daemon


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daemon

[′dē·mən]
(computer science)
In Unix, a program that runs in the background, such as a server.

daemon

(operating system)
/day'mn/ or /dee'mn/ (From the mythological meaning, later rationalised as the acronym "Disk And Execution MONitor") 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 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.

Unix systems run many daemons, chiefly to handle requests for services from other hosts on a network. Most of these are now started as required by a single real daemon, inetd, rather than running continuously. Examples are cron (local timed command execution), rshd (remote command execution), rlogind and telnetd (remote login), ftpd, nfsd (file transfer), lpd (printing).

Daemon and demon are often used interchangeably, but seem to have distinct connotations (see demon). 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.

daemon

Pronounced "dee-mun" as in the word for devil, as well as "day-mun," a daemon is a Unix/Linux program that executes in the background ready to perform an operation when required. Functioning like an extension to the operating system, a daemon is usually an unattended process that is initiated at startup. Typical daemons are print spoolers and email handlers or a scheduler that starts up another process at a designated time. The term comes from Greek mythology, meaning "guardian spirit." See agent and mailer-daemon.
References in periodicals archive ?
We are proud to partner with Hitachi on the CrystEna project and incorporate our Grid Daemon software platform to demonstrate the significant impact this energy storage system will have on grid stabilization."
In this epic twist on Adam and Eve--replete with angels, witches, and ursine warriors--the church is a malevolent force, characters have animal soulmates called daemons, and, far from sinful, the loss of innocence of protagonists Lyra and Will is a saving grace.
This is all heady stuff to incorporate into a fantasy series featuring talking bears, daemons, witches, interdimensional travel, and visits to hell, but the framework allows Pullman to play with the ideas, develop them, and chew them in a way he could not in a philosophical or theological text.
Lyra could see his dark eyes searching among the Scholars as they peered up at the slide of the Aurora, and the green glow of his daemon's eyes beside him.
As well as a winning performance by Amy McAllister in the central role of Lyra, one of its obvious successes is the puppetry by Blind Summit which supplies the "daemons" - souls in visible animal form-which accompany human beings in the invented world where most of the action takes place.
"With no disrespect to the late Michael Crichton, Daniel Suarez's techno-nightmare, Daemon, illustrates what I call Crichton's Law: Some ideas are so good that nobody can mess them up.
All of the technical heft is necessary to fully realise Pullman's fantastical parallel universe, in which humans are bound to a reflection of their soul called a daemon, which takes the form of an animal.
Not only does she enlist the help of a talking armoured bear (voiced by Sir Ian McKellen), but one of the conceits of the story is that in this universe, every person has their own daemon (pronounced demon), which is a physical manifestation of their personality or soul, in animal form.
Horror writer Ian Tremblin holds a short story writing contest with an unusual prize: the five finalists will get to spend the evening with him in Daemon Hall, and the winner will be published.
The Daemon in Our Dreams is a grim suspense novel about ominous, impending doom.
The free half-day seminars will demonstrate the Centrify solution, which provides a native daemon for UNIX and Linux servers that enables them to join an Active Directory domain.