[TUHS] History of cal(1)?

[Clem Cole via TUHS]

On Thu, Sep 18, 2025 at 12:54 PM Dan Cross via TUHS <tuhs at tuhs.org> wrote:

> ...
>
> But this also rekindles my curiosity about something I've always
> wondered: what _was_ the level of communication between the folks at
> Bell Labs and the Multics people after 1969?  By all accounts,
> individuals remained friendly and collegial with one another, but it
> seems like communication (let alone collaboration) between the two
> "camps" was minimal.  Is that accurate?
>
Doug and Ken are the best to answer for the MH folk.

But I'll take a stab at the communications within the CS Research Community
during the 70s, which I lived in.

As we all know, Unix spread quickly outside of MH to researchers, and a
great deal of development took place "on the outside."  Some of those ideas
came back to the Research versions, but not all.   But I think there was a
good bit of cross-pollination within the community — even before Usenet or
the Internet itself.   Sometimes we would swap magnetic tapes directly, and
often we would bring tapes to a conference with our work and come home
with work from others.  We knew each other and talked.

Taking MetCalfe's law into account, because there so many Unix
installations (and we were all talking to each other), that style of
sharing could not happen with Multics,  I will posit that by 1975 most, if
not nearly all, researchers in the systems world were at least familiar
with Elliott Organick's 1972 book — "*The Multics System: An Examination of
its Structure*," and many of us had read it and trying to learn lessons
from it.  It was a text that was referred to in my undergrad OS course, and
by the time I was a grad student working in systems, it was pretty much
assumed that everyone in the room had read it.

I certainly thought Multics had some cool ideas. However, I barely touched
a Multics system in those days via my limited remote access (MIT's system).
And I never physically saw a Multics-capable processor until many years
later. I admit that from reading Organski's book, I had some wild images of
computer operators mounting mag tapes so a program could continue execution
after a segment defined as not being directly addressable.  So while I was
familiar with Multics,  I certainly "knew" a lot more about UNIX.  I had
it, and I was hacking its kernel.   I personally did little of what we call
programming on Multics, and at the same time, I was being paid to program
in Unix (and some TOPS-10/TOPS-20 shop).

I don't think I'm really unique here.   If the data from website
Multicians.org is correct, there were just too few Multics installations to be
found (11 in 1975), and only two were at universities (MIT and the
University of Louisiana). The other nine were at commercial sites.  Note
that in 1975, we know there were at least 5 times the number of Unix
installations.  Most of these sites were ones that had had some level of CS
Research.  By 1979, the numbers were 25 for Multics and over 600 for Unix.

By 1979, Multics OS was stable, and the hardware to run it (the "3rd
generation" H6180 had been on the market since 1973) had certainly matured
from the original GE-645. So why did Multics not play a more significant
role? Once again, core economics of the time played a huge part. If you use
Google AI, it will tell you that a Honeywell H6180 computer system running
Multics, like MIT was running in 1979, had a list price of about $7 million
when it was introduced. This price included a complete system with multiple
components, not just the central computer unit.  Now think about a PDP
11/34, with full 256K bytes of memory, a couple of RK05 and probably an
RP04 equivalent as its disk, 9-track tape, Printonix printer, and 16 serial
ports using after-market DH11 — a pretty standard V7 installation, which
costs approximately $100-150K.  Even if you ran it on a Vax, it was not
more than approximately 3 times that number.  But this is a massive
difference from the $7M for a Multic system.

It's a simple Christenson disruption —  the "lesser" system wins over the
earlier, more "mature", and full-featured, "better" one.  As a result,
cross-pollination opportunities were not available.   Unix/V7 and its
derivatives got the attention of units because the economics favored it.
Just like Linux receives today.

Clem