UNIV4VINU | ENGINEERING ACHIEVERS

DISTRIBUTED SYSTEMS-April/May-2008

PART A – (10 x 2 = 20 marks)

1. What are thin clients? How are they implemented?

2. What are omission failures?

3. What is a persistent object?

4. Define: Name Spaces and Naming Domains.

5. What do you mean by clock skew and clock drift?

6. What is a starvation state?

7. What are Nested Transactions?

8. Distinguish between the logging techniques and the shadow versions technique.

9. What is a digital signature?

10. Define: Replication.

PART B – (5 x 16 = 80 marks)

11. (a) (i) Discuss the various challenges in the design of distributed systems. [Marks 8](ii) Describe

the types of architectural models. [Marks 8]

Or

(b) (i) Explain the two different approaches to external data representation and marshalling. [Marks

8]

(ii) Explain the request-reply protocol in client – server communication. [Marks 8]

12. (a) (i) With a neat sketch describe the Distributed Object Model. [Marks 8]

(ii) Discuss the design issues for RMI [Marks 8]

Or

(b) Discuss in detail the File Service Architecture. [Marks 16]

13. (a) (i) Describe the internal and external synchronization of Physical clocks. [Marks 8]

(ii) Explain the Chandy and Lamport’s snapshot algorithm for determining the global states of

distributed systems. [Marks 8]

Or

(b) (i) Define the distributed mutual exclusion problem. [Marks 4]

(ii) Describe any one algorithm for distributed mutual exclusion. [Marks 12]

14. (a) (i) Using the ‘lost update’ problem explain about concurrency control. [Marks 8]

(ii) Discuss about the various methods for recoverability from aborts. [Marks 8]

Or

(b) (i) Explain the two phase commit protocol with neat sketch. [Marks 8](ii) Discuss the methods of

transaction recovery. [Marks 8]

15. (a) Explain the various techniques and mechanisms for securing distributed systems and

applications. [Marks 16]

Or

(b) With a neat sketch, describe the Gossip architecture. [Marks 16]