Why is linux not unix?

[dmb]

I have been trying to research this in books, wikipedias and newsgroups. I can't seem to figure out why linux is not considered unix, and cannot be called unix. It seems like linux is fully posix complient. Why exactly does linux not pass the unix certification?

In some groups, people actually say linux is unix, and some say its its only kind of unix. Anyone willing to clear this up for people and me?

[Kimm]

Linux works just like UNIX does, the difference is that Linux has not bought a license, so Linux is not allowed to be called UNIX.

[Kronoz]

Linux is a variant of Unix in the same way Ubuntu is a variant of GNU/Linux.

[dmb]

How is it that freebsd/openbsd/netbsd are able to call themselve unix? I doubt they payed for a unix license.

[Kimm]

They did, or atleast BSD, I supose they can call themeselfes that since they are based off of eachother (and no: Linux is not based on UNIX, they have no code incommon)

[Almighty]

Actually the Free/openBSDs are concidered clones of Unix. I don't really know if people actually call them Unix systems.

[DoktorSeven]

Because GNU (as in GNU/Linux) ->Gnu's Not Unix

[Kimm]

GNU can be used in FreeBSD/Solaris (and so on) too, but they are still UNIX, GNU is just a collection of tools, Linux is one of the Kernels avilable that uses GNU, but that doesnt effect if it is UNIX or not.

(GNU is Not UNIX, means that the utilities, that resemble UNIX utilities are as a mather of fact, not, they are GNU utilities)

[Qrk]

http://www.unix.org/what_is_unix/fla...nix.html#linux

This page is interesting. Scroll down to read about Windows.

Should the functionality meet the requirements of the UNIX brand then indeed it could become a registered UNIX system.

[stoeptegel]

I have been trying to research this in books, wikipedias and newsgroups. I can't seem to figure out why linux is not considered unix, and cannot be called unix. It seems like linux is fully posix complient. Why exactly does linux not pass the unix certification?

Because of the history. In the movie "revolution OS" Richard Stallman himself tells about this.
( /me mumbles something about a torrent on demonoid)

EDIT
Sorry, i misunderstood your question.