Real Time Systems Assignment No. 01. Question 1. Does a random scheduler obey the Queue discipline? Explain your answer with an example. Question 2. Determine whether the following task set is RM-schedulable or not. If yes show an RM schedule else check whether it is EDF schedulable and give an EDF schedule. All tasks arrive at time 0. TASK PERIOD COMPUTATION TIME A 35 2 B 15 2 C 10 1 D 6 1 E 2 1 Question 3. Give an RM-schedule for the following task set. All tasks arrive at time 0. TASK PERIOD COMPUTATION TIME A 32 1 B 16 1 C 8 1 D 4 1 E 2 1 Question 4. If a given task set is RM schedulable, then will the RM and EDF schedule be the same or different. Prove with an example. Question 5. Check whether the following task set is FIFO schedulable or not. If yes then give a FIFO schedule. TASK PERIOD COMPUTATION TIME ARRIVAL TIME A 15 1 0 B 10 1 1 C 7 1 0 D 5 1 0 E 3 1 1 Question 6. Give an EDF schedule for the following task set. All tasks arrive at time 0. TASK PERIOD COMPUTATION TIME A 30 2 B 20 1 C 15 1 D 10 1 E 5 2 Question 7. Give an LLF schedule for the above task set. Question 8. Construct a task set that can be scheduled by the RM, EDF and LLF algorithms. Question 9. Construct a task set that can be EDF scheduled but not RM scheduled. Question 10. Explain instances where the static and dynamic scheduler would be equivalent and when they would differ. Which is more suitable for an operating system? Question 11. Prove the optimality of the LL algorithm. Question 12. We have assumed in lectures that context-switching due to preemption incurs no overhead. Now suppose context- switching (from one task to another) requires 'x' time units. Consider a system with 2 tasks with computation times c1, c2 and periods p1, p2 (which are equal to their deadlines and p1 < p2). Derive the maximum value of 'x' for which this task set is EDF-schedulable. Show calculations. Question 13. A periodic process must be executed once in every period of the process. A system is schedulable if all the processes can be scheduled as defined. Suppose our system has five processes with periods 30, 50, 75, 200 and 300 msec each. These four processes require 5, 10, 15, 35 and 'x' msec of CPU time, respectively. What is the largest value of 'x' for which the system is schedulable?. Show calculations and the schedule. Question 14. Determine whether there is a feasible schedule for the following set of periodic processes. If yes, show the schedule and the steps used to derive it. T1: c11 = 2, c12 = 2, d1 = 7, p1 = 8 T2: c2 = 0.5, d2 = p2 = 16 T3: c31 = 2, c32 = 3, d3 = p3 = 16 T4: c4 = 0.5, d4 = p4 = 16 T1 must rendezvous with T3 after the first scheduling block of T1. T3 must rendezvous T1 after first and second scheduling block of T3.