As I read in Wikipedia, Unix started as a revolutionary operating system written mostly in C allowing it to be ported and used on different hardware. Descendants of Unix is mentioned next, mostly BSD. Clones of Unix, Minix/Linux are discussed as well.

But what happened to the original Unix operating system?

Does it exist as an operating system any more or is it nothing more than a standard like POSIX nowadays?

Do note that I am aware of this answer but it has no mention of the fate of the original Unix beyond the derived works.

  • 3
    Lets see, I saw PDP-11 running AT&T Unix in a production environment in 1995... – dmckee --- ex-moderator kitten Jun 12 '11 at 17:26
  • The SVG image Wikipedia displays on Unix article explains Unix's history perfectly. 1. en.wikipedia.org/wiki/Unix 2. en.wikipedia.org/wiki/File:Unix_history-simple.svg – anilmwr Jun 13 '11 at 5:36
  • As answers point out Wikipedia does cover this. The question seems to have a false assumption that an os could go on without evolving. The various history traces discussed and graphed do show what happened to the original Unix. – Caleb Jun 13 '11 at 8:53
  • Did you notice the mistake in the chart? Not perfect, more here. -1 – user2362 Sep 18 '11 at 16:07
  • apt-cache search simh - Emulators for 33 different computers... then find the disk image of dmr... unix.stackexchange.com/questions/58660/… – ixtmixilix May 13 '13 at 21:46

We can distinguish UNIX the trademark from Unix the code-base.


Unix was initially developed at Bell Labs, owned by AT&T. This Unix team became AT&T's Unix System Laboratories (USL) and produced Unix System V (Roman numeral for five) or SysV for short. The University of California at Berkeley (UCB) also licenced Unix for academic use, their Computer Systems Research Group (CSRG) later made many important changes and additions (notably TCP/IP) in their Berkeley Software Distribution (BSD) which were later incorporated into many descendants of Unix leading to the BSD vs SysV split. Ultimately a lot of the BSD changes were back-ported into SysV (which we can consider the main "ancestral Unix" code base).

Along the way, many different businesses have licenced this code-base (at various stages in it's development) and used it as the basis of their proprietary Unix operating systems - AIX, HPUX, IRIX, Solaris, Ultrix and dozens of others.

Novell (Attachmate)

USL was purchased by Novell. At this time, the ancestral Unix code was known as Unix system V release 4 - or SVR4 for short. Novell named their product Unixware to complement the name of their legacy network OS Netware. Novell have been Acquired by Attachmate.

The Santa Cruz Operation

Novell eventually sold their Unix business to an old SVR3.2 licensee The Santa Cruz Operation (SCO) whose main business up to that point was selling a product named OpenServer that was based on Unix SVR3.2. Novell (since bought by Attachmate) still own some rights‡ to Unix but do not do any work on the source code.

Caldera / The Sco Group / TSG Group Inc

The Santa Cruz Operation later sold their Unix business to a Linux company Caldera who later renamed themselves to The SCO Group (sometimes referred to as new SCO or SCOG) and who had a disastrous failure of leadership leading to chapter-11 bankruptcy and sale of the Unix business to UnXis, a business formed for this purpose. Subsequently The SCO Group were reorganised into TSG Group Inc and TSG Operations Inc. They have no role regarding maintenance of the ancestral Unix code base. In August 2012 TSG Group Inc converted to chapter 7 bankruptcy.

UnXis / Xinuos

So now UnXis are responsible for marketing and developing/maintaining Unixware - the ancestral AT&T Unix code base. Because the Santa Cruz Operation (old SCO) originally ported† Unix to the x86 platform, I believe x86 and x86_64 are the only target platforms that UnXis directly support.

On June 12 2013, UnXis announced it had been renamed Xinuos.

Microsoft licensed Unix and ported it to 16-bit Zilog Z8000 - old SCO purchased Xenix from them and ported it to the 16-bit 8086 architecture (used by IBM for their original IBM PC). Old SCO later ported SVR3.2 to x86 as 32-bit SCO-Unix later renamed OpenServer

Novell's rights were contested, somewhat futilely, by The SCO Group (now named TSG Group Inc), the bankrupt remnants of the old Linux company Caldera. It is not yet clear whether TSG Group Inc have finally discontinued this and related litigation as a result of August 30, 2011 court decisions against them

  • Exactly the answer I was looking for. – Oxwivi Jun 13 '11 at 18:51
  • 1
    I think that the SCO-Linux Controversies, have somewhat quieted since suing IBM and Novell has largely failed. SCO, according to the Tenth Circuit's report, was rejected from appealing the case and the court ruled in favor of Novell. – new123456 Oct 16 '11 at 0:00
  • @new123456: I think the remaining parties are not "SCO" but TSG Group Inc and TSG Operations Inc who are in the hands of Edward N. Cahn, Chapter 11 Trustee. As I understand it, several sets of litigation are stayed pending resolution of the Chapter-11 bankruptcy process. As you say, not much of interest seems to be happening and the eventual final tidying up and closure may not be very interesting either. The answer above is primarily about identifying the trail of ownership of the ancestral Unix code-base not about the litigation. I'll tidy up the answer a little. – RedGrittyBrick Oct 16 '11 at 11:05
  • 1
    Another company that you wouldn't nowadays associate with Unix - Microsoft (with Xenix). – PC Luddite Jul 1 '16 at 17:34

Not the answer you're looking for? Browse other questions tagged or ask your own question.