UNIVERSITY EXAMINATIONS: 2011/2012
SECOND YEAR EXAMINATION FOR THE BACHELOR OF
SCIENCE IN INFORMATION TECHNOLOGY
BIT 2303 DISTRIBUTED SYSTEMS
DATE: AUGUST, 2012 TIME: 2 HOURS
INSTRUCTIONS: Answer Question ONE and any other TWO
QUESTION ONE
a) Briefly explain the meaning of the following terms
i. Distributed system (2 Marks)
ii. Remote procedure call (2 Marks)
iii. Binding (2 Marks)
b) Briefly explain any three types of middle ware models. (6 Marks)
c) Describe any four characteristics of distributed system . (4 Marks)
d) State and explain two concurrency problems in distributed systems (4 Marks)
e) There are various design approaches that have been suggested for building
dependable distributed systems that exhibit a high level of stability and fault
tolerance. Describe any three of these approaches (4 Marks)
f) Briefly explain three categories of faults that can occur in a distributed system
(6 Marks)
QUESTION TWO
a) State and describe five importance of IPC (inter-process communication)
(5 Marks)
b) With the help of a clearly labeled diagram explain the elements of RPC (8 Marks)
c) Explain the following replication approaches. (7 Marks)
i. Active replication
ii. Passive replication
QUESTION THREE
a) With the aid of diagrams briefly explain three differences between loosely
coupled systems and tightly coupled systems. (6 Marks)
b) Describe any three desirable features of a message passing system. (6 Marks)
c) Describe the term dependability, explaining four requirements for dependability.
(6 Marks)
d) Explaining the meaning of the term ‘remote method invocation (RMI)’ (2 Marks)
QUESTION FOUR
a) Define mutual exclusion and describe using diagrams three algorithms for
achieving mutual exclusion (8 Marks)
b) Differentiate between shared and write locks as used in concurrency control
(4 Marks)
c) There are various strategies of handling deadlocks. Outline any four of these
strategies (8 Marks)
QUESTION FIVE
a) Describe the architectural models. (3 Marks)
b) Discuss the services provided by distributed file system (3 Marks)
c) State and explain four features of a good distributed file system (8 Marks)
d) Describe three techniques that can be employed to implement a scalable and fault
tolerant directory service (6 Marks)
