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Subject: Re: Ken Thompson's Endgame DBs....Still no copyright?

Author: Robert Hyatt

Date: 11:21:57 04/26/00

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On April 26, 2000 at 13:09:09, John Merlino wrote:

>On April 25, 2000 at 23:55:32, Robert Hyatt wrote:
>>On April 25, 2000 at 16:04:25, Pete Galati wrote:
>>>On April 25, 2000 at 14:01:24, John Merlino wrote:
>>>>Is it true that you can still ship your engine with Ken Thompson's endgame
>>>>databases (and code to access them, of course) with only a credit to the author?
>>>>My version of these CDs that I have is four years old, but that's what it
>>>>implies in the readme file....
>>>It is my understanding that Ken Thompson no longer uses CCC.  You may however be
>>>able to contact him if you can find an email address for him, I don't have it.
>>I can give it to you if you contact me via private email.  I hate to post
>>email addresses in public places, as the riff-raff pick up on it and cause
>I already found his e-mail address, asked him what the status was, and he
>replied very quickly! Apparently, his databases are still not copyrighted, and
>only require giving him credit somewhere in the program.
>p.s. Crafty uses a different tablebase format, correct? If so, why?

yes, they are different.  For several reasons:

(1) the Nalimov tables are distance to mate, not distance to conversion, which
(IMHO) makes them easier to use.

(2) the N tables can be decompressed on the fly with absolutely no loss of speed
(on anything but the fastest of drives, it is actually faster to use the on-the
fly compression than to have uncompressed files.

(3) the N tables handle en passant.  I don't know if Ken ever fixed that or

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