Harry Lewis Nelson
Encyclopedia
Harry Lewis Nelson is an American mathematician and computer programmer. He was a member of the team that won the World Computer Chess Championship
in 1983 and 1986, and was a co-discoverer of the 27th Mersenne prime
in 1979 (at the time, the largest known prime number). He also served as editor of the Journal of Recreational Mathematics
for five years. Most of his professional career was spent at Lawrence Livermore National Laboratory
where he worked with some of the earliest supercomputers. He was particularly noted as one of the world's foremost experts in writing optimized assembly language
routines for the Cray-1
and Cray X-MP
computers. Nelson has had a life-long interest in puzzles of all types, and since his retirement in 1991 he has devoted his time to his own MiniMax Game Company, a small venture that helps puzzle inventors to develop and market their products.
In 1994, Nelson donated his correspondence from his days as editor of the Journal of Recreational Mathematics
to the University of Calgary Library as part of the Eugène Strens Recreational Mathematics Special Collection.
Initially, Nelson worked for Autonetics
, an aerospace company in southern California. In 1960 he went to work for the Lawrence Radiation Laboratory (later renamed Lawrence Livermore National Laboratory or LLNL), in Livermore, California. He remained working there until his retirement in 1991. Nelson worked on a variety of computers at LLNL, beginning with the IBM 7030
(nicknamed Stretch). In the 1960s, early units of a new computer were typically delivered as "bare metal," i.e. no software of any kind, including no compiler and no operating system. Programs needed to be written in assembly language, and the programmer needed to have intimate and detailed knowledge of the machine. A lifelong puzzle enthusiast, Nelson sought to understand every detail of the hardware, and earned a reputation as an expert on the features and idiosyncrasies of each new machine. Over time he became the principal person at LLNL in charge of doing acceptance testing of new hardware.
to devise a program that would hunt for the next Mersenne prime, while simultaneously being a legitimate diagnostic program. On April 8, 1979, the team found the 27th Mersenne prime: 244497 - 1, the largest prime number known at that time.
written by Robert Hyatt
. Using his detailed knowledge of the Cray-1 architecture, Nelson re-wrote a key routine in assembly language and was able to significantly speed up the program. The two began collaborating along with a third team member, Albert Gower, a strong correspondence chess
player. In 1983, Cray Blitz won the World Computer Chess Championship, and successfully defended its title in 1986.
The 1986 Championship was marred by controversy when the HiTech
team, led by Hans Berliner
, accused the Cray Blitz team of cheating. The charge was investigated for a few months by the tournament director, David Levy
, and dismissed. Despite the dismissal, the experience somewhat soured the computer chess scene for Nelson.
(formerly Binary Arts).
Harry and Claire Nelson live in Livermore, California. They have 4 children.
World Computer Chess Championship
World Computer Chess Championship is an annual event where computer chess engines compete against each other. The event is organized by the International Computer Games Association...
in 1983 and 1986, and was a co-discoverer of the 27th Mersenne prime
Mersenne prime
In mathematics, a Mersenne number, named after Marin Mersenne , is a positive integer that is one less than a power of two: M_p=2^p-1.\,...
in 1979 (at the time, the largest known prime number). He also served as editor of the Journal of Recreational Mathematics
Journal of Recreational Mathematics
The Journal of Recreational Mathematics is an American journal dedicated to recreational mathematics, started in 1968. It is published quarterly by the Baywood Publishing Company....
for five years. Most of his professional career was spent at Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
where he worked with some of the earliest supercomputers. He was particularly noted as one of the world's foremost experts in writing optimized assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
routines for the Cray-1
Cray-1
The Cray-1 was a supercomputer designed, manufactured, and marketed by Cray Research. The first Cray-1 system was installed at Los Alamos National Laboratory in 1976, and it went on to become one of the best known and most successful supercomputers in history...
and Cray X-MP
Cray X-MP
The Cray X-MP was a supercomputer designed, built and sold by Cray Research. It was announced in 1982 as the "cleaned up" successor to the 1975 Cray-1, and was the world's fastest computer from 1983 to 1985...
computers. Nelson has had a life-long interest in puzzles of all types, and since his retirement in 1991 he has devoted his time to his own MiniMax Game Company, a small venture that helps puzzle inventors to develop and market their products.
In 1994, Nelson donated his correspondence from his days as editor of the Journal of Recreational Mathematics
Journal of Recreational Mathematics
The Journal of Recreational Mathematics is an American journal dedicated to recreational mathematics, started in 1968. It is published quarterly by the Baywood Publishing Company....
to the University of Calgary Library as part of the Eugène Strens Recreational Mathematics Special Collection.
Early years
Born on January 8, 1932 in Topeka, Kansas; the third of four children. He attended local schools and was active in the Boy Scouts, earning the rank of Eagle Scout. Nelson attended Harvard University as a freshman, but then had to drop out for financial reasons. He attended the University of Kansas as a sophomore, but was able to return to Harvard for his junior and senior years, receiving a bachelor's degree in mathematics from Harvard in 1953. In 1952, just before the start of his senior year, he married his high school sweetheart, Claire (née Rachael Claire Ensign). After graduating, he was inducted into the U.S. Army, but was never deployed overseas. He was honorably discharged in 1955, having attained the rank of sergeant. He enrolled in graduate studies at the University of Kansas, earning a Master's degree in Mathematics in 1957. It was during this period that he became fascinated by the then-new programmable digital computer. Nelson worked towards a Ph.D until 1959, but the combination of his GI Bill educational benefits running out, needing to support a wife and three children, and the mathematics department rejecting his proposal to do his thesis on computers, convinced him to leave the university without completing his Ph.D, and to get a job.Initially, Nelson worked for Autonetics
Autonetics
Autonetics was a division of North American Aviation. Through a series of mergers, Autonetics is now part of Boeing.- General Background of the Anaheim Facility :...
