Editing Richard Greenblatt (programmer) (section)

==Significant software developed==
He was the main implementor of [[Maclisp]] on the [[PDP-6]]. He wrote [[Mac Hack]], the first computer program to play tournament-level chess and the first to compete in a human chess tournament.  AI skeptic [[Hubert Dreyfus]], who famously made the claim that computers would not be able to play high-quality chess, was beaten by the program, marking the start of "respectable" [[computer chess]] performances. In 1977, unbeaten chess champion<!--This term was chosen because his world title was relinquished by forfeit--> [[Bobby Fischer]] played three games in [[Cambridge, Massachusetts]] against Greenblatt's computer program, and Fischer won all of them.<ref>{{cite web |url=http://www.bobby-fischer.net/Bobby_Fischer_Biography.html |archive-url=https://web.archive.org/web/20060103073409/http://www.bobby-fischer.net/Bobby_Fischer_Biography.html |url-status=dead|archive-date=2006-01-03|title=Bobby Fischer Biography |last=Ayoub |first=Chuck |date=2003–2008 |publisher=Chuck Ayoub |access-date=January 1, 2009}}</ref> Greenblatt, along with [[Tom Knight (scientist)|Tom Knight]] and [[Stewart Nelson (hacker)|Stewart Nelson]], co-wrote the [[Incompatible Timesharing System]] (ITS), a highly influential [[time-sharing]] operating system for the [[PDP-6]] and [[PDP-10]] used at [[MIT]].<ref name="Hackers"/>