many of those magazines are bedaubed with felt-tip where I marked my progress whiling away hours typing in those programs.

I got into computers in the mid 70s with the advent of the Altair. Reading your comment was like a flashback. I remember you’d finally get through, meticulously typing in all the pages of code. So your cross your fingers and ran it and got an error. But I was hooked. I still have my Altair, Timex/Sinclair, Ti 99 & 994a. I had/have everything imaginable for the Ti. You needed a kitchen table to spread all that out on.

Later on, as you say, demos became a big thing, I loved the demos. I would write just about anyone giving away a demo of something. Game demos would at least let you play one or two levels.