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Xenix is not so much forgotten as it simply not spoken of because of it being tainted by association with SCO.
As soon as I saw that kernel boot screen in the article it was like seeing an old friend. I look back on my years at SCO(C) very fondly. Seeing what happened when Caldera (SCOX) got involved deeply saddens me. I always wonder what would have happened if the SCO OS development had turned from SVR UNIX to Linux how different things may have been.
I seem to recall there was a Linux binary loader for OpenServer, along with the Skunkworks project ...?

Yeah. Management dropped the ball big-time in 1994. SCO could have been Red Hat really easily if they'd had even a tiny amount of vision. Instead they missed the bus, went into terminal decline, and ended up split between Borland (the good bits) and the ambulance chasers from Utah (the bad bits, who everybody remembers).

Who are the ambulance chasers? Caldera?
Yup.

Caldera started as a legit Linux distro circa 1994-5, but burned through their funds too quickly. As a pivot they bought out Digital Research including their anti-trust lawsuit against Microsoft (for blocking Win95 from running atop DR-DOS). They won big, and the rest is history -- they used a chunk of the funds to buy what they thought was SCO's IP rights, then sued IBM (because that never ends badly, right?).

How did it actually end? or has it even ended? (I know that cases sometimes go on for years, and I vaguely remember reading something about it lately.) I tracked what was happening for a while, at the time - just out of interest - mainly via Pamela Jones' groklaw site, but don't think I read about the end.
Last i read the zombie was still stumbling about...
I worked sysadmin contract at an IBM global services subsidiary in the summer of 1997. I had a task that needed a Unix machine and I installed Linux on it. One of the senior mgmt type people threw up a big fuss about it being Linux and Linux being bad, m'kay, bad stuff, and insisted that the machine should be running a licensed SCO Unix. He ended up getting outvoted but I remember even in 1997 being like "what year is it?"

The next year or the year after IBM announced their big Linux pivot where they went all-in on Linux on everything as a big strategy.

SCO and Caldera were a merger that should never have happened. SCO made all of its money off of line items in very expensive deals done by channel sales guys who integrated complex products.

Caldera made all of its money by going into shops with SCO-based point-of-sales or industrial control or what-have-you, and cutting the integrators/resellers out of the loop.

Putting those two businesses under one roof was doomed to failure.

Not forgotten here. My second job had some TRS80 68000 systems running Xenix and 6-10 terminals.

> Slowly, Microsoft started losing interest in Xenix

It seemed more like they lost interest the moment it was released.

I remember working on 286 based systems with multiple users on serial terminals running SQL based database applications.
I worked as a tech author on the release notes for the last shipped release of Xenix, SCO Xenix 2.3.4, in late 1991.

The Microsoft legacy lingered in SCO's codebase for a long time -- the MS C compiler was standard right through Open Server (disclaimer: I left in 1995 and happily never had to use that festering dungheap ever again, much less write and maintain chunks of the docset for it).

I used to make some decent side money maintaining a Xenix records and billing system for a local doctor. It's been a long time, but I remember the system as being pretty solid.
Imagine a Windows based on Unix, like OSX, instead of being a derivative of VMS. It could so easily have happened.
It could still happen given the work Microsoft Research did on Drawbridge. It is public knowledge that they use it on Azure and with Drawbridge, they could rebase on UNIX.

I doubt that it would happen given that Microsoft's modus operandi is to make as much money as possible by trying to lock people into their products, with Windows being the primary product on which they want people to be dependent.

Wow, just looked up Drawbridge. It's a shame MS Research stuff rarely goes anywhere. That looks like top-shelf engineering.
That is a misconception.

Drawbridge powers the pico kernels infrastructure on Windows and is the basis of the new Ubuntu/Windows subsystem.

The research in Singularity and Midori were used in MDIL compilers targeting .NET AOT native code generation on Windows 8.x and the follow up changes that lead to .NET Native.

Also F# started as a MS Research project.

The theorem provers used to validate Windows drivers were also a MS Research project.

