[TUHS] PDP-11/70 in Cory Hall, Berkeley '74 or 75

[Jim Mellander via TUHS]

Thanks!

A little more of my experiences with Unix in those days:

I was 18 and too clever for my own good. Not being a student, I managed to
"get" a student's account by looking over their shoulder surreptitiously. I
then wrote a trivial C program to mimic the login prompt and harvested a
few other accounts. I created a hidden dot directory for my experiments,
which mainly consisted of writing chess and checker programs for my own
amusement.

I devoured the thick white Unix manual of the day, and, I hesitate to
admit, wrote a trivial shell fork bomb which just spawned additional copies
of itself in the background. I remember firing it up on an ASR-33, and it
printed out the PIDs slower and slower until the system froze. I tore off
the printout and left.

The next time I showed up, the aforementioned long-hairs approached me, and
told me that they knew what I had done. In contrast to what would happen
today, they told me that they would give me a guest account for my
enjoyment if I promised to stay in my lane. I took their words to heart and
continued tinkering with my programs for the rest of my time stationed in
the Bay Area.

I also got an account somehow on the CDC-6400 in the basement of Evans
Hall, and ran a few interesting batch-mode programs from punch cards.

I often wondered who those guys were, since their kindness actually pointed
me on the straight and narrow. Probably my fork bomb caused them to
re-engineer the process table, so that could be my minor contribution to
Unix.

My career ended up in cybersecurity, of course (it takes a thief...) at LBL
right up the hill from the Berkeley campus, so it all worked out OK.

As an aside to the discussion about 'true', it seems reasonable that in the
usual case ("while true"), the shell version wouldn't be significantly, if
any, slower than a separate binary, since the shared libraries would
already be in core. On my apple silicon mac 'true' is a 84128 byte dual
architecture binary.....

Thanks to all the Unix pioneers!

Jim Mellander


On Sun, Oct 5, 2025 at 2:45 PM Eric Allman <tuhs at eric.allman.name> wrote:

>
> On 10/4/25 14:15, Jim Mellander via TUHS wrote:
> > Hi all:
> >
> > I had the occasion to use the PDP-11/70 on the ground floor of Cory
> Hall. I
> > was not a student, but was in the Navy stationed at Treasure Island, but
> > groked Unix & visited there on my time off to tinker, among other things.
>
> I believe that would have been the instructional PDP-11/70. There was
> also an 11/45 that was, to the best of my knowledge, shared by CS, Math,
> and Statistics. Math and Stat wanted to run the vendor OS but CS wanted
> to run UNIX, so ⅓ of the time it ran UNIX and 2/3 of the time it ran
> something else, maybe RSTS.
>
> I worked on the INGRES project, which eventually got their own
> PDP-11/70, which was on the 4th floor of Cory. There were a few guest
> accounts, but it wasn't an instructional machine other than for the
> graduate DBMS class.
>
> My recollection is that Berkeley was running 5th Edition when I got my
> first account, but that didn't last long. I was mostly insulated from
> the transition to 6th Edition, but I remember that it required a lot of
> changes in INGRES due to changes in both the libraries and the C
> language itself. I was not insulated from the transition to 7th Edition,
> which was a lot of work but easier to work with.
>
> There were other transitions when the VAXen started to appear, but those
> were later.
>
> > I always have wondered who were the long hairs who were working inside
> the
> > glass partition on the system.
>
> These were probably the usual suspects: Bill Joy and Chuck Haley
> (certainly), Bob Fabry (who convinced the department to run UNIX in the
> first place), Ken Thompson (when he was on sabbatical while at
> Berkeley), Jeff Shriebman, and many others that I'm forgetting at the
> moment. There were also a lot of other folks who weren't doing a lot of
> kernel work like Ken Arnold, Kirk McKusick (who shared an office with
> Bill), Tom Ferrin (UCSF, but spent time in Berkeley working with other
> UNIX folks), Eric Schmidt, Kurt Shoens, etc. For the most part they were
> not working inside the glass box.
>
> Bonus recollection: Ken Thompson gave a free evening class that was a
> walk-through of the v6 kernel. I think about a dozen people showed up.
> The Computer History Museum in Mountain View has an audio recording of
> the talk and an annotated listing with my personal notes. Yes, I held on
> to that listing for almost 50 years.
>
> >
> > Also, I played with a PDP-11/45 in Evans Hall.
> >
> > I'm interested in any information anyone has about those times and
> places.
>
> You might also want to check out videos of Kirk McKusick's talks on the
> history of UNIX at Berkeley. A search for "Kirk McKusick Berkeley UNIX
> history" should do the trick, or check out his Youtube channel at
> https://www.youtube.com/@marshallkirkmckusick1756.
>
> >
> > Thanks in advance,
> >
> > Jim Mellander
>
> eric
>
>