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From: daniel@thumper.UUCP
Newsgroups: comp.arch
Subject: Re: big memories, who needs >~1G
Message-ID: <506@thumper.UUCP>
Date: Tue, 17-Mar-87 11:50:24 EST
Article-I.D.: thumper.506
Posted: Tue Mar 17 11:50:24 1987
Date-Received: Sun, 22-Mar-87 14:57:25 EST
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Lines: 26

Since they haven't spoken for themselves, I'll try.  My information is based
from my vague recollection of one talk given long ago. caveat, caveat . . .

There is a project at Princeton called the Massive Memory Machine.  Their goal
is to build a machine in the near future that has something like a terabyte
of core. I may be off by a couple of orders of magnitude, but you get the idea.
They had a big viewgraph with LOTS of 0's.

It is a one-level store taken to the extreme.
The object of the game is to ALWAYS keep EVERYTHING in core.
Obviously one has to worry about what happens when the lights go out.
Their answer is (I think) dual porting the memory and running disks to
constantly back up the core. They use similar tricks to load all that core
quickly at power-up.

They had lots of examples of programs that can benefit from
lots of core.  For instance, database applications pay a heavy cost for
trying to keep things straight given disk latency.  If all data is kept
in core the problem just goes away and gets rid of lots of fancy programming,
and programs run faster, have simplier operating characteristics, etc.

Someone who knows more about the project should fill in the details
and correct my misrepresentations.

Dan Nachbar
bellcore!daniel