The KIM-1, 50 years old as of 2026, was the first 6502-based home computer, designed by the legendary Chuck Peddle and sold by MOS Technologies themselves. (Well, we’re not sure if the Apple I or the KIM-1 was first. Or maybe it was the JOLT? As I’ve said before, there’s always something you’ve never heard of before out there, waiting to make you look like a fool.)
Someone on Mastodon (I can’t find the post now) mentioned that the KIM-1 had excellent programming guides, as it rightfully must have had, considering a freshly-assembled KIM had to have been programmed in raw machine code, and coming from an era before the World Wide Web. I had a look and, lo, it did!
Have a look for yourself, from a copy hosted by Rich’s Classic Computer Pages (PDF). Explained in an early chapter is how to properly add together numbers of arbitrary sizes, something that I had to find out from random sources. I wish I had this book when I was programming on the Commodore 64; I did have the famous Programmer’s Reference Guide, but that’s just it. It’s a reference work, and very difficult to learn the principles of assembly coding through it directly. (That said, there are pages in the C64 PRG that will look very familiar to someone flipping through the KIM-1 Programmer’s Guide.)
If you sat down and read this all the way through, and it’s quite readable for a programming manual, you’d be well placed to write code for, not just the KIM-1, but any 6502 computer. While for other machines you would need more information, like memory maps and hardware documentation, and you might like to have an assembler too, you’d still have a great foundation for whatever crazy programming adventure you were about to embark upon. I love it.
