- 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.
- 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".
CPU Z80A at 3.5MHz
Text 32x24 (16 colours)
Graphics 256x192 (16 colours)
1 channel sound
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.
CPU 68008 at 7.5MHz
Graphics 512x256 (4 colours), 256x256 (8 colours)
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.