History of Unix

Origins of Unix

UNIX development was started in 1969 at Bell Laboratories in New Jersey. Bell Laboratories was (1964–1968) involved on the development of a multi-user, time-sharing operating system called Multics (Multiplexed Information and Computing System). Multics was a failure. In early 1969, Bell Labs withdrew from the Multics project.

Bell Labs researchers who had worked on Multics (Ken Thompson, Dennis Ritchie, Douglas McIlroy, Joseph Ossanna, and others) still wanted to develop an operating system for their own and Bell Labs’ programming, job control, and resource usage needs. When Multics was withdrawn Ken Thompson and Dennis Ritchie needed to rewrite an operating system in order to play space travel on another smaller machine (a DEC PDP7 [Programmed Data Processor 4K memory for user programs). The result was a system called UNICS (UNiplexed Information and Computing Service) which was an
’emasculated Multics’.

Unix Development

The first version of Unix was written in the low-level PDP-7 assembler language. Later, a language called TMG was developed for the PDP-7 by R. M. McClure. Using TMG to develop a FORTRAN compiler, Ken Thompson instead ended up developing a compiler for a new high-level language he called B, based on the earlier BCPL language developed by Martin Richard. When the PDP-11 computer arrived at Bell Labs, Dennis Ritchie built on B to create a new language called C. Unix components were later rewritten in C, and finally with the kernel itself in 1973.

Since it began to escape from AT&T’s Bell Laboratories in the early 1970’s, the success of the UNIX operating system has led to many different versions: recipients of the (at that time free) UNIX system code all began developing their own different versions in their own, different, ways for use and sale. Universities, research institutes, government bodies
and computer companies all began using the powerful UNIX system to develop many of the technologies which today are part of a UNIX system. By the late 1970’s, a ripple effect had come into play.

Key Factors

1969 The Beginning

The history of UNIX starts back in 1969, when Ken Thompson, Dennis Ritchie and others started working on the “little-used PDP-7 in a corner” at Bell Labs and what was to become UNIX.

1980 Xenix

Microsoft introduces Xenix. 32V and 4BSD introduced.

1983 System V

Computer Research Group (CRG), UNIX System Group (USG) and a third group merge to become UNIX System Development Lab.
AT&T announces UNIX System V, the first supported release. Installed base 45,000.


UNIX System Laboratories (USL) becomes a company – majority owned by AT&T. Linus Torvalds commences Linux development.
Solaris 1.0 debuts.

1998 UNIX 98

The Open Group introduces the UNIX 98 family of brands, including Base, Workstation and Server. First UNIX 98 registered products shipped by Sun, IBM and NCR. The Open Source movement starts to take off with announcements from Netscape and IBM. UnixWare 7 and IRIX 6.5 ship.


Apple Mac OS X certified to UNIX 03.