Microsoft Xenix

[Bert Driehuis]

My PIDP11 is blinking its LED's for me, a gorgeous sight! Unfortunately, it's still running UNIX v7, which at the time I couldn't lay my hands on. The PDP11/23 I was maintaining ran Microsoft Xenix, which as we all know was the enterprise OS of the future to complement that other great Microsoft product for desktop computers, MS-DOS.

Going on this trip down memory lane, I was reminded of my very first support call to Microsoft. The man page for uucp(1) on Xenix mentioned as step 1 to recompile a certain .c file with the UUCP host name embedded, and strings(1) told me that Xenix shipped with the documentation example host name burned into the binary, so it was impossible to hook up to UUCP. Putting my blondest voice to work, I asked the Microsoft support guy where I could find the source code mentioned in the man page. The only thing he knew for sure was that I was not going to lay my grubby paws at their hard earned source code.

Ten years later, I finally got access to the VMS source code micro fiches and found Dave Cutler's signature on the change in the VAXCRTL that broke source code compatibility between UNIX and VMS without invalidating POSIX compliance. This confirmed that POSIX was a waste of time, but I digress.

Now that time has been kind to Microsoft and everyone has forgotten about their promise that Xenix would be as great as Copilot is today, I would love to lay my grubby paws at a binary distribution of Xenix for the PDP11/23. Would anyone happen to have a copy of it laying around?

[Steve Platt]

Wow, I never knew Xenix ran on the pdp11! I have many memories, more fun than not, of running Xenix on my 386 system. A beast, 387 coprocessor, 8M of RAM. Even a small L1 cache, as I remember.

I wrote device drivers for a data translation image capture card (with builtin/hardware hsv conversion). A primitive touchscreen and window/menu system with dialog boxes, buttons, etc. Device independence -- worked w both DT and TARGA graphics cards. Pretty advanced for the era.

Ah, the fun days...

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[Warner Losh]

I believe there's partial system dumps or tapes somewhere... let me go poking..

warner

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[terry-...@glaver.org]

At Lifeboat Associates we had an 11/34 with Xenix. Had a bunch of incompatible (non-DEC-emulating) Plessy controllers.

[isy...@gmail.com]

Dear All,

 Well, this is interesting. I had a go a long while ago at finding a Xenix distro ... without success.

 So, I went down the Ultrix path instead and finally ended up with a working system on an emulated 11/24 ver 3.1.

 I also would be interested if anyone can find anything.

Regards, Ian.

[Mike Kostersitz]

Yes, when I started at Microsoft in the early 90s our mail server for Germany, Austria and Switzerland ran on an PDP11 in Munich on Xenix mail. Using the XNS protocol 🙂🙂

Mike

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From: pid...@googlegroups.com <pid...@googlegroups.com> on behalf of Warner Losh <i...@bsdimp.com>
Sent: Wednesday, August 6, 2025 8:22 PM
To: Steve Platt <steve...@comcast.net>
Cc: Bert Driehuis <drie...@playbeing.org>; [PiDP-11] <pid...@googlegroups.com>
Subject: Re: [PiDP-11] Microsoft Xenix

 

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[fr...@wortner.com]

Many years ago, I thought I had a tape of PDP-11 Xenix in my attic. I also remember Lireboat Associates.  If I recall correctly, I got the tape from them.  I could also swear I had a printout of the installation instructions on green bar paper,. but I can find neither now.  I recall that the printout had an annotation stating that it was printed on the "Microsoft Heating Plant," a PDP-10.  ;-)