[COFF] Other OSes?

[Theodore Y. Ts'o]

On Mon, Jul 09, 2018 at 08:52:00AM -0400, Clem Cole wrote:
> 
> rIght and the RIM loaded was printed on front panel of the console.  btw
> the disk was 19” in diamete.  Danny Klein has the original disk platter
> from the one of the original PDP-8 - before marriage it used to hang in his
> living room. FYI that was the system at the computer museum from the EE
> Dept after it died in approx ‘75  I was there the disk crashed.

I don't think it was 19" --- the DF32 was mounted in a 19" rack, yes.
But the platter was in an enclosure which was distinctly smaller than
the overall width of the DF32, and the platter was smaller still.  See
the pictures here[1] and here[2].

[1] https://www.pdp8.net/dfds32/dfds32.shtml 
[2] https://www.pdp8.net/dfds32/pics/df32diskorig.shtml?small

I once physically held the DF32 platter in my hands.  My dad and I
pulled it out of the enclosure, wiped it down with alcohol, looked at
both sides of the platter to see which was less scratched up, and put
the "better" side face down on top of the fixed heads, and then
screwed the platter back into place.  And it worked, afterwards, too!
You can't do that with today's HDD's!  :-)

> > Later PDP-8's would run more a sophisticated OS, such as OS/8, which
> > had a "Concise Command Language" (CCL) that was designed to be similar
> > to the TOPS-10 system running on the PDP-10.  OS/8 was a single-user
> > system, though; no time-sharing!
> 
> Be careful grasshopper.   TSS/8 is available on those web sites although I
> admit it does not run on my PiDP-8 and I have not figured why (Something is
> corrupt and I have not spent the time or energy to chase it).  Anyway,
> TSS/8. Supported 4-8 ASR-33 terminals, each had 4K words as you described
> before.  There was assembler, basic, focal, Fortran-IV and an Algol circa
> 1965 extensions.

I had forgotten about TSS/8.  OS/8 was indeed only single-user,
although apparently there was a multi-user BASIC interpreter which was
available as an option.  Our PDP-8/i only had 8k of core memory so
while in theory it was possible (barely) to run OS/8, we never did.
My knowledge of OS/8 was only from the manuals.  (And indeed, how I
first learned binary arithmatic, and programming in general, was via
thet Digital's "Introduction to Programming" book[1] which I inhaled
when I was maybe seven or eight.)

[1] https://web.archive.org/web/20051220132023/http://www.bitsavers.org:80/pdf/dec/pdp8/IntroToProgramming1969.pdf

TSS/8 was so far beyond the capabilities of the PDP-8 in my father's
lab that I never spent much time learning about it.  I think some of
the DECUS books we had referenced it, so I knew of its existence, but
not much more than that.

> RIght this is really the model for RT11 which would begat CP/M and last
> DOS-86 (aka PC-DOS, later renamed MS-DOS).

We had a PDP-11 at my computer lab in high school.  It was actually
running TSX-11 (the time-sharing extension of RT-11), so it could
support a dozen or so virtual instances of RT-11, where we learned
PDP-11 assembler in the advanced comp-sci class.

I remember two fun things about the TSX-11; the first was that when
you logged out of TSX-11, it would print the time used on the console,
and that was being printed by the underlying RT-11 --- so if you typed
control-S right at that point, it would lock up the whole system, and
all of the other users would be dead in the water.

The other fun thing was if you could get physical access to the
PDP-11, and brought the secondary disk off-line, and then forced a
reboot, RT-11 wouldn't be able to bring the TSX-11 system up fully,
and so the LA36 console would drop to a RT-11 command line prompt
without asking for a password.  This would allow you to run the
account editing program to set up a new privileged TSX-11 account.
(Basically, the equivalent of editing /etc/passwd and adding another
account with uid == 0.)

My knowledge of these facts was, of course, purely hypothetical.  :-)

In any case, that was why the first Linux FTP site in North America
was named "tsx-11.mit.edu"; it was a Vax VS3800 running Ultrix that
was sitting in my office when I was working at MIT as a full-time
staff member.  At first, tsx-11 was my personal workstation, but over
time it became a dedicated full-time server and migrated to larger and
more powerful machines; first a Dec Alpha running OSF/1, and later on,
a more powerful Intel server running Linux.  Shortly afterwards, I
started working at VA Linux Systems, and while tsx-11 was operating
for a while after that, after a while we shut it down since the
hardware was getting old and I no longer had access to the machine
room in MIT Building E40 where it lived.

	   	     	      	    	    - Ted