Path: utzoo!mnetor!uunet!steinmetz!davidsen
From: davidsen@steinmetz.steinmetz.UUCP (William E. Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: More than 32 bits needed where?
Message-ID: <9653@steinmetz.steinmetz.UUCP>
Date: 23 Feb 88 15:40:13 GMT
References: <9495@steinmetz.steinmetz.UUCP> <3815@megaron.arizona.edu> <15781@beta.UUCP>
Reply-To: davidsen@kbsvax.steinmetz.UUCP (William E. Davidsen Jr)
Organization: General Electric CRD, Schenectady, NY
Lines: 28

In article <15781@beta.UUCP> jxdl@beta.UUCP (Jerry DeLapp) writes:
> [...]
>Address space is like disk space is like memory is like money. You can
>always use up everything you have and then some.

While there are always problems which could be solved to another
significant digit with more power, even on the Cray2, which can have up
to 2GB of memory, few problems larger than 500MB are run because the CPU
takes a lot of real time to clear/search/etc it. Until faster CPUs are
common, I doubt that there will be a switch to much larger (ie. 64 bit)
address space, because of market pressures.

Vendors don't make computers, they make money. If a change increases the
speed of the CPU, virtually every user will notice. If the address space
is made larger only a few users will notice, and most of those have
problems too large for the CPU.

I expect the next step to be in supercomputers, to 36 or 40 bits,
although the address *registers* will probably jump to 64 bits, the CPU
won't have that many address pins.

Educational activity: if you have access to the accounting file and can
see the process size, a look at the data will probably convince you that
few processes are pushing what we have available now.
-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me