MULTICS
       MULTiplexed Information and Computing Service (OS, MIT, Bell)
       

Multics
 /muhl'tiks/, n.

    [from ?MULTiplexed Information and Computing Service?] An early timesharing
    operating system co-designed by a consortium including MIT, GE, and Bell
    Laboratories as a successor to CTSS. The design was first presented in
    1965, planned for operation in 1967, first operational in 1969, and took
    several more years to achieve respectable performance and stability.

    Multics was very innovative for its time ? among other things, it provided
    a hierarchical file system with access control on individual files and
    introduced the idea of treating all devices uniformly as special files. It
    was also the first OS to run on a symmetric multiprocessor, and the only
    general-purpose system to be awarded a B2 security rating by the NSA (see 
    Orange Book).

    Bell Labs left the development effort in 1969 after judging that 
    second-system effect had bloated Multics to the point of practical
    unusability. Honeywell commercialized 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, and 
    Unix deliberately carried through and extended many of Multics' design
    ideas; indeed, Thompson described the very name ?Unix? as ?a weak pun on
    Multics?. 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 80s, and development on Multics
    was stopped in 1988. Four Multics sites were known to be still in use as
    late as 1998, but the last one (a Canadian military site) was
    decommissioned in November 2000. There is a Multics page at http://
    www.stratus.com/pub/vos/multics/tvv/multics.html.

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.

   <http://multicians.org/>.

   Usenet newsgroup: <news:alt.os.multics>.

   [Jargon File]

   (2002-04-12)