ten interesting computer scientists dr. raymond greenlaw armstrong atlantic state university school...

Ten Interesting Computer Scientists

Dr. Raymond GreenlawArmstrong Atlantic State

UniversitySchool of Computing

Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing 2

Outline• History of Computer Science• John Backus• Stephen Cook• Seymour Cray• Edsger Dijkstra• Bill Gates• Alan Kay• Donald Knuth• Leslie Lamport• John McCarthy• Alan Turing


History of Computer Science• 1673 – Gottfried Wilhelm von Leibniz

invents a machine to do multiplication• 1821 – Charles Babbage builds a machine

to calculate exponential functions, begins designing Analytical Engine

• 1832 – Ada Lovelace begins writing programs (on punch cards) for the nonexistent Analytical Engine, inventing such concepts as loops and subroutines

• 1935 – Alan Turing defines a model for computation


History of Computer Science• 1937 – Claude Shannon links Boolean

logic to digital circuit design• 1939 – Turing’s work plays a key role

in breaking the Germans’ Enigma code machine

• 1943 – Small computers are being built in multiple countries

• 1950 – Turing proposes a test of machine intelligence, the Turing test

• 1956 – John McCarthy coins the term “artificial intelligence”


History of Computer Science• 1957 – FORTRAN is released by John

Backus and the IBM team• 1958 – John McCarthy invents Lisp• 1959 – John Backus and Peter Naur

propose the use of context-free grammars to describe programming languages

• 1961 – Edsger Dijkstra applies the semaphore principle used in train signaling systems to mutual exclusion in computer operations


History of Computer Science• 1962 – Donald Knuth begins work on

The Art of Computer Programming• 1971 – Alan Kay develops the first

object-oriented programming language, Smalltalk

• 1971 – Stephen Cook publishes a paper on non-deterministic polynomial completeness (NP-completeness), defining a new family of problems that is not computable in a practical sense


History of Computer Science• 1973 – Leonid Levin publishes a

paper identifying the class of NP-complete problems independently of Cook (research was conducted in 1971)

• 1977 – Leslie Lamport defines a model of time for distributed systems based on a partial order of events

• 1980 – Microsoft is founded, helping to push PCs into widespread use with the public


John Backus“We simply made up the language as we went along.

We did not regard language design as a difficult problem, merely a simple prelude to the real

problem: designing a compiler which could produce efficient programs...”


Biography - John Backus• 1949 – Graduated from Columbia

University with a B.S. in Mathematics• 1950 – Joined IBM and worked on the

SSEC (Selective Sequence Electronic Calculator) for three years

• Collaborated with Peter Naur to create Backus-Naur Form

• Developed FP which helped push functional programming

• Retired in 1991


Achievements - John Backus• Designer of FORTRAN• Backus-Naur Form• Designed FP, a functional

programming language• 1977 – Turing Award winner• 1987 – named an IBM Fellow• 1993 – awarded a Draper Prize


Trivia - John Backus• Has a plate in his head of his own

design after having a bone tumor• Roughly half the work of designing

FORTRAN went into generating efficient machine code

• After retiring in 1991, has completely withdrawn from computer science

• Practices meditation


Stephen Cook“The idea that there won’t be an algorithm to

solve it—this is something fundamental that won’t ever change—that idea appeals

to me.”


Biography - Stephen Cook• 1961 – B.S. in Mathematics from

University of Michigan• 1962, 1966 – M.S. and Ph.D. in

Mathematics from Harvard• 1966-1970 – Assistant Professor,

University of California, Berkeley• 1970 – Joined University of Toronto as

Associate Professor, Professor in 1975, and University Professor of Computer Science and Mathematics in 1985


Achievements - Stephen Cook• Formalized the notion of NP-

completeness• Cook’s Theorem – concerns itself with

reducing NP-complete problems to a general Satisfiability problem

• 1977 – Steacie Fellowship• 1982 – Turing Award winner• Fellow of Royal Society of Canada


Seymour Cray

"If you were plowing a field, which would you rather use: Two strong

oxen or 1024 chickens?"


