The ZX81 was the first cheap, mass-marketed home computer, selling a total of 1.5 million units before it was discontinued in 1984. It was truly innovative, and allowed the general public to get their hands on something that was once only available to businesses and hobbyists with huge amounts of cash to spare.
However, those who rushed out to buy a ZX80 will probably have been regretting the move after the release of the ZX81 (labelled the Timex Sinclair 1000 and 1500 in the U.S.). For a start it was half the price (£49.95 or £69.95 in kit form), it used just five chips (the ZX80 used 21) and it had a much better BASIC programming language.
As with virtually all other home computers around at the time, programs were loaded and saved via an external cassette recorder, which was the most popular and cheapest method in the early 80s. However, anyone who experienced using this method will know that it wasn't always reliable! Floppy Disk drives were available to purchase as extras with other, more expensive computers such as the Atari 800, Commodore Vic 20 and IBM PC.
Rather than a dedicated monitor, the video display was viewed on a UHF CRT TV set (which was pretty standard at the time for home computers) which you connected via an aerial lead.
Although the ZX81 was, by far, the cheapest computer available at the time, it was also the least powerful. It had just 1kB of RAM, although this was expandable to 16kB. With a maximum resolution of just 64 x 44 characters and mono display, it couldn't match the higher resolutions of the IBM PC with its 640 x 200 res, 16 colour display and the Atari 800 with a 320 x 192 res, 256 colour display. However, you had to be pretty well off to buy one of those superior models, and the whole point of the ZX81 was to make computing affordable for everyone.
An IBM PC would set you back $1265, an Atari 800 was $899.95 and a Commodore Vic-20 was $260. So at $99.95, the ZX81 was truly affordable and allowed more people than ever to join the home computing revolution, and you have to admire it for that. Plus, unlike other models, you could pick one up from a your high street store, such and Boots or WHSmith.
Learning to program the ZX81 was a fun experience on the whole, although somewhat frustrating, too, given the machine's limitations. But this was a challenge that forced the user to code their machine in a tight style that used as little code as possible, saving the use of the precious memory.
It was, of course, very satisfying to see the result of your very first playable game that you had programmed entirely by yourself, even if it was very basic!
The membrane QWERTY keyboard could become problematic over time and wasn't particularly ideal for large amounts of typing. Nonetheless, it was cheap to manufacture and also didn't suffer from dirt and dust getting in-between the keys - a quick wipe and the dust was gone!
