[Term of the Day]: Daemon

Term of the Day

"Daemon"

Definition — What is Daemon and it does?

In multitasking computer operating systems, the Unix term daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user.

A daemon is usually either created by forking a child process and then exiting the parent, which will cause it to be orphaned (on purpose) and adopted by the init process, the granddaddy of all processes in the system (which is also a daemon itself). It is then left to run, waiting silently in the background until when an event to occur.

There are many common daemons in use. One that you might have often seen is the MAILER_DAEMON that routes and processes emails. If an e-mail message is returned to you as undeliverable, you may receive a message from the mailer daemon.