Biography - Seymour Cray• 1950 – B.S. in Electrical Engineering,

University of Minnesota• 1951 – Awarded a M.S. in Applied

Mathematics, University of Minnesota• 1950 – Joined Engineering Research

Associates• 1960 – Joined Control Data Corporation• 1965 – The CDC 6600, the first

commercial supercomputer, is released• 1972 – Founded Cray Research


Biography - Seymour Cray• 1976 – The Cray-1 is released• 1980 – Cray steps down as CEO of

Cray Research and becomes an independent contractor

• 1989 – Founded Cray Computer Corporation

• 1995 – Set up SRC Computers, Inc• 1996 – Died in a car accident


Achievements - Seymour Cray• Founder of Cray Research and Cray

Computer Corporation• Released the first commercial

supercomputer• Designed computers concerned with

total computing speed• Worked hard to improve I/O

bandwidth as opposed to just concentrating on processor speed


Trivia - Seymour Cray• The vehicle Cray was driving when he

died, a Jeep Cherokee, was designed on a Cray supercomputer

• In 1986, Apple bought a Cray X-MP and announced it would be used to design the next Macintosh, Cray replied that he was using a Macintosh to design the Cray-2 supercomputer


Edsger Dijkstra"Computer Science is no more about

computers than astronomy is about telescopes."


Biography - Edsger Dijkstra• Studied physics at the University of

Leiden• 1970s – Worked as a research fellow

for Burroughs Corporation • Worked at the Eindhoven University

of Technology in the Netherlands • Held the Schlumberger Centennial

Chair in Computer Sciences at the University of Texas at Austin

• Retired in 2000• Died August 6, 2002


Achievements - Edsger Dijkstra

• Dijkstra’s algorithm (shortest path) which has been used to solve numerous routing problems

• The semaphore construct which helped solve the problem of critical regions

• Formulated the dining philosophers problem

• 1972 – Turing Award winner• Has archive of technical papers at

University of Texas at Austin


Trivia - Edsger Dijkstra• At age 12, attended Gymnasium

Erasminium, an elite Dutch high school• “Go To Statement Considered Harmful”

was the revised title by Niklaus Wirth (then editor of CACM), originally titled “A case against the goto statement”

• On team to invent first compiler for ALGOL 60, made a deal with collaborator not to shave until project was complete, kept the beard until his death


Trivia - Edsger DijkstraDining Philosophers• Imagine that five philosophers are

sitting around a table. Before each is a bowl of rice and a chopstick to either side of the bowl. The rules for dining:– Each philosopher thinks for a while,

eats for a while, and then waits for a while

– To eat, he must hold both his right and left chopstick

– They only communicate by lifting and lowering their chopsticks


Trivia - Edsger Dijkstra

Dining Philosophers• In order to eat, the following

algorithm must be utilized:– Pick up the right chopstick when

available (wait if right neighbor has it)– Pick up the left chopstick when

available (wait if left neighbor has it)– Eat

• Using this algorithm, a few scenarios can occur leading to certain situations


Trivia - Edsger Dijkstra

Dining Philosophers• Deadlock occurs when all

philosophers decide to eat at the same time, they succeed at the first step, but wait forever at the second

• Starvation can occur for other philosophers if one philosopher never releases his chopsticks

• Even if all eat, some may eat more than others which can cause “lack of fairness”


Bill Gates"The best way to prepare [to be a programmer] is to write

programs, and to study great programs that other people have written. In my case, I went to the garbage cans at the

Computer Science Center and fished out listings of their operating system."


Biography - Bill Gates• 1975 – Founded Microsoft with Paul

Allen after developing a version of BASIC that ran on Altair systems

• 1976 – Wrote an article denouncing people who used software and didn’t pay for it, helped push closed-source development, after openly admitting he took source code from dumpsters

• 1980 – Sold IBM a relabeled version of QDOS, known as PC-DOS


Biography - Bill Gates• Early 1980s – Aggressively marketed

MS-DOS to PC clone manufacturers• Late 1980s – Microsoft Windows

began to be preinstalled on a number of PCs

• 1990 – Windows 3.0 is released• 1998 – Gates steps down as CEO of

Microsoft, but continues to serve as Chairman of the Board and Chief Software Architect


Achievements - Bill Gates• Helped port BASIC to the Altair• Co-founded Microsoft with Paul Allen• Chairman and Chief Software

Architect of Microsoft• Provided a GUI operating system to

many PC clone manufacturers• Has positioned Microsoft as the

leading software company in the world


Trivia - Bill Gates• Dropped out of Harvard in his third

year to pursue software development• Attained the rank of Life Scout in the

Boy Scouts of America• Named wealthiest person in the world

by Forbes magazine for several years• Has a house in Washington valued at

over $113 million, all visitors get a microchip that adjusts temperature and other conditions to their preferences


Alan Kay

“All understanding begins with our not accepting the world as it appears.”