LINQ, .NET contracts and Fakes framework also started as MS Research projects.

Some Haskell and OCaml researchers are on MS Research payroll.

There are tons of other examples.

> I doubt that it would happen given that Microsoft's modus operandi is to make as much money as possible by trying to lock people into their products, with Windows being the primary product on which they want people to be dependent.

How easy is it to port the average program from MacOS to Linux?

While the Kernel may be close enough, the window library is so vastly different that it's probably the same work to port from windows to Linux as to port from MacOS to Linux

Possibly GNUStep can help with the older APIs.
This seems like the path forward as far as MS is concerned. Laying a *Nix user land on top of NT which they seem very happy with and in no rush to throw away.
That would have been very interesting to see. I have often wondered what would have happened if they'd gone in that direction, perhaps including some sort of WINE-derived code to allow legacy applications to run.
I also wonder why such a comment is worthy of downvoting. Perhaps someone would care to enlighten me?
Had they worked out the MS-DOS compatibility, it could have.

The other issue was performance. UNIX systems at the time needed a far faster CPU and graphics, and far more RAM and disk space. Faster = much more expensive. Which is also why Windows systems were 1/4 the price.

> Had they worked out the MS-DOS compatibility, it could have.

Xenix collector here, I would say they had (sort-of) MS-DOS binary compatibility, as you could run some DOS programs on Xenix 386. I think it's only limited to real mode programs, but I tried it a couple of years ago and it worked.

Not to mention that on Xenix you could develop for both platforms (well, more than that: with the right setup you could target DOS, Xenix 8086, Xenix 286 or Xenix 386), that's quite an advantage.

On a side note, a good collection of Xenix manuals can be found at http://www.tenox.net/docs/.

Xenix had a DOS compatibility layer called VP/ix.

Sometimes, it even worked!

The problem with Windows isn't its NT underpinnings. NT is a well-designed kernel designed by some really smart people.

The problem was the absolutely awful userspace and Win32 they pasted over it. And then let that dig tendrils down into the lower levels of the kernel.

I remember administrating systems running NT 3.51 and finding it actually not that bad apart from the usual Windows fault of having to use the GUI for almost everything.

NT 351 was a rock, I used it on desktop for a year or so and it never crashed. Compared to daily crashes on consumer Windows it was a revelation.
Even MS wants to get away from win32. Problem is that their continued support of it is what keeps corporations from looking elsewhere, as the business specific stuff is likely to be win32 based.
That's not much of an article --- this one has a lot more information:

http://www.softpanorama.org/People/Torvalds/Finland_period/x...

pcjs.org has a Xenix image in its library, but no preconfigured example. Anyone know enough about pcjs to set one up?

Fascinating, missed this earlier. There is a lot of revisionism today and I think Gates always gets the short end of the stick.

It took a lot of work to build Microsoft and the PC industry with it. Hopefully in later years he will be redeemed.

Given the first instinct is always to be closed and profit the openness of the PC ecosystem must have taken gargantuan effort to build. Gates clearly believed in more accessibility, affordability and wider outreach for computing than closed systems in some deeper way, whatever his motives and the outcome on hindsight completely blew open the floodgates.

Thanks to that we have open systems on PCs instead of closed blackboxes and a massively rich ecosystem. This in itself is an impressive achievement.

People tend to forget before the PC all the other systems had vendor specific hardware and with OSes being burned in ROMs, upgrading meant buying a new computer, sounds familiar?

Also, back in the day, at least in Portugal, many of us dreamed to work at Microsoft and usually applied to work there at the end of the CS degree.

I have a machine with the OS burned in ROM (BBC Micro). I can use and EEPROM and write my own if I want to.

I can also switch between ROMs to boot from - I have BBC Basic, Word*, Publisher, Forth.

It was a great idea when you only have 32K RAM. The ROMs are page mapped in.

ROM boot was only true of 8-bit micros. The standard for mainframes and minis was to boot an OS from tape/disk/(paper tape.)

OS choices and OS upgrades happened regularly. You could run all sorts of things on a PDP/11, VAX, DG Nova, etc.

