Computers as Components, 2nd Edition

306 CHAPTER 6 Processes and Operating Systems

does not have any useful work to do, the round-robin scheduler moves on to the

next process in order to fill the time slot with useful work. In this example, all

three processes execute during the first hyperperiod, but during the second one,

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has no useful work and is skipped. The processes are always evaluated in the

same order.The last time slot in the hyperper iod is left empty;if we have occasional,

non-periodic tasks without deadlines, we can execute them in these empty time

slots. Round-robin scheduling is often used in hardware such as buses because it is

very simple to implement but it provides