a) What are the five major activities of an operating system in regards to memory management? (Unit 3)

b) List the functions of OS. How operating system perform management task in a system? (Unit 1)

a) Give an example of an application in which data in a file should be accessed in following order.
i) Sequentially
ii) Randomly (Unit 2)

b) Suppose that a disk drive has 5000 cylinders numbered 0 to 4999. The drive is currently serving a request at cylinder 143 and the previous request was at cylinder 125. The queue of pending request in FIFO order is -
86, 1470, 913, 1774, 948, 1509, 1022, 1750, 750, 750, 750, 750, 750, 130.
Starting from current head position, what is the total distance that the disk arm moves to satisfy all pending request for each of following.
i) SSTF
ii) SCAN
iii) LOOK (Unit 2)

a) Consider a variant of the RR algorithm where the entries in the ready queue are pointers to the PCB
i) What would be the effect of putting two pointers to the same process in the ready queue.
ii) What would be the major advantages and drawback of this scheme. (Unit 3)

b) How many page faults occur for an optimal page replacement strategy for the following reference string for four page frames.
1 2 3 4 5 3 4 1 6 7 8 7 8 9 7 8 9 5 4 5 4 2 (Unit 3)

a) Suppose a process P wants to wait for two messages, one from mailbox A and one from mailbox B. What sequence of send and receive should it execute. (Unit 4)

b) Why might a system use interrupt driven I/O to manage a single serial port but polling I/O to manage a front end processor, such as a terminal concentrator. (Unit 4)

a) What aspects of a distributed system would you select for a system running on a totally reliable network. (Unit 5)

b) To build robust distributed systems, you must know what kinds of failures can occur. List three possible types of failures in a distributed system. (Unit 5)

a) Define a semaphore for dining philosopher's problem. (Unit 4)

b) Describe a method for process migration across different architecture running.
i) The same operating system
ii) Different operating system (Unit 5)

a) Explain concurrency controls? What are the differences between real and virtual concurrency? (Unit 4)

b) How process is differing from program? Describe process transition diagram in detail. (Unit 3)

Write short notes on following. (any two)

a) Deadlock prevention and avoidance (Unit 4)

b) Kernel architecture in Unix (Unit 5)

c) System calls (Unit 1)