No, it was also the way in the Amiga, Mac and Atari, the floppies only had a partial implementation, all 16 bit.

As for the mainframes and minis, I never worked with them, besides the AS/400.

But from my collection of old papers and manuals, many of them had "bytecodes" with microcoded execution (more higher level than plain CISC Assembly) burned on their processors.

Supposedly even the original PC had a BASIC boot option.

And frankly, its design is not that far from the other micros (ISA cards can extend the BIOS by responding to specific memory address ranges, much like a ROM cart on a C64). Its just so damn well wallpapered over these days.

Yes, some were microcoded. And you were able to replace that microcode with your own creations!

See for example this paper, where they took a VAX and rewrote its microcode so that it executed instructions for the Warren Abstract Machine, the output format of their Prolog compiler.

It's like you would reprogram your Core i7 to directly consume JVM bytecode.

http://hps.ece.utexas.edu/pub/gee_micro19.pdf

Thanks for the link.

I was a big Prolog fan during my degree.

I don't know about that, there were a bunch of different computers systems that were available before Windows/DOS killed everything but the Mac off. That also may have been due to the fact you could get PC clones after Compaq came into being...
How much of it was Gates, and how much of it was IBM and their allowing IBM-compatible hardware?
Virtually all of it was IBM, both because they allowed other vendors to release PC-compatible hardware and because they did not negotiate an exclusive license for MS-DOS, allowing Microsoft to sell it to other companies. I frankly can't see giving Gates any credit for the open PC ecosystem at all; his role was pure opportunism.
It's hard to make a case against Bill Gates being a massive player in the astounding success of personal computing without delving deeply into emotional reasoning, so I'm curious what feeling you have that justifies your stance.

For instance, perhaps you feel having the appropriate moral tone to a vision is the requirement to deserve credit for achievement?

>It's hard to make a case against Bill Gates being a massive player in the astounding success of personal computing without delving deeply into emotional reasoning

The only thing he really did was not get in the way of making billions.

If not for MS, other companies would have filled its place (DR-DOS?)

If not for IBM creating and then opening up the PC market?

If you believe that the only thing Bill Gates did was stay out of the way, you've clearly not read even a cursory survey of the history of computing. It's so dismissive I'm a little agape.
I think you're reading something into my comment I didn't intend. Gates and Microsoft generally did a lot of important work that made the open PC ecosystem a long term success, but IBM is the one that created that ecosystem, and Gates took advantage of that opportunity.

edit: Looking back on my original comment, I can see where I should've phrased things better. When I said I couldn't see giving Gates any credit for the open PC ecosystem, I should've said "the creation of" the open PC ecosystem. We may still disagree, but at least now we'll be on the same page about where the points of disagreement are. =)

> Given the first instinct is always to be closed and profit the openness of the PC ecosystem must have taken gargantuan effort to build.

The openness of the PC ecosystem was built almost entirely on IBM's failure to legally secure it (which was neither intentional nor something for which Gates was responsible), and the willingness of third-party hardware vendors to take risks in testing the degree to which IBM had failed to legally secure it (which, again, was not something Gates was responsible for.)

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Why Gates gets the short end of the stick. Instead of buy a license to make BASIC, they wrote their own version of it. Wrote their own COBOL and FORTRAN without a license as well. This took money away from IP holders, but gave birth to a lot of Microcomputers.

Before MS-DOS there was CP/M and UNIX. After selling IBM PC-DOS, Gates had MS-DOS 2.0 made for PC clones after Compaq and a few others wrote a clone BIOS. They had to reverse engineer the BIOS in one room, and build their own BIOS in another. It was the cheaper PC clones that put an end to TRS-80, CP/M, Apple //, etc.

Windows was a cheap knock off of the Macintosh GUI, I used to have a blog that had an article that Bill Gates stole from Steve Jobs to make Windows because Steve Jobs would not give him permission to license the Mac OS. Sure Apple and Microsoft settled it out of court by Microsoft investing money in Apple to save it. But a lot of Apple fans don't like how Gates had cheated Jobs originally.

