Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!stan!dce
From: dce@Solbourne.COM (David Elliott)
Newsgroups: comp.unix.wizards
Subject: Re: malloc: not enough core
Keywords: df malloc core
Message-ID: <925@marvin.Solbourne.COM>
Date: 2 May 89 19:10:38 GMT
References: <170@larry.sal.wisc.edu>
Reply-To: dce@Solbourne.com (David Elliott)
Organization: Solbourne Computer Inc., Longmont, Colorado
Lines: 20

In article <170@larry.sal.wisc.edu> jwp@larry.sal.wisc.edu (Jeffrey W Percival) writes:
>We have seen this while running the News expire program, as
>well as when running a large data analysis program.  What's the
>deal here?  How can a virtual memory machine deny memory to
>the puny df(1) program?

It's funny.  I've known a number of very smart software engineers who
believe that "virtual memory" means "infinite memory".  Sometimes,
these folks write their code without ever checking to see if malloc()
fails.

It's often important (or at least reasonable) for the OS to expect
there to be enough swap space when a program is running.  What would
happen if df was running and the os needed to swap it out to run
something else?  Would you rather df just keep running while your
network drops packets and fails to update the filesystems?

-- 
David Elliott		dce@Solbourne.COM
			...!{boulder,nbires,sun}!stan!dce