Five states

New. The process is being created.

Running. Instructing are being executed.

Waiting. The process is waiting for some event to occur(such as an I/O completion or reception of a siganal.

Ready. The process is waiting to be assigned to a processor.

Terminated. The process has finished execution.

 

Why are the states divided into 5, not 4, or 7?

Because it has the highest efficiency while the processes are scheduled.