🚀 go-pugleaf

1.  What is the source of the opening book in GNU chess?  

2.  Is the format of the opening book with the current gnuchess the same as
the format for the DOS version (version 4.0 pl 62?) ?  The problem is that the
DOS version has a limited book.

3.  What is the relationship between the files eco.pgn and gnuchess.bk3.gz?
(Besides one having a lot more information and being compressed.)  Is eco.pgn
a subset of gnuchess.bk3.gz?

4.  What do the codes in the files mean?  For example, the first (non-blank)
line of the file eco.pgn is:

[ECO    C99 Ruy Lopez: closed, Chigorin, 12...c5d4]

What does the C99 mean?  Does it refer to something from the original source
(see question 1)?  I know what Ruy Lopez is.  


Why do I ask?  The blind community has a need for a chess program, and
gnuchess is perfect since the gnuchessr version is ascii based.  The speech
programs are most developed for DOS, with Windows somewhat farther behind, and
of course, graphics are useless and counter-productive.  

--
Clark Dorman
http://cns-web.bu.edu/pub/dorman/Dorman.html