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The man who founded Shugart Associates and later co-founded Seagate Technology. Alan Shugart left Shugart Associates in 1974 [did he quit or was he fired?] and took a break from the disk-drive business. In 1979, he and Finis Conner founded a new company that at first was called Shugart Technology and later Seagate Technology.

Last updated: 2000-02-09

A-language

<language>

An early ALGOL-like surface syntax for Lisp.

["An Auxiliary Language for More Natural Expression--The A-language", W. Henneman in The Programming Language LISP, E.C. Berkeley et al eds, MIT Press 1964, pp.239- 248].

Last updated: 1994-10-28

A Language Encouraging Program Hierarchy

<language>

(ALEPH) A language developed in about 1975.

["On the Design of ALEPH", D. Grune, CWI, Netherlands 1986].

Last updated: 1997-02-27

A Language for Attributed Definitions

<language>

(ALADIN) A language for formal specification of attributed grammars. ALADIN is the input language for the GAG compiler generator. It is applicative and strongly typed.

["GAG: A Practical Compiler Generator", Uwe Kastens <[email protected]> et al, LNCS 141, Springer 1982].

Last updated: 1995-04-14

A Language with an Extensible Compiler

<language>

(ALEC) A language Implemented using RCC on an ICL 1906A.

["ALEC - A User Extensible Scientific Programming Language", R.B.E. Napper et al, Computer J 19(1):25-31].

Last updated: 1995-04-19

Alan Kay

<person>

The leader of the Software Concepts Group at Xerox Palo Alto Research Centre which developed Smalltalk, the pioneering object-oriented programming system, in 1972.

Last updated: 1994-11-24

Alan M. Turing

Alan Turing

Alan Shugart

Alan F. Shugart

Alan Turing

<person>

Alan M. Turing, 1912-06-22/3? - 1954-06-07. A British mathematician, inventor of the Turing Machine. Turing also proposed the Turing test. Turing's work was fundamental in the theoretical foundations of computer science.

Turing was a student and fellow of King's College Cambridge and was a graduate student at Princeton University from 1936 to 1938. While at Princeton Turing published "On Computable Numbers", a paper in which he conceived an abstract machine, now called a Turing Machine.

Turing returned to England in 1938 and during World War II, he worked in the British Foreign Office. He masterminded operations at Bletchley Park, UK which were highly successful in cracking the Nazis "Enigma" codes during World War II. Some of his early advances in computer design were inspired by the need to perform many repetitive symbolic manipulations quickly. Before the building of the Colossus computer this work was done by a roomful of women.

In 1945 he joined the National Physical Laboratory in London and worked on the design and construction of a large computer, named Automatic Computing Engine (ACE). In 1949 Turing became deputy director of the Computing Laboratory at Manchester where the Manchester Automatic Digital Machine, the worlds largest memory computer, was being built.

He also worked on theories of artificial intelligence, and on the application of mathematical theory to biological forms. In 1952 he published the first part of his theoretical study of morphogenesis, the development of pattern and form in living organisms.

Turing was gay, and died rather young under mysterious circumstances. He was arrested for violation of British homosexuality statutes in 1952. He died of potassium cyanide poisoning while conducting electrolysis experiments. An inquest concluded that it was self-administered but it is now thought by some to have been an accident.

There is an excellent biography of Turing by Andrew Hodges, subtitled "The Enigma of Intelligence" and a play based on it called "Breaking the Code". There was also a popular summary of his work in Douglas Hofstadter's book "Gödel, Escher, Bach".

http://AlanTuring.net/.

Last updated: 2001-10-09

ALARP

As Low As Reasonably Practicable

A-law

<standard>

The ITU-T standard for nonuniform quantising logarithmic compression.

The equation for A-law is

      |    A
      | ------- (m/mp)                   |m/mp| =< 1/A
      | 1+ln A
  y = |
      | sgn(m)
      | ------ (1 + ln A|m/mp|)   1/A =< |m/mp| =< 1
      | 1+ln A

Values of u=100 and 255, A=87.6, mp is the Peak message value, m is the current quantised message value. (The formulae get simpler if you substitute x for m/mp and sgn(x) for sgn(m); then -1 <= x <= 1.)

Converting from u-LAW to A-LAW introduces quantising errors. u-law is used in North America and Japan, and A-law is used in Europe and the rest of the world and international routes.

[The Audio File Formats FAQ]

Last updated: 1995-02-21

Nearby terms:

AL ♦ al ♦ Aladdin Enterprises ♦ Aladdin Systems, Inc. ♦ ALADIN ♦ ALAM

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