<A HREF="http://www.multicians.org/"
  >Multics</a> is the "great" *(OS) (written in _(PL/I)) whose design began in the late 60's, co-written by MIT, AT&T Bell Labs and GE, that was meant to become the be-all- end-all of _(OS) technology by having just every (un)imaginable feature, and that was supplanted by _(Unix), despite the fact that Multics was much better(?) designed, because _(Unix)' simple and stubborn design was much more adapted to the very resource-poor architectures of the time. Ken Thompson began UNIX after AT&T Bell Labs pulled out of the Multics project in 1969. The official story is that it was a research system, but we all know that it was really so he could port SpaceWar to the PDP-7. Eventually, Multics was aquired by Honeywell, and supported by them. The last known Multics mainframe was taken offline in October, 2000.