It's been a fantastic start to the campaign, so could anyone that hasn't posted/tweeted/shared or otherwise mentioned the book please do so, as I'd love to reach 100 supporters by Friday!

Even though this means I lose the magic number 81 from my supporter count!

It was the ZX81, after all, that got me my start in computing. Its name is a logical continuation of Sinclair's previous machine, the ZX80, released in the year (yes, you guessed it) 1980. Its name was also a reference to the Zilog Z80 chip inside it, with some Xtra magic.

Given the original ZX81 only had 1K of memory, and a full screen of text took 768 bytes, you needed to employ some clever tricks to make good use of the machine. Entries 3 and 768 in the book both contain some of these tricks.