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daemon: /day'mn/ or /dee'mn/ [from the mythological meaning,
   later rationalized as the acronym `Disk And Execution MONitor'] n.
   A program that is not invoked explicitly, but lies dormant waiting
   for some condition(s) to occur.  The idea is that the perpetrator
   of the condition need not be aware that a daemon is lurking (though
   often a program will commit an action only because it knows that it
   will implicitly invoke a daemon).  For example, under ITS
   writing a file on the LPT spooler's directory would invoke the
   spooling daemon, which would then print the file.  The advantage is
   that programs wanting (in this example) files printed need neither
   compete for access to nor understand any idiosyncrasies of the
   LPT.  They simply enter their implicit requests and let the
   daemon decide what to do with them.  Daemons are usually spawned
   automatically by the system, and may either live forever or be
   regenerated at intervals.

Daemon and demon are often used interchangeably, but seem to have distinct connotations. The term `daemon' was introduced to computing by CTSS people (who pronounced it /dee'mon/) and used it to refer to what ITS called a dragon. Although the meaning and the pronunciation have drifted, we think this glossary reflects current (1993) usage.