Commodore 64 (not really an OS though

), then moved on to DOS 5.0 and eventually Windows 3.1. From there, I got into Unix for a while and then to Windows 95/98 days while I ran Red Hat/Mandrake distros as well as Novell Netware on my spare box.

Lately I've delved into the usual XP/XP x64 as well as Ubuntu and test run the Vista RC.