Zylog Z80 assembler? Please tell me it was on an Amstrad CPC, I felt so lonely, all my friends had Spectrums and C64's!
No, it was not.
Back in the 80's, during Brazil's military government, the brazilian computer market was closed to foreign makers, in a (frustrated) intention of boosting the national industry. The only exception was that mainframes could be imported.
From 1980 to 1985 I worked for a Brazilian computer maker called Polymax (the company doesn't exist anymore). That company, as well as all the competitors, used to develop and sell 8 bit CP/M based microcomputers, by practicing a mix of reverse engineering and pure native engineering. Polymax's clients used those machines not only for word processing, but also for systems like payroll, accounts, finances, etc. My job was to develop disk drives, disk testing software, memory testing software, some OS tweaking, EPROM programming software, that kind of stuff.
Here's one of the Polymax models I worked with. As I recall, the system had 48 KB RAM, two 8" floppy drives, keyboard, 10-12" monochrome CRT monitor, parallel and serial outputs. The only ROM was on the video board. Upon turning on the computer, the diskettte drive intiated the boot, by calling a bootstrap loader located on track 0, sector 0 of the "A" disk. That loader then initiated the loading of the CP/M OS from that disk.
For me, those were very good times. You just had to know Assembler in order to fully understand the whole operating system in a couple of days...