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5.3: Process Hierarchy

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    Whilst the operating system can run many processes at the same time, in fact it only ever directly starts one process called the init (short for initial) process. This isn't a particularly special process except that its PID is always 0 and it will always be running.

    All other processes can be considered children of this initial process. Processes have a family tree just like any other; each process has a parent and can have many siblings, which are processes created[15] by the same parent.

    Certainly children can create more children and so on and so forth.

    Example 5.2. pstree example
      1 init-+-apmd
      5      |-dhclient
             |             |-java_vm---java_vm---13*[java_vm]
             |             `-swf_play

    [15] The term spawn is often used when talking about parent processes creating children; as in "the process spawned a child".

    This page titled 5.3: Process Hierarchy is shared under a CC BY-SA 3.0 license and was authored, remixed, and/or curated by Ian Wienand via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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