[TUHS] PDP-11 questions

Clem cole clemc at ccc.com
Mon Jan 25 12:14:43 AEST 2016

UNIX was cheap (free with a$100 tape coping fee) but processors were not as discounted as much as you might think. Yes there was a university price sheet but DEC was still making 45% gross margins on them.   And DEC was no different than its competitors

Sent from my iPhone

> On Jan 24, 2016, at 8:55 PM, David Ritchie <deritchie at yahoo.com> wrote:
> 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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