Richard Greenblatt (programmer)

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Richard D. Greenblatt
Greenblattrpg-6cropped.jpg
Richard Greenblatt in 2009
Born (1944-12-25) December 25, 1944 (age 79)
Portland, Oregon, United States
Education Massachusetts Institute of Technology (MIT)
Known for
Scientific career
Fields Computer programming
Institutions

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 community, [1] and holds a place of distinction in the communities of the programming language Lisp and of the Massachusetts Institute of Technology (MIT) Artificial Intelligence Laboratory.

Contents

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. [2]

Career

Becoming a hacker

Greenblatt enrolled in 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 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 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. [3]

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 [4] 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 championBobby Fischer played three games in Cambridge, Massachusetts against Greenblatt's computer program, and Fischer won all of them. [5] Greenblatt, along with Tom Knight and 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. [1]

Related Research Articles

The hacker ethic is a branch of philosophy, originating from hacker culture and pertaining to the idea that intellectual goods, like information and data, cannot be owned by an individual, hence sharing them with others is an ethical imperative. It shares several traits with concepts such as freedom of information, and political philosophies such as anti-authoritarianism, socialism, liberalism, anarchism, and libertarianism.

<span class="mw-page-title-main">Lisp (programming language)</span> Programming language family

Lisp is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in the late 1950s, it is the second-oldest high-level programming language still in common use, after Fortran. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket, and Clojure.

<span class="mw-page-title-main">Lisp machine</span> Computer specialized in running Lisp

Lisp machines are general-purpose computers designed to efficiently run Lisp as their main software and programming language, usually via hardware support. They are an example of a high-level language computer architecture. In a sense, they were the first commercial single-user workstations. Despite being modest in number Lisp machines commercially pioneered many now-commonplace technologies, including effective garbage collection, laser printing, windowing systems, computer mice, high-resolution bit-mapped raster graphics, computer graphic rendering, and networking innovations such as Chaosnet. Several firms built and sold Lisp machines in the 1980s: Symbolics, Lisp Machines Incorporated, Texas Instruments, and Xerox. The operating systems were written in Lisp Machine Lisp, Interlisp (Xerox), and later partly in Common Lisp.

Maclisp is a programming language, a dialect of the language Lisp. It originated at the Massachusetts Institute of Technology's (MIT) Project MAC in the late 1960s and was based on Lisp 1.5. Richard Greenblatt was the main developer of the original codebase for the PDP-6; Jon L. White was responsible for its later maintenance and development. The name Maclisp began being used in the early 1970s to distinguish it from other forks of PDP-6 Lisp, notably BBN Lisp.

The hacker culture is a subculture of individuals who enjoy—often in collective effort—the intellectual challenge of creatively overcoming the limitations of software systems or electronic hardware, to achieve novel and clever outcomes. The act of engaging in activities in a spirit of playfulness and exploration is termed hacking. However, the defining characteristic of a hacker is not the activities performed themselves, but how it is done and whether it is exciting and meaningful. Activities of playful cleverness can be said to have "hack value" and therefore the term "hacks" came about, with early examples including pranks at MIT done by students to demonstrate their technical aptitude and cleverness. The hacker culture originally emerged in academia in the 1960s around the Massachusetts Institute of Technology (MIT)'s Tech Model Railroad Club (TMRC) and MIT Artificial Intelligence Laboratory. Hacking originally involved entering restricted areas in a clever way without causing any major damage. Some famous hacks at the Massachusetts Institute of Technology were placing of a campus police cruiser on the roof of the Great Dome and converting the Great Dome into R2-D2.

<span class="mw-page-title-main">Tech Model Railroad Club</span>

The Tech Model Railroad Club (TMRC) is a student organization at the Massachusetts Institute of Technology (MIT). Historically, it has been a wellspring of hacker culture and the oldest such hacking group in North America. Formed in 1946, its HO scale layout specializes in the automated operation of model trains.

Incompatible Timesharing System (ITS) is a time-sharing operating system developed principally by the MIT Artificial Intelligence Laboratory, with help from Project MAC. The name is the jocular complement of the MIT Compatible Time-Sharing System (CTSS).

<span class="mw-page-title-main">Guy L. Steele Jr.</span> American computer scientist (born 1954)

Guy Lewis Steele Jr. is an American computer scientist who has played an important role in designing and documenting several computer programming languages and technical standards.