Even if Microsoft was not the first company to invent these things, they filed for patents anyway.

But I will say something positive about Gates, his monopoly created a Windows standard by forcing OEMs to pay the Windows tax per PC even if they didn't use Windows. So that killed the Amiga, Atari ST and other third parties as PC clones became so cheap in the early 1990s that the market was flooded by them.

Jack Tramiel founded Commodore and got into war with other companies in the same way Steve Jobs went to war with IBM. Without Jack Tramiel and the home computer wars that lead to $200 Commodore 64 ect systems, a lot of families would not be able to afford a computer to learn on. Commodore got a primitive version of Microsoft BASIC so they got a cheap license per computer.

The open system PC was IBM using off the shelf parts from Intel and other companies. Using the ISA bus for example for expansion cards.

Wrote their own COBOL and FORTRAN without a license as well. This took money away from IP holders, but gave birth to a lot of Microcomputers.

What IP holders? Those of other FORTRAN implementations?

So if I'm writing a C compiler I'm "taking money away" from the developers of existing compilers? Like, I'm doing something despicable, as apparently, that money belongs to them?

You have to remember it was in the 1970s before free and open source software existed.

Back then if you wanted to use C or UNIX you had to license it from Bell Labs. If you wanted BASIC you had to license it from Dartmouth, if you wanted COBOL you had to license it from The navy and Grace Hopper, etc.

Over times things have changed and free and open source versions of those languages got written. But try to make a free and open source version of the Intel Mac BIOS, try to make a clone of MacOSX, try to make a version of XCode that runs in Linux and submits apps to the Apple App Store, etc. You need an Intel Mac for that and Apple's MacOSX and XCode. So not everything is free and open source or has an alternative to it.

For example Microsoft made Windows that basically stole the Mac GUI IP without permission. Windows sold so well that Apple started to have financial problems. In that case it was taking money away from Apple.

In the case of FORTRAN, there already was a language standard as early as 1966. At the same time there existed implementations of it that were independent of IBM.

Also, while you had to get a UNIX license from AT&T, they didn't make any money from it (well, they weren't allowed to) and at the time, it came with full sources. Yes, the term FOSS didn't exist yet but people shared source code anyway, at least in the academic/research environments where UNIX was popular.

You're right in that things were much worse in the commercial office and home computer market.

That's awesome! Thanks for the link as it fills the big picture in nicely for me. Should be the original article given level of detail. Trips me out that NT was developed on OS/2 with mail servers running Xenix. Combined with other articles, I actually see Microsoft playing it smarter than I thought drawing from all the best tech families:

1. Create a better UNIX than UNIX. UNIX microcomputer market forms as a side-effect due to marketing.

2. Move UNIX features into CP/M in MS-DOS.

3. Clone OpenVMS architecture with enhancements and emulators for older OS's.

4. Develop on OS/2 for better reliability, pace, and inspiration. I'm sure OS/2 stuff ended up in NT past the emulator. I'd be interested in a link that went into that in detail.

5. Run mail and gateways on Xenix as UNIX was great at that sort of thing.

6. Run whole business on a single AS/400 that just gets shit done mainframe-style.

7. Replace all of the above with one product that has key attributes of all of them in usable package on cheaper hardware.

They don't look as dumb now as I thought when I was younger comparing MS-DOS to BSD's or Linux. ;)

re Linux

The author asserts multiple times that Linux comes from Xenix somehow but didn't seem to prove it. Says the architecture, standard, and microcomputer UNIX was first done by Xenix. Then Linux did one. Past that, nothing. Is there some resource with specific evidence that Linus got Linux design aspects from Xenix as opposed to another UNIX? And my original sources said he started with Minix changing stuff in his design that didn't suit his hardware or needs. So that needs to be factored in.

OS/2 and NT were the same codebase at one time. It was a joint IBM/Microsoft project.

Windows 3.x was way more successful than Microsoft anticipated. They wanted to pivot the Win32 layer in NT to be the primary API and make the user interface more Windows-like. IBM didn't want that so they parted ways.

