My first computer was one I designed and built myself, starting the day the 8080 CPU was released, in late 1974. There was no commercially available microcomputer in those days. By Feb. 1975 I had it up and running, with a huge 1K of RAM! I had to put a small boot program using the front panel switches, and I had an old 33ASR teletype with a paper tape punch and reader for mass storage, as well as keyboard input and printed output.