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Consider the multilevel feedba

[问答题]

Consider the multilevel feedback queue used by CTSS and Multics. Consider a program that consistently uses 7 time units everytime it is scheduled before it performs an I/O operation and blocks.How many time units are allocated to this program when it is scheduled for

execution at different points of time?

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Answer:Assume that the process is iniially scheduled Tor one time unit.Since the process does not finish by the end of the time quantum, it is moved to a lower level queue and its time quantum is raised to two time units.This process continues till it is moved to a level 4 queue

with a time quantum of 8 time units.In certain multilevel systems, when the process executes next and does not use its full time quantum,the process might be moved back to a level 3 queue.

发表于 2018-05-05 21:07:46 回复(0)