David Cutler (designer of VMS) was the architect for NT. Many people don't know it has a single root filesystem that takes the unix philosophy even further... objects like mutexes exist in the root, not just files. Everything has full ACL support. The IO completion ports and async support were way ahead of their time. It originally even ran things like the video driver in user space.

Windows 3.x being so successful almost killed everything that was great about NT. It also caused Microsoft to completely miss the mobile revolution.

Success hides problems indeed.

Appreciate the tips. In case you don't have it, here's the reference showing all the VMS stuff in NT:

http://windowsitpro.com/windows-client/windows-nt-and-vms-re...

Be interesting at some point to collect all the attributes of NT to see what came from VMS, OS/2, UNIX, DOS, Win 3.x, etc. Then one might also see how it could be done even better esp without baggage. :)

Attending a session about the Windows internals at Microsoft was an eye opener for me, back when Windows 2000 was the latest version.

For those of us that enjoy delving into OS details, Windows is full of interesting goodies.

Even the way .NET is integrated with the OS, is somehow similar to how bytecode and JITs used to work in mainframes.

I always liked the architecture but just hated implementation and holdovers from prior business. Another goodie was how the DOS, etc subsystems are similar to the current container craze. I just wish BeOS advantages got merged in there early on. They buy them or something.
... and when they finally noticed their problem in mobile, it seems like all the good stuff was thrown out (e.g. .Net) in order to chase that tail. Seems they're finally coming around now with the windows store being opened for all windows apps (wow... duh?), but at the same time smartphones seem abandoned and tablets are IMO still clunky compared to iPads. Was Gates the genius behind dominating PC? Was his absence during the mobile revolution the reason for MS's relative stagnation (when compared to Apple's and Google's growth)?
At least looking at the stores, they seem to be making a come back at least in what concerns tablets/hybrid laptops.

Hybrid tablets have killed the netbooks and the majority of people are going for 2GB/4GB + 32/64 eMMC hybrids with Windows 10, and not to those Android ones that kind of look like a desktop. For most pockets across the world, an iPad Pro isn't an option.

The whole thing with .NET, Longhorn, Windows 7 and 10, was also a causality of the typical Windows Dev vs DevTools "wars" and most of us that follow MSFT blogs and news, know to which side Sinofsky was sponsoring.

Somehow UWP seems to be what .NET and eventually Longhorn should have been all along, lets see how it goes.

> Everything has full ACL support.

Got bitten by that once when i thought i could just copy the user dir between Windows installs and discovered that the registry had its own ACL on top of the FS ACL...

I was having a similar problem reinstalling Ubuntu last night. I couldnt copy files to external HD over permissions. Re-ran file manager with sudo. As root, I still couldnt do it. So I changed permissions of files until I could. I'd worry about changing them back but they were bookmark backups haha.

All that trouble to move files on a LiveCD that has full access to the disk anyway. Wth lol...

I worked on both OS/2 and NT and can say they were never the same code base. The NT kernel was 100% new code. At one point there was an effort to port the OS/2 GUI apis on top of the NT kernel. That effort was abandoned when it was decided to focus on a new 32 bit Windows API on NT. Scores of devs switched what they were working on overnight - fun times!
I would not call Xenix a forgotten Operating System. I sent Steve Ballmer an email when he was still CEO of Microsoft asking if they were ever going to do a new release of Xenix. He replied no.
That would be because Microsoft sold the rights to Xenix to SCO -- at that time about two hackers and their hot tub in downtown Santa Cruz -- in return for 30% of the shares in the (then private) company. That was in the mid-to-late 80s (before my time there).
What's the "where are they now" on the two hackers in S.C with the hot tub?
Ran it in college, on an Intel iPSC. I didn't know at the time that it was a Microsoft product, as it had been licensed and rebranded by Intel. And probably tweaked to run on the compute nodes.
I seem to recall that when Microsoft sold Xenix, they agreed to never enter the Unix market again. I've searched for that online but have never been able to find more information.
Obviously it looks very different today, but if they had made such an agreement, would things like the Linux sunsystem in Windows 10 or the older Windows Services for UNIX not be a problem?
I think they might be. On the other hand, SCO isn't the company they used to be, so who knows if it would even be an issue.
I'm reminded of a story Hugh Daniel told me about Xenix.

