computer systems I have used
1984 I got employed by the Kuwait Petroleum Refinery in Rotterdam.
my first job was the creation of interactive input screens in HP basic to replace batch punch-card input for the batch IBM system.
The legend is that one owner of Kuwait Petroleum was sitting next to Ken Thompson during a long international flight. The interesting result was that from then on managment was forced to leave the IBM eco system and move all systems over to AT&T 3B2 systems running UNIX. This totally changed my life and carriere.
Soon we started to use UNIX workstations running SCO on the IBM PC. At some point we met with Andrew S. Tanenbaum, and shortly I was using an early version of Minix. Very soon however, Linus posted the first version of Linux to the minix usenet group, which I started using on my personal IBM Clone at home, and later also in the office.