CMT202
CARDIFF UNIVERSITY
Sample Exam
Academic Year: 2022-2023
Module Code: CMT202
Class Test Title: Distributed and Cloud Computing
Duration: Two and a half hours
Please read the following information carefully:
Structure of class test:
There are THREE pages.
There are FOUR questions in total.
There are no appendices.
The maximum mark for the class test is 60 marks and the mark obtainable for a question or part of a
question is shown in brackets alongside the question.
Instructions for completing the class test:
Answer THREE questions.
Important note: if you answer more than the number of questions instructed, then answers will be
marked in the order they appear only until the above instruction is met. Extra answers will be ignored.
Clearly cancel any answers not intended for marking.
1 Please Turn Over
1 (a) Describe the difference between a distributed and a non-distributed computer system. [5]
(b) Define what is meant by the term process replication in a distributed system. Describe a real
world example of process replication in a distributed system. [5]
(c) A timing failure is a particular type of failure which can happen in a distributed system. Provide a
real world example of such a failure and in doing so explain the consequences of such a failure.
[5]
(d) Describe two potential disadvantages of using cloud computing? [5]
2 (a) Provide an example of a distributed system which uses a client-server architecture. [5]
(b) Provide an example of a distributed system which uses a peer-to-peer (P2P) architecture. [5]
(c) RPC (Remote Procedure Call) provides location transparency. Justify this statement.
[5]
(d) Describe one potential problem which may occur when using the token-ring algorithm to provide
mutual exclusion access to a shared resource. [5]
3 (a) Describe a useful benefit of using queues as the data structure to store messages in MOM
(Message Oriented Middleware). [5]
(b) Explain how virtualization can be used to help migrate code in heterogeneous systems. [5]
(c) Provide a real-world example of a transient communication service. [5]
(d) Provide pseudocode for map and reduce functions in a MapReduce computer program which,
given a set of documents, counts the number of occurrences of each word.
[5]
4 (a) Assume a server has a procedure which a client wishes to call but RPC cannot be used for some
reason. Describe an alternative solution the client could use to call the procedure in question. [5]
(b) Describe why mobile code poses a security threat. [5]
(c) Describe a context or situation in which it is not possible to use a GPS receiver to determine the
location of a computer. [5]
(d) Estimating location using a GPS receiver is subject to several factors that influence the accuracy
of the estimation in question. Describe two such factors. [5]