Suppose an application is assigned 4 pages of physical memory and the memory is initially empty. It then references pages in the following sequence: ABCDCAEFCFAGECA Show how the system would fault pages into the four frames of physical memory when each of the following replacement policies is used (clearly state the number of page faults for each policy, and justify this number by a diagram similar to the one discussed in lectures). 1- FIFO 2- LRU 3- MIN (optimal)

Real-time Scheduling: Choose all true assertions. Rate Monotonic (RM) scheduling divides time into equal parts and requires each process to seek a portion upon starting. RM schedules real-time systems with CPU utilization below 1. When CPU utilization is less than 1, Earliest Deadline First (EDF) may schedule a real-time system. A process is initiated every p time unit. RM scheduling prioritizes shorter processes. EDF scheduling prioritizes processes with the shortest time frame.

Suppose processes P1-P4 with the given priorities and resource allocations. 1 is the highest priority and 4 is the lowest priority.   Let us also assume that the "no preemption" condition is now relaxed by allowing preemption of resources by processes of higher priority. For example, P3 may preempt P2 or P4 if it needs a resource which they are holding. If P3 preempts one of these processes, say P4, then P4 release all the resources it is holding. Show one sequence of events in which resources are allocated to the 4 processes and the resulting preemptions, if any, until all new requests are serviced. Current allocations are shown below. Each resource has 4 instances. Try to minimize the preemptions as they are expensive. Process ID Process Priority Current allocation New request     R1 R2 R1 R2 P1 1 2 1 2 1 P2 3 0 1 1 0 P3 2 1 1 0 1 P4 4 1 1 2 1

Part I Assume that the ready queue has just received for processes: P1, P2, P3, P4, in that order. All at time 0. The CPU execution times for these processes are as follows: Process Execution Time P1 P2 P3 P4 13 8 15 6 Draw the Gantt chart and calculate the metric listed in parentheses for each of the following scheduling algorithms: 1. First Come, First Served (Total Wait Time) 2. Shortest Job First (Total Wait Time) 3. Round Robin, with a time quantum of 5 ms (Total Wait and Response Times) Part II Now assume that P1 arrives in the ready queue at time 0, P2 arrives at time 4, P3 arrives at time 10, and P4 arrives at time 20. The CPU execution times for the processes are the same as in Part I: Process Execution Time P1 P2 P3 P4 P1 13 P2 8 P3 15 P4 6 Draw the Gantt chart and calculate the total wait time for each of the following scheduling algorithms: 1. Shortest Job First 2. Shortest Remaining Time Next (remember, this is a preemptive algorithm) 3. Preemptive priority with the…