unix

UNIX was originally developed circa 1969 in AT&T Bell Labs. Key developers: Dennis Richie and Ken Thompson.

Development was coupled to the invention of the C programming language, which allowed UNIX to be semi-portable to different hardware. (11,000 lines of portable C and 1000 lines of machine dependent assembler in those early days)

As discussed below, UNIX includes a kernel and a number of small components and utilities built to work with the kernel.

Circa 1974 the source was made available to selected Universities, including the U of T and especially Berkeley. This led to different "flavors" of UNIX. The code remained property of AT&T and the Universities signed non-disclosure agreements.

In about 1979 various commericial vendors began to adopt UNIX under license from AT&T. The number of flavors increased (System V, BSD, HP-UX, Solaris, IRIX, etc.).

In 1984 Richard Stallman drove the beginnings of the Open Source movement with the foundation of GNU. (GNU stands for "Gnu is Not Unix."). Later this became the Free Software Foundation. They began introduce open source products to work under UNIX.
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One of their first and biggest successes was developing a C compiler, gcc, that was superior to any commercially available ones.

Virtually all of the proprietary utilities, shells, etc. that are associated with UNIX have now been re-written by GNU as Open Source.

In 1991 21 year old Linus Torvalds wanted to buy a UNIX for his own computer but couldn't afford it. So he began writing a UNIX-like operating system called Linux. He made it Open Source.

With the Linux kernel and all of the GNU utilities available as Open Source, the GNU/Linux computing environment is at least as rich and powerful as the proprietary UNIX one.

Below we will occasionally refer to "UNIX/Linux," implying that UNIX and Linux are synonyms. From the standpoint of a user this is largely true. We should more properly refer to "UNIX-GNU/Linux" to give proper credit to GNU for their important role in the Linux computing environment.



Under the terms of the GPL, any person may obtain and change the code covered under the license, but must make those changes available at no charge to the world.
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The terms of the license means, for example, that a commercial vendor of GNU/Linux, such as Red Hat, must make their distribution available at no charge.