PDP-11 Xenix

Warren Toomey wkt at henry.cs.adfa.oz.au
Fri Oct 10 09:00:59 AEST 1997

I just received this email from Frank Wortner. Anybody have a copy of PDP-11


----- Forwarded message from Frank Wortner -----

From: "Frank Wortner" <fwortner at prodigy.net>
To: <wkt at cs.adfa.oz.au>
Subject: Re: Request to Join PUPS

I've sent off email to a friend of mine who preserved some materials from a
now-defunct software company we used to work for.  He *might* have that
tape.  I regret not keeping track of it,  but fifteen years have elapsed
since I last booted it.

Too bad.  PDP-11 Xenix had a number of nice features.

o It was based on the Seventh Edition.
o It ran on everything from a PDP-11/23 on up.
o It could simulate split instruction and data space on non I&D machines.
o It had a complete shutdown procedure (an elaborate /etc/shutdown script)
o The kernel was delivered as an archive library (".a" file),  so you could
reconfigure without source.

Perhaps someone at SCO (or Microsoft) may still have a tape of it.  Most
software firms archive their products in secure vaults,  so it might still
exist in some warehouse.

(*) The scheme involved paging the instructions while the data remained
resident.  The first 8K of the program was always resident and contained a
jump table and supporting software.  The next 8K held whatever instructions
were executing at the time,  while the remaining 48K was reserved for the
data and stack segments.  Building a simulated I&D executable required the
user to link once as a pure executable,  once as a split executable, and
finally running both executables through a program which built the final
simulated split I&D executable.  The compiler had an option ('-j' if I
recall correctly) that performed these three links automatically.

Sorry for the rambling note,  but I'm just a bit overwhelmed by nostalgia.

----- End of forwarded message from Frank Wortner -----

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