My first computing was on an IBM 370 mainframe.
My first home computer was a Heathkit -- I don't remember the model number. That was around 1979. I indulged in a IBM PC/AT when those first came out (maybe 1982). It was quite expensive at the time.
For software -- mostly I used IBM 370, either MVS or VM. That Heathkit used HDOS, with a FAT12 file system. I think Heathkit bought that from the same small developer that Microsoft used for its early software. Later I went to CPM (on the Heathkit). After that it was mostly IBM 370 at work and MSDOS at home, until around 1995, when I started to play with linux -- initially slackware. I was also using a Sun Solaris system at work at that time. I joined evcforum at around the time I was moving from Sun Solaris to openSUSE (well, to SUSE 10.1, before openSUSE existed).
Fundamentalism - the anti-American, anti-Christian branch of American Christianity