SEMESTER 2

DUBLIN CITY UNIVERSITY
SEMESTER 2 EXAMINATIONS 2013/2014
MODULE:
PROGRAMME(S):
EC
ECSA
ECSAO
YEAR OF STUDY:
CA485/A – Cloud Computing
BSc in Enterprise Computing
Study Abroad (Engineering & Computing)
Study Abroad (Engineering & Computing)
4,O,X
EXAMINERS:
Dr Kevin Casey
Dr. Declan O'Sullivan
(Ext:5639)
TIME ALLOWED:
2 Hours
INSTRUCTIONS:
Answer 3 questions. All questions carry equal marks.
PLEASE DO NOT TURN OVER THIS PAGE UNTIL YOU ARE INSTRUCTED TO DO SO
The use of programmable or text storing calculators is expressly forbidden.
Please note that where a candidate answers more than the required number of questions, the
examiner will mark all questions attempted and then select the highest scoring ones.
Requirements for this paper (Please mark (X) as appropriate)
Log Tables
Graph Paper
Dictionaries
Statistical Tables
CA485/A – Cloud Computing
Semester 2 Examinations 2013/2014
Thermodynamic Tables
Actuarial Tables
MCQ Only – Do not publish
Attached Answer Sheet
Page 1 of 4
QUESTION 1
[TOTAL MARKS: 33]
Q 1(a)
[9 Marks]
Explain what is meant by SaaS, PaaS and IaaS. Give an example of each.
Q 1(b)
[6 Marks]
In the context of cloud computing what is meant by an earthbound application?
Ensure you give an example.
Q 1(c)
[12 Marks]
Explain, with the aid of a diagram, the terms over-provisioning and
under-provisioning. Identify the consequences to a company in each scenario.
Q 1(d)
[6 Marks]
Lock-in (both data lock-in and application lock-in) is a concern that many potential
cloud clients have. Explain what lock-in is, and how cloud vendors might address
these concerns so that prospective clients are no longer worried about it.
[End of Question 1]
QUESTION 2
[TOTAL MARKS: 33]
Q 2(a)
Outline the differences between grid computing and cloud computing.
[9 Marks]
Q 2(b)
Explain the role of virtualisation in cloud computing.
[6 Marks]
Q 2(c)
[8 Marks]
What is multi-tenancy? Distinguish between simple multi-tenancy and fine grained
multi-tenancy. In general, why does fine-grained multi-tenancy lead to better
resource utilisation than simple multi-tenancy.
Q 2(d)
[10 Marks]
Compare IaaS and PaaS in terms of cost vs flexibility. Ensure you discuss ease of
scaling.
[End of Question 2]
CA485/A – Cloud Computing
Semester 2 Examinations 2013/2014
Page 2 of 4
QUESTION 3
[TOTAL MARKS: 33]
Q 3(a)
[6 Marks]
Explain the purpose of the Oauth protocol. Illustrate your explanation with an
example of where Oauth would be useful. Why is Oauth better than basic
authentication?
Q 3(b)
Outline how the Oauth protocol operates.
[12 Marks]
Q 3(c)
[6 Marks]
Privacy laws vary around the world and may impact upon operation in or migration to
the cloud. Identify at least two such privacy laws you are aware of, including the
country (or countries) where this law applies.
Q 3(d)
[9 Marks]
What is Federated Authentication? How does SAML allow for Federated
Authentication? What is the main difference between SAML and OpenID?
[End of Question 3]
QUESTION 4
[TOTAL MARKS: 33]
Q 4(a)
[6 Marks]
One of the significant accounting changes as a company migrates to the cloud is the
transition from CAPEX to OPEX. Explain what these two terms mean and why the
change from one to the other occurs as a company migrates its operations to the
cloud.
Q 4(b)
[12 Marks]
What is a hybrid cloud? In this context, explain what cloud bursting is. Why is
compatibility a serious issue when using a hybrid cloud? What is a regional cloud
and when is one useful?
Q 4(c)
[9 Marks]
Studies have shown large variation in the scaling latency for different cloud vendors.
Identify the main economic consequence of a large scaling latency from a customer's
point of view. Which tends to suffer from larger scaling latencies, IaaS or PaaS?
Explain your answer.
Q 4(d)
[6 Marks]
The CloudCmp research tool compares computational performance for many
different cloud vendors' offerings. In general, the researchers found that the smallest
VM instance size was the most cost effective. In your opinion, is this conclusion
entirely fair? Justify your answer.
[End of Question 4]
CA485/A – Cloud Computing
Semester 2 Examinations 2013/2014
Page 3 of 4
APPENDICES
[END OF APPENDICES]
[END OF EXAM]
CA485/A – Cloud Computing
Semester 2 Examinations 2013/2014
Page 4 of 4