[TUHS] A PDP-10 used for UNIX just after the PDP-7?

[Phil Budne via TUHS]

Another PDP-10 footnote, which brings things back around to Ken
and UNIX:

BB&N had done a VM LISP for the PDP-1, but wanted a larger, timeshared
system with VM.  They looked at the PDP-6 as ideal (a 36 bit word
could hold two 18 bit pointers for the CAR and CDR of a LISP list
element), but it was cancelled, but then they heard about development
of the PDP-10.  BB&N tried to interest DEC in building in hardware for
paging, but as I previously noted, the DEC's emphasis at the time was
NOT making another overblown white elephant; the 24-bit SDS 940 (the
commercial version of the Berkeley modified SDS 930) had limited
address space, so BB&N picked the PDP-10 and built their own external
MMU (paging box). The project was led by Daniel Bobrow, and was named
TENEX.  PDP-10s were a major share of systems on the early ARPAnet,
and most of them were running TENEX.

Here's the cruicial bit of UNIX co-history:

TENEX was designed in 1969 (and was up and running in under a year?),
and took feedback from the Multics team on complicated stuff they
should throw out, as well strong influences from the Berkeley "Genie"
time sharing system; The term for a process in TENEX is "fork").
Ken had used the Berkeley system before joining the Multics team.
(See DMR's "incomplete history of QED"(*))

In Ken's paper "Reflections on Trusting Trust" on the receipt
of the Turing award, he wrote:

    I thank the ACM for this award. I can't help but feel that I am
    receiving this honor for timing and serendipity as much as technical
    merit. UNIX swept into popularity with an industry-wide change from
    central mainframes to autonomous minis. I suspect that Daniel Bobrow
    would be here instead of me if he could not afford a PDP-10 and had
    had to "settle" for a PDP-11

Dan Murphy (who had created TECO for the PDP-1 at MIT) who had worked
on the TENEX VM system, and later went to DEC (first to port TENEX to
the KI10, the second PDP-10 CPU, which BB&N again failed to convince
DEC to implement their VM design in, but DID implement a much simpler
paging system, using the same page size as TENEX) to turn TENEX into
TOPS-20 has a page on TENEX, and whose reminiscences I have likely
mis-remembered above:

https://opost.com/tenex/

And includes a version of his history published by IEEE (in an issue
that also includes an interview with Gordon Bell including some
history of the PDP-6):

https://opost.com/tenex/ahc_20150101_jan_2015.pdf

And a longer version, written for a never-published book on PDP-10
history/lore, perhaps for the 1984 20th anniversary of the PDP-6?

https://opost.com/tenex/hbook.html

(*) https://www.nokia.com/bell-labs/about/dennis-m-ritchie/qed.html

Ken wrote a version of QED for the MIT CTSS time sharing system on the
7090, that the Multics team was using for bootstrapping, then QED for
Multics.