B4C062 Pages: 3

PART D
Answer any two full questions. 9 Marks for each question.

12. a. A semaphore ensures mutual exclusion even if it is built of sequence of instructions.

Justify. (3)

b. Consider a banking system that maintains an account balance with two functions:
deposit (amount) and withdraw (amount). These two functions are passed the
amount that is to be deposited or withdrawn from the bank account balance.
Assume that a husband and wife share a bank account. Concurrently, the husband
calls the withdraw() function and the wife calls deposit(). Describe how a race
condition is possible and whatmight be done to prevent the race condition from
occurring. (6)

13. Draw the Gantt chart and find the average waiting time for the following algorithms:

i) FCFS ii) Shortest Remaining Time First 111) Priority Scheduling (9)

Process No. Arrival Time Burst Time Priority

(msec) (msec)

14. a. What are the conditions which may lead to deadlock? (4)
b. What are the strategies to recover from deadlock? (5)
PARTE

Answer any four full questions. 10 Marks for each question.

15. a. What is the function of a translation look-aside buffer (TLB). (5)
b. What is the structure and purpose of an inverted page table? (5)
16. a. Why are page sizes always powers of 2? (4) b. With

the help of a diagram explain the steps involved in handling a page fault. (6)

17. a. Differentiate between internal and external fragmentation. (4)

Page 2 of 3