a) In a multiprogramming and time sharing environment several users share system simultaneously. This situation can result in various security problems.
i) What are two such problems?
ii) Can we ensure the same degree of security in a time shared machine as we have in a dedicated machine? Explain your answer? (Unit 1)

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

a) Why do some systems keep track of the type of file, while others leave it to the user or simply do not implement multiple file types? Which system is better? (Unit 2)

b) Consider a file system on a disk that has both logical and physical block sizes of 512 bytes. Assume that the information about each file is already in memory. For each of three allocation strategy (continuous, linked and indexed), how is the logical to physical address mapping accomplished in this system? (for indexed allocation assume that a file is always less than 512 blocks long). (Unit 2)

a) What resources are used when a thread is created? How do they differ from those when a process is created? (Unit 3)

b) Consider the following segment table:

What are the physical addresses for the following logical address?
i) 0430
ii) 110
iii) 2500
iv) 3400 (Unit 3)

a) What is the meaning of the term busy waiting? What another kind of waiting are there in an operating system? Can busy waiting be avoided altogether? Explain your answer. (Unit 4)

b) Can a system detect that some of its processes are starving? If your answer "Yes" explain how it can? If your answer no, explain how the system can deal with the starvation problem. (Unit 3)

a) What are the advantages and disadvantages of making the computer network transparent to the user? (Unit 5)

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

a) What are the benefits of mapping objects into virtual memory? Explain in detail. (Unit 3)

b) What are the benefits of a DFS when compared to a file system in a centralized system? (Unit 5)

a) Why Semaphore is important in OS? Explain Binary and counting semaphores with suitable example. (Unit 4)

b) What is Overlay? How to dynamic linking and loading perform in memory management? (Unit 3)

Write short notes on following (any two):

a) Synchronization (Unit 4)

b) Paging (Unit 3)

c) System Calls (Unit 1)