HAKMEM, alternatively known as AI Memo 239, is a February 1972 "memo" of the MIT AI Lab containing a wide variety of hacks, including useful and clever algorithms for mathematical computation, some number theory and schematic diagrams for hardware – in Guy L. Steele's words, "a bizarre and eclectic potpourri of technical trivia". Contributors included about two dozen members and associates of the AI Lab. The title of the report is short for "hacks memo", abbreviated to six upper case characters that would fit in a single PDP-10 machine word.

<span class="mw-page-title-main">Bill Gosper</span> American mathematician and programmer

Ralph William Gosper Jr., known as Bill Gosper, is an American mathematician and programmer. Along with Richard Greenblatt, he may be considered to have founded the hacker community, and he holds a place of pride in the Lisp community. The Gosper curve and the Gosper's algorithm are named after him.

TOPS-10 System is a discontinued operating system from Digital Equipment Corporation (DEC) for the PDP-10 mainframe computer family. Launched in 1967, TOPS-10 evolved from the earlier "Monitor" software for the PDP-6 and PDP-10 computers; this was renamed to TOPS-10 in 1970.

Lisp Machines, Inc. was a company formed in 1979 by Richard Greenblatt of MIT's Artificial Intelligence Laboratory to build Lisp machines. It was based in Cambridge, Massachusetts.

Stewart Nelson is an American mathematician and programmer from The Bronx who co-founded Systems Concepts.

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.

<span class="mw-page-title-main">Alan Kotok</span> American computer scientist

Alan Kotok was an American computer scientist known for his work at Digital Equipment Corporation and at the World Wide Web Consortium (W3C). Steven Levy, in his book Hackers: Heroes of the Computer Revolution, describes Kotok and his classmates at the Massachusetts Institute of Technology (MIT) as the first true hackers.

Peter R. Samson is an American computer scientist, best known for creating pioneering computer software for the TX-0 and PDP-1.

New Implementation of LISP (NIL) is a programming language, a dialect of the language Lisp, developed at the Massachusetts Institute of Technology (MIT) during the 1970s, and intended to be the successor to the language Maclisp. It is a 32-bit implementation, and was in part a response to Digital Equipment Corporation's (DEC) VAX computer. The project was headed by Jon L White, with a stated goal of maintaining compatibility with MacLisp while fixing many of its problems.

The Jargon File is a glossary and usage dictionary of slang used by computer programmers. The original Jargon File was a collection of terms from technical cultures such as the MIT AI Lab, the Stanford AI Lab (SAIL) and others of the old ARPANET AI/LISP/PDP-10 communities, including Bolt, Beranek and Newman, Carnegie Mellon University, and Worcester Polytechnic Institute. It was published in paperback form in 1983 as The Hacker's Dictionary, revised in 1991 as The New Hacker's Dictionary.

<span class="mw-page-title-main">David A. Moon</span> American computer scientist

David A. Moon is a programmer and computer scientist, known for his work on the Lisp programming language, as co-author of the Emacs text editor, as the inventor of ephemeral garbage collection, and as one of the designers of the Dylan programming language. Guy L. Steele Jr. and Richard P. Gabriel (1993) name him as a leader of the Common Lisp movement and describe him as "a seductively powerful thinker, quiet and often insulting, whose arguments are almost impossible to refute".

Robert Alan Saunders was an American computer scientist, most famous for his involvement with Spacewar. Saunders joined the Tech Model Railroad Club (TMRC) led by Alan Kotok, Peter Samson, and himself. They then met Marvin Minsky and other influential pioneers in what was then known as Artificial Intelligence.

References

  1. 1 2 Levy, Steven (1984). Hackers: Heroes of the Computer Revolution. Massachusetts: MIT Press. ISBN   0-262-51087-1.)
  2. Oral History of Richard Greenblatt Archived 2010-02-23 at the Wayback Machine
  3. Structure and Interpretation of Computer Programs. MIT Press.
  4. "Richard Greenblatt and Thomas Knight with the CADR LISP Machine at MIT in 1978". Computer History Museum. 1978. Retrieved 2018-11-16.
  5. Ayoub, Chuck (2003–2008). "Bobby Fischer Biography". Chuck Ayoub. Archived from the original on 2006-01-03. Retrieved January 1, 2009.