My first job straight out of engineering school in 1983 was developing Z80 embedded code. My 'development system' was some kind of semi home made floppy disk ba

My first job straight out of engineering school in 1983 was developing Z80 embedded code. My 'development system' was some kind of semi home made floppy disk based CP/M computer with 48K of RAM and the native Dev tools including ED a command line editor and ASM an 8080 assembler (which was basically sufficient if not ideal for writing Z80 code). For the first few days I recall being confused about the difference between the ED command line and the CP/M command prompt. In other words, I was all at sea. But it was basically being thrown into the deep end and I learned fast. Within a year or so I was writing my own BIOS for an Intel bubble memory based customer CP/M computer that we were embedding into a field application. I didn't have the proper OEM documentation, but if you understood the CP/M architecture you didn't really need it.