OS/2 warp had preemptive multitasking and a badass BSD-based networking stack before unix was "in". writing PM programs was not the asinine exercise that making anything in win32 was(/is). the registry made sense even to the uninitiated. loading new device drivers was often a simple matter of adding another line to CONFIG.SYS. IBM's DOS emulation was often a superior performer for playing games than straight DOS if you were so inclined. the list goes on ... it was a helluva of an OS at the time.