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From: MANAGER@SMITH.BITNET (Mary Malmros)
Newsgroups: comp.os.vms
Subject: 8xxx system problems
Message-ID: <8707110150.AA27978@ucbvax.Berkeley.EDU>
Date: Thu, 9-Jul-87 14:38:00 EDT
Article-I.D.: ucbvax.8707110150.AA27978
Posted: Thu Jul  9 14:38:00 1987
Date-Received: Sun, 12-Jul-87 14:10:05 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 44

Paul Clayton listed a number of problems that he's experienced with his
8500 since Jan 1.  We got an 8500 shortly before that.  I haven't run up
against any of the problems that he mentioned EXCEPT the crashes that are
associated with doing things to/with the console.  Specifically, I have crashed
my system while doing the following three things:

   1.  Doing CONNECT CONSOLE -- system crashed about 5-10 minutes following
       the command.

   2.  Scanning console log -- system crashed sometime within 15 minutes of
       when I started looking at the log.

   3.  Using the console as a terminal to do TYPE and EDT -- console got hung
       up totally when it received several quick XOFF/XON combinations while
       typing a file.  Similar behavior in EDT when receiving several PAGE
       commands (or other commands requiring a screen redraw) in rapid
       succession.  I did this about five times in two days last December,
       right after we had got it out of the box, and the console was the
       only thing that could talk to the CPU, so I really don't know if
       it crashed the system, hung the system, or just confused the console
       such that it would eventually have crashed.


I would really like to hear from other people with bothersome consoles
because I don't know a)what it is or b)what comprehensive steps I can
take to avoid it, short of never touching the console at all. Someone told me
once that it had something to do with the very small bus connecting the console
to the CPU.  Because the bus is small, it can't handle too much stuff going in
both directions, and it gets confused and the system crashes.  Aside from the
lack of detail, I don't like that explanation because at least in case 2, stuff
should only be going in one direction (CPU to console).  Maybe it's got
something to do with acknowledgements--CPU is trying to send stuff to console,
console is busy doing something else and can't accept new stuff or acknowledge
that it got it.  Anyway...I'm almost inclined to think that the problem runs a
little deeper than the operating system and that 4.6 won't fix it.

Warning for all others with 8500/8530 systems:  STABACKIT does a CONNECT
CONSOLE.  I found this out when I had to rebuild my standalone kit following
a microcode upgrade (8500 to 8530).  I called DEC and the answer I got was that
you can't get there from here, and that I would have to build a standalone kit
on something else.  I built the kit on the system disk, so it's no big deal,
but I don't think DEC warns you about this explicitly (just "don't CONNECT
CONSOLE).  I really don't get it because I did do STABACKIT once before and I
got away with it...maybe I just got lucky :)