Path: utzoo!attcan!uunet!cs.utexas.edu!swrinde!emory!hubcap!fineman
From: fineman@ptolemy.arc.nasa.gov (Charles Fineman)
Newsgroups: comp.parallel
Subject: Re: Limits of sequential computation
Message-ID: <9505@hubcap.clemson.edu>
Date: 29 Jun 90 13:34:26 GMT
Sender: fpst@hubcap.clemson.edu
Lines: 31
Approved: parallel@hubcap.clemson.edu

In article <9490@hubcap.clemson.edu>, shaffer@crd.GE.COM (Phillip L. Shaffer) writes:
|> I have heard discussions on the theoretical limits to the speed
|> of sequential computation, as one justification for research on
|> parallel processing (not that I think there are no other
|> reasons).  Such limits might be based on minimum size of
|> computing elements and the speed of light.  In a quick look, I
|> couldn't find any references on this topic.
|> 
|> Can anyone provide references or original thoughts on this
|> subject?
|> 
|> On a related topic, I saw a chart of computational speed (MIPS or
|> some other inadequate measure, but let's not quibble) versus
|> historical time (log scale for computational speed, linear for
|> time).  The data points represented various real microprocessors,
|> but the chart was far from complete.  A straight line was drawn
|> through the points, and was not too bad a fit.  I didn't see any
|> curvature in the data, but the author had drawn an extrapolation
|> (beyond 1990) as leveling off.  Has anyone seen or done a serious
|> study of trends of computing speed versus time, and if so, does
|> any evidence of leveling off exist, or is this a supposition
|> based only on the above mentioned theoretical limits to
|> computational speed?
|> 
This sounds a lot like an article I saw in Scientific American. If
I had to guess, I'd say it was in an issue in the latter part of last
decade (not much of a guess, sorry). I think the title was something 
like "The Fundamental Limits of Computation". I'm not positive, but
it may have even been the cover story.

	Chuck