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From: brooks@lll-crg.ARpA (Eugene D. Brooks III)
Newsgroups: net.arch
Subject: Re: Page size and the meaning of life
Message-ID: <939@lll-crg.ARpA>
Date: Wed, 23-Oct-85 20:36:04 EDT
Article-I.D.: lll-crg.939
Posted: Wed Oct 23 20:36:04 1985
Date-Received: Fri, 25-Oct-85 02:16:01 EDT
References: <926@decwrl.UUCP> <931@lll-crg.ARpA> <7459@watdaisy.UUCP>
Reply-To: brooks@lll-crg.UUCP (Eugene D. Brooks III)
Organization: Lawrence Livermore Labs, CRG Group
Lines: 15

>Perhaps the question to ask is do we need disk paging?
>With large memories becoming available rolling pages out to disk may become
>unneccessary, but the concept of virtual memory and its associated attributes
>is probably still useful.
I'm sorry I was not precise enough.  The question was meant to be do we need
disk paging?  The much needed firewall protection and address space shareing
for programs in a multiprocessor can be provided by a simple {base,limit}
segmentation scheme.  One or course needs several sets of such registers
to establish the several segments, code, static data, stack, shared static
data, ... that one needs in a program.  Do we really need the page oriented
virtual memory systems that occur in todays micros and mini computers?  If
we have more than enough physical memory, do we need the overhead associated
with the page mapping hardware?  It is difficult to make such hardware operate
at supercomputer speeds and poses severe difficulties for non bus oriented
architectures (large N multiprocessors).