I grew up on a CoCo3; loved that thing as well :) OS-9 Level II was where I first learned a Unix-like OS (on a tiny 6809 machine!) OS-9 Level II was truly a remarkable achievement for such a tiny machine: multi-tasking, windowing, and more. Dungeons of Daggorath was also an epic game. Basic09 was an interesting Basic-dialect that provided more structural programing to the normal sprawling Basic program. And of course who could forget Rainbow Magazine.

I was pro-Apple and anti-Tandy back then, so I looked down on the CoCo and didn't realize how cool a computer it was until later. Now that I'm older and wiser (?) I realize how silly technology partisanship is. Each device and technology should be evaluated on its own merits and not by which camp it comes from.

Old habits are hard to break! I took a fun loving shot at TRS-80s on the cOS Test/Demo disk. There is a goofy Windows 9 "release" on there where I labeled the trash can... wait for it... "TRS-80". I just saw some old CoCos at a vintage computer show. Actually really cool what people were doing with them!

You could do the same with the C64 (probably quite a few other 80's home machines). The ROM's were bank-switched in, and if you want to you can copy the ROM into RAM and switch out the ROM banks. Quite a few extensions made use of that.