25 January 2010

Sinclair ZX-80

Although not truly the first Sinclair computer, that honour going to the MK14, the ZX80 is widely considered to be the machine that kick-started the home computer market, particularly as the MK14 has more in common with a calculator than a computer. Although, like the MK14, it was available in kit form, a ready-built version was also available, and it was this that made home computing accessible to everyone - not just those who were handy with a soldering iron and confident enough to assemble and solder together a hundred pounds worth of kit.

£99.99, actually. In 1980 the ZX80 became the first computer available in the UK for less than a hundred pounds, and these two factors - price and the fact that it worked right out of the box - led to an immense popularity, selling 70,000 units in about a year and easily paving the way for the success of the ZX81 and its worthy successor the ZX Spectrum.


Containing a total of twenty-one chips, the ZX80s specifications were groundbreaking, though now they seem almost paltry. At its heart was the processor: an NEC 780-1, a clone of Zilog's Z80 chip, running at 3.25MHz. RAM amounted to 1 kilobyte, and its display, black and whiteonly, could manage 22 x 32 text characters. Cassette ports were provided for loading and saving data, and there was an extra memory port which one could use to bring the RAM to 16K, sadly also exposing oneself to the dangers of RAM pack wobble in the process; one slight knock and three hours of work disappeared into the black hole of a hard reset. The ZX80 also included a 4K ROM chip containing Sinclair BASIC. There was also support for the Sinclair ZX Printer, released in 1981, provided you updated the ZX80 ROM chip.

The Operating System: Sinclair BASIC

Sinclair BASIC itself is worth a moment of reflection. Each key on the machine produced an entire keyword: pressing 'R' would enter 'RUN', whereas 'K' would produce the command 'LET'. Other commands were produced by using modifier keys such as shift. Although this approach introduced a slight learning curve, it had a number of advantages. Proficiency was quickly established through repeated use, and the system entirely avoided potential spelling errors, and allowed each command to take up only one byte of the precious 1024 available.

The minimalist design of the computer meant that the generation of the video signal was partly done in software, with the processor taking up most of the strain. This had the unfortunate side-effect that the display was blanked out whenever the processor was doing something other than waiting for an input. Moving graphics were, therefore, out of the question: if a program was running then the screen was blank. There were ways round this, but they were hardly efficient - one website offers a version of Space Invaders which hacks its way round the problem by repeatedly calling the display routines manually. The problem was partially solved with the ZX81, which allowed the BASIC interpreter to run in 'slow' mode, with graphics, or without them in a 'fast' mode. Moving on further, the Spectrum's hardware, with considerable improvements, had no such problems.


The physical design of the machine reflects two factors. Most prominently, the industrial design work of Rick Dickinson, who produced a white, plastic shell about the size of two paperback novels. Also clearly visible is the influence of the sub-£100 price tag. A one-piece membranekeyboard graced the top of the machine, threatening to wear out rapidly unless handled with care, a clear nod toward price-cutting.

America and beyond:

In February of 1980, the ZX80 was also launched in the US, at a price tag of $199.95, just one month before their release of the ZX81 in the UK. Later, American company Timex would begin selling the ZX81 as the Timex Sinclair 1000, halving the price tag to $99.95.

Finally, we reach the glory days of Sinclair Research: A year after its release in the UK, January of 1983 saw the Timex Sinclair 2000, more popularly known as the ZX Spectrum, go on general release to the American public.

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