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,
vhand and dbflush 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).