrum+128 with 128k RAM. The rights were sold to Amstrad who continued the range.
QL
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Released 1984
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CPU 68008 at 7.5MHz
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RAM 128k
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ROM 32k
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Text 85x25
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Graphics 512x256 (4 colours), 256x256 (8 colours)
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Two integral Microdrives
The first 16bit(ish) home computer. This machine was released a year before the Atari ST and Commodore Amiga, but initial production problems, use of microdrives instead of floppy discs and the slower 68008 CPU stopped it from becoming as popular.