I was coding for my old Amstrad CPC 464 in my tween years. I distinctly remember not having access to a firmware manual, or the funds to purchase one. So when

I was coding for my old Amstrad CPC 464 in my tween years. I distinctly remember not having access to a firmware manual, or the funds to purchase one. So when I wanted to know how something worked (say, the cassette data interface) I'd write to Amstrad, asking for the relevant documentation. They'd then photocopy the wrong pages from the firmware manual, and return them to me in the enclosed S.A.E. I'd then write to them again, explaining what I wanted, and they'd send a different but still wrong set. We'd repeat this several times, with a lag of weeks between each iteration. I also learned a lot from listings in magazines. Each monthly edition of Computing with the Amstrad would have program listings (games, utilities, lessons) in BASIC and Z80 Assembler. One could figure out a lot about how the machine worked by careful inspection of those listings. Funnily enough, I remember spending entire evenings at the tender age of 9 and 10, coding away without any distractions like email, web, music etc. I might have been more productive then than I am now :-(