[comp.arch] PDP9 - what's it good for?

jim@lsuc.on.ca (Jim Mercer) (07/25/89)

a friend of mine has a PDP9 with 2 8" drives ram and some "software".

he says i can have it if i want.

is there anything useful this machine can do?

i would like to have it run UNIX of one flavour or another.
Is it too early a model?

please reply email and i will post a summary of the perceived
abilities of the PDP9.

jim@lsuc attcan!lsuc!jim 

mark@spot.megatek.uucp (mark thompson) (07/26/89)

jim@lsuc.on.ca (Jim Mercer) writes:
>a friend of mine has a PDP9 with 2 8" drives ram and some "software".
>he says i can have it if i want.
>is there anything useful this machine can do?
>i would like to have it run UNIX of one flavour or another.
>Is it too early a model?

Sigh. I wonder if dmr will see this posting?

-mark

jpainter@tjp.East.Sun.COM (John Painter - Sun BOS Hardware) (07/27/89)

This is the machine that UNIX was first developed on/for (TTBOMK)
the PDP-11 was the next in line.  How downward compatible is UNIX???
(not very, I suspect)

/Tjp 
-This signature intenionally left blank-

The opinion of the author are just that.

jdm@h.cs.wvu.wvnet.edu (James D Mooney,205K,7,2913548) (07/27/89)

From article <1989Jul25.155034.20792@lsuc.on.ca>, by jim@lsuc.on.ca (Jim Mercer):
> 
> 
> a friend of mine has a PDP9 with 2 8" drives ram and some "software".
> 
> he says i can have it if i want.
> 
> is there anything useful this machine can do?
> 
> i would like to have it run UNIX of one flavour or another.
> Is it too early a model?
> 
> please reply email and i will post a summary of the perceived
> abilities of the PDP9.

I tried an e-mail reply but neither of the author's addresses could
be reached.

I once maintained a PDP-9 system at Ohio State University around
1970.  I still have some of the manuals.

The PDP-9 was a preliminary version of the PDP-15.  Compared to a PDP-8
it was powerful.  We did some fairly sophisticated stuff on it, but I
doubt it has the capacity to run UNIX.  It had an 18-bit word size, and
a maximum capacity of 32K words (all core).  As I recall, our
peripherals included a teletype, paper tape reader and punch, DECtape
(which I still think is marvelous), a big line printer, and a bigger
disk that occupied a corner of the room and had a capacity on the order
of 1MB.  We also used homebrew A-D equipment including a storage-type
video display.

The system software was decent but limited and strictly single-user.
It was probably most similar to RT-11 for the PDP-11.  There was a
good macro assembler, debugger, and FORTRAN IV compiler, line editors
and simple utilities, and lots of diagnostic software.  Floating
point was handled by software, in which we found a few bugs.

An interesting note:  while I was managing the PDP-9 at OSU, a small
new company contracted to use our PDP-9 to develop some software while
waiting for their PDP-15 to be delivered.  The name of this company
was CompuServe.

I can probably answer some more detailed questions if you have any.

Jim Mooney				Dept. of Stat. & Computer Science
(304) 293-3607				West Virginia University
					Morgantown, WV 26506
INTERNET: jdm@a.cs.wvu.wvnet.edu

mrc@Tomobiki-Cho.CAC.Washington.EDU (Mark Crispin) (08/09/89)

In article <627@east.East.Sun.COM> jpainter@tjp.East.Sun.COM (John Painter - Sun BOS Hardware) writes:
>This is the machine that UNIX was first developed on/for (TTBOMK)
>the PDP-11 was the next in line.  How downward compatible is UNIX???
>(not very, I suspect)

Actually, Unix was developed on the PDP-7, which preceeded the PDP-9
by a couple of years.  The 7 and the 9 were largely compatible; in
fact the 4, 7, 9, and 15 had more in common with each other than the
various PDP-11 machines did.

Unix on the PDP-7 was written in assembly language, as was the first
version on the PDP-11.  I don't think that there ever was a C version
of Unix for the PDP-7, or for that matter a C compiler for any of
DEC's 18 bit machines.  DEC cancelled the 18-bit architecture in 1977
after the PDP-11, VAX, and PDP-10/DEC-20 squeezed it out of any
market.

Mark Crispin / 6158 Lariat Loop NE / Bainbridge Island, WA 98110-2020
mrc@CAC.Washington.EDU / MRC@WSMR-SIMTEL20.Army.Mil / (206) 842-2385
Atheist & Proud / 450cc Rebel pilot -- a step up from 250cc's!!!
tabesaserarenakerebanaranakattarashii...kisha no kisha ga kisha de kisha-shita
sumomo mo momo, momo mo momo, momo ni mo iroiro aru
uraniwa ni wa niwa, niwa ni wa niwa niwatori ga iru