difference between linux and unix

What exactly is the difference between unix and linux? Are they related at all?

In practice, there really is no difference. The same programs are available and will run on both a Linux and the various UNIX machines (BSD, Solaris, AIX, IRIX, etc.) They both have a similar file structure, similar commands, and the like. There are some very minute differences between how some things are implemented, but for the most part, you can interchange the two and you'd never know the difference. Perhaps the biggest user-visible differences in Linux and UNIX are that drivers, such as ATi or NVIDIA display drivers are not interchangeable between Linux and UNIX. Also, Linux is GPL v2 code and the licenses in UNIX range from the BSD license to proprietary licenses.

In principle, Linux and UNIX are their OSes' kernel- the backest of back-end part of the OS that takes system requests and talks to drivers. The Linux and UNIX kernels are of a little different structure and are not related in structure, but accomplish the same function. Richard Stallman and his GNU group wrote the rest of the backend for most UNIX-like OSes. The GNU system tools are slightly tweaked between UNIX and Linux to deal with each individual kernel but provide the same interfaces on the front end to the programs and such- that is why UNIX and Linux seem so similar.

About the only good thing SCO did to the UNIX source was to help remove MS copyright claims to some of the Xenix components. But then the irony is that at the time MS owned a 20% investment in SCO. Vr4 Licences were making MS cash.

Thanks for posting but it looks like the forum software dug up another ancient post from three years ago. Oops.

Linux is not descended from Unix, it is a complete re-write.

Linux is also free and open source.

Note that there are a couple of free, open-source, genuine Unixes available - BSD and OpenSolaris.

Ijack - Is Solaris really Unix? I can't see that SCO would allow an unlicensed Unix implementation.

Unix can also be MacOS X, AIX (IBM's Unix) and HP-UX (HP's Unix).

Anyways, Unix and Linux has many similarities and some differences. For example, most commands used on a Linux system can be used on a Unix (Solaris, BSD, Mac OS X) with little or no variation in switches and behavior. Unix and Linux have similar design, and their kernel use the same general idea, though with each Unix/Linux variation, it has its differences. However, Unix was engineered in the late 60s, ran on large computers and wasn't really what it is today. Although the newest Unix systems (OS X, Solaris and Unix variants [Linux]) use some of the same concepts that were in use in the late 60s, it wasn't until BSD and System 7 (AT&T) when Unix began to be engineered the way we see it today. And that's not to say that Unix isn't being added on, although not much.

There is something called POSIX compliant, which is a set of standards (POSIX is Portable Operating System Interface) - Unix was the root of POSIX. However, Windows NT (NT, 2000, XP, Server, Vista, 7) is somewhat POSIX compliant. Linux, surprisingly, is only somewhat compliant, simply because there are too many variations of it, but Solaris, BSD and OS X are fully POSIX compliant. However, just because it is POSIX compliant doesn't mean its Unix. (Ha! Windows Vista, for example, is FAR from it!)

The advantages of Unix and Linux is that it is very robust, secure and trusted for heavy duty tasks. You wouldn't use Windows XP, for example, to run a nuclear power plant or keep billing information for a large cell-phone provider company. You'd use Unix or a variant of it. Unix and Linux are inherently secure in their design, and most Unix variants have features to help keep it that way. Unix and Linux are also very versatile--you could put Unix to use for tasks as big as a Net server of a popular site all the way to a desktop business computer, and, since some Linux distros are easy to use, such as Ubuntu, it could also be used in schools and homes.

Right now, Windows is the only non-Unix operating system in wide use (note I said wide use--I know there's Non-Unix, Non-Microsoft OSes out there, but who uses them but a select few?). I'm sure down the road that the NT kernel will over stay its welcome at Redmond and find itself in the digital Dumpster behind their headquarters and that Microsoft will adapt a Unix kernel much like Apple did with Mac OS X. Everything else (that's widely in use) runs Unix or a variant. So once Microsoft makes that change and only if they decide to, then the world will be 99% Unix or Unix-variant.

Does anyone else find it ironic that apple switched its operating system to be unix-based? They aren't exactly "thinking differently" by moving back towards a system that has been a long established standard in OS design. It was probably a smart move on their part, but that doesn't mean it isn't hypocritical

--Zorak

P.S. As I have become interested in different operating systems, I think it would be cool if we saw other non-MS, non-Unix-derivative OSes become more prominent. I'd kind of like to try out SkyOS, MenuetOS/KolibriOS, Haiku/BeOS, and AmigaOS just to see what kind of different ideas are available. Maybe if I ever have free time ever again (probably not anytime this semester), I might eventually give them a whirl.

SCO have nothing to do with it (nothing to do with much nowadays!). It's been established in court that Novell, not SCO, holds the rights to Unix.

That's an interesting statement. Although many GNU programs were ported to BeOS I've never heard anyone suggest that it is based on Unix. It's not even a multi-user OS.

Mac OS is not Unix, any more than Linux is.

You're quite correct BeOS is not Unix, officially or otherwise.

Does the word 'NeXT' mean anything to you?

Steve Jobs has been doing Unix (or, at least, Unix-like OSes) for twenty years.

If you want to play with a NeXT environment then take a look atOpen Step. You can take a bit of a look at it running on Mach here