Hugh and John Gilmore visited Microsoft around the time of Sun 1, to see if there was anything they could learn / exchange. The Microsoft guys asked excitedly how they made SunOS so fast on the limited hardware.

Hugh and John looked at each other, shrugged, and said "Caching?".

The response was "Oh no, we tried that. It didn't work."

Hugh and John concluded there was nothing to learn here.

The follow up is that sun ended up having trouble making money and sold to Oracle, while Microsoft ended up being a juggernaut who even in its bad time stayed one of the most stable and lucrative company in the world.
To be fair, Sun outlasted its market; the problem was that *nix desktop companies were targeting $10K "3M" workstations and ignoring the PC market (which offered a tenth of the capability at a tenth of the price). When consumer machines caught up and replaced technical and academic workstations, Microsoft was able to grow with the market, while Sun, SGI, etc. didn't have the same opportunity to "grow down." That left Sun dependent on the server market, and exposed to the first dot-com collapse and subsequent glut of used mid- and high-end systems on the aftermarket.
There are some good reasons why caching might not have worked for Microsoft you know... The much smaller memory size of a typical PC being a bit potential reason.
easier to just be condescending instead of thinking that out.
The original Sun-1 only had 256K of memory, not the multi-megabytes you wound find in late 80's workstations.
Xenix was my first contact with UNIX, back in 1993.
The story I heard was that the reason MS-DOS stagnated for a while in the mid-80s was that Microsoft considered Xenix "the future".

Then the legal uncertainty around Unix copyrights started happening and the need for a cross-platform system evaporated because PC's won, so Microsoft shifted to Windows and OS/2 as its future.

OS/2 was produced by IBM, not MS.
It was a joint project, with ms eventually pulling out to work on NT
NT was originally known as OS/2 3.0.
Pre-warp then. Those WARP commercials made me really want it when I was a kid, even though they (on purpose) never communicated what was so amazingly bout it.
Ah yes, that's true. Totally forgot about that. Thanks!
Indeed, that OS/2 2.0 fiasco went so badly that it is one of the favorite topics.
In the 1980s, XENIX 286 was able to use the 286 protected mode to deliver real protected memory and pre-emptive multitasking on a PC-AT. That more or less guaranteed a certain market share, because a PC-AT was a lot cheaper than anything with a 68k or a 386.

Xenix was successful because it delivered a lot of bang for the buck. It ran on relatively inexpensive hardware and delivered a lot of UNIX flavor despite the limitations.

Really early versions of Xenix would run on an actual 8086, with no protected memory whatsoever. I don't think any other UNIX ever managed that.

Back then I built systems with Xenix on a PC-AT that had three simultaneous users, one on the console and two WYSE-60 terminals attached to the serial ports. The system ran a database server and the applications that I built to manage factory inventory and orders.

Mind you, on a 4.77 Mhz PC at home, I ran Windows 1.0 and used it to multitask two sessions. In the foreground GUI I used Notepad to write C code, while the DOS session in the background ran the compiler. Back then compiling took a long time. Few people even then realized that Windows 1.0 did real pre-emptive multitasking on the original IBM-PC between the front-end GUI and a backend DOS session.

It was not preemptive.
It depends. The Windows 3.x 386 "enhanced" mode kernel was in fact what we would call a "hypervisor" today. A 32-bit hypervisor to be specific. It ran 16-bit Windows applications inside one VM, along with any number of DOS VMs. The VMs themselves were preemptively multitasked, but the design of the 16-bit Windows API prevented preemption in that VM (a problem also faced by Apple).

If you weren't using an "real-mode" drivers then it never bothered to talk to DOS, it just did everything itself... for example the "32-bit disk mode" stuff was a 32-bit disk and filesystem driver that completely replaced DOS disk routines.

