OS CPU Scheduling

Question 51

Which of the following statements is not true for Multi Level Feedback Queue processor scheduling algorithm?

• Queues have different priorities
• Each queue may have different scheduling algorithm
• Processes are permanently assigned to a queue
• This algorithm can be configured to match a specific system under design

Question 52

Consider the following justifications for commonly using the two-level CPU scheduling: I. It is used when memory is too small to hold all the ready processes. II. Because its performance is same as that of the FIFO. III. Because it facilitates putting some set of processes into memory and a choice is made from that. IV. Because it does not allow to adjust the set of in-core processes. Which of the following is true ?

• I, III and IV
• I and II
• III and IV
• I and III

Question 53

In a multi-user operating system, 30 requests are made to use a particular resource per hour, on an average. The probability that no requests are made in 40 minutes, when arrival pattern is a poisson distribution, is _________.

• e^-15

• 1 - e^-15

• 1 - e^-20

• e^-20

Question 54

Consider the following three processes with the arrival time and CPU burst time given in milliseconds:

Process       Arrival Time        Burst Time
P1     0                  7
P2     1                  4
P3     2                  8

The Gantt Chart for preemptive SJF scheduling algorithm is _________.

• 
• 
• 
• 

Question 55

In which of the following scheduling criteria, context switching will never take place ?

• ROUND ROBIN
• Preemptive SJF
• Non-preemptive SJF
• Preemptive priority

Question 56

Consider the following set of processes, assumed to have arrived at time 0. Consider the CPU scheduling algorithms Shortest Job First (SJF) and Round Robin (RR). For RR, assume that the processes are scheduled in the order P₁, P₂, P₃, P₄. If the time quantum for RR is 4 ms, then the absolute value of the difference between the average turnaround times (in ms) of SJF and RR (round off to 2 decimal places) is _________ . Note - This question was Numerical Type.

• 5.0
• 5.25
• 5.50
• 5.75