MS OS/2 2.0??? 2.0 was long after the split with MS, I think you mean IBM os/2. Also 32 bit programming had been around for a long time before Microsoft got around to it. Os/2 had protected mode 32 bit in 1992, and PC hardware had been running 386 based 32 but unix variants since the mid 80's. even before that the 68000 had been running unix in 32 bit. Just because the win32 programming crowd didn't get to play with 32bit (and the joys of thunking) until '95 doesn't mean it was popular for a long time before.