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I'm just asking out of curiosity, is there a way to obtain a 'pure' so to say copy of Unix? So, not OS X or Linux with Unix in the background, but simply Unix..
Like I said, this is simply out of curiosity; also, I'm not to familiar with the world of Unix yet, so this may be a dumb question. I'm honestly not sure..

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Linux is GNU software based and therefore not unix... Check what GNU stands for ^_~ –  Sardathrion Mar 8 '12 at 10:11
Unix is dead. Long-live Unix! –  mikeserv Jun 22 at 3:11
The closest to original version of Unix I've been able to find for free online is AT&T UNIX System V Release 4 Version 2.1. You can get it at winworldpc.com. –  Strato1 Jul 3 at 17:11
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6 Answers 6

Unix as a standalone entity doesn't exist as a modern operating system.

As indicated by the comments for unix-derivatives:

Several systems started with Unix source code, but this was written out over time so that no original Unix code remains. The best known examples are OpenSolaris, FreeBSD, NetBSD and OpenBSD.

FreeBSD 5.3   2004-08
OpenBSD 4.6   2009-10
NetBSD 5.0.2  2010-02
OpenSolaris build 135 2010-03

and unix-clones

There have been many systems which implement the Unix system calls, library APIs and commands, but which did not include any original Unix source code. Here is a small selection.

Minix 1.1 1987-01
Xinu  1987-01
Minix 1.5 1989-11
Linux 0.96c   1992-07
Coherent 4.2  1994-12
Minix 2.0 1996-10
Linux    2010-04

Modern distributions don't contain any original unix code, or at least - none of the open source variants that are freely available.

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Oh okay. I believe that answers my question then. –  James Litewski Mar 8 '12 at 10:18
@JamesLitewski, you should accept the answer then. –  HalosGhost Jun 22 at 1:14
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This image shows a simplified version of the history of the unix-like operating systems. Depending on what you call the "one true unix system", you may download it as open source or you can buy a license for it. The latter will be expensive if at all possible.

For more in depth information, see unix history as pointed out by AProgrammer in the comment.

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Well, that's a simplified version of the history. See levenez.com/unix for a more complete one. –  AProgrammer Mar 8 '12 at 10:12
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As soon as Unix got out of the Bell Labs in 74 or so, Unix became a family of OS more than an OS. And since 89, there have been no release on the original branch. The trademark "Unix" has changed multiple time of owner and currently it is defined by a set of interface and you can by the right to use it if you show that you comply to the current definition.

You may be able to use one of the ATT one on an emulator (I've seen some packaging for some release, but not the latest one).

Commercial Unix (Solaris, AIX, HP-UX) have usually taken the pain to go through the certification process. Solaris was available at no cost from Sun (I think Oracle changed the condition) and has been put in open source. Going that path is probably the cheapest way to get something near of what has been allowed to use the label. But affirming that it is a "pure" unix is under debate. Some BSD derivatives have good arguments for "purity" as well.

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If you want to be hard core, you can run a V7 Unix on a PDP-11 emulator. I've done this, and it had better performance than VAX running 4.2BSD I used in college.

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Cool. We admin'd the same way back when. Always laughed at the paper tape boot loader on our DG mainframe. –  Arcege Mar 8 '12 at 19:19
That's pretty cool. So it pretty much simulates an original version of Unix? –  James Litewski Mar 8 '12 at 19:33
It is the original version of Unix, running on simulated hardware. And the source is available too. Reading through the source of a C compiler written by Dennis Ritchie himself was kind of a religious experience for me... –  TMN Mar 8 '12 at 19:36
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You mean something like


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Maybe, I'm just looking for a non GUI based system pretty much, that runs on Unix. –  James Litewski Mar 8 '12 at 10:15
If it was not unix i would recommend linuxfromscratch.org –  tonymarschall Mar 8 '12 at 10:17
@JamesLitewski. you got the things in the reverse order. Undex Unix, the GUI is mostly an application layer which run over the OS. Any variant will easily provide you with a command line interface and just that (with the potential exception of MacOS about which I know very little). –  AProgrammer Mar 8 '12 at 10:33
@tonymarschall, I'd not recommend linux from scratch to someone not yet familiar with Unix. –  AProgrammer Mar 8 '12 at 10:33
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What do you mean by UNIX? The last "true" Bell Labs unix was Version 10 from 1989, never released to the public. Most modern UNIXes descend ultimately from Version 7. The history of UNIXes is very messy, a brief version is available here. From there, it gets very messy. You can trace UNIX from there to either (closed-source) System V UNIX or BSD. If you want to go down the BSD path, FreeBSD is a good option. For a System V-like system, your only real free option would be OpenSolaris. But nowadays, Linux is as pure a unix-like system as any, with its own, even messier heritage. (You can get a taste of it here.)

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