Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!husc6!caip!sri-spam!parcvax!hplabs!sdcrdcf!trwrb!desint!geoff
From: geoff@desint.UUCP (Geoff Kuenning)
Newsgroups: net.unix-wizards
Subject: need BSD and System V VM/paging expertise
Message-ID: <251@desint.UUCP>
Date: Fri, 29-Aug-86 00:36:57 EDT
Article-I.D.: desint.251
Posted: Fri Aug 29 00:36:57 1986
Date-Received: Fri, 29-Aug-86 23:25:57 EDT
Reply-To: geoff@desint.UUCP (Geoff Kuenning)
Distribution: na
Organization: SAH Consulting, Manhattan Beach, CA
Lines: 28

Some of you may have noticed that I am writing the "UNIX and Real-Time"
chapter of "The UNIX Papers".  As part of shooting off my mouth, I find
that I need to be able to talk about the System V virtual memory
system and compare it to the BSD implementation.  Unfortunately, I don't
know much about either, and don't have access to the sources.

I would appreciate it very much if somebody knowledgeable could e-mail
me answers to the following questions:

    (1) In general terms, how does System V virtual memory perform
	compared to BSD?
    (2) As I understand it, in the BSD implementation all processes page
	against all other processes.  This is as opposed to the more
	modern method used in VMS, where each process pages only against
	itself.  Am I right about BSD?  And which method does System V
	use?
    (3) BSD has a swapper which will page out an entire process under
	certain conditions (presumably when it is hurting the CPU too badly).
	This swapper does not seem to communicate much with the paging daemon.
	Is this also true of System V?
    (4) For both systems, what sort of pathological situations (notably
	thrashing) do they tend to get into?

Thanks very much for the help.
-- 

	Geoff Kuenning
	{hplabs,ihnp4}!trwrb!desint!geoff