good question. let me dig in my memory.
the first computer i got to use was a TRS-80 III i believe in highschool. this thing was already old at the time which was the late 90s, but it did the job. we had a full classroom of them, one of which was acting as a server with two floppy disks, and all the others were booting off the server, freeing the floppy drive for our data. we learned BASIC on it, so i guess that is all that was running on there.
the school also had a 286 i believe, (i am guessing by what models were common in the late 80s) in the library running Novell Netware that i was allowed to use. i distinctly remember wondering if that was unix, trying some unix commands that i had read about. i was able to use turbo pascal on it and a few other programs.
the science teacher had an Apple II i think that i was also allowed to play with occasionally. i remember pranking the teacher with a function that would turn the desktop upside down. and at home we had a PC or compatible. most likely a Tandy 1000 from RadioShack. i remember that the family bought some software for it. was it DeskMate? i don't recognize the screenshots that i can find online now. i do remember using word perfect and connecting to BBS systems with a modem, downloading software that i would try out and play around with.
oh, before all that i did a 3 week internship at a machine design company where i got to use autocad on a PC on whatever that was running on. probably DOS as well.
i had friends with ataris or amigas. but i never got a chance to actually use them, the friends were just showing them to me.
one more interesting detail from that time. at one point we visited friends who had an amiga i believe with a floppy drive that could write 10MB on a 3.5" floppy. i could not find a reference to that on wikipedia, so i don't know what that was. but i am pretty confident that i remember the 10MB capacity correctly.
when i entered university in the early 90s i got my first computer that was actually my own. it came with DOS obviously, while we were using unix at the uni (SunOS/Solaris/AIX (also one class where we got access to VMS)) and when i discovered linux, i made it dual boot, and i remember every time i reinstalled linux to upgrade it, i shrank the DOS partition until finally it was gone completely.
around the same time when i visited my grandparents, grandma, who was volunteering as a secretary for some NGOs wished for a computer. grandpa sent me out to get one, and i picked OS/2 to run on it. i believe i installed emacs for her to use, and LaTeX which i had learned about at uni. when i came back a year later, someone helped her by installing windows on it. could not have that. then i decided to change universities and study in my grandparents home town, so moved in with them, of course bringing my linux computer. grandma was intrigued and wanted to learn linux too. again, emacs and LaTeX set up for her and the G.R.E.A.T desktop system.
wow, long answer. i got a but carried away, sorry. i hope it is interesting.