The following table represents a set of 5 processes, and their arrival and service times accordingly. Given these processes simulate the following two process scheduling policies. make a timeline/diagram that traces the execution of each process for each discrete time step (for example, simply giving AABCDDAA… as your timeline is sufficient).

Simulate a Round-Robin policy with a time slice quantum of 2. Remember that if a process arrives at the same time that the running processes time slice quantum expires, by convention we will determine that the arriving process is placed on the round robin queue first, then the expiring process is placed back on the queue after any arriving processes.

Also simulate a highest response ratio next (HRRN) policy. Recall that HRRN is non-preemptive, and it decides which process to run when the current process finishes by calculating the ratio

R=(w+s)s{“version”:”1.1″,”math”:”R = frac{(w + s)}{s}”}

where w is the time spent waiting so far and s is the expected service time. If 2 processes have the same response ratio when a scheduling decision needs to be made, fall back to selecting the process that has been waiting the longest.

Process Arrival Time Service Time

A 0 6

B 3 5

C 5 4

D 6 3

E 8 3

Using the table of processes and information , perform the following simulation of a processor scheduler. Imagine you have a system that has 2 CPUs. Maintaining a single ready queue (e.g. you will use dynamic scheduling, where a process can change which CPU it executes on), and using round-robin scheduling with a time slice quantum of 2, simulate the scheduling of the processes among the 2 CPU system. When a CPU is idle, the dispatcher should simply take the next ready process from the head of the queue, and when a process times out of its time slice, it should be returned to the end of the common queue. There can be situations where a CPU is idle because no process is available to be scheduled (e.g. at time 0-4, only process A is available, so cpu 2 will be idle for the first 4 time steps). As with the previous question, show the timeline/diagram that traces the execution of your processes (giving AABB etc. is acceptable, but you need a timeline for each CPU, and indicate a CPU being idle using I or 0 to indicate nothing scheduled during a time step). You will need to indicate in some manner the executions on CPU1 and CPU2 respectively