While booting, special process called the 'swapper' or 'scheduler'
is created with Process-ID 0. The swapper manages memory allocation for processes
and influences CPU allocation. The swapper inturn creates 3 children:
the process dispatcher,
with IDs 1,2 and 3 respectively.
This is done by executing the file /etc/init. Process dispatcher gives birth to
the shell. Unix keeps track of all the processes in an internal data structure called
the Process Table (listing command is ps -el).