Editing Process (computing) (section)

==Representation==
[[File:Htop_3.0.1_screenshot.png|thumb|right|400px|A list of processes as displayed by [[htop]]]]
[[File:KSysGuard 5.22.0 process table screenshot.png|alt=A process table as displayed by KDE System Guard|thumb|401x401px|A process table as displayed by [[KDE System Guard]]]]
In general, a computer system process consists of (or is said to ''own'') the following resources:
* An ''image'' of the executable [[machine code]] associated with a program.
* Memory (typically some region of [[virtual memory]]); which includes the executable code, process-specific data (input and output), a [[call stack]] (to keep track of active [[subroutine]]s and/or other events), and a [[Heap memory|heap]] to hold intermediate computation data generated during run time.
* Operating system descriptors of resources that are allocated to the process, such as [[file descriptor]]s ([[Unix]] terminology) or [[Handle (computing)|handles]] ([[Microsoft Windows|Windows]]), and data sources and sinks.
* [[Computer security|Security]] attributes, such as the process owner and the process' set of permissions (allowable operations).
* [[Central processing unit|Processor]] state ([[context (computing)|context]]), such as the content of [[processor register|registers]] and physical memory addressing. The ''state'' is typically stored in computer registers when the process is executing, and in memory otherwise.<ref name="OSC Chap4"/>

The operating system holds most of this information about active processes in data structures called [[process control block]]s.  Any subset of the resources, typically at least the processor state, may be associated with each of the process' [[Thread (computer science)|threads]] in operating systems that support threads or ''child'' processes.

The operating system keeps its processes separate and allocates the resources they need, so that they are less likely to interfere with each other and cause system failures (e.g., [[deadlock (computer science)|deadlock]] or [[thrashing (computer science)|thrashing]]). The operating system may also provide mechanisms for [[inter-process communication]] to enable processes to interact in safe and predictable ways.