Download AKTU B-Tech 7th Sem 2015-2016 ECS 701 Distributed Systems Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 7th Semester (Seventh Semester) 2015-2016 ECS 701 Distributed Systems Question Paper

Printed Pages: 4 I37 ECS-701
(F allowing Paper ID ?nd Roll No. to be filled in your
Answer Book)
R011 No.
B.T?ch.
(SEM. VII) THEORY EXAMINATION, 2015-16
DISTRIBUTED SYSTEMS
[Time:3 hours] [MaximumMarksleO]
SECTION-A "
Note : Attempta_11 questions. All question carry equal marks.
Write answer of each part in short. (10 X2=20)
' Q1. (a) How shadow Versions are helpful in recovery?
(b) Differentiate between local and global check
. pointing; ?
(c) Discuss the role of ?le system in distributed
system.
((1) What is consistent cut & inconsistent cut?
(e) Explain desirable features of a good message
passing system.
(f) What is termination detection problem?
ECS-701 , (1) P.T.O.

(g) What are distributed shared memory design issues?
(h) Where distributed transactions can be used?
(i) Why clocks need to be' synchronized?
(j) List the goals of distributed systems?
SECTION-B
Note: Attempt any m questions. All question carry equal
Q2.
CB-
05.
marks.? (5x10=50)
Discuss at least three main issues that are-relevant to
the understanding of distributed fault tolerance system.
Explain how that make it important.
Explain how the two phase commit protocol for nested
transaction ensures that if the top ,level transactions
commit, all the right descendents are cOmmitted or
aborted?
What are Lamport logical clocks? List the importand
conditions' to be satis?ed by Lambort logical clocks.
If A and B represent two distinct events in a process
.and if A->B then C(A) < C(B) but vica-versa not true.
J ustify the statement.
_ Caching is one of the techniques used to improve '
access to naming data. What are the bene?ts of caching
and what assumptions must hold for it to be useful?
(2) ECS-70l
Q6.
Q7.
Q8.
Q9.
What do you mean by backward and forward error
recovery? Discuss recovery in concurrent systems in
detail.
What are distributed systems? What are signi?cant
advantages, applications & limitations of distributed
systems? Explain.with examples, what could be the
impactofabsence of global clock & shared memory.
I .
What are agreement protocol? Discuss the general
system model where agreement protocols are used.
Give the applications 'of agreement protocols.
Discuss the optimistic methods for distributed
concurrency control. What are the different validation
conditions for optimistic concurrency control?
Explain.
SECTION-C
Note: Attempt any tlo questionsfrom this section.
Q10.
(2x15=3oy
How distributed mutual exclusion is different of mutual
exclusion in single-computer_system? Classify mutual
exclusion algorithms? How the performance of mutual
exclusion algorithms is measured? Compare the
performance of token and non-token based algorithms?
How the Ricart-Agraw ala al gorithm optimize the
lamport?s algorithm.
9 ? (3) I P.T.O.

Q11.
Q12.
What do you mean by casual ordering of messages? If
process P sends two message m1 & m2 ti to another
process Q, what problems may arise if the two
messages are not received by recipient Q, in the order
they were sent by process P.?Develop an algorithm
which guarantees the casual ordering of message in
distributed system. '
Discuss following terms in context of distributed
systems:
(a) 2PL & Strict 2PL
_ (b) Timestamp ordering for transziction management
(c) Highly available services
(d) Wait for graph with the example of distributed
transaction.
(e) chuentialConsistency.
(4) > ' ECS-701 / 13400