2014-04-26 10:52:28 -04:00
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daemon
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2014-04-26 11:54:15 -04:00
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/daymn/ , /deemn/ , n. [from Maxwell's Demon, later incorrectly retronymed
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as Disk And Execution MONitor ] A program that is not invoked explicitly,
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but lies dormant waiting for some condition(s) to occur. The idea is that
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the perpetrator of the condition need not be aware that a daemon is lurking
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(though often a program will commit an action only because it knows that it
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will implicitly invoke a daemon). For example, under ITS , writing a file on
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the LPT spooler's directory would invoke the spooling daemon, which would
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then print the file. The advantage is that programs wanting (in this
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example) files printed need neither compete for access to nor understand any
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idiosyncrasies of the LPT. They simply enter their implicit requests and let
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the daemon decide what to do with them. Daemons are usually spawned
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automatically by the system, and may either live forever or be regenerated
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at intervals. Daemon and demon are often used interchangeably, but seem to
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have distinct connotations. The term daemon was introduced to computing by
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CTSS people (who pronounced it /deemon/ ) and used it to refer to what ITS
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called a dragon ; the prototype was a program called DAEMON that
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automatically made tape backups of the file system. Although the meaning and
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the pronunciation have drifted, we think this glossary reflects current
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(2003) usage.
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