Definition
Process Hierarchy
A process hierarchy is the parent-child relationship between processes. Every process (except the first system process) is created by another, forming a tree-like structure.
Mechanism
Parent Process
A process that spawns one or more new processes.
Child Process
Created by a parent. May inherit properties (open files, environment variables). Assigned a unique PID and recorded in the process table.
Properties
Resource Control
Parent can control or limit resources used by children.
Cascading Termination
In some systems, terminating a parent automatically terminates all children.
Parallel Tasks
A single logical task can be broken into multiple parallel child processes for improved performance.