PEP OS INPUT

Dirty bit is used to show the

• page with corrupted data

• wrong page in the memory

• page that is modified after being loaded into cache memory

• page that is less frequently accessed

Fence register used for

• CPU Protection

• memory protection

• file protection

• all of the above

Which of the following is a service not supported by the operating system?

• protection

• accounting

• compilation

• I/O operation

A computer system has 6 tape drives, with 'n' processes competing for them. Each process may need 3 tape drives. The maximum value of 'n' for which the system is guaranteed to be deadlock free is

In Round Robin (RR) CPU scheduling, as the time quantum is increased, the average turn around time

• increases

• decreases

• remains constant

• varies irregularly

Suppose that a process is in 'BLOCKED' state waiting for some I/O service. When the service is completed, it goes to the

• running state

• ready state

• suspended state

• terminated state

In which of the following scheduling policies does context switching never take place?

• Round-robin

• shortest job first

• Preemptive

• FCFS

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

A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units then, deadlock

• can never occur

• may occur

• has to occur

• none of the above

A process refers to 5 pages, A, B, C, D and E in the order - A; B; C; D; A; B; E; A; B; C; D; E. If the page replacement algorithm is FIFO, the number of page transfers with an empty internal store of 3 frames is

• 7

• 8

• 9

• 10