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Subject: Re: For Mr. Lykke-- Re Rebel auto232 log file.

Author: Ed Schröder

Date: 12:16:31 01/17/01

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On January 17, 2001 at 14:47:52, Peter McKenzie wrote:

>On January 17, 2001 at 14:05:21, Ed Schröder wrote:
>
>>On January 17, 2001 at 12:49:50, James T. Walker wrote:
><snip>
>>Your log-file is certainly extreme. The number in brackets is the total
>>number of positions searched. This should be 3707485. If not the "engine
>>damaged" message is displayed.

>Ed,

Hi Peter,

>this situation obviously isn't helping your cause at all.  I think it would be
>in everybody's best interests if the bug (where ever it may be) is found and
>fixed.

I agree.

But after 2-3 years of searching I still have no clue. So I build the
engine check and when I saw its results I dropped the whole case as
un-solved.

Since many of my most loyal customers want to autoplay Rebel after all
(buggy or not) I left the autoplayer software. Also the autoplayer software
is useful for a new feature of Century 3 (CAT).


>If the bug is in the autoplayer, then it would seem likely that whoever makes
>the autoplayer is likely to fix the bug IF you can isolate its exact cause.
>Have you tried pinning down exactly when the corruption of Rebel occurs?  Eg. is
>it always late in the game, or early, or in a particular type of position etc
>etc.  Perhaps it is timing related?
>
>Do you know what part of Rebel is being corrupted?  If so, is it always the same
>part?

The problem is that the autoplayer is an external driver driven by
interrups (an old fashioned DOS TSR program) and I don't have access
to the source code. The suspect is the TSR program writes outside its
available memory. When it writes in Rebel itself the program is most
likely going to crash (which does not happen frequently). If the TSR
program writes in the hash table of Rebel (more likely) anything can
happen, from zero damage (likely) to much damage (unlikely). Rubbish
information in the hash table is not going to crash Rebel.

I have no idea how to trace a TSR program writing outside its own
memory. Do you?

Ed




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