[TUHS] PDP-11 questions

David Ritchie deritchie at yahoo.com
Mon Jan 25 11:55:46 AEST 2016

But wasn't a big part of the reason that DEC was successful in academia that PDP's were pretty heavily discounted vs. commercial pricing for similar compute power? Likewise with pricing for Unix?

David Ritchie

Sent from my iPhone

> On Jan 24, 2016, at 17:40, Norman Wilson <norman at oclsc.org> wrote:
> Noel Chiappa:
>  I'd lay good money that the vast majority of PDP-11's never ran Unix. And
>  UNIX might have happened on some other machine - it's not crucially tied to
>  the PDP-11 - in fact, the ease with which it could be used on other machines
>  was a huge part of its eventual success.
> =======
> I have to disagree in part: the PDP-11 is a big part of
> what made UNIX so widespread, especially in university
> departments, in the latter part of the 1970s.
> That wasn't due so much to the PDP-11's technical details
> as to its pricing.  The PDP-11 was a big sales success
> because it was such a powerful machine, with a price that
> individual departments could afford.  Without a platform
> like that, I don't think UNIX would have spread nearly the
> way it did, even before it began to appear in a significant
> way on other architectures.  Save for the VAX, which was
> really a PDP-11 in a gorilla suit, that didn't really happen
> until the early 1980s anyway, and I'm not convinced it
> would have happened had UNIX not already spread so much
> on the PDP-11.
> It worked both ways, of course.  I too suspect that a
> majority (though I'm not so sure about `vast') of PDP-11s
> never ran UNIX.  But I also suspect that a vast majority
> of those that did might not have been purchased without
> UNIX as a magnet.  I don't think those who weren't
> around in the latter 1970s and early 1980s can appreciate
> the ways in which UNIX captured many programmers and
> sysadmins (the two were not so distinct back then!) as
> no other competing system could.  It felt enormously
> more efficient and more pleasant to work on and with
> UNIX than with any of the competition, whether from DEC
> or elsewhere.  At the very least, none of the other
> system vendors had anything to match UNIX; and by the
> same token, had UNIX not been there, other hardware
> vendors' systems would have had better sales.
> Sometime around 1981, the university department I worked
> at, which already had a VAX-11/780 and a PDP-11/45 running
> UNIX, wanted to get another system.  Data General tried
> very hard to convince us to buy their VAX-competitor.
> I remember our visiting their local office to run some
> FORTRAN benchmarks.  The code needed some tweaking to
> work under their OS, which DG claimed was better than
> UNIX.  Us UNIX people had trouble restraining our chuckles
> as we watched the DG guys, who I truly believe were experts
> in their own OS, taking 15 or 20 minutes to do things that
> would have taken two or three with a few shell loops and
> ed commands.
> DG did not get the sale.  We bought a second-hand VAX.
> Blame UNIX.
> Norman Wilson
> Toronto ON

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