OS Process Management

Question 81

There are three processes in the ready queue. When the currently running process requests for I/O how many process switches take place?

• 1
• 2
• 3
• 4

Question 82

Which is the correct definition of a valid process transition in an operating system?

• Wake up: ready → running
• Dispatch: ready → running
• Block: ready → running
• Timer runout: ready → running

Question 83

The correct matching of the following pairs is

(A) Disk check              (1) Roundrobin
(B) Batch processing        (2) Scan
(C) Time sharing            (3) LIFO
(D) Stack operation         (4) FIFO

• A B C D
   3 4 2 1
  

• A B C D
  4 3 2 1
  

• A B C D
  3 4 1 2
  

• A B C D
  2 4 1 3
  

Question 84

Consider three CPU-intensive processes, which require 10, 20 and 30 time units and arrive at times 0, 2 and 6, respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end.

• 1
• 2
• 3
• 4

Question 85

The performance of Round Robin algorithm depends heavily on

• size of the process
• the I/O bursts of the process
• the CPU bursts of the process
• the size of the time quantum

Question 86

Consider a set of 5 processes whose arrival time, CPU time needed and the priority are given below:

Process       Arrival Time   CPU Time Needed     Priority
              (in ms)

P1              0             10                 5
P2              0             5                  2
P3              2             3                  1
P4              5             20                 4
P5              10            2                  3

(smaller the number, higher the priority) If the CPU scheduling policy is priority scheduling without preemption, the average waiting time will be

• 12.8 ms
• 11.8 ms
• 10.8 ms
• 9.8 ms

Question 87

Process is:

• A program in high level language kept on disk
• Contents of main memory
• A program in execution
• A job in secondary memory

Question 88

Four jobs to be executed on a single processor system arrive at time 0 in the order A, B, C, D . Their burst CPU time requirements are 4, 1, 8, 1 time units respectively. The completion time of A under round robin scheduling with time slice of one time unit is

• 10
• 4
• 8
• 9

Question 89

Which of the following need not necessarily be saved on a context switch between processes?

• General purpose registers
• Translation look-aside buffer
• Program counter
• All of the above

Question 90

With Round-Robin CPU scheduling in a time shared system

• using very large time slices (quantas) degenerates into FirstCome First served (FCFS) algorithm.
• using extremely small time slices improves performance
• using very small time slices degenerates into Last-In First-Out (LIFO) algorithm.
• using medium sized times slices leads to shortest Request time First (SRTF) algorithm