Linux - A Brief History

A good history of the Unix operating system is available at Wikipedia1. UNIX wasan operating system originally written at AT&T Bell Labs in the late 1960's by Ken Thompson, Dennis Ritchie, and others. Thompson had been working on an earlier operating system project named Multics (Multiplexed Information and Computing Service) in conjunction with MIT and General Electric. While working on the project, Thompson had written a game called Space Travel for the GE mainframe being used for Multics development.

After AT&T Bell Labs withdrew from the Multics project, Thompson began porting his Space Travel game to a DEC PDP-7 minicomputer at Bell Labs, and in the process began work on a new
operating system he named Unics (for Uniplexed Information and Computing Service); the spelling was later changed to Unix and when it was owned by AT&T was written in all capitals as UNIX.

Over time, Thompson, Ritchie, and others at Bell Labs continued developing UNIX. In 1973 the entire operating system was rewritten in Ritchie's new C programming language, and during this time AT&T began giving the operating system to universities, research institutions, and the US government under licenses, which included all source code. In 1982, when AT&T realized that they had an OS on their hands that was worth something, they changed their licensing model and began selling UNIX as a commercial product without source code.

Meanwhile, at the University of California, Berkeley, Bill Joy and others had begun to develop BSD5 Unix as an alternative to the now-commercialized AT&T Unix. BSD Unix went on to become immensely popular, especially in the academic world, and Bill Joy eventually left Berkeley to go to work for a small startup named Sun Microsystems where he created the SunOS version of Unix which eventually became Sun Solaris.

Throughout the next two decades, many companies and organizations produced their own versions of Unix, usually under license from AT&T or from the Berkeley branch. This led to a proliferation of differing operating systems that were called Unix. For example, at one time, one could acquire "Unix" from various entities such as: AT&T (System V), UC-Berkeley (BSD Unix), IBM (AIX), SGI (IRIX), Microsoft (Xenix), SCO, HP (HP-UX), and others. During the late 1980's, it was thought that Unix would become the dominant operating system among PC users, but the divisions among the participants and the wrangling for control of Unix created an opportunity for Microsoft Windows NT to fill the gap in the market, and for Microsoft Windows to, instead, dominate the industry.

Eventually, while getting out of the computer business, AT&T washed their hands of Unix and sold all rights to Novell, which eventually transferred control to the Open Group. The Open Group is not a company, but rather is an industry consortium which sets standards for Unix. The Open Group published the Single Unix Specification (SUS) in 2002 which is a family of standards that defines what Unix is, is not, and what OS's qualify for the name. The SUS is now maintained by the Austin Group for the Open Group.
  

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