Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ukma!gatech!hubcap!ncrcae!ncrlnk!uunet!mcvax!unido!infbs!ramz!ruediger
From: ruediger@ramz.UUCP (Ruediger Helsch)
Newsgroups: comp.unix.xenix
Subject: Re: SCO Xenix System Hang
Message-ID: <832@ramz.UUCP>
Date: 15 Dec 88 17:56:50 GMT
References: <766@wasatch.UUCP> <329@bilver.UUCP>
Reply-To: ruediger@ramz.UUCP (Ruediger Helsch)
Organization: TU Braunschweig Mechanikzentrum, Germany
Lines: 24

In article <329@bilver.UUCP> bill@bilver.UUCP (bill vermillion) writes:
>In article <766@wasatch.UUCP> kessler%cons.utah.edu@wasatch.UUCP (Robert R. Kessler) writes:
>>                  You can still type on the terminal, characters are
>>echoed, but nothing happens.  You can also switch to a different
>>screen and bring up the system prompt.  However, if you try to type on
>>this screen, nothing is echoed.
>
>Sounds like it might be being "swapped to death" and/or run out of processes.
>Still can be related to "one user" loggin in multiple times.
>

Our system (Xenix release 2.2.1 on an AT) showed the same behaviour when i
once tried to run it out of memory (repeated forking or repeated malloc()ing).
Malloc() of fork() should eventually return an error (after swapping 
everything out, what i wanted to do). But they don't. They just seem to try 
forever.

It seems to me that request for memory can't fail in Xenix. Of course they
also can't return if memory limits are exceeded. They just hang there, and
the system does its best searching for memory, swapping round and round.

Possibly the COBOL runtime system requests more and more memory, without
ever freeing it. After some hours they exceed the available memory and
swapping starts.