Xenix for the PDP11

Software
1

Microsoft XENIX for the DEC PDP11 has anyone still got a functioning example of this?

Cheers Ivan

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Welcome! An interesting question, and evidently one which pops up from time to time. Here’s a Usenet thread from 2020: XENIX VAX / PDP

"Supratim Sanyal

6 years ago

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Post by Arne Vajhøj

Was there a XENIX release available from Microsoft (or maybe SCO) for
VAX or PDP ?

Xenix - Wikipedia claims it ran on PDP-11.
Arne

Yes and someone looked for it in 2010, but looks like drew a blank. A
tape etc. may have surfaced in the 9 years since, hence asking.

http://www.vcfed.org/forum/showthread.php?19786-Wanted-PDP-or-VAX-Xenix

Post by "Supratim Sanyal
Hi all,
Was there a XENIX release available from Microsoft (or maybe SCO) for
VAX or PDP ?
TIA
Supratim

I just happened to stumble across this question months after Supratim asked it. :wink:

The answer – from personal experience – is yes, there was a PDP-11 distribution of Xenix from Microsoft. I remember running it on a PDP-11/23 many years ago. It was based on V7 and included additional support for DEC hardware that the original V7 did not. The updates included the ability to regenerate the kernel without source code, support for peripherals beyond those provided by Bell Labs – in my case, RL01 and RL02 disks – and an emulation of split instruction and data space for machines like the 11/23. (In fact, the program that created these special executables was called “23fix.”) I remember a set of instructions printed on a line printer. The banner page mentioned that it was produced on the “Microsoft Heating Plant.” :slight_smile: In terms of features, it might have been similar to DEC’s V7M.

via
XENIX - Computer History Wiki

(Sorry to say I can’t help with finding it, but it would be good if it could be found!)

There are mentions of PDP-11 in the Xenix Software Development Guide, for example

3.2.1 The Standard I/O Library
The standard I/O library was designed with the following goals in mind.

  1. It must be as efficient as possible, both in time and in space, so that there will be no hesitation in using it no matter how critical the application.
  2. It must be simple to use, and also free of the magic numbers and mysterious calls whose use mars the understandability and portability of many programs using older packages.
  3. The interface provided should be applicable on all machines, whether or not the programs which implement it are directly portable to other systems, or to machines other than the PDP-II running a version of XENIX.

See also the man page for factor:

Maximum time to factor is proportional to sqrt(n) and occurs when n is prime or the square of a prime. It takes 1 minute to factor a prime near 10^14 on a PDP11.