Reg No.:_ Name:

Max. Marks: 100

10

G1079 Pages: 2

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(S), MAY 2019

Course Code: CS407
Course Name: DISTRIBUTED COMPUTING

PARTA
Answer all questions, each carries 4 marks.

List and explain the three generations of distributed systems.

Differentiate between synchronous and asynchronous Inter Process
Communication.

What are the different placement strategies followed in a distributed system.
Explain briefly any four transparency requirement for distributed file system.
Differentiate between forward and backward validation. Which is better?
Mention the factors that evaluate the performance of communication channels.

How does Andrew File System ensure that the cached copies of files are up-to-
date?

With an example describe the working of ring based election algorithm.
Why are hierarchic locks required? Explain with example.

In Maekawa’s Voting algorithm for all ij=1,2,.....N ; Pi belongs to set Vi, what
problems can arise if the sets Vi are chosen so that Vi A Vj = ¢.
PART B

Answer any two full questions, each carries 9 marks.
How can the security of a distributed system be achieved? How can processes
and their interactions be secured?
Distinguish between mini computer model and work station model.
Consider two communication services for use in asynchronous distributed
system. In service A, messages may be lost, duplicated or delayed and check
sums apply only to headers. In service B, messages may be lost, delayed or
delivered too fast for the recipient to handle them, but those that are delivered

arrive with the correct contents.

Page lof 2

Duration: 3 Hours

Marks
(4)
(4)

(4)
(4)
(4)
(4)
(4)

(4)
(4)
(4)

(5)

(4)
(9)