And not a mention of CP/M, the 8-bit Disk Operating System that was ubiquitous till about 1985.

I still use it, but with a Z80 emulator on a 64-bit machine. One of my emulators if rendered in the real hardware of the era would have cost somewhere around 40-50 thousand dollars. These days it's merely about 140 megabytes of data tucked away in a directory