what defines if it is Unix or not?

[Chooco]

Windows is not Unix
BSD is Unix
Linux is NOT Unix, it is Unix-like
BeOS is not Unix
Solaris is Unix

what is Unix then? why is Linux not Unix but BSD is Unix, you can download .tar.gz files and install them on either BSD or Linux systems and both will work fine.

 

[Barnaby W. Füi]

bsd and linux are neither unix. unix was made by bell labs (right?) in the 70's. everything since then that gets referred to as a unix, is just built to be similar and/or compatible with unix. you're best off calling them "unix-like".

bsd and linux are unix-like, windows is not, beos is. (IIRC, i never used it personally)

 

[Nothinman]

beos is not, although it had a decent POSIX layer (because it was an easy way to get a fair number of apps working quickly)

POSIX is a standard that all unixes try to abide by, although most have their quirks. UNIX is basically just a trademark that you pay to use (I think SCO owns it now).

tar.gz files are basically zip files, they're not tied to any OS. They work on most unixes because they're usually source code you compile on the host system, if they were binary they wouldn't work because differnent unixes have different CPUs (i.e. Tru64 only runs on Alpha, Solaris on Sparc (x86 support is poor at best and might not be continuted), Irix on MIPS, etc) and different binary format (most have switched to elf, but some still use COFF).

 

[manly]

Unix is simply a trade name that's been transferred a few times now (SCO was the last company to acquire it, so Caldera owns the Unix trademark now?). But it also refers to any systems derived from the original AT&T sources; specifically SVR4 is the last major release that commercial systems were derived from.

BSD (aka Berkeley Unix) is definitely considered Unix, because it was a fork of earlier AT&T Unix sources.

Note that in reality "Unix" doesn't mean much anymore. Even though Solaris is derived from SVR4, I doubt there's much from the original sources that's survived until now.

And Linux is called Unix-like because it didn't license any Unix source code, and instead was completely independently created (largely from scratch). IMHO, in spirit, it's a Unix system; in legal terms it is not.

 

[Bremen]

Unix was created by Bell Labs back in the stone age of computing ;0) Anyway, since AT&T was a monopoly back then they were legally barred from profitting from it. So they gave it away, and this is were BSD comes from, as well as many others. Today Unix is a trademark, where you have to follow certain rules and then pay lots of money to be certified as following those rules. Anyway, BSD (and I believe linux too) both qualify as Unix's, however the communities that produce them do not have the money nor the motivation to become certified. There was even a group that managed to get WinNT to comply with the Unix specification.

 

[Nothinman]

Anyway, BSD (and I believe linux too) both qualify as Unix's,

Linux does not, the BSDs may because they were derived from 386BSD, although by now I'm sure none of the original code remains.

There was even a group that managed to get WinNT to comply with the Unix specification.

NT 4 was POSIX compliant, it was not Unix. And even so, it's POSIX support was poor at best, it only got certified through loopholes in the certification process, which have been fixed according to some USENIX people, which is why you don't see Win2K or XP being mentioned as POSIX compliant.

 

[Bremen]

<< Linux does not, the BSDs may because they were derived from 386BSD, although by now I'm sure none of the original code remains. >>

You seem to be under the impression that there needs to be a common code base in order to become a Unix. This is not true, although that needs to happen is that it support the Single Unix Specification. Which is currently at version 3.

Also regardless of M$'s efforts at posix compliance there are a number of companies that did provide add-ons for additional functionality. From the OpenGroup's website:

<< Should the functionality meet the requirements of the UNIX brand then indeed [WinNT] could become a registered UNIX system. >>

 

[Nothinman]

You seem to be under the impression that there needs to be a common code base in order to become a Unix. This is not true, although that needs to happen is that it support the Single Unix Specification. Which is currently at version 3.

To be really called UNIX you need to pay for certification, I thought.

Also regardless of M$'s efforts at posix compliance there are a number of companies that did provide add-ons for additional functionality. From the OpenGroup's website:

The only one I know of off hand is Interix, and didn't MS buy them a while back?