Microsoft being Microsoft, if you had DOS TSRs, DOS drivers, or other random DOS crap they would hook those things and drop down to real mode to call them the way they expected to be called... going so far as synchronizing the DOS in-memory data structures before and after the calls to make sure the lie was as complete as possible.

OP was talking about Windows 1.0 not Windows 3.0
I worked at a MicroAge during the heyday of Xenix, selling any system we could get our hands on. We even had some weird System/36?/38? variant because IBM was still trying to keep the PC from killing midrange sales.

Hard to believe but we had three different UNIX offerings: Microsoft Xenix, AT & T 3B1/PC 7300 and what sold by far the best: Altos systems. We sold the hell out of 4, 6 and 8 user Altos systems because everything was connected to cheap dumb terminals. The Xenix systems could not come close at the time for speed.

But then Novell commoditized cheap networking and file sharing on the PC and that was that. The PC had far more software selection and despite the price difference offered Lotus 123 which took the industry by storm.

>> Really early versions of Xenix would run on an actual 8086, with no protected memory whatsoever. I don't think any other UNIX ever managed that.

Minix?

This should be no surprise- the 286 was faster than the PDP-11 where UNIX originated.

I used SCO Xenix on 386. It had a very good Lotus 123 clone called SCO Professional- you could have 5 or 6 users all sharing a PC. SCO was sued over it, had to stop selling it.

As for 8086 and MMU-less unix systems, xenix is certainly not unique in this. In 90's there even was heavily modified Linux kernel that ran on such systems.

And as for 286, there were (and probably even still are in production systems) multi-user multi-tasking CP/M derivates. Two large niches for such systems were industrial automation (IIRC some versions of Siemens Simatic ran that) and point of sale (IBM).

Even beyond the 90s, in uClinux (microcontroller Linux). While it was technically bad to access hardware directly, it was definitely possible to, for example, write a bit-banging I2C driver in userspace.
8086 Linux still exists; people are working on it:

https://github.com/jbruchon/elks

But it's still pretty unstable. If you have a spare 8086 and want a Unixoid, go look up Minix 2 (not 3). It's not very comfortable on a 8086 with 640kB, but it works. Proper filesystem, processes, Bourne shell, the lot. It even has a self-hosted C compiler. You can get real work done on it (slowly).

https://www.minix-vmd.org/pub/minix/2.0.2/

Later versions really want a 286, but that gives you proper memory protection too.

Of course, if you want any processes bigger than 64kB code / 64kB data, you need to upgrade to Minix 386.

Xenix ran on the master node of the Intel iPSC, a commercial hypercube used for parallel computation starting in the mid-to-late 80s. The compute nodes used a proprietary OS.

I also worked for a retailer that used SCO Xenix for Point of Sale and other applications. 386/16s and 386/20s with 16, 24 or 32 port serial boards running serial printers and dumb terminals. Fun times.

I also worked for a retailer with a very similar setup (I wonder if it was the same one). It was amazing how many terminals you could sling on to a 386/20 and still have the whole thing work. The retail software was custom-written C that used a UI toolkit/library for the screens, but the name of the toolkit escapes me. I was in support at the time and didn't actually code the software, so I have no problem saying that it was a hot mess. :-)

I managed to grab some SCO Xenix installation floppy disks when I left (they had moved on to Netware/MS-DOS at that point, so the disks were just going to get thrown out). I still have them around somewhere...

> Even though it came first, Unix was probably more powerful than MS-DOS.

This is the understatement of the decade. Of course it was more powerful. I used Xenix in 1987 on an IBM PC, probably a 80286. It was a Xenix/MS-DOS dual booting system. Multiuser and multitasking with Xenix or single user and monotask with MS-DOS.

I used various flavors of Unix on Z8000 or 68k architectures in those years. All of them were obviously better than MS-DOS.

