Daemon

Daemon is a program that continuously runs as a background process rather than being under the direct control of an interactive user. It exists for the purpose of handling periodic service requests that a computer system expects to receive. The term was coined by programmers at MIT’s Project MAC who took the name from Maxwell’s demon, which was an imaginary being from a thought experiment that continuously worked in the background. Unix systems then inherited this term, which is also consistent with Greek mythology’s interpretation of a daemon as a supernatural being that works in the background with neither a good or evil bias.

While the term became well known with Unix, most operating systems use daemons in some form or another. Traditionally, the process names of a daemon end with the letter d, in order to clarify that the process is indeed a daemon and for differentiation between a daemon and a normal computer program.

Unix daemon examples

Below is a list of daemons found in Unix-like operating systems

  • biod: Works in cooperation with the remote nfsd to handle NFS requests
  • crond: Time-based job scheduler that runs jobs in the background
  • fingerd: Provides a network interface for the finger protocol. Used by the finger command
  • ftpd: Services FTP requests from a remote system
  • httpd: Web server daemon
  • lpd: The line printer daemon that manages printer spooling
  • ntpd: Network Time Protocol daemon that manages clock synchronization across the network.
  • sshd: Listens for secure shell requests from clients
  • syslogd: System logger process that collects various system messages
  • systemd: Replacement of init, the Unix program that spawns all other processes
  • syncd: Periodically keeps the file systems synchronized with system memory
  • vhand: Releases pages of memory for use by other processes.
  • ypbind: Finds the serves for an NIS domain and stores the information in a file

Vangie Beal
Vangie Beal
Vangie Beal is a freelance business and technology writer covering Internet technologies and online business since the late '90s.

Top Articles

List of Windows Operating System Versions & History [In Order]

The Windows operating system (Windows OS) refers to a family of operating systems developed by Microsoft Corporation. We look at the history of Windows...

How to Create a Website Shortcut on Your Desktop

Website Shortcut on Your Desktop reviewed by Web Webster   This Webopedia guide will show you how to create a website shortcut on your desktop using...

What are the Five Generations of Computers? (1st to 5th)

Reviewed by Web Webster Each generation of computer has brought significant advances in speed and power to computing tasks. Learn about each of the...

Hotmail [Outlook] Email Accounts

Launched in 1996, Hotmail was one of the first public webmail services that could be accessed from any web browser. At its peak in...

XiaoBa Ransomware

XiaoBa is a type of file-encrypting ransomware that runs on Windows and encodes...

Team Management Software

Team management software is a type of organizational software that supports remote team...

Kaseya Ransomware Attack

The 2021 ransomware cyberattack on U.S.-based software solutions company, Kaseya, is known as...