Code No. 4141/M OSMANIA UNIVERSITY

FACULTY OF ENGINEERING M.Tech (CSE) I-Semester Regular & PTPG (Make-up) Examination, July 2012

ADVANCED OPERATING SYSTEMS Time : 3 hours Max. Marks : 80 Note : 1. Answer Question No. 1 (Marks 20) and any four questions from the

remaining. 2. Missing data, if any, may suitably be assumed.

1. a) What are “Distributed systems”. Do the Internet and Intranet qualify as

Distributed Systems? [2] b) How is the concept of logical clocks proposed by Lamport useful to

overcome the limitations due to absence of Global Clock? [2] c) How is Ricart-Agrawala Algorithm an optimization of Lamport’s algorithm? [2] d) Why is the one phase Ho-Ramamoorthy centralized deadlock detection

algorithm better than the two phase Ho-Ramamoorthy centralized deadlock detection algorithm? [2]

e) What are livelocks? How are they different from Deadlocks? Enlist simple

solutions to overcome them. [2] f) Enlist the events of 2 Phase Commit Blocking Protocol. [2] g) Enlist the advantages and Drawbacks of Capabilities as Protection

mechanism [2] h) Why is the “Multistage interconnection network” architecture said to be

more effective as compared to cross-bar switch architectures? [2] i) What are the specific problems with the 2-Phase locking mechanism for

concurrency control? [2] j) What are the Optimistic Concurrency Control Algorithms more useful? Give

the Specific Use case Scenario. [2]

2. a) How are “Naming” and “Resource Management” addressed in the design of Distributed Systems? [8] b) Using simple example bring out the importance of Vector Clocks in Distributed Systems. [7]

3. a) Discuss any TWO Token based Mutual exclusion algorithms. Compare their performance. [8]

b) Explain any TWO algorithms for Distributed Deadlock Detection. [7]

4. a) Explain the various types of agreement problems and the relation between them. [6] b) Discuss the different approaches for – Naming, Location and Caching in Sun NFS and CODA File Systems. [9]

5. What is the need for Non Blocking Commit Protocols in ensuring resilience to Site Failures? Explain the Non Blocking Commit Protocol for Single Site Failure using its Finite state Automata. [15]

6. a) Using a Suitable Diagram explain the construction of 8 X 8 Omega multistage interconnection Network constructed from 2 X 2 switches Cross-bar Switches architecture. [8] b) How is the Multiversion Timestamp Algorithm different from the basic Timestamp algorithm for Concurrency in Database operating systems? [5]

7. Write a short notes on

a. Algorithms for implementing Distributed Shared Memory [5] b. Implementation of KERBEROS authentication system. [10]

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