Sunday, June 3, 2007

Question 25

Which of the following descriptions concerning task scheduling by an operating
system is correct?

a) The multiple queuing method first allocates low priority and long CPU times to the task for which allocation is requested, and then increases priority and gradually reduces the CPU time for it.
b) The first-come first-served (FCFS) method allocates to tasks, CPU time with priorities in the order that the tasks are created. This aims at giving higher priorities to the tasks which started ahead of others and having them finish early.
c) The shortest expected processing time first (SEPT) method improves the overall efficiency of system processing by increasing priorities of the tasks which have been using little CPU time, and by decreasing priorities of the tasks which have been using much CPU time.
d) The round robin method allocates CPU time to the tasks in the requested order, and places at the end of the queue the task which has consumed the CPU time allocated to it.

answer

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