Biography - Alan Kay• 1966 – B.S. in Mathematics and

Molecular Biology, University of Colorado

• 1969 – M.S. in Electrical Engineering, Ph.D. in Computer Science, University of Utah

• 1970 – Professor, Stanford Artificial Intelligence Laboratory

• 1972 – Group Leader, Xerox Palo Alto Research Center

• 1984 – Apple Fellow, Apple Computers


Achievements - Alan Kay• Designer of Smalltalk• Coined the term “object-orientation”• Conceived the laptop computer• Architect of the modern windowing

GUI• 2001 – UdK 01-Award winner• 2003 – Turing Award winner• 2004 – Kyoto Prize and Charles Stark

Draper Prize winner


Trivia - Alan Kay• Could read by the age of three• Expelled from Bethany College for

protesting the Jewish quota• Made a living as a professional

guitarist in the 1960s• Used his degree in molecular biology

to help form the basic ideas of OOP• Very interested in using computers to

further education


Donald Knuth

“Computer programming is an art form, like the creation of poetry or

music.”


Biography - Donald Knuth• In 8th grade, won competition by

composing words from “Ziegler’s Giant Bar”; Knuth found 4,500 in two weeks of feigning illness, the judge’s master list had 2,500, has said he would have found more if he had thought to use the apostrophe

• Graduated from high school in 1956 with the highest GPA ever achieved at that school


Biography - Donald Knuth• Graduated in 1960 from Case Institute of

Technology with a B.S. in Mathematics, was simultaneously awarded an M.S. for his achievements, an unprecedented move

• Received a Ph.D. in Mathematics from California Institute of Technology in 1963

• Joined Stanford University as a Professor of Computer Science in 1968

• In 1993, became Professor Emeritus of The Art of Computer Programming at Stanford, where he is still currently located


Achievements - Donald Knuth

• Authored The Art of Computer Programming, a multi-volume tome on CS

• Inventor of TeX and METAFONT• LR(k) parsing• Knuth-Morris-Pratt algorithm• 1974 – Turing Award winner• 1979 – National Medal of Science• 1995 – John von Neumann Medal


Trivia - Donald Knuth• The Art of Computer Programming

began as a text about compilers• Loves organ music, mostly 4 and 8-

hand music which he plays on an organ in his home, he studied piano as a child

• Pays $2.56 (one hexadecimal dollar) for errors found in his books

• Quit using email in 1990• Processes all communications in

batch-mode


Leslie Lamport“A distributed system is one in which the failure

of a computer you didn’t even know existed can render your own computer unusable.”


Biography - Leslie Lamport• 1960 – B.S. in mathematics,

Massachusetts Institute of Technology • 1963 – M.A., Brandeis University• 1972 – Ph.D., Brandeis University• 1970-1977 – Massachusetts Computer

Associates • 1977-1985 – SRI International• 1985-2001 – Digital Equipment

Corporation/Compaq• 2001-Present – Works for Microsoft


Achievements - Leslie Lamport

• Bakery Algorithm – an improvement to Djikstra’s semaphore idea, which involves each participant getting a ticket

• Lamport Clocks – A relative time idea used in distributed computing

• Developed a technique using digital signatures to aid in fault-tolerant systems

• Designer/developer of LaTeX, a macro system that sits on top of Knuth’s TeX and is used by many scientists for papers


Trivia - Leslie Lamport• LaTeX started as a side project to

improve the “new version” of TeX introduced in 1982, Lamport estimates he spent about 10 months developing LaTeX

• Very modest about his involvement with many of his ideas, saying “most of it seems like dumb luck—I happened to be looking at the right problem, at the right time, having the right background.”


