... Unix¹

One of the few names that is not an acronym, but actually a play on words of Multics (Multiplexed Information and Computing Service). Multics was one of the first timesharing operating systems, apparently conceived of in terms of telephone network multiplexes. UNIX was initially a single-user system, hence the name. Ironically, it has kept the name even after it had developed timesharing.

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... POSIX.²

(Portable Operating System Interface for Computer Environment Spec 1170)

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... License³

The General Public License is not exactly public domain, but is more like a copyright against further copyrights and patents. The source code to software covered by this license must be made available by anyone who copies or modifies it for further distribution.

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... necessary.⁴

Torvalds had the following to say on this issue :

The day people think linux would be better served by somebody else (FSF being the natural alternative), I'll "abdicate". I don't think that it's something people have to worry about right now - I don't see it happening in the near future. I enjoy doing linux, even though it does mean some work, and I haven't gotten any complaints (some almost timid reminders about a patch I have forgotten or ignored, but nothing negative so far).

Don't take the above to mean that I'll stop the day somebody complains: I'm thick-skinned (Lasu, who is reading this over my shoulder commented that "thick-HEADED is closer to the truth") enough to take some abuse. If I weren't, I'd have stopped developing linux the day ast ridiculed me on c.o.minix. What I mean is just that while linux has been my baby so far, I don't want to stand in the way if people want to make something better of it.

(Taken from Linus's reply to someone worried about the future of Linux)

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... FreeBSD⁵

FreeBSD is actually one of a series of loose derivatives of 386BSD, along with NetBSD and OpenBSD.

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... clone.⁶

Torvalds himself would beg to differ :

``Other than the fact Linux has a cool name, could someone explain why I should use Linux over BSD?''

``No. That's it. The cool name, that is. We worked very hard on creating a name that would appeal to the majority of people, and it certainly paid off: thousands of people are using linux just to be able > to say "OS/2? Hah. I've got Linux. What a cool name". 386BSD made the mistake of putting a lot of numbers and weird abbreviations into the name, and is scaring away a lot of people just because it sounds too technical.''

(Linus Torvalds' follow-up to a question about Linux)

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... GNU⁷

GNU's Not Unix, an example of a ``recursive'' acronym appreciated by computer programmers

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... GNOME⁸

GNU Network Object Model Environment

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