UNIVERSITY EXAMINATIONS: 2020/2021
EXAMINATION FOR THE DEGREES OF BACHELOR OF SCIENCE IN
INFORMATION TECHNOLOGY / BUSINESS I.T/
SOFTWARE DEVELOPMENT
BIT 2303/BBIT 305/BSD 2308: DISTRIBUTED SYSTEMS
FULLTIME/ PART TIME/DISTANCE LEARNING
ORDINARY EXAMINATION
DATE: DECEMBER, 2021 TIME: 2 HOURS
INSTRUCTIONS: Question ONE IS COMPULSORY, Choose TWO OTHER Questions
QUESTION ONE (20 marks) Compulsory
a) Describe the six components that make up a Distributed System. (6 Marks)
b) Differentiate between local procedure call (lpc) and a remote procedure call (rpc)
(4 Marks)
c) Differentiate between Network Operating Systems (NOS) and Distributed Operating
System (DOS). (4 Marks)
d) Differentiate between the following:
i). Blocking and non-blocking semantics (2 Marks)
ii). Differentiate between RPC and RMI (2 Marks)
iii). Multiprocessor and multicomputer (2 Marks)
QUESTION TW0 (15 marks)
a) Define the term “message” in the context of Inter-Process Communication (IPC).
(2 Marks)
b) Discuss four advantages of replication in a Distributed System. (4 Marks)
c) Describe the basic file replication architectural model (5 Marks)
d) Discuss two mechanisms of improving fault tolerance in Distributed Systems (4 Marks)
QESTION THREE (15 marks)
a) Differentiate between a process and a program (2 Marks)
b) Define the term transparency and explain its importance in the design of DOS. (3 Marks)
c) Briefly explain the mechanisms for implementing Remote IPC. (6 Marks)
d) Describe the following elements of the RPC model highlighting their functionalities.
(4 Marks)
i). Client stub
ii). Server stub
iii). Client RPCRuntime
iv). Server RPCRuntime
QUESTION FOUR (15 marks)
a) State and explain four attacks on Distributed Systems (4 Marks)
b) Describe five security requirements of DOS (5 Marks)
c) Discuss three classes of faults common in Distributed Systems (6 Marks)
