demon
    n 1: an evil supernatural being [syn: devil, fiend, demon,
         daemon, daimon]
    2: a cruel wicked and inhuman person [syn: monster, fiend,
       devil, demon, ogre]
    3: someone extremely diligent or skillful; "he worked like a
       demon to finish the job on time"; "she's a demon at math"

Demon \De"mon\, n. [F. d['e]mon, L. daemon a spirit, an evil
   spirit, fr. Gr. dai`mwn a divinity; of uncertain origin.]
   1. (Gr. Antiq.) A spirit, or immaterial being, holding a
      middle place between men and deities in pagan mythology.
      [1913 Webster]

            The demon kind is of an intermediate nature between
            the divine and the human.             --Sydenham.
      [1913 Webster]

   2. One's genius; a tutelary spirit or internal voice; as, the
      demon of Socrates. [Often written d[ae]mon.]
      [1913 Webster]

   3. An evil spirit; a devil.
      [1913 Webster]

            That same demon that hath gulled thee thus. --Shak.
      [1913 Webster]

demon
 n.

    1. Often used equivalently to daemon ? especially in the Unix world,
    where the latter spelling and pronunciation is considered mildly archaic.

    2. [MIT; now probably obsolete] A portion of a program that is not invoked
    explicitly, but that lies dormant waiting for some condition(s) to occur.
    See daemon. The distinction is that demons are usually processes within a
    program, while daemons are usually programs running on an operating system.

    Demons in sense 2 are particularly common in AI programs. For example, a
    knowledge-manipulation program might implement inference rules as demons.
    Whenever a new piece of knowledge was added, various demons would activate
    (which demons depends on the particular piece of data) and would create
    additional pieces of knowledge by applying their respective inference rules
    to the original piece. These new pieces could in turn activate more demons
    as the inferences filtered down through chains of logic. Meanwhile, the
    main program could continue with whatever its primary task was.

demon

   1.  (Often used equivalently to daemon,
   especially in the Unix world, where the latter spelling and
   pronunciation is considered mildly archaic).  A program or
   part of a program which is not invoked explicitly, but that
   lies dormant waiting for some condition(s) to occur.

   At MIT they use "demon" for part of a program and "daemon"
   for an operating system process.

   Demons (parts of programs) are particularly common in AI
   programs.  For example, a knowledge-manipulation program
   might implement inference rules as demons.  Whenever a new
   piece of knowledge was added, various demons would activate
   (which demons depends on the particular piece of data) and
   would create additional pieces of knowledge by applying their
   respective inference rules to the original piece.  These new
   pieces could in turn activate more demons as the inferences
   filtered down through chains of logic.  Meanwhile, the main
   program could continue with whatever its primary task was.
   This is similar to the triggers used in relational
   databases.

   The use of this term may derive from "Maxwell's Demons" -
   minute beings which can reverse the normal flow of heat from a
   hot body to a cold body by only allowing fast moving molecules
   to go from the cold body to the hot one and slow molecules
   from hot to cold.  The solution to this apparent thermodynamic
   paradox is that the demons would require an external supply of
   energy to do their work and it is only in the absence of such
   a supply that heat must necessarily flow from hot to cold.

   Walt Bunch believes the term comes from the demons in Oliver
   Selfridge's paper "Pandemonium", MIT 1958, which was named
   after the capital of Hell in Milton's "Paradise Lost".
   Selfridge likened neural cells firing in response to input
   patterns to the chaos of millions of demons shrieking in
   Pandemonium.

   2.  Demon Internet Ltd.

   3. A program generator for differential equation problems.

   [N.W. Bennett, Australian AEC Research Establishment,
   AAEC/E142, Aug 1965].

   [Jargon File]

   (1998-09-04)

Demon
   See DAEMON.