Source : Free On-Line Dictionary of Computing

Multics
     
         /muhl'tiks/ MULTiplexed Information and
        Computing Service.  A {time-sharing} {operating system}
        co-designed by a consortium including {MIT}, {GE} and {Bell
        Laboratories} as a successor to MIT's {CTSS}.  The system
        design was presented in a special session of the 1965 Fall
        Joint Computer Conference and was planned to be operational in
        two years.  It was finally made available in 1969, and took
        several more years to achieve respectable performance and
        stability.
     
        Multics was very innovative for its time - among other things,
        it was the first major OS to run on a {symmetric
        multiprocessor}; provided a {hierarchical file system} with
        {access control} on individual files; mapped files into a
        paged, segmented {virtual memory}; was written in a
        {high-level language} ({PL/I}); and provided dynamic
        inter-procedure linkage and memory (file) sharing as the
        default mode of operation.  Multics was the only
        general-purpose system to be awarded a B2 {security rating} by
        the {NSA}.
     
        Bell Labs left the development effort in 1969.  {Honeywell}
        commercialised Multics in 1972 after buying out GE's computer
        group, but it was never very successful: at its peak in the
        1980s, there were between 75 and 100 Multics sites, each a
        multi-million dollar {mainframe}.
     
        One of the former Multics developers from Bell Labs was {Ken
        Thompson}, a circumstance which led directly to the birth of
        {Unix}.  For this and other reasons, aspects of the Multics
        design remain a topic of occasional debate among hackers.  See
        also {brain-damaged} and {GCOS}.
     
        MIT ended its development association with Multics in 1977.
        Honeywell sold its computer business to {Bull} in the mid
        1980s, and development on Multics was stopped in 1988 when
        Bull scrapped a Boston proposal to port Multics to a
        {platform} derived from the {DPS-6}.
     
        A few Multics sites are still in use as late as 1996.
     
        The last Multics system running, the Canadian Department of
        National Defence Multics site in Halifax, Nova Scotia, Canada,
        shut down on 2000-10-30 at 17:08 UTC.
     
        The {Jargon file} 3.0.0 claims that on some versions of
        Multics one was required to enter a password to log out but
        James J. Lippard , who was a Multics
        developer in Phoenix, believes this to be an {urban legend}.
        He never heard of a version of Multics which required a
        password to logout.  Tom Van Vleck 
        agrees.  He suggests that some user may have implemented a
        'terminal locking' program that required a password before one
        could type anything, including logout.
     
        {Home (http://www.multicians.org/)}.
     
        {Usenet} newsgroup: {news:alt.os.multics}.
     
        [{Jargon File}]
     
        (2002-04-12)