PID – Process ID

Each process in unix has a parent process. When a system is booted, a special process called the swapper or scheduler is created with PID = 0.

Swapper creates three children using the etc/init file: 1. Process Dispatcher 2. vhand & 3. bdflush (1,2,3 being the process id respectively).

Process dispatcher in turn creates shell. All user processes are children of the shell.

Thus:
Swapper/scheduler

• Process Dispatcher


• Shell


• All user processes


• vhand


• bdflush

getpid() – Gets process id
getppid() – Gets parent process id