Mid Model Viva

Job pool is available in ---

• Main memory

• cache memory

• Secondary memory

• CPU

Which scheduler is choosing process from ready queue and put it in CPU

• Long term scheduler

• short term scheduler

• mid term scheduler

• task scheduler

Which of the following is NOT a valid deadlock prevention scheme?

• Number the resources uniquely and never request a lower numbered resource than the last one requested

• Request and all required resources be allocated before execution.

• Release all resources before requesting a new resource

• Never request a resource after releasing any resource

Let m[0]…m[4] be mutexes (binary semaphores) and P[0] …. P[4] be processes. Suppose each process P[i] executes the following:

wait (m[i]);

wait(m[(i+1) mod 4]);

------

release (m[i]);

release (m[(i+1)mod 4]);

This could cause ---

• Thrashing

• Starvation, but not deadlock

• Deadlock

• None of the above

Given that at a particular time of computation, the value of a counting semaphore is 7, then if 20 P operations and 15 V operations were completed on this semaphore, what is the resulting value of the semaphore?

(a) 12

(b) 2

(c) 7

(d) 42

• 12

• 7

• 2

• 42

What is dirty bit used to show?

• Page with corrupted data

• Wrong page

• Page that is modified after being loaded into cache memory

• Page with low frequency occurrence

When a process executes the code

fork();

fork();

fork();

What are the total number of child processes created?

• 4

• 3

• 8

• 7

A critical section is a program segment

• which should run in a certain specified amount of time.

• which avoids deadlocks.

• where shared resources are accessed.

• which must be enclosed by a pair of semaphore operations, P and V.

A computer system has 6 tape drives, with n process 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:

• 2

• 4

• 3

• 1

Which page replacement policy sometimes leads to more page faults when size of memory is increased?

• Optimal

• LRU

• FIFO

• LIFO