My first computer was a 1K Sinclair ZX81 as well that I purchased already built. After just over a year with only 1K ram I saved up and purchased the 16K expansion module that plugged into the back. It actually only had 15K in it. The 16K written on it referred to the total memory once it was plugged in. I used to purchase the imported British magazines and type in the games code printed in the pages. I remember later on once I upgraded to the ZX Spectrum tying in the code to build Manic Miner and Jetset Willy from the original printed code that came out in one of the Spectrum magazines before the games went commercial and became available on Tape.
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