View source for Richard Greenblatt (programmer)

{{short description|American computer programmer (born 1944)}}
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| name                      = Richard D. Greenblatt
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| image                     = Greenblattrpg-6cropped.jpg
| alt                       = Color photograph of older Caucasian man with grey hair wearing blue flannel shirt and glasses.
| caption                   = Richard Greenblatt in 2009
| birth_date                = {{Birth date and age|1944|12|25}}
| birth_place               = [[Portland, Oregon|Portland]], [[Oregon]], United States
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| relatives = [[Aliza Greenblatt]] (paternal grandmother)<br>[[Marjorie Guthrie]] (aunt)
| fields                    = [[Computer programming]]
| workplaces                = {{Plainlist|
*MIT
*[[Lisp Machines]]}}
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| education                 = [[Massachusetts Institute of Technology]] (MIT)
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*[[Mac Hack]] chess computer
*[[Maclisp]]
*[[Transposition table]]
*[[Incompatible Timesharing System]]}}
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'''Richard D. Greenblatt''' (born December 25, 1944) is an American [[computer]] [[programmer]].  Along with [[Bill Gosper]], he may be considered to have founded the [[Hacker (programmer subculture)|hacker]] community,<ref name="Hackers">{{cite book |last=Levy |first=Steven |author-link=Steven Levy |url=https://mitpress.mit.edu/sites/default/files/sicp/ |title=Hackers: Heroes of the Computer Revolution |date=1984 |publisher=MIT Press |isbn=0-262-51087-1 |location=Massachusetts}}</ref> and holds a place of distinction in the [[Community of practice|communities]] of the programming language [[Lisp (programming language)|Lisp]] and of the [[Massachusetts Institute of Technology]] (MIT) [[MIT Computer Science and Artificial Intelligence Laboratory|Artificial Intelligence Laboratory]].

==Early life==
Greenblatt was born in Portland, Oregon on December 25, 1944. His family moved to Philadelphia, Pennsylvania when he was a child. He later moved to Columbia, Missouri with his mother and sister when his parents divorced.<ref>{{Cite web |last=Hendrie |first=Gardner |date=January 12, 2005 |title=Oral History of Richard Greenblatt |url=https://www.computerhistory.org/chess/related_materials/oral-history/greenblatt.oral_history.2005.102634500/index.php/?iid=orl-433440f03cfe1 |archive-url=https://web.archive.org/web/20100223052945/http://www.computerhistory.org/chess/related_materials/oral-history/greenblatt.oral_history.2005.102634500/index.php?iid=orl-433440f03cfe1 |archive-date=2010-02-23 |access-date=2024-09-23 |website=Computer History Museum}}</ref>

==Career==
===Becoming a hacker===
Greenblatt enrolled in [[Massachusetts Institute of Technology|MIT]] in the fall of 1962, and around his second term as an undergraduate student, he found his way to MIT's famous [[Tech Model Railroad Club]].  At that time, [[Peter Samson]] had written a program in [[Fortran]] for the [[IBM 709]] series machines, to automate the tedious business of writing the intricate timetables for the Railroad Club's vast model train layout. Greenblatt felt compelled to implement a Fortran [[compiler]] for the [[PDP-1]], which then lacked one.  There was no computer time available to [[Debugging|debug]] the compiler, or even to type it into the computer.  Years later, elements of this compiler (combined with some ideas from fellow TMRC member Steven Piner, the author of a very early [[PDP-4]] Fortran compiler while working for [[Digital Equipment Corporation]]) were typed in and "showed signs of life".  However, the perceived need for a Fortran compiler had evaporated by then, so the compiler was not pursued further.  This and other experiences at TMRC, especially the influence of [[Alan Kotok]], who worked at DEC and was the junior partner of the design team for the [[PDP-6]] computer, led Greenblatt to  the [[MIT Artificial Intelligence Laboratory|AI Lab]], where he proceeded to become a "hacker's hacker" noted for his programming acumen as described in [[Steven Levy]]'s ''[[Hackers: Heroes of the Computer Revolution]]'', and as acknowledged by [[Gerald Jay Sussman]] and [[Harold Abelson]] when they said they were fortunate to have been apprentice programmers at the feet of [[Bill Gosper]] and Richard Greenblatt.<ref>{{cite book |url=http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-8.html#%_chap_Temp_5 |title=Structure and Interpretation of Computer Programs |publisher=MIT Press}}</ref>

Indeed, he spent so much time programming the [[Programmed Data Processor]] (PDP) machines there that he failed out of MIT as a first-term junior and had to take a job at a firm, Charles Adams Associates, until the AI Lab hired him about 6 months later.

===Lisp Machines, Inc.===
In 1979, he and [[Tom Knight (scientist)|Tom Knight]]<ref>{{cite web |url=http://www.computerhistory.org/chess/full_record.php?iid=stl-431614f64ea3e |title=Richard Greenblatt and Thomas Knight with the CADR LISP Machine at MIT in 1978 |author=<!--Unstated--> |date=1978 |website=Computer History Museum |access-date=2018-11-16}}</ref> were the main designers of the MIT [[Lisp machine]]. He founded [[Lisp Machines]], Inc. (later renamed Gigamos Systems), according to his vision of an ideal hacker-friendly computer company, as opposed to the more commercial ideals of [[Symbolics]].

==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"/>

== References ==
{{Reflist|30em}}

==External links==
{{Commons category|Richard Greenblatt}}
*[https://www.gnu.org/gnu/rms-lisp.html A speech] by [[Richard Stallman]] in which he gives some background about Greenblatt

{{Lisp programming language}}
{{Authority control}}

{{DEFAULTSORT:Greenblatt, Richard}}
[[Category:1944 births]]
[[Category:Living people]]
[[Category:Lisp (programming language) people]]
[[Category:People from Portland, Oregon]]
[[Category:Massachusetts Institute of Technology alumni]]
[[Category:American computer businesspeople]]
[[Category:American artificial intelligence researchers]]