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Subject: Re: Upper Elo Limits for chess programs on very Slow Processors

Author: Jonathan Parle

Date: 16:52:27 02/16/02

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On February 15, 2002 at 23:25:23, Lyn Harper wrote:

>   I've got a Novag Expert, dating back to 1985. A faithful old friend
> of mine.
>   I just now did a little calculation based on the theory about a 70
> elo point increase in playing strength for every doubling of clock speed.
>   If I could get the program out of my Novag Expert and put it on a
> floppy disk, it would play at about 2680, right up there with the best
> of them. Does this mean there have been no improvements in chess
> programming in the lasst 17 years?
>   I suggest the theory is flawed. The truth is that it works for a
> few doublings, then there is a diminishing return.

It is a very interesting question, but one that is very hard to answer.
Unfortunately Mhz is a horses for courses thing, with there being different
processor types. Lyn's Novag Expert, for example, ran on a 6502 processor. Not
comparable in clock speed to any PC processor since the 386. And then you have
RISC chips, 68000 chips, the 6301Y, Pentiums, Athlons, etc...the list goes on
and on. Unfortunately the shear number of hardware combinations and totally
different methods of programming make this a question that will always be
theorectical. One program might respond "according to theory" by being
underclocked and another might totally debunk any theory. Certainly if you could
take the program out of a 17 year old dedicated machine and run it somehow on an
Athlon 1900XP, you would see an enormous increase in playing strength, but I
think it would still be noticeably weaker than other recent programs. Back in
the 80's programs were written with one combination of very specific hardware in
mind, and consequently they were highly optimised as such. They were actually
very efficient, with ELO ratings of over 1900 being achieved on tiny 5Mhz
machines with only 32K programs. The PC revolution brought with it significant
changes to the way programs could be written. For starters there was much
greater processor scaling potential, the ability to incoporate massive opening
libraries, large amounts of memory for hash tables (that dedicated machines
could only dream about) and the ability to easily and routinely modify reference
files used by the program (OK some dedicated machines could do this in a
reltively primitive fashion but it was the exception rather than the rule).
Today, if you told a programmer they were writing a program for a single, very
specific PC, and that PC only, chances are the program would be a little
stronger on that PC than a generic program - due to the ability to fine tune the
code and the search algorythms. I also believe the reverse also applies. That
is, if you could take a first class program of today like Junior or Rebel and
somehow port it to run on a 5 Mhz 6502 machine, I believe it would lose a match
to a dedicated machine such as Mephisto Polgar.



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