The purpose of process is to ensure consistency.
The major difference between program and process is that program is a group of instructions to carry out a specified task whereas the process is a program in execution. While a process is an active entity, a program is considered to be a passive one.
Five states:
new: The process is being created.
ready: The process is waiting to be assigned to a processor.
running: Instructions are being executed.
waiting: The process is waiting