hw06 - EE 4770 Homework 6 Due 30 April 1997 The tasks below...

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Unformatted text preview: EE 4770 Homework 6 Due: 30 April 1997 The tasks below are run on an otherwise empty system having a quantum of 10 ms, using rst-come, rst-served scheduling, and which is not task preemptive. Task Creation Run Other Name Time = ms Time = ms A 0 1 15 until 30 B 7 1 19 for 8 C 22 21 Nothing Special Task A computes for 15 ms then sleeps goes into the wait state; it wakes up moves to ready at the next multiple of 30 ms. That is it's woken up at t = 30 ms, t = 60 ms, etc. After waking up it performs another 15 ms of computation and sleeps again, to be woken up at the next multiple of 30 ms. Task B performs I O after every 19 ms of computation; the I O takes 8 ms to complete. That is, after each 19 ms of computation B will perform the I O. Show the states of the CPU and tasks from t = 0 to 100 ms. Problem 2: The tasks in the table below are run on an otherwise empty system having a quantum of 11 ms and which is not task preemptive. Task Creation Round 1 Round 2 Run Name Time = ms Class Deadline Time = ms A 0 1 NA 20 B 10 1 NA 20 C 20 1 NA 20 D 30 2 60 20 E 40 2 95 20 A multilevel scheduling scheme is used with round robin used in the rst round. In the second round rst-come, rst-served is used for class-1 tasks and deadline scheduling is used for class-2 tasks. Show the states of each task and the which task the CPU is running from t = 0 until the last task nishes. Problem 1: Problem 3: Task Creation Round 1 Round 2 Run Name Time = ms Class Deadline Time = ms A 0 1 NA 1 B 10 1 NA 1 C 20 1 NA 1 D 30 2 60 20 E 40 2 95 20 Like the tasks in the previous problem the class-2 tasks in the table above, which have deadlines, must share CPU with the class-1 tasks. Suppose that tasks A and B must run regularly, but that task C could wait. Show how the scheduling could be modi ed so that the running of C could not cause D, E, or any new class-2 tasks to miss deadlines, but A and B still get CPU time regularly. Of course, C must run some time. The solution must describe how the scheduling algorithms presented in class can be used. ...
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This note was uploaded on 11/28/2011 for the course EE 4770 taught by Professor Staff during the Fall '99 term at LSU.

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