Mac Hack

Computer chess program

Released: —
Platforms: —
Genres: Chess software Computer chess
Developers: —
Publishers: —

About

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.

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

The articlegameplay, story, development, reception

Development

Greenblatt was inspired to write Mac Hack upon reading MIT Artificial Intelligence Memo 41, 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.

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.

Legacy

Mac Hack played by teletype, was ported to the PDP-10 and was the first computer chess program to be widely distributed. 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.