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Showing posts with label Preemptive. Show all posts
Showing posts with label Preemptive. Show all posts

Saturday, 19 November 2011

Preemptive Vs Non preemptive Scheduling


The Scheduling algorithms can be divided into two category with respect to how they contract with clock interrupt:-

Non preemptive Scheduling:- 
A scheduling regulation is non preemptive if, once a process has been given the CPU, the CPU cannot be taken away from that process.

Following are some characteristics of non preemptive scheduling:-
  • In non preemptive system, short jobs are made to wait by longer jobs but the overall action of all processes is fair.
  • In non preemptive system, response times are extra predictable because incoming high priority jobs can not displace waiting jobs.
  • In non preemptive scheduling, a scheduler executes jobs in the follow two situations.
  • When a process switches from running state to the waiting state.
  • When a process terminate. 

Preemptive Scheduling:-
A scheduling regulation is preemptive if, once a process has been given the CPU can taken away.

The plan of allowing processes that are logically run-able to be temporarily balanced is called Preemptive Scheduling and it is contrast to the "run to completion" method.

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