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Path: utzoo!watmath!clyde!bonnie!akgua!gatech!ut-sally!seismo!cmcl2!lanl!jlg
From: jlg@lanl.ARPA
Newsgroups: net.arch
Subject: Re: 128Mb - I give up!
Message-ID: <34249@lanl.ARPA>
Date: Wed, 4-Dec-85 00:24:02 EST
Article-I.D.: lanl.34249
Posted: Wed Dec  4 00:24:02 1985
Date-Received: Fri, 6-Dec-85 06:45:56 EST
References: <285@frog.UUCP>
Reply-To: jlg@a.UUCP (Jim Giles)
Organization: Los Alamos National Laboratory
Lines: 18




The claim that I read was that 256MW (that's WORDS - as in 64 bits, not
those little 8 bit things) would eliminate the need for paging.  This
seems reasonable since 256MW is half the entire virtual memory space of
32 bit addressing schemes on VAX-like machines anyway (2GB).  The
machine under discussion was the Cray-2 which presents other problems
for the would-be memory management device: like disk is MUCH too slow to
be very useful as a page swap device.

Actually, I can't remember a time when the fastest machines on the
market had virtual memory.  Page swapping can, at best, improve
throughput (usually not).  Page swapping is almost guaranteed to degrade
turn-around of individual tasks.

J. Giles
Los Alamos