Changes

[[File:machackdisplay02.jpg|border|right|thumb | Mac Hack [[Lawrence J. Krakauer#DEC340|display]] <ref>[http://ljkrakauer.com/LJK/60s/resign.htm I resign] by [[Lawrence J. Krakauer]]</ref> <ref>[http://ljkrakauer.com/LJK/60s/chess1.htm Chess stories] by [[Lawrence J. Krakauer]]</ref> <ref>see also [http://projects.csail.mit.edu/video/history/aifilms/63-chess.mp4 63-chess.mp4] hosted by [https://www.csail.mit.edu/ MIT CSAIL]</ref>]][[File:TV-Ocm.png|border|right|thumb|Mac Hack on bitmapped display]]

In his 1970 paper ''A New Hashing Method with Application for Game Playing'' <ref>[[Albert Zobrist]] ('''1970'''). ''A New Hashing Method with Application for Game Playing''. Technical Report #88, Computer Science Department, [https://de.wikipedia.org/wiki/University_of_Wisconsin%E2%80%93Madison The University of Wisconsin, Madison]], reprinted ('''1990''') in [[ICGA Journal#13_2|ICCA Journal, Vol. 13, No. 2]], [http://www.cs.wisc.edu/techreports/1970/TR88.pdf pdf]</ref>, where he introduced [[Zobrist Hashing|Zobrist hashing]], [[Albert Zobrist]] mentions a possible hashing method to obtain an integer which describes the board configuration, and then to [https://en.wikipedia.org/wiki/Division_algorithm divide] the integer by the hash table size and use the [https://en.wikipedia.org/wiki/Remainder remainder] as hash address and the [https://en.wikipedia.org/wiki/Quotient quotient] as key. However, the integer which describes the board may occupy many computer words, and the divide will be complicated and slow. Further the quotient may occupy several words as well, thus most of the transposition table would be occupied by these keys if [[Transposition Table#KeyCollisions|type 1 errors]] were to be avoided. While Zobrist mentions Mac Hack VI used a 32K hash table, he does not made it explicit that Mac Hack used this divide technique.  More recently, [[Robert Hyatt]], who had a chance to talk with Greenblatt several times, mentioned Mac Hack's hash function used a series of xor operations on occupied squares <ref> [http://www.talkchess.com/forum3/viewtopic.php?f=10&t=73644&start=50 Re: What are you allowed to learn from a GPL engine (eg. Stockfish) ?] by [[Robert Hyatt]], [[CCC]], June 02, 2020 (Engine Origins requires registration)</ref>.

==Robert Q<span id== First tournament game by a computer, Carl Wagner (2190) - Mac Hack VI aka "Robert QRobertQ", January 21, 1967 <ref>''[http://news.google.com/newspapers?nid=1928&dat=19670123&id=O2ggAAAAIBAJ&sjid=1GYFAAAAIBAJ&pg=2308,2313204 MIT Computer Loses to Human in Chess]''. [https://en.wikipedia.org/wiki/Sun_Journal_%28Lewiston%29 Sun Journal (Lewiston)], January 23, 1967, [https://en.wikipedia.org/wiki/Google_News Google News]</refspan>"Robert Q", a computer programmed to play chess, was beaten in its first competition with a human, Carl Wagner. The [[PDP-6|computer]], at [[Massachusetts Institute of Technology|MIT]] in [https://en.wikipedia.org/wiki/Cambridge,_Massachusetts Cambridge, Mass.], was operated by Allen Moulton, and [[Bill Gosper|R. William Gosper]] (rear right), while Wagner made his moves several miles away in the YMCU in [https://en.wikipedia.org/wiki/Boston Boston]. The moves were relayed into the computer by teletype operated by [[Alan Baisley]]. "== {{Robert Q" was entered as an experiment, in the monthly [http://www.boylstonchessclub.org/ Boylston Chess Club] Tournament at the [https://en.wikipedia.org/wiki/Boston_Young_Men%27s_Christian_Union Young Mens Christian Union].}}

Allen Moulton and [[Bill Gosper|R. William Gosper]] operating "[[Mac Hack#RobertQ|Robert Q]]" on a [[PDP-6]] <ref>''[https://news.google.com/newspapers?nid=1928&dat=19670123&id=O2ggAAAAIBAJ&sjid=1GYFAAAAIBAJ&pg=2308,2313204&hl=en MIT Computer Loses to Human in Chess]''. [https://en.wikipedia.org/wiki/Sun_Journal_%28Lewiston%29 Sun Journal (Lewiston)], January 23, 1967, [https://en.wikipedia.org/wiki/Google_News Google News]</ref> <ref>See also [https://www.reddit.com/r/chess/comments/5tcwhw/50_years_ago_robert_q_a_computer_programmed_to/ 50 years ago “Robert Q”, a computer programmed to play chess, was beaten in its first competition with a human in the monthly Boylston Chess Club Tournament in Boston]. [https://en.wikipedia.org/wiki/Reddit Reddit]</ref>

Carl Wagner and [[Alan Baisley]] (right) <ref>[[Richard Greenblatt]], [[Donald Eastlake]], [[Stephen D. Crocker]] ('''1967'''). ''The Greenblatt Chess Program''. Proceedings of the AfiPs Fall Joint Computer Conference, Vol. 31, pp. 808</ref> <ref>[https://lichess.org/kyBnGoLK Carl Wagner vs Robert Q from lichess.org]</ref>

[[Herbert Simon]], an AI pioneer, watched the match. He said <ref>[http://www.chess.com/article/view/machack-attack Mac Hack Attack] by [[Bill Wall]], [https://en.wikipedia.org/wiki/Chess.com/ [Chess.com]], May 13, 2008</ref> :

* [[Richard Greenblatt]], [[Donald Eastlake]], [[Stephen D. Crocker]] ('''1967'''). ''[https://www.computerhistory.org/chess/doc-431614f6c7a98/ The Greenblatt Chess Program]''. Proceedings of the AfiPs Fall Joint Computer Conference, Vol. 31, reprinted ('''1988''') in [[Computer Chess Compendium]], [httphttps://archived1yx3ys82bpsa0.computerhistorycloudfront.orgnet/projectschess/the-greenblatt-chess/related_materials/text/2-4program.Greenblatt_Chess_Program/The_Greenblatt_Chess_Program.Greenblatt_Eastlake_Crockergreenblatt-eastlake-crocker.1967.Fall_Joint_Computer_Conferencefall-joint-computer-conference.062303060.sm.pdf pdf] from [[The Computer History Museum]] or as [http://dspace.mit.edu/handle/1721.1/6176 pdf or ps] from [http://libraries.mit.edu/dspace-mit/ DSpace] at [[Massachusetts Institute of Technology|MIT]]

* [[Monroe Newborn]] ('''1975'''). ''Computer Chess''. [https://en.wikipedia.org/wiki/Academic_Press|Academic Press]], New York, N.Y. ISBN 0-125-17250-8.

* [http://www.chess.com/article/view/machack-attack Mac Hack Attack] by [[Bill Wall]], [https://en.wikipedia.org/wiki/Chess.com/ [Chess.com]], May 13, 2008