Z80 @ 3.25Mhz - 8KB ROM - 1KB RAM (Upgradable with 16, 32 & 64KB RAM Packs)

The year after the ZX80, came it's successor and ultimately better remembered ZX81. This computer had really only a few changes from it's predecessor, but those changes proved very popular. Where the ZX80 opened the market to the home, the ZX81 cemented Sinclair's position. Sir Clive Sinclair's company had adopted the Sinclair Research Ltd title also shortly before the release of the ZX81.

The design was by Rick Dickinson once more, and really has a high-tech yet accessible look. You almost want to pick it up and press the keys when you see it. Although still encumbered by the cheap keyboard, the ZX81 proved to be an instant success. Previous users of the ZX80 were not left out either - an upgrade kit was available that provided the larger ROM and new keyboard to make it almost a ZX81.

The differences between the two models, firstly was the price. This cut in price was partly due to the reduction in chips on the motherboard, and also partly because of increased activity in the production of chips generally - along with Sinclair having a better understanding of the production of the computer. The ZX81 retailed for £70 fully assembled and only £50 in kit form. And the kit was really a kit - you would need a soldering iron, and some basic electronics know-how to assemble it! The other differences were in the ROM, as the ZX81 now boasted floating-point arithmetic, as opposed to it's integer only older brother. There were also two modes available, to get around the flicker on the ZX80. A "Fast" mode which was exactly how the ZX80 operated, and a "Slow" mode that would allow the screen to be redrawn while doing other things. it doesn't seem that big now, but back then it was what every ZX80 owner was waiting for. The pay off for the slow mode was a reduced speed of about a 1/4 of that in fast mode.

The ZX81 had a bigger and better upgrade path than the ZX80 also, with RAM Packs that supported up to 64Kb in size. Also during it's release peripherals like the ZX Printer became available, as well as various add-ons that would enhance the ZX81 even further. It appeared 3rd party companies were also taking note and realising the potential Sinclair Research were creating.

Image source: Public Domain