John McCarthy“If you want the computer to have general

intelligence, the outer structure has to be commonsense knowledge and reasoning.”


Biography - John McCarthy• 1948 – B.S. in Mathematics from the

California Institute of Technology• 1951 – Ph.D. in Mathematics from

Princeton• Short-term appointments at

Princeton, Stanford, Dartmouth, and MIT

• 1962 – Full Professor at Stanford University

• Retired at the end of 2000, is now Professor Emeritus


Achievements - John McCarthy

• Coined the term “artificial intelligence” in 1955 at the Dartmouth Conference

• Designer of LISP, the principle language of artificial intelligence

• 1961 – First to propose publicly the selling of computing as a utility, like electricity or water

• 1962 – Set up the Stanford AI Laboratory

• 1971 – Turing Award winner


Trivia - John McCarthy• As a high school junior, bought the

calculus books used for freshman and sophomore math, worked out all the exercises which allowed him to skip the first two years of math when he attended the school in 1944

• Like Backus and Kay, eventually lost control over the language (LISP) he invented


John McCarthyLISP – list processing language• All lists are contained within

parentheses (A B C), with the elements as atoms

• Supports recursion and has an eval operation to define new functions and execute them as part of that program

• CAR returns the first element of the list, (CAR ‘(A B C)) returns A

• CDR returns a list with everything but the first element, (CDR ‘(A B C)) returns (B C)


Alan Turing“…I believe that at the end of the century the use of

words and general educated opinion will have altered so much that one will be able to speak of

machines thinking without expecting to be contradicted.”


Biography - Alan Turing• 1934 – Graduated from King’s College,

Cambridge with a distinguished degree• 1935 – Elected a Fellow at King’s• 1938 – Received his Ph.D. from

Princeton• During WWII worked at Bletchley Park,

his work there was kept secret until the 1970s

• 1945-1947 – Worked on the design of ACE (Automatic Computing Engine) at the National Physical Laboratory


Biography - Alan Turing• 1949 – Became deputy director of the

computing laboratory at the University of Manchester

• 1952-1954 – Worked on mathematical biology

• 1954 – Died of cyanide poisoning from a half-eaten apple, death ruled a suicide


Achievements - Alan Turing• Often considered to be the father of

modern computer science• Turing Test• Turing Machine• Church-Turing Thesis• Worked at Bletchley Park during WWII• Invented an electromechanical

machine which could find settings for Enigma

• Created one of the first designs for a stored program computer


Trivia - Alan Turing• Said to have taught himself to read in

three weeks• At age 14, rode a bike 60 miles to

attend his first day at Sherborne School

• Was gay during a time when it was illegal, many believe this led to his security clearance being revoked, and possibly his death

• Was forced to undergo hormonal treatment in lieu of prison


Conclusions• This is only a small sampling of

people who have contributed greatly to the field of computer science. We would like to thank the many others who haven’t been recognized, but have given greatly to our pool of knowledge. The future is bright, there are many active fields of research, and we look forward to acknowledging other pioneers in computer science.


References• “Computer Science: Prof Cook.” Cook, Stephen. November

2005 <http://www.cs.toronto.edu/DCS/People/Faculty/sacook.html>

• Dewdney, A.K. The New Turing Omnibus. New York: Henry Holt and Company, 1989.

• “Don Knuth’s Home Page.” Knuth, Donald. November 2005 <http://www-cs-faculty.stanford.edu/~knuth/>

• Knuth, Donald. The Art of Computer Programming. United States of America: Addison-Wesley Pub Co, 1997.

• Knuth, D. E. and Bendix, P. B. "Simple Word Problems in Universal Algebra." In Computational Problems in Abstract Algebra (Proc. Conf., Oxford, 1967). Pergamon Press, pp. 263-297, 1970.

• Shasha, Dennis Elliott. Out of their minds: the lives and discoveries of 15 great computer scientists. New York: Copernicus, 1995.

• Winston, Patrick Henry. LISP. Reading: Addison-Wesley Publishing Company, 1984.

• Multiple Articles, November 2005 <http://wikipedia.org>

ten interesting computer scientists dr. raymond greenlaw armstrong atlantic state university school...

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