Parent process creates child processes, which, in turn create other processes, forming a tree of processes. It is called process creation.
✦ Parent and child share all resources.
✦ Children share the subset of parent’s resources.
✦ Parent and child share no resources.
✦In the Operating System, the Parent process and child process execute simultaneously.
✦ Parent waits until child terminates.
✦ Child duplicate of the parent.
✦ The child has a program loaded into it.
✦ fork system call creates a new process.
✦ exec system call used after a fork to replace the process’ memory space with a new program.
- The process executes the last statement and asks the operating system to decide it (exit).
✦ Output data from child to parent (via wait).
✦ Process’ resources are deallocated by an operating system.
- A parent may terminate execution of children processes (abort).
✦ The child has exceeded allocated resources.
✦ The task assigned to the child is no longer required.
✦ Parent is existing.
✔ An operating system does not allow the child to continue if its parent terminates.
✔ Cascading termination.