Unix Is Dead. Long Live Unix!

It's the end of an era. As The Reg covered last week, IBM has transferred development of AIX to India. Why should IBM pay for an expensive US-based team to maintain its own proprietary flavor of official Unix when it paid 34 billion bucks for its own FOSS flavor in Red Hat?

Here at The Reg FOSS desk, we've felt this was coming ever since we reported that Big Blue was launching new POWER servers which didn't support AIX – already nearly eight years ago. Even if it was visibly coming over the horizon, this is a significant event: AIX is the last proprietary Unix which was in active development, and constitutes four of the 10 entries in the official Open Group list.

Within Oracle, Solaris is in maintenance mode. Almost exactly six year ago, we reported that the next major release, Solaris 12, had disappeared from Oracle's roadmap. HPE's HP-UX is also in maintenance mode because there's no new hardware to run it on. Itanium really is dead now and at the end that's all HP-UX could run on. It's over a decade since we reported that HP investigated but canceled an effort to port it to x86-64.

The last incarnation of the SCO Group, Xinuos, is still around and offers not one but two proprietary UNIX variants: SCO OpenServer, descended from SCO Xenix, and UnixWare, descended from Novell's Unix. We note that OpenServer 10, a more modern OS based on FreeBSD 10, has disappeared from Xinuos's homepage. It's worth pointing out that the SCO Group was the company formerly known as Caldera, and isn't the same SCO as the Santa Cruz Operation which co-created Xenix with Microsoft in the 1980s.

There used to be two Chinese Linux distros which had passed the Open Group's testing and could use the Unix trademark: Inspur K/UX and Huawei EulerOS. Both companies have let the rather expensive trademark lapse, though. But the important detail here is that Linux passed and was certified as a UNIX™. And it wasn't just one distro, although both were CentOS Linux derivatives. We suspect that any Linux would breeze through because several many un-Unix-like OSes have passed before.

Other OSes have passed or probably easily would, though. IBM's z/OS is alive and well: version 2.5 came out in 2021 and in 2022 Big Blue started offering cloud instances. z/OS has a Unix-compatible environment which has passed the compatibility tests so officially, it's a UNIX™, even if that wasn't its original native API.

The "open" in the name "OpenVMS" originally referred to the POSIX compatibility it gained with version 5, way back in 1991, and was first applied to the new version for DEC's Alpha CPUs. Last year VMS Software released version 9.2 for x86-64 hypervisors (and a single supported box, HPE's DL380).

Ever since Windows NT in 1993, Windows has had a POSIX environment. Now, with WSL, it arguably has two of them, and we suspect that if Microsoft were so inclined, it could have Windows certified as an official Unix-compatible OS.

IBM shifts remaining US-based AIX dev jobs to India – source Haiku beta 4: BeOS rebuild / almost ready for release / A thing of beauty What did Unix fans learn from the end of Unix workstations? NixOS 22.11 'Raccoon': Like a proof of concept you can do things with In our recent story on Beta 4 of Haiku, we said it wasn't really a Unix. As you can see, there's an editor's note attached to the end of the story explaining why.

We had heard from Haiku's primary full-time developer, who vigorously disagreed with our point of view. To his mind, the fact that Haiku now has strong Unix compatibility, with some of the main Unix directories present in its filesystem, a quite complete set of Unix API calls, a Unix shell, and so on, means that Haiku is quite definitely a Unix. We feel that inasmuch as it's a reimplementation of BeOS, with its own native filesystem, API, GUI and so on, it's something different, which offers Unix compatibility as well.

But this illustrates the difficulty of defining precisely what the word "Unix" means in the 21st century. It hasn't meant "based on AT&T code" since Novell bought Unix System Labs from AT&T in 1993, kept the code, and donated the trademark to the Open Group. Since that time, if it passes the Open Group's testing (and you pay a fee to use the trademark), it's UNIX™. Haiku hasn't so it isn't. Linux has so it is. But then so is z/OS, which is a direct descendant of OS/390, or IBM MVS as it was called when it was launched in 1974. In other words, an OS which isn't actually based on, similar to, or even related to Unix.

Which means that the last officially trademarked commercial UNIX™ is Apple's macOS 13, which underneath the proprietary GUI layer is mostly an open source OS called Darwin anyway. The kernel, XNU, is based on Mach with an in-kernel "Unix server" derived from FreeBSD.

So, as of 2023, open source really has won. There are more Unix-like OSes than ever, and some very un-Unix-like OSes which are highly compatible with it, but the official line is, to all intents and purposes, dead and gone. All the proprietary, commercial Unixes are now on life support: they will get essential bug fixes and security updates, but we won't be seeing any major new releases.

Xenix was a port of System 7 as sold to Microsoft by Bell Labs. I still have a TRS80 Model 16A running the 68000 version of Xenix. I worked directly with David Korn to port his Korn shell to 30 different UNIX/Xenix environments. It was always fun when I found a bug and reported it to David. He would confirm the bug in his master source code base. I often sent a suggested fix and it was often accepted.

wow. takes me back to the 70’s, learning to write OS’s, compilers, etc. just me and unix and long long hours in the math lab.

wow. takes me back to the 70’s, learning to write OS’s, compilers, etc. just me and unix and long long hours in the math lab.

My apologies, but, reading in haste, I thought your phrase was "long long hours in the meth lab."

lol. well, no. my all nighter fuel in those days was in-n-out and and a liter (or two) of caffeinated soda. but there might have been some others in the lab inclined or driven to something harder. there was no coddling whatsoever back in those days.

Very nice details about your work with Korn. I’m impressed!

I don’t have anything to match, but I did have lunch with Michael Tiemann, and corresponded with Jon Postel when he was personally administering the .US Domain (and a lot of other things) https://en.wikipedia.org/wiki/Jon_Postel and I got Bjarne Stroustrup to sign a copy of the C++ language book.

I went to Software Development 88. Great conference. As I was leaving from a talk and entered the elevator, Bjarne Stroustrup stepped in as well. I thanked him personally for creating C++. At UseNIX, I had a chance to hang out with Dennis Richie. Keith Muller at UCSD extended an invite to a talk at UCSD where Ken Thompson was speaking. In person he could pass for a biker. My days of rubbing shoulders with the UNIX community ran from 1983 to 1992. After that point, I was too busy with customer contracts to dash off to UseNIX. Postel's name is very familiar from all of the TCP/IP documentation in the early days of the internet. I relied upon those foundation documents as I wrote my early networking applications and kernel device drivers.

Nice write up by Cerf. I've heard him speak at a few conferences. We were privileged to be part of the generation that built the internet. I still have my early work with Phil Karn, KA9Q on his NET/NOS code to do TCP/IP over AX.25 on ham radio. I used the same code to drive a SLIP link to UCSD from the Xenix box. When PPP was finally ready for use, I upgraded to Xenix drivers to use PPP. I only had a 2400 bps modem at the time, so internet connectivity was slow. Tolerable for my budget in 1985.

AT&T Research UNIX

The 7th edition released in 1979 was the basis for the distribution to Microsoft and Tandy. It was the precursor to System III. The 68000 Xenix I had in August 1983 was System III flavor. It was difficult to backport the System V uucp to that version of the OS. Tandy had a later release that I installed along with the 68010 CPU to support demand paged virtual memory. That was a big improvement to the responsiveness of the OS. I'm pretty certain that the current OS on my 68010 Xenix box is a System V environment. It hasn't been booted since 2000 when I moved to Idaho, so the power supply may be in tough shape.

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