, an aerospace company in southern California. In 1960 he went to work for the Lawrence Radiation Laboratory (later renamed Lawrence Livermore National Laboratory or LLNL), in Livermore, California. He remained working there until his retirement in 1991. Nelson worked on a variety of computers at LLNL, beginning with the IBM 7030
IBM 7030
The IBM 7030, also known as Stretch, was IBM's first transistorized supercomputer. The first one was delivered to Los Alamos National Laboratory in 1961....
(nicknamed Stretch). In the 1960s, early units of a new computer were typically delivered as "bare metal," i.e. no software of any kind, including no compiler and no operating system. Programs needed to be written in assembly language, and the programmer needed to have intimate and detailed knowledge of the machine. A lifelong puzzle enthusiast, Nelson sought to understand every detail of the hardware, and earned a reputation as an expert on the features and idiosyncrasies of each new machine. Over time he became the principal person at LLNL in charge of doing acceptance testing of new hardware.
The 27th Mersenne Prime Number
During the process of acceptance testing, a new supercomputer would typically run diagnostic programs at night, looking for problems. During the acceptance testing of LLNL's first Cray-1 computer, Nelson teamed up with Cray employee David SlowinskiDavid Slowinski
David Slowinski is a mathematician involved in prime numbers. His career highlights have included the discovery of several of the largest known Mersenne primes:1* 244497−1 on April 8 1979* 286243−1 on September 25 1982...
to devise a program that would hunt for the next Mersenne prime, while simultaneously being a legitimate diagnostic program. On April 8, 1979, the team found the 27th Mersenne prime: 244497 - 1, the largest prime number known at that time.
Computer Chess
In 1980, Nelson came across a copy of the chess program Cray BlitzCray Blitz
Cray Blitz was a computer chess program written by Robert Hyatt, Harry Nelson, and Albert Gower to run on the Cray supercomputer. It was derived from "Blitz" a program that Hyatt started to work on as an undergraduate. "Blitz" played its first move in the fall of 1968, and was developed...
written by Robert Hyatt
Robert Hyatt
Dr. Robert Hyatt is an Associate Professor of Computer science at the University of Alabama at Birmingham, in the Department of Computer and Information Sciences . He is the author of the computer chess program Crafty and the co-author of Cray Blitz, a two-time winner of the World Computer Chess...
. Using his detailed knowledge of the Cray-1 architecture, Nelson re-wrote a key routine in assembly language and was able to significantly speed up the program. The two began collaborating along with a third team member, Albert Gower, a strong correspondence chess
Correspondence chess
Correspondence chess is chess played by various forms of long-distance correspondence, usually through a correspondence chess server, through email or by the postal system; less common methods which have been employed include fax and homing pigeon...
player. In 1983, Cray Blitz won the World Computer Chess Championship, and successfully defended its title in 1986.
The 1986 Championship was marred by controversy when the HiTech
HiTech
HiTech was a chess machine built at Carnegie Mellon University under the direction of World Correspondence Chess Champion Dr. Hans J. Berliner, by Berliner, Carl Ebeling, Murray Campbell, and Gordon Goetsch....
team, led by Hans Berliner
Hans Berliner
Hans Jack Berliner , a Professor of , is a former World Correspondence Chess Champion, from 1965–68. He is a Grandmaster of Correspondence Chess, and an International Master for over-the-board chess. He directed the construction of the chess computer HiTech. Berliner is also a chess writer.-Life...
, accused the Cray Blitz team of cheating. The charge was investigated for a few months by the tournament director, David Levy
David Levy (chess player)
David Neil Laurence Levy , is a Scottish International Master of chess, a businessman noted for his involvement with computer chess and artificial intelligence, and the founder of the Computer Olympiads and the Mind Sports Olympiads. He has written more than 40 books on chess and computers.- Life...
, and dismissed. Despite the dismissal, the experience somewhat soured the computer chess scene for Nelson.
Puzzles and Problems
Nelson has always enjoyed intricate and surprising puzzles, both mental and mechanical. He is active with the International Puzzle Party, and is a long time contributor to the Journal of Recreational Mathematics. He served as Editor of the Journal for 5 years, and continues to sit on its editorial board. He founded the Minimax Game Corporation in 1972, and has devoted himself to it full time since his retirement from LLNL. The company serves as a "think-tank" to develop and market games and puzzles from various designers. They work largely, but not exclusively, with ThinkFunThinkFun
ThinkFun, formerly known as Binary Arts, was founded in 1985 by Bill Ritchie and Andrea Barthello. The two started the company from the basement of their home in Virginia, with a product base that initially consisted of four games invented by a family friend William Keister...
(formerly Binary Arts).
Harry and Claire Nelson live in Livermore, California. They have 4 children.
Further reading
- Robert M. Hyatt and Harry L. Nelson, "Chess and Supercomputers, details on optimizing Cray Blitz", proceedings of Supercomputing '90 in New York (354-363).