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Thread: History behind the disk images of AT&T UNIX System V Release 4 Version 2.1 for 386?

  1. #11
    Join Date
    Mar 2011
    Atlanta, GA, USA


    AT&T was a bit new at the direct sales game in the 80s. The big divestiture free'd them up from an earlier anti-trust consent decree that for-bayed them from selling computers commercially.

    All of our 3B2s were actually leased from AT&T and returned after they were taken out of service. It's my understanding this was pretty common among 3B2 installations at least. After most of those machines went off-lease and EoL, AT&T used a lot of them to carpet-bomb universities and sent the others to the land-fill. One of the reasons a series of machines fairly common in the 80s is near extinct today.
    "Good engineers keep thick authoritative books on their shelf. Not for their own reference, but to throw at people who ask stupid questions; hoping a small fragment of knowledge will osmotically transfer with each cranial impact." - Me

  2. #12
    Join Date
    Sep 2006
    Silicon Valley


    Quote Originally Posted by atdt916 View Post
    In my opinion, having an AT&T SVR4v2.1 release included with an AT&T branded x86 system, especially one with a 386, in a single combined package represents the canonical starting point of the UNIX/Linux world as it exists today.
    It is much more confusing than that because of the other vendors x86 Unix products including Microsoft/SCO and Interactive Systems' product, which IBM sold.
    I was talking to a Unix greybeard on Tuesday, and he reminded me that you can thank Onyx Systems for getting AT&T to create the Unix binary license in 1981.
    Before that, you had to spend $25,000 for a Unix source license.

    I think the 6386 WGS is an interesting canonical example of Unix before AT&T teamed with Sun (who made their own weird 386i).
    There are many paths not taken by Unix clones on the 386, like support for Xenix binaries.
    This was also when networking was in flux and AT&T was pushing Starlan when the rest of the
    world was going Cheapernet (10-baseT).

  3. #13
    Join Date
    Jan 2007
    Pacific Northwest, USA
    Blog Entries


    I seem to recall that before 1981, there were two tiers of Unix source licenses. There was an "educational" license sold to universities and the like and it was nowhere near the $25K for a commercial license. AT&T also briefly toyed with the idea of a lower initial license, but with a per-seat payment. It was a strange time for Ma Bell, culminating in the 1982 consent decree. Another item sometimes missed was that after divestiture, Unix distribution was handled by a now-forgotten spinoff, called AT&T Computer Systems, which, in turn was a spinoff of AT&T Information Systems. The whole affair lasted until about 1991 and was remarkable for its management ineptitude.

    Judge Green has since written that he didn't like the consent decree, but by the time it arrived on his desk for signature, it was a done deal and he had no choice but to ratify it. I believe that the Bell System breakup was one of the biggest blunders in US corporate history.

  4. #14
    Join Date
    Jan 2014
    Northfield, MN USA


    Quote Originally Posted by ScutBoy View Post
    I looked at your links, and the AT&T branded 386 machines we had look different than the two you call out. I'll see if I can find a photo of what we ran. All ours also had QIC tape drives for backups.
    Ours looked like this, with a QIC tape in the bay under the floppy drive.

  5. #15


    I was doing some more digging on the various UNIX versions and I think I found some more answers, but yet another question!

    Here's an interesting tidbit from Eric S. Raymond's March 31st, 1992 posting on comp.unix.sysv386, in his "SVr4 and clone hardware buyer's FAQ" post. In it, he said:

    AT&T's own 386 UNIX offering is not covered here because it is available and supported for AT&T hardware only.
    It seems that AT&T wanted to avoid the competition against Xenix and all the other vendors, and was content on selling vendor licenses for competing in the open-box 386 market. That would explain why their own releases were not as popular as the other vendors, the larger market simply couldn't obtain it without buying AT&T hardware. From the various 80s/90s magazines that I've read on, Xenix had the large majority of the x86 UNIX market and was the defacto SVR3 openbox king. With SVR4, AT&T continued to let the vendors fight it out.

    Around the time SVR4.2 was being developed, AT&T made a last ditch effort to try their hand in the open-box 386 market, by forming Univel with Novell. Their press release stated:

    The companies anticipate that Univel's products will enable computer users to run UNIX applications on standard hardware and utilize the UNIX system as a scalable applications environment across computer networks. Product development is intended to tightly integrate NetWare network services from Novell with the UNIX SVR4 applications platform.
    This effort would produce the first UnixWare release, which is SVR4.2 + NetWare + 'Destiny' desktop stuff. Soon after the release of UnixWare 1.0, AT&T would decide to exit the market and sell USL to Novell, leaving UNIX entirely. That being said, AT&T's last two UNIX efforts were the base SVR4.2 build and the first UnixWare release. That lead me to thinking that these disk images would be from that base SVR4.2 AT&T build, without the UnixWare/Univel additions.

    As I was looking further on the possible release date for these disk images, I'd guesstimate that they would have come out during the 1992-1993 timeframe. I found this press release on the SVR4.2 completion date, dated June 16th, 1992:

    UNIX System V Release 4.2 will be licensed in source code form by USL to computer industry hardware and software vendors worldwide. Those vendors will provide commercial "binary" versions for their customers.
    AT&T, not being a vendor and the owner of USL, simply produced their own build and released it along with their systems. About six months after that, AT&T and Novell signed their agreement to transfer UNIX System Laboratories from AT&T to Novell. This was finalized on February 16th, 1993:

    Tuesday announced the signing of a definitive agreement with AT&T for the acquisition of UNIX System Laboratories, developer of the UNIX operating system.

    The definitive agreement has been approved by the boards of directors of both Novell and AT&T, and follows the letter of intent signed by the two companies on Dec. 20, 1992.
    It's not clear that AT&T stopped all development efforts and maintenance of their own internal port at this time (was USL their development and support arm for all things UNIX?), but I'd say it's safe to date these disk images to between June 1992-Feb. 1993 and distributed only with their hardware.

    Now for the kicker:

    When I first found these disk images, it was from But now, I found another release on, which I think is the original unmodified disks that the release was based on. The readme included with the disks from is dated Dec. 21st, 1999, but the disk image .DCF files themselves are dated January 28th, 1992, which is before SVR4.2 was even completed. So now, that leads me this: Is "Release 4.0 Version 2.1" not the same as "SVR4.2"?!

    Apparently not, it seems!

    If "Release 4.0 Version 2.1" is not SVR4.2, then likely this is just the last SVR4 release and that the only SVR4.2 build readily available is the UnixWare 1.0 installers that are around the internet. I have not encountered any disk images for Univel's SVR4.2 release that Eric S. Raymond's buyers guide references.


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