Timeline: 40 years of Unix

Year-by-year details of Unix' history


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.


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."


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.


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.)


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.


Ken Thompson and Dennis Ritchie
Thompson and Ritchie in the early days of Unix.

Dennis Ritchie develops the C programming language.


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.


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.


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

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