Daemons: Difference between revisions
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{{#set: Priority=1 | Summary=In Unix, a daemon is a background process belonging to the system.}}<!-- | {{#set: Priority=1 | Summary=In Unix, a daemon is a background process belonging to the system.}}<!-- | ||
-->{{#invoke:Dependencies|add|Processes,3}} | -->{{#invoke:Dependencies|add|Processes,3}} | ||
In computing terms a “daemon” is not evil – in practice | In computing terms a “daemon” is not evil – in practice they are very helpful. “Daemon” is a Unix term: in | ||
they are very helpful. “Daemon” is a Unix term: in | Windows equivalent [[processes]] would be called “Windows Services”. | ||
Windows equivalent [[ | |||
“Windows Services”. | |||
These are <em>background</em> [[ | These are <em>background</em> [[processes]] which do helpful services and are not responsible to any user or user process. A nice (Unix) example is [https://en.wikipedia.org/wiki/Cron cron] – which is a job scheduler which you can use to run other processes at regular intervals (such as making a file backup in the early morning, each day). | ||
services and are not responsible to any user or user process. A nice | |||
(Unix) example is [https://en.wikipedia.org/wiki/Cron cron] – which | |||
is a job scheduler which you can use to run other processes at regular | |||
intervals (such as making a file backup in the early morning, each | |||
day). | |||
If you have access to a Unix terminal, run the <code>top</code> utility. It will | If you have access to a Unix terminal, run the <code>top</code> utility. It will reveal several daemons lurking in the machine, typically owned by <code>root</code>. It is conventional to end a daemon’s name with ‘d’, which makes them easier to identify. | ||
reveal several daemons lurking in the machine, typically owned by | |||
<code>root</code>. It is conventional to end a daemon’s name with | |||
‘d’, which makes them easier to identify. | |||
You can find more details in the [https://en.wikipedia.org/wiki/List_of_Unix_daemons usual places]. | You can find more details in the [https://en.wikipedia.org/wiki/List_of_Unix_daemons usual places]. | ||
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{{BookChapter|2.4|74-75}} | |||
{{PageGraph}} | {{PageGraph}} | ||
{{Category|Processes}} | {{Category|Processes}} | ||
{{Category|User}} | {{Category|User}} | ||
Latest revision as of 10:02, 5 August 2019
| Depends on | Processes |
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In computing terms a “daemon” is not evil – in practice they are very helpful. “Daemon” is a Unix term: in Windows equivalent processes would be called “Windows Services”.
These are background processes which do helpful services and are not responsible to any user or user process. A nice (Unix) example is cron – which is a job scheduler which you can use to run other processes at regular intervals (such as making a file backup in the early morning, each day).
If you have access to a Unix terminal, run the top utility. It will reveal several daemons lurking in the machine, typically owned by root. It is conventional to end a daemon’s name with ‘d’, which makes them easier to identify.
You can find more details in the usual places.
| Also refer to: | Operating System Concepts, 10th Edition: Chapter 2.4, pages 74-75 |
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Articles on Processes
About this resource • Atomicity • Containers • Context • Context Switching • Daemons • Fork Unix • Hypervisor • Idle • Interprocess Communication • Multi Threading • Mutual exclusion • Pipes • Pointer Arithmetic • Process Control Block (PCB) • Process Priority • Process Scheduling • Process States • Processes • Queues • Queues Extra • Race Conditions • Real Time • Resources • Scheduler • Signal and Wait • Sleep • Starvation • Synchronisation • Thrashing • Threads • Unix SignalsArticles on User
"Everything is a File" • Application Binary Interface (ABI) • Arrays • Boot • Buffer Overflow • Containers • Daemons • Disk Partition • Dynamic Memory Allocation • Emulator traps • Environment Variables • Errors • Exceptions • File Attributes • File Locking • File Permissions • Introduction to Operating Systems • Journalling File System • Links • Locks • Man(ual pages in Unix) • Memory Mapped Files • Monitoring • Network File System (NFS) • PATH • Pipes • Pointers • Relocatable Code • Reset • SETUID • Shell • Sockets • Spooling and Buffering • Streams • Structures • Superuser • System Calls • Unix Signals • User • Using Peripherals
