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Subject: Re: Would This Configuration Work?

Author: David Dory

Date: 13:39:03 05/31/02

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On May 31, 2002 at 11:16:32, Robert Henry Durrett wrote:

>On May 31, 2002 at 01:19:57, David Dory wrote:
>
>>>You have some very interesting ideas in your post.  But before getting to them,
>>>I want to make sure we are "singing on the same sheet of music," so to speak.
>>>My interest in this topic developed while thinking about the upcoming >DF/Kramnik match in October. I tried to imagine a configuration which would >have a reasonable chance of being built in time for that match.  Since no one >has posted anything here about the computer that is to be used for that match, >I found myself speculating as to what could possibly be planned.  The first
>>>thought that came to me was:  "Whatever it is, it's going to have to be
>>>something they can build and deliver by August, if Kramnik is to have an
>>>opportunity to play with it for a few weeks before the match."  This led to
>>>recall of the often quoted principle "Keep it Simple Stupid [KISS]."  To me,
>>>that meant that anything that would require extensive design, development, and
>>>testing would be absolutely out of the question.  This prompted the question
>>>"What could be put together in just a few months?"  Although non-optimal, the
>>>configuration I asked about seemed to me to be one possible choice for that
>>>match.
>>=============
>>This configuration is already available. It's called a "cluster". It has a
>>number of independent m/board's fitted into a common bus (backplane). Each mobo
>>works independently of the other, and has it's own memory, etc.
>
>That brings back memories.  I have been monitoring this bulletin board off and
>on for a number of years now.  I vaguely recall bulletins discussing clusters.
>Also saw clusters discussed in technical journals before I retired.  [Don't look
>at technical journals now since no motivation to do so.]
>
>At the risk of sounding like an irritating broken record, the key issue in my
>mind is the speed of the microprocessors.  [Also speed of the boards.]  Although
>the cluster configuration concept has been around for years, the clusters built
>and evaluated always are limited by the availability of suitable components.  A
>cluster built two years ago necessarily had to use some comparatively slow
>hardware, for example.  It does no good to use a 100% efficient design if the
>components have to be terribly slow!

No. Clusters are FAST CPU's. There are no shared memory issues. Bandwidth
between the processors is not a problem.

You're referring to the shared memory multi-CPU computers. They do run slower,
but taken together, with a good parallel program - they do romp!


>
>>
>>The computer for the Kramnik match is (IIRC), already chosen. It's from Compaq.
>
>Forgive me, but I forgot what IIRC means.

IIRC = if I remember correctly. (don't worry, I usually don't rc :-) )

>Are you sure?  Some of these companies give the likes of Kasparov and Kramnik
>millions of dollars just to get a little publicity!  Crazy!
I'm sure! They may let Chessbase have a go with their latest multi-cpu board,
but they won't be bringing out some Itanium3. Maybe an Itanium2 (formerly named
McKinley).

>Don't be afraid to talk about information bandwidth and Shannon's theorems if
>you want to.  There are quite a few people here who can discuss them
>intelligently.  [I've seen the bulletins.]  Back in the 70s, when I was working
>on my MS degree in Electrical Engineering, my major was "Communication and
>Information Theory."  We studied all that good stuff then, but all the examples
>and problems were in the context of communication systems.
Bandwidth I know a tad about (and only a tad). Shannon's theorems I don't even
have a clue about.

>I guess we need an input here from someone more familiar with this.  I don't
>have a good feel for how long it would take. Perhaps finding the most attractive
>eight or sixteen two-ply sequences would be sufficient.

Move generation is done VERY fast. Not to worry.

> That would save a
>little time.  Also, it may not be necessary to have a "high fidelity"
>evaluation.  A rough estimate might be sufficient.  There are tradeoffs here.

Yes, and certainly yes. You're batting 1,000!


>>I'm not sure if PCI bus will support 400 MB/sec or not. Sounds high, maybe??
>
>True.  I picked 400 MHz as an "upper bound."
>
>Another "broken record":  The only motivation for selecting a non-optimal >design
>was to enable use of very fast processors.  I suspected that the speed of the
>processors was more important than the efficiency of the design.  If fast
>processors could be used, no one in his/her right mind would select anything
>except the most efficient design.

I went into a "deep think" on this (and this is always dangerous for a guy with
a shallow head). And I think this idea (which as you can tell I've been playing
with for a while, not willing to "GET WET", has more merit than I anticipated.
A holy terror for more work though, in the coding. (at least for my coding)

>Maybe that's in Rosch's new book, but I haven't seen it there yet.  Just got the
>book and haven't read it all. [1348 pages of text!!!!!!!]
Little light reading, have we? <grin>


>What I was considering was a "network" [or "bus"] which would be completely
>enclosed by a standard 19" rack.  The small size would facilitate speed.  A much
>larger network/bus might be a real mess, especially if messages had to be routed
>through routers [and much more] as on the Internet.  Probably totally
>impractical if speed is the objective.

Yes, physical proximity is a priority for the cluster.
(hard to imagine that came out of my keyboard, actually)

>
>All "computer-chess geeks" surely are rooting for the computer.  Right?
>
Both, actually. I just want to see a good match - no dumby "computer" moves, and
a close score and I'm dancing on the ceiling!


>There is a lot of information in Rosch's book about PCI.  It will take me >awhile to digest it all.

No problemo, amigo. Beano, anyone?

Check this out: http://www.pcworld.com/news/article/0,aid,100544,00.asp

What a story!!

Dave



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