[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.
