Editing Parent process (section)

== Unix-like systems ==
In [[Unix-like]] [[operating system]]s, every process except {{nowrap|[[Linux startup process|process 0]]}} (the swapper) is created when another process executes the [[fork (operating system)|fork()]] [[system call]]. The process that invoked fork is the ''parent process'' and the newly created process is the ''child process''. Every process (except process 0) has one parent process, but can have many child processes.

The [[operating system kernel]] identifies each process by its process identifier. {{nowrap|Process 0}} is a special process that is created when the system boots; after forking a child process {{nowrap|(process 1),}} {{nowrap|process 0}} becomes the [[Scheduling (computing)|swapper process]] (sometimes also known as the "[[idle task]]"). {{nowrap|Process 1}}, known as {{mono|[[init]]}}, is the ancestor of every other process in the system.<ref name="Tanenbaum">{{cite book |last1=Tanenbaum |first1=Andrew |title=Modern operating systems |date=2007 |publisher=Pearson Prentice Hall |isbn=978-0136006633 |pages=752 |edition=3rd}}</ref>

=== Linux ===
In the [[Linux kernel]], in which there is a very slim difference between processes and [[POSIX threads]], there are two kinds of parent processes, namely real parent and parent. Parent is the process that receives the ''SIGCHLD'' signal on child's termination, whereas real parent is the thread that actually created this child process in a multithreaded environment. For a normal process, both these two values are same, but for a POSIX thread which acts as a process, these two values may be different.<ref>{{cite web|last=Srinivasan |first=Sundar |url=http://sunnyeves.blogspot.com/2010/09/sneak-peek-into-linux-kernel-chapter-2.html |title=An Engineer's Options & Futures: A Sneak-Peek into Linux Kernel - Chapter 2: Process Creation |publisher=Sunnyeves.blogspot.com |date=2010-09-01 |accessdate=2014-04-30}}</ref>