Mac Hack

This article is about the computer chess program. For the Macintosh software developers conference, see MacHack.

Mac Hack is a computer chess program written by Richard D. Greenblatt. Also known as Mac Hac and The Greenblatt Chess Program, it was developed at the Massachusetts Institute of Technology. Mac Hack VI was the first chess program to play in human tournament conditions, the first to be granted a chess rating, and the first to win against a person in tournament play. A pseudocode for the program is given in Figure 11.16 of.[1]

Its name comes from Project MAC ("Multi-Level Access Computer" or "Machine-Aided Cognition"[2]) a large sponsored research program located at MIT. The number VI refers to the PDP-6 machine for which it was written.

Development

Greenblatt was inspired to write Mac Hack upon reading MIT Artificial Intelligence Memo 41,[3] or a similar document describing Kotok-McCarthy, which he saw while visiting Stanford University in 1965. A good chess player, he was inspired to make improvements at MIT in 1965 and 1966.[4]

In about 2004, he had an opportunity to tell Alan Kotok that searching the 7 best moves at each of the first two plies, and limiting the search depth to two would have done better than the default widths of "4 3 2 2 1 1 1 1", attempting eight plies in Kotok-McCarthy's REPLYS subroutine which generated each player's next plausible moves.[5]

Greenblatt added fifty heuristics that reflected his knowledge of chess. Mac Hack was written in MIDAS macro assembly language on the PDP-6 computer DEC donated to MIT (the first working PDP-6, serial number 2). Many versions may exist. During this period the program was compiled about two hundred times.

Tournament play

By the time it was published in 1969 Mac Hack had played in eighteen tournaments and hundreds of complete games. The PDP-6 became an honorary member of the Massachusetts State Chess Association and the United States Chess Federation,[6] a requirement for playing tournaments. In 1966 the program was rated 1243 when it lost in the Massachusetts Amateur Championship. In 1967, the program played in four tournaments, winning three games, losing twelve, and drawing three. In 1967 Mac Hack VI defeated Ben Landy with a USCF rating of 1510 in game 3, tournament 2 of the Massachusetts State Championship.[4][7]

Greenblatt published the program with Donald E. Eastlake III and Stephen D. Crocker in MIT Artificial Intelligence Memo 174 and recorded some games there.[8]

Influence

Mac Hack played by teletype, was ported to the PDP-10 and was the first computer chess program to be widely distributed.[9] Mac Hack was the first chess computer to use a transposition table, which is a vital optimization in game tree search. Greenblatt and Tom Knight went on to advance artificial intelligence and build the Lisp machine in 1973.[10]

References

  1. ^ Newell, Allen; Simon, Herbert Alexander (2019). Human problem solving. Brattleboro, Vermont: Echo Point Books & Media. ISBN 978-1-63561-792-4.
  2. ^ Snover, Janet and Bill Litant (n.d.). "Acronyms and Abbreviations Used at MIT". Massachusetts Institute of Technology. Retrieved 29 December 2006.
  3. ^ *Kotok, Alan (n.d.). "A Chess Playing Program (AIM-41 - PDF)" (PDF). Massachusetts Institute of Technology. Archived from the original (PDF) on 6 July 2017. Retrieved 26 December 2006.
  4. ^ a b Greenblatt, Richard D. (12 January 2005). "Oral History of Richard Greenblatt" (PDF). Computer History Museum. Retrieved 1 July 2006. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ Hendrie, Gardner (12 January 2005). "Oral History of Richard Greenblatt" (PDF). Computer History Museum. Retrieved 6 April 2016.
  6. ^ LEVY, D. (29 June 2013). Computer Chess Compendium. Springer Science & Business Media. ISBN 9781475719680.
  7. ^ Levy, David N. L. (6 December 2012). Computer Games I. Springer Science & Business Media. ISBN 9781461387169.
  8. ^ "The Greenblatt Chess Program" (PDF). Massachusetts Institute of Technology. Richard Greenblatt, Donald Eastlake III, Stephen Crocker. April 1969. Retrieved 6 April 2016.
  9. ^ "A history of computer chess - from the "Mechanical Turk" to "Deep Blue" - High Tech History". Retrieved 6 April 2016.
  10. ^ "Richard Greenblatt and Thomas Knight with the CADR LISP Machine at MIT". computerhistory.org. Retrieved 6 April 2016.

Bibliography