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: <9495@steinmetz.steinmetz.UUCP>
Date: 10 Feb 88 15:45:53 GMT
References: <235@unicom.UUCP> <28200089@ccvaxa> <3104@watcgl.waterloo.edu> <4340@ames.arpa> <1333@vaxb.calgary.UUCP> <41350@sun.uucp>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: General Electric CRD, Schenectady, NY
Lines: 45

I've had this discussion with one of the Cray gurus here, and I'll just
mention my point again in relation to the current discussion.

Given any computer, there are a certain percent of all problems which do
not exceed its addressing, mass storage and accuracy limits, and which
execute in a reasonable time (see below).  As the hardware becomes more
powerful the percent of soluble problems increases. 

There are people who say that there will always be a need for more power
are only partially correct. There will always be a *use* for more power,
but as the percentage of problems requiring a given level of power
decreases, the economic justification for creating such hardware
decreases. The problems tend to be more abstract and the value of the
solutions harder to determine.

I am not saying that we are at that "stopping point," and if the cost of
hardware continues to decrease there may not be such a point. But when
someone claims that they need a system two orders of magnitude faster
than a Cray, I have to question the term "need." Not that there is any
lack of problems requiring that level of power for solution, but that
the solution is needed as opposed to being technically interesting, I
question.

The typical accountants answer to buying more CPU power is "what will
happen if we don't get it?" If the answer is "the paychecks won't go out
on time" or "we can't do our billing," there is a "need." If the answer
is "our weather map will be 5% less accurate than it could be," you
better be making money on weather maps (or have the taxpayers bottomless
pockets to tap).

There will always be people who could ligitimately use more than 2 GB of
memory, or more than 64 bit words, the question is if the problems to be
solved justify the expense. Looking at the history of hardware cost, I
would guess that there will be more problems solved with existing
hardware, and fewer which need more than state of the art.
--
Acceptable response: depends on the time taken to use the data. Someone
making a ray traced motion picture generates frames which are used in a
fraction of a second, and lot of them. Some engineer who takes three
weeks to analize the output of one simulation run will not be a lot less
productive waiting four hours to get those results.
-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me