Ultrix and 4.2 and der Mouse

[Will Edgington/Ejeo]

  I'm not sure I want to get involved in this mess, but I felt I ought to, due
to the fact that we run VMS (4.2), Ultrix 1.0, *and* BSD 4.2 (not to mention
BSD 2.9) here.  We have source only for BSD; Ultrix didn't come with source
(at least not at a decent price) when we got it.  All three are on VAX
11/750's, though we also have a 780 (VMS).  I am one of the two staff people
here that does major work maintaining and upgrading the Unix (& Ultrix)
machines.  We have full field support only for VMS, though we do have full
*hardware* support on the Unix/Ultrix machines; software support was felt to
be too expensive (both before I was hired and now; I have little to do with
such decisions).
  First, hardware failures are at least as common as 'system crash'-type
software failures are.  Nearly all our disks are ra81s and ra80s; they have
been at the root of all hardware failures under BSD *or* Ultrix in the year
I've worked here.
  Second, the two major software failures under BSD:  one was indirectly due
to the large disks (sign extension); the second was due to an incorrect (at
least, to *our* kernel) bugfix from this network.  Other major 4.2 bugs have
either already been fixed, don't apply to our system, or haven't shown up
here yet and we haven't ever seen them.  Ultrix won't have these partly because
we don't have source and partly because DEC has learned from 4.2's failures
and fixed them already.
  Third, the major device driver changes:  we recently installed ethernet
(DEUNAs) between all the VAXes (even VMS, though they don't have TCP/IP yet).
Ultrix already had the driver (of course); I just had to reconfigure the system
and do the make.  For the BSD machine, I got a copy of Lou Salkind's driver
(from 'der Mouse', as a matter of fact), reconfigured and did the make.
Again, the major difference was due to the fact that Ultrix could take
advantage of the time difference:  it was written later.  At about the same
time, we added a System Industries tri-density (800, 1600, and 6250 bpi) tape
drive (dual ported to the BSD machine and the Ultrix machine).  Under BSD, I
had to make a few changes to the source to be able to write at 6250, reconfig,
and make.  Under Ultrix, no source.  So I copied the BSD driver over, reconfig,
slight mods to the makefile to add the driver as a source file, and a make.
NO CHANGES TO SOURCE CODE.  If that's not compatibility, I don't know what is.
Only major difference: lack of source on the Ultrix machine.
  Fourth, bug fixes to user programs:  these are hard to do without source,
so we make the changes to the BSD machine and copy the new program to the Ultrix
machine.  Every time, the *executable* from BSD has run under Ultrix without
change.  Identical system directory structure and username/UID pairs has helped.
Major programs done in this fashion include tip, rpr (a locally written program
that uses tip to print a file on a printer, possibly on VMS, over our MICOM
dataswitch), and getty (autobaud changes).  tip and getty, especially, show
how compatible BSD 4.2 and Ultrix are; they depend rather heavily on system
internals.
  Fifth, while we are an educational institution, that has little to do with
our preference for BSD over Ultrix:  no students, not even workstudies in my
department (which is *NOT* academic; it is an administrative department) have
access to any system source, VMS nor Unix nor Ultrix nor VOS nor MCP/CANDE nor
etc., etc. (We also have a Burroughs 5920, a Harris 500, and a Harris 1000).
Our preference for BSD lies primarily in the fact that we have source for it
and can therefore modify it more easily into what we require.  DEC would never
write half the programs that we *must* have, with such a mix of equipment.
BSD and Ultrix are otherwise equal in our eyes.
-- 
Will Edgington		 | Phone: (303) 871-2081 (work), 722-5738 (home)
Computing Services Staff | USnail: BA 469, 2020 S. Race, Denver CO 80210
University of Denver	 | Home: 2035 S. Josephine #102, Denver CO 80210
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