Timeline: 40 years of Unix

Unix at 40

• The past, present and future of a revolutionary OS
• Timeline: 40 years of Unix
• On the shoulders of giants:
  3 Unix movers and shakers
• Survey: Unix has a long and healthy future, say users
• Graphic: The Unix family tree

Computerworld - Ever wonder about how Unix got started, not to mention all the twists and turns it took along the way? Here are some milestones of the operating system's four-decade-long history.

1956

A U.S. Department of Justice consent decree enjoins AT&T from "engaging ... in any business other than the furnishing of common carrier communication services."

1969

Mar. -- AT&T-owned Bell Laboratories withdraws from development of Multics (Multiplexed Information and Computing Service), a pioneering but overly complicated time-sharing system. Some important principles in Multics will be carried over into Unix.

Unix got its start on the PDP-7 minicomputer.
Credit: Toresbe (cc-by-sa 1.0)

Aug. -- Ken Thompson at Bell Labs writes the first version of an as-yet-unnamed operating system, in assembly language for a DEC PDP-7 minicomputer.

1970

Thompson's operating system is named Unics, for Uniplexed Information and Computing Service and a pun on "emasculated Multics." (The name is later mysteriously changed to Unix.)

1971

Feb. -- Unix moves to the new Digital Equipment Corp. PDP-11 minicomputer.

Nov. -- The first edition of the "Unix Programmer's Manual," written by Ken Thompson and Dennis Ritchie, is published.

1972

Thompson and Ritchie in the early days of Unix.

Dennis Ritchie develops the C programming language.

1973

Unix matures. The "pipe," a mechanism for sharing information between two programs, which will influence operating systems for decades, is added to Unix. Unix is rewritten from assembler into C.

1974

Jan. -- The University of California at Berkeley receives a copy of Unix.

July -- "The UNIX Timesharing System," by Dennis Ritchie and Ken Thompson, appears in the monthly journal of the Association for Computing Machinery (ACM). The authors call it "a general-purpose, multi-user, interactive operating system." The article produces the first big demand for Unix.

1976

Bell Labs programmer Mike Lesk develops UUCP (Unix-to-Unix Copy Program) for network transfer of files, e-mail and Usenet content.