Xref: utzoo unix-pc.general:740 comp.sys.att:3356
Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!n8emr!uncle!jbm
From: jbm@uncle.UUCP (John B. Milton)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: Swapping and wmgr
Message-ID: <271@uncle.UUCP>
Date: 28 May 88 21:22:17 GMT
References: <449@bacchus> <153@elgar.UUCP> <459@bacchus> <3030@crash.cts.com>
Reply-To: jbm@uncle.UUCP (John B. Milton)
Organization: Just me and my computer, Columbus Ohio
Lines: 32

In article <3030@crash.cts.com> ford@crash.CTS.COM (Michael Ditto) writes:
>In article <459@bacchus> darren@bacchus.UUCP (Darren Friedlein) writes:
>>In article <153@elgar.UUCP> ford@kenobi.UUCP (Mike Ditto) writes:
>>>In article <449@bacchus> darren@bacchus (Darren Friedlein) writes:
...
>The Unix PC supports 4M of virtual memory PER PROCESS, with a total amount
>dependant on your physical memory + swap space.

I read somewhere in the docs that the UNIXpc actually limits each process to
2.5M virtual. It could not be as high as 4.0M because the kernel ALWAYS takes
up some 340k+. Then there are loadable drivers, etc. If user processes were
allowed to get near 4M, they could easily force the machine into constant
thrash and eventual crash.

I just whipped up a quicky, and here's what I got (2.5M=2609152)

max allocate ~= 2535424

main()
{
	int first,last,old;

	first=sbrk(0);
	while ((old=sbrk(4096))!=-1)
		last=old;
	printf("max allocate ~= %d\n",last-first);
}

John
-- 
John Bly Milton IV, jbm@uncle.UUCP, {ihnp4|osu-cis}!n8emr!uncle!jbm
home: (614) 294-4823, work: (614) 459-7641; talk to me about fractals