You beat me to it. I was just about to point out that ridiculous sentence.
The entire article is incoherent.
Hey I know this is super off topic but can you please email me? I'm in the process of fixing an old computer (an i486 'portable' system) and I need to find some stuff to get it up and running. I'm looking for someone who can point me to where I can find a bootable 5 1/4 drive to see if my IO card is good. I have asked a few professors at my college but all of them have cleaned out their old hardware.

I know this may be strange but there aren't many people left that can debug these kinds of systems. Sorry for disturbing this thread!

Those computers I wrote about are gone a long time ago. I don't know where to look for those components. Maybe ebay?
I've looked, nothing bootable sadly. I hope some day someone sees this message and emails me. I'd be willing to pay at least 10 bucks + shipping for a DOS image or something.
Not sure if this will help any. http://www.emsps.com/oldtools/msdos.htm I also read about using a CF to IDE adapter. http://www.yqcomputer.com/1118_467_1.htm
I could make the image provided I had both a 5 1/4 floppy drive and an actual 5 1/4 floppy. I don't have either of those for my new computers.

It's like trying to write a DVD with no burner. Where do you have a computer that still has a DVD drive burner? Same problem I'm having.

My laptop came with a DVD burner a couple of years ago. Maybe used once. I swapped it with a 1 TB SSD earlier this year but I can connect it with USB if I have to.
A 486 with a 5.25 drive? that's an odd combo to put it mildly.
> obviously better

What is better critically depends on the "coordinate system". There was (and still is) something infinitely precious about MS-DOS. Simplicity, ease of accessing hardware, and all that alongside the vast multitude of extremely powerful and useful software that was available for it. In other words, DOS had something that few, if any, other OS could offer at the time.

https://archive.org/details/byte-magazine-1981-06 has a very good description of Xenix starting on page 248. This was just before the IBM PC was announced.

In page 286 of https://archive.org/details/byte-magazine-1983-11-rescan one of the main advantages of MS-DOS 2.0 is supposed to be its Xenix compatibility. That is why MS-DOS 1 had CP/M style system calls while MS-DOS 2 added Unix style ones.

At that time Microsoft was thinking that eventually MS-DOS and Xenix would be merged into a single operating system (I read it in yet another Byte article but can't look for it right now) but things ended up going in a different direction.

One thing INFOSEC people might find interesting about Xenix is the re-implementation done by Trusted Information Systems: Trusted Xenix. It was the first, certified, security-oriented UNIX that had a combo of features for extra security plus backward compatibility with Xenix apps. These included trusted path, mandatory controls, integrity controls to limit viral damage, some suppression of covert channels, and especially their solution to setuid problem. That they published a solution while mainstream UNIX just kept the problem around was an early illustration of a recurring problem in mainstream INFOSEC where prior, proven solutions get ignored.

Here's the evaluation report with all of its security features and such for anyone interested in learning about it. Or comparing it to security of modern UNIX's:

http://webapp1.dlib.indiana.edu/virtual_disk_library/index.c...

Particularly interesting to compare it to SELinux, FreeBSD w/ SEBSD, or OpenBSD.

Xenix was the tits back in the day, and the first Unix I ever worked with. Because of TRS-XENIX, the Tandy Model 16 (essentially a Model II kitbashed with a 68000 daughtercard with 512 KiB or so of RAM) was the only desktop workstation computer not made by Sun that could run Unix in 1982.
I used Xenix briefly and did some tinkering including writing a device driver. Just remember it as being a pleasant but mostly useless ;)

Now I think this was on IBM's PC/RT but Googling I can't find much. At any rate I'm pretty sure it was some "special" PC variant. Anyone remembers that one? There were quite a few other oddball "PC" platforms like the one that ran VM/CMS and was like a little 370 mainframe in a PC box. I think that one was PC/370 or something.

Looks like the PC/RT was AIX .. Yet another Unix. Perhaps my Xenix machine was just a standard PC then...
I don't think it is forgotten by all of us in IT! I once had the dubious distinction of supporting/administrating a 20 user Xenix system (Compaq server with numerous VT-100 terminals attached.) Solid system until it wasn't ... the Compaq hardware was always less reliable than the OS, however!