Operating System CT-1

_________________are programs that designed to help users to be more productive with their personal tasks.

• Software
• System Software
• Application software
• Utility program

Select the most efficient scheduling algorithm:

• First-Come-First-Serve (FCFS)

• Shortest Job First (SJF)

• Priority with preemption

• Round Robin (RR)

For a set of CPU-bound processes with unequal burst lengths arrived at same time in the ready queue, which scheduling algorithm minimizes the average waiting time in the ready queue?

• Shortest Remaining Time First

• Round Robin with a time quantum less than the shortest CPU burst

• Uniform random

• Highest priority first with priority proportional to CPU burst length

The maximum number of processes in the Ready state for a computer system with n CPUs is:

• n

• n^2

• 2n

• Independent of n

Which scheduling scheme yields the lowest average turnaround time for the given processes?

Process    Arrival Time    Processing Time

  A              0                            3

  B              1                            6

  C              4                            4

  D              6                            2

• FCFS

• Non-preemptive SJF

• Shortest Remaining Time First (SRTF)

• Round Robin with a time quantum of 2

Which statement about Shortest Job First Scheduling (SJF) is True?

• It minimizes average waiting time.

• It can cause starvation.

• Both S1 and S2 are correct.

• Neither S1 nor S2 is correct.

Consider three processes Po, p1, and p2 with burst times 2, 4, and 8 units. Arrival time is 0 for all the processes. Using Longest Remaining Time First (LRTF), the average turnaround time is:

• 13 units

• 14 units

• 15 units

• 16 units

Given processes P1, P2, and P3, and their arrival times and time units required, identify the correct completion order for FCFS and RR2 (Round Robin with a time quantum of 2 units):

Process           Arrival time         Time Units Required

   P1                0                                  5

   P2                1                                  7

   P3                3                                  4

• FCFS: P1, P2, P3

  RR2: P1, P2, P3
  

• FCFS: P1, P3, P2

  RR2: P1, P3, P2

• FCFS: P1, P2, P3

  RR2: P1, P3, P2

• FCFS: P1, P3, P2

  RR2: P1, P2, P3

Which of the following statements are true?

I. Shortest Remaining Time First scheduling may cause starvation.
II. Preemptive scheduling may cause starvation.
III. Round Robin is better than FCFS in terms of response time.

• I only

• I and III only

• II and III only

• I, II, and III

When an interrupt occurs, the operating system:

• Ignores the interrupt

• Always changes the state of the interrupted process to 'blocked' and schedules another process

• Always resumes execution of the interrupted process after processing the interrupt

• May change the state of the interrupted process to 'blocked' and schedule another process