The Scheduling algorithms can be divided into two parts with respect to how they deal with clock interrupts.
1) Nonpreemptive Scheduling:
A scheduling discipline is no preemptive if, once a process has been given the CPU, the CPU cannot be taken away from that process.
Following are some characteristics of nonpreemptive scheduling
a) In nonpreemptive system, short jobs are produced to wait by longer jobs but the complete treatment of all processes is fair.
b) In nonpreemptive system, response times are more expected because incoming high priority jobs cannot relocate waiting jobs.
c) In nonpreemptive scheduling, a scheduler executes jobs in the following two conditions.
o When a process switches from running condition to the waiting state.
o When a process come to an end.
2) Preemptive Scheduling:
A scheduling regulation is preemptive if, one time a process has been given the CPU can taken away.
The policy of allowing processes that are logically run able to be for now suspended is called Preemptive Scheduling and it is contrast to the "run to completion" technique.