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From: sewilco@mecc.UUCP (Scot E. Wilcoxon)
Newsgroups: net.arch
Subject: Re: VERY LARGE main memories
Message-ID: <588@mecc.UUCP>
Date: Mon, 8-Sep-86 11:31:15 EDT
Article-I.D.: mecc.588
Posted: Mon Sep  8 11:31:15 1986
Date-Received: Tue, 9-Sep-86 02:22:23 EDT
References: <15505@ucbvax.BERKELEY.EDU> <5100121@ccvaxa>
Reply-To: sewilco@mecc.UUCP (Scot E. Wilcoxon)
Organization: MN Ed Comp Corp, St Paul, MN
Lines: 21
Summary: 200 bits of address space may not be enough, but it's all we have.

>As I think I've mentioned before, it is believed that there are
>approximately 2^200 electrons in the universe.  Since it is unlikely that
>anybody would want to reference more things than there are electrons in the
>universe, 200 bits seems like a good upper bound for the length of a memory
>address.
>
>Roy Smith, {allegra,philabs}!phri!roy

Present technologies all require use of many electrons per bit stored.
Therefore the number of electrons in the universe is an actual upper bound.
Particularly since a few electrons are needed for the computer which will use
the memory :-)

Collecting all the electrons in the universe for the factory is left as an
exercise for the reader.  Simulating this action and the forces involved will
use more memory than the number of electrons.
-- 
Scot E. Wilcoxon    Minn Ed Comp Corp  {quest,dicome,meccts}!mecc!sewilco
45 03 N  93 08 W (612)481-3507 {{caip!meccts},ihnp4,philabs}!mecc!sewilco

	"BOOKS" in five-foot neon letters means pictures are sold there.