Multics /muhl'tiks/ N. [from "MULTiplexed Information And Computing Service"] An Early Time-sharing Operating System Co-designed By A Consortium Including MIT

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Multics /muhl'tiks/ n.

[from "MULTiplexed
Information and Computing Service"] An early time-sharing
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

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. There is a Multics
page at