A report on Daemon (computing)

Components of some Linux desktop environments that are daemons include D-Bus, NetworkManager (here called unetwork), PulseAudio (usound), and Avahi.

Computer program that runs as a background process, rather than being under the direct control of an interactive user.

- Daemon (computing)
Components of some Linux desktop environments that are daemons include D-Bus, NetworkManager (here called unetwork), PulseAudio (usound), and Avahi.

12 related topics with Alpha

Overall

OS/360 was used on most IBM mainframe computers beginning in 1966, including computers used by the Apollo program.

Operating system

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OS/360 was used on most IBM mainframe computers beginning in 1966, including computers used by the Apollo program.
PC DOS was an early personal computer OS that featured a command-line interface.
Mac OS by Apple Computer became the first widespread OS to feature a graphical user interface. Many of its features such as windows and icons would later become commonplace in GUIs.
The first server for the World Wide Web ran on NeXTSTEP, based on BSD.
Ubuntu, desktop Linux distribution
Linux, a unix-like operating system was first time released on September 17, 1991, by Linus Torvalds. Picture of Tux the penguin, mascot of Linux.
A kernel connects the application software to the hardware of a computer.
Privilege rings for the x86 microprocessor architecture available in protected mode. Operating systems determine which processes run in each mode.
Many operating systems can "trick" programs into using memory scattered around the hard disk and RAM as if it is one continuous chunk of memory, called virtual memory.
File systems allow users and programs to organize and sort files on a computer, often through the use of directories (or "folders").
A screenshot of the Bash command line. Each command is typed out after the 'prompt', and then its output appears below, working its way down the screen. The current command prompt is at the bottom.
A screenshot of the KDE Plasma 5 graphical user interface. Programs take the form of images on the screen, and the files, folders (directories), and applications take the form of icons and symbols. A mouse is used to navigate the computer.

An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.

Example of tunneling an X11 application over SSH: the user 'josh' has "SSHed" from the local machine 'foofighter' to the remote machine 'tengwar' to run xeyes.

Secure Shell

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Cryptographic network protocol for operating network services securely over an unsecured network.

Cryptographic network protocol for operating network services securely over an unsecured network.

Example of tunneling an X11 application over SSH: the user 'josh' has "SSHed" from the local machine 'foofighter' to the remote machine 'tengwar' to run xeyes.
Logging into OpenWrt via SSH using PuTTY running on Windows.
Diagram of the SSH-2 binary packet.

An SSH client program is typically used for establishing connections to an SSH daemon accepting remote connections.

Windows service

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Computer program that operates in the background.

Computer program that operates in the background.

It is similar in concept to a Unix daemon.

Background process

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Computer process that runs behind the scenes and without user intervention.

Computer process that runs behind the scenes and without user intervention.

In the latter case when the session ends, the child processes are not terminated, either because they are not sent SIGHUP or because they ignore it, and thus become orphan processes, which are then adopted by the init process (the kernel sets the init process as their parent), and they continue running without a session, now called daemons.

Version 7 Unix: /etc listing, showing init and rc

Init

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First process started during booting of the computer system.

First process started during booting of the computer system.

Version 7 Unix: /etc listing, showing init and rc
Version 7 Unix: contents of an /etc/rc Bourne shell script
sysv-rc-conf, a TUI utility that selects which SysV-style init scripts will be run in each runlevel

Init is a daemon process that continues running until the system is shut down.

Example usage of cron utility

Cron

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Job scheduler on Unix-like operating systems.

Job scheduler on Unix-like operating systems.

Example usage of cron utility

The crontab files are stored where the lists of jobs and other instructions to the cron daemon are kept.

Principle of Super-server

Super-server

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Principle of Super-server
Example

A super-server or sometimes called a service dispatcher is a type of daemon run generally on Unix-like systems.

File descriptors for a single process, file table and inode table. Note that multiple file descriptors can refer to the same file table entry (e.g., as a result of the dup system call) and that multiple file table entries can in turn refer to the same inode (if it has been opened multiple times; the table is still simplified because it represents inodes by file names, even though an inode can have multiple names). File descriptor 3 does not refer to anything in the file table, signifying that it has been closed.

File descriptor

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Unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket.

Unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket.

File descriptors for a single process, file table and inode table. Note that multiple file descriptors can refer to the same file table entry (e.g., as a result of the dup system call) and that multiple file table entries can in turn refer to the same inode (if it has been opened multiple times; the table is still simplified because it represents inodes by file names, even though an inode can have multiple names). File descriptor 3 does not refer to anything in the file table, signifying that it has been closed.

Each Unix process (except perhaps daemons) should have three standard POSIX file descriptors, corresponding to the three standard streams:

CP-6 Community wall Plaque at CHM

Universal Time-Sharing System

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Discontinued operating system for the XDS Sigma series of computers, succeeding Batch Processing Monitor (BPM)/Batch Time-Sharing Monitor (BTM).

Discontinued operating system for the XDS Sigma series of computers, succeeding Batch Processing Monitor (BPM)/Batch Time-Sharing Monitor (BTM).

CP-6 Community wall Plaque at CHM

System Daemons, called "ghost jobs" were used to run monitor code in user space.

Schematic figure of Maxwell's demon thought experiment

Maxwell's demon

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Thought experiment that would hypothetically violate the second law of thermodynamics.

Thought experiment that would hypothetically violate the second law of thermodynamics.

Schematic figure of Maxwell's demon thought experiment

Daemons in computing, generally processes that run on servers to respond to users, are named for Maxwell's demon.