How to spell “unix,”
with links

The name can be spelled three ways:

UNIX

This commercial trademark has been owned by Bell Labs/AT&T, The Santa Cruz Operation, Novell Inc., Unix International, and the X/Open Consortium, now known as The Open Group. It refers to any computer operating system package that is derived from the code base developed at Bell Labs beginning in 1969.

The Bell Labs documentation was very careful to always spell UNIX in all capital letters, and small caps whereever possible.

The name pokes fun at a mainframe operating system called MULTICS. The authors of UNIX thought MULTICS was far too complicated for what it does. Excessive complexity is considered a sign of poor software design, and indicates poor software design management.

unix

This is a generic name for all UNIX-like operating systems, including Linux. The last patent on unix expired in Septmber 1989, and it became legal to freely distribute a unix that was not derived from UNIX. On that date, unix (the conceptual design and its associated technological cullture) ceased to be the intellectual property of whatever corporation owned the UNIX code base, and became part of the human cultural heritage.

Unix

Capitalize the word “unix” if you use it at the beginning of a sentence.

Related names

Linux

1. This trademark belongs to Linus Torvalds. It refers to an operating system kernel which he designed to be usable with GNU. (He wanted to call it “Freeix,” but the people who ran his university's FTP server talked him out of that. It sounded too much like “freaks.” Linux was to be a temporary name until someone came up with something better. That was in 1991.)
2. Any operating system package or “distribution” which uses the Linux OS kernel.
3. The cultural phenomenon of freeware successfully competing with proprietary software in commercial, academic, NGO, and consumer environments.

   I believe Linux (the whole phenomenon) is fairly close to what the authors of UNIX intended UNIX to become.

BSD

Berkeley Software Distribution or Berkeley Standard Distribution. AT&T UNIX developed slowly in the 1970s and 1980s. They made the code base available to universities, and some schools derived their own operating system distributions from it instead of waiting for AT&T to get its act together. The UC Berkeley unix became more popular with technical users than UNIX. Sun Microsystems' SunOS (renamed Solaris 1) was derived mostly from BSD. Their Solaris 2 OS was an attempt to recombine UNIX and BSD. Today there are several “free” BSD products for PC-compatible computers. Yahoo runs on FreeBSD.

GNU

This acronym stands for “GNU's Not UNIX." The GNU project set out to replace UNIX with a freely distributable system with similar functions. They couldn't afford to do it all at once, so they replaced parts of UNIX one by one, beginning with the C/C++ compiler. GNU products are generally regarded as the highest quality freeware available. Most Linux distributions would be more respectfully called GNU distributions.