BCS1333 OS : Assignment 2

CHAPTER 3

1 Explain short-term and long-term scheduling and describe the differences among them.
Describe the actions taken by a kernel to context-switch between processes.


CHAPTER 5

2. Why is it important for the scheduler to distinguish I/O-bound programs from CPU-bound programs?

3. Discuss how the following pairs of scheduling criteria conflict in certain
settings.
a. CPU utilization and response time
b. Average turnaround time and maximum waiting time
c. I/O device utilization and CPU utilization

4. Consider the following set of processes, with the length of the CPU-burst time given in milliseconds:
Process        Burst Time            Priority
P1                    10                        3
P2                     1                         1
P3                     2                         3
P4                     1                         4
P5                     5                         2


a) Draw four Gantt charts illustrating the execution of these processes
using FCFS, SJF, a nonpreemptive priority (a smaller priority
number implies a higher priority), and RR (quantum = 1)
scheduling.


b) What is the average waiting time  for each of the scheduling
algorithms in part a?


c) Which of the schedules in part a results in the minimal average
waiting time (over all processes)?