Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!uw-beaver!blake!Tomobiki-Cho!mrc
From: mrc@Tomobiki-Cho.CAC.Washington.EDU (Mark Crispin)
Newsgroups: comp.arch
Subject: Re: PDP9 - what's it good for?
Message-ID: <3152@blake.acs.washington.edu>
Date: 8 Aug 89 19:21:34 GMT
References: <1989Jul25.155034.20792@lsuc.on.ca> <627@east.East.Sun.COM>
Sender: news@blake.acs.washington.edu
Organization: Mendou Zaibatsu, Tomobiki-Cho, Butsumetsu-Shi
Lines: 23

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