Editing Multics (section)

==Influence on other projects==

===Unix===
The design and features of Multics influenced the [[Unix]] operating system, which was originally written by two Multics programmers, [[Ken Thompson]] and [[Dennis Ritchie]].<ref name="Seibel" /> Influence of Multics on Unix is evident in many areas, including the [[hierarchical file system]], [[redirection (computing)|redirection]], the [[shell (computing)|shell]], and the naming of some commands. But the internal design philosophy is quite different, focusing on keeping the system small and simple, and so correcting some perceived deficiencies of Multics because of its high resource demands on the limited computer hardware of the time.

The name ''Unix'' (originally ''Unics'') is itself a [[pun]] on ''Multics''. The ''U'' in Unix is rumored to stand for ''[[wikt:uniplex|uniplex]]ed'' as opposed to the ''[[wikt:multiplex|multiplex]]ed'' of Multics, further underscoring the designers' rejections of Multics' complexity in favor of a more straightforward and workable approach for smaller computers. (Garfinkel and Abelson<ref>Garfinkel, Simson and Abelson, Harold. Architects of the Information Society: Thirty-Five Years of the Laboratory for Computer Science at MIT. MIT Press, 1999. {{ISBN|978-0262071963}}</ref> cite an alternative origin: Peter Neumann at Bell Labs, watching a demonstration of the prototype, suggested the pun name UNICS – pronounced "[[eunuchs]]" – as a "castrated Multics", although Dennis Ritchie is said to have denied this.<ref>{{cite newsgroup|author=Karn, Phil|title=Origins of unix|date=1981-10-28|newsgroup=fa.unix-wizards|message-id=4743@Aucbvax.UUCP|url=http://article.olduse.net/4743@Aucbvax.UUCP|access-date=2014-04-11}}</ref>)

Ken Thompson, in a transcribed 2007 interview with Peter Seibel<ref name="Seibel">Peter Seibel. [[Coders at Work]]: Reflections on the Craft of Programming. APress Publications, 2007. {{ISBN|978-1-4302-1948-4}}</ref> refers to Multics as "overdesigned and overbuilt and over everything. It was close to unusable. They [Massachusetts Institute of Technology] still claim it's a monstrous success, but it just clearly wasn't". On the influence of Multics on Unix, Thompson stated that "the things that I liked enough (about Multics) to actually take were the hierarchical file system and the shell — a separate process that you can replace with some other process".

Dennis Ritchie wrote that the design of UNIX was influenced by [[Compatible Time-Sharing System|CTSS]].<ref>{{cite conference |last=Ritchie |first=Dennis M. |author-link=Dennis Ritchie |year=1977 |title=The Unix Time-sharing System: A retrospective |conference=Tenth Hawaii International Conference on the System Sciences |url=https://www.bell-labs.com/usr/dmr/www/retro.pdf |quote=a good case can be made that UNIX is in essence a modern implementation of MIT’s CTSS system}}</ref>

===Other operating systems===
The [[Prime Computer]] operating system, [[PRIMOS]], was referred to as "Multics in a shoebox" by [[William Poduska]], a founder of the company. Poduska later moved on to found [[Apollo Computer]], whose AEGIS and later [[Domain/OS]] operating systems, sometimes called "Multics in a matchbox", extends the Multics design to a networked graphics workstation environment.

The [[Stratus VOS]] operating system of Stratus Computer (now [[Stratus Technologies]]) is very strongly influenced by Multics, and both its external user interface and internal structure bear many close resemblances to the older project. The high-reliability, availability, and security features of Multics are extended in Stratus VOS to support a new line of [[fault tolerant]] computer systems supporting secure, reliable [[transaction processing]]. Stratus VOS is the most directly related descendant of Multics still in active development and production usage today.

[[General Motors]]' [[Multiple Console Time Sharing System]] (MCTS) for the [[Control Data Corporation]] [[CDC STAR-100|STAR-100]] computer was based on Multics.

The protection architecture of Multics, restricting the ability of code at one level of the system to access resources at another, was adopted as the basis for the security features of [[International Computers Limited|ICL]]'s [[ICL VME|VME]] operating system.

The [[Edinburgh Multiple Access System]] (EMAS) draws particularly on the one-level store concept used by Multics, providing access to files only by mapping them into memory. All memory space is associated with a segment.
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