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DSA612S - DISTRIBUTED SYSTEMS AND APPLICATIONS - 2ND OPP - JAN 2024 |
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n Am I BI A un IVER s ITY
OF SCIEnCE Ano TECHnOLOGY
FACULTY OF COMPUTING AND INFORMATICS
DEPARTMENTOF SOFTWAREENGINEERING
QUALIFICATION:BACHELOROF COMPUTERSCIENCE
QUALIFICATIONCODE:07BCMS, 07BAIT
COURSE:DISTRIBUTEDSYSTEMSAND APPLICATIONS
DATE:JAN 2024
DURATION: 3 HRS
LEVEL:6
COURSECODE: DSA612S
PAPER:THEORY
MARKS: 100
SUPPLEMENTARY/ SECONDOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER(S)
Ms. NDINELAGONASHANDI
MODERATOR:
PROFJOSEQUENUM
THIS QUESTIONPAPERCONSISTSOF 3 PAGES
(Including this front page)
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INSTRUCTIONS TO STUDENTS:
1. Read all the questions, passages,scenarios, etc., carefully before answering.
2. Answer all the questions.
3. Number each answer clearly and correctly.
4. Write neatly and legibly.
5. Making use of any crib notes may lead to disqualification and disciplinary action.
6. Use the allocated marks as a guideline when answering questions.
7. Looking at other students' work is strictly prohibited.
8. This paper consists of four (4) pages including the cover page.
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SECTION A: 68 marks
• Answer all the questions in the provided booklet.
• The section consists of 11 questions.
1. List and explain the key characteristics of Distributed Systems? [6 marks]
2. List and explain the three techniques used in failure handling in Distributed Systems. [6
Marks]
3. Compare and contrast replication and partitioning in distributed systems, discussing their
purposes, benefits, and challenges. [8 marks]
