Author: David Blackman
Date: 00:57:48 04/16/00
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On April 14, 2000 at 19:02:08, Robert Hyatt wrote: >MackHack wasn't written in lisp. It was written in assembly language for the >Digital PDP-10 processor. I had a copy of this I got from Greenblatt somewhere >in the very early 70's. MackHack played in the 60's. That's interesting. I've only ever seen the binary brogram for MacHack. Back in the early 1980s i was feeling bored and decided to try to work out the language that a lot of binary programs on the PDP-10 were written in, just by looking at the binary. I could identify new Fortran, seriously old Fortran, Dec Pascal, and Hedrick's Pascal fairly easily, also Assembler provided they used the MACRO-10 assembler and left everything in the default places. I've forgotten most of the details now, but it involved looking at printable ASCII strings, also looking for subroutine call and return instructions and examining nearby instructions. Program start address from DDT was another strong hint. MacHack was one of a large list of programs that was none of the above. My best guess was compiled MacLisp but compiled with a different version of the compiler to the one we had, since some details weren't quite right. Later i read in at least one book that MacHack was written in Lisp. I don't consider any of that very strong evidence, but in the absence of anything else, i tended to believe it. Although now that i think about it, i have vague memories of telling someone once that it was written in Lisp, and being told that they thought it was assembler. So i'd be interested in why you think it was written in Assembler. If you have a clear memory of seeing the source code, or of hearing Greenblatt say so, then the "existence and uniqueness proof" for strong chess programs written in Lisp goes out the window. Even if you are guessing based on something you half remember, it puts serious doubt on the Lisp theory. Is Richard Greenblatt still out there somewhere? Still at all interested in Computer Chess? If he has a personal web-page, it's not easy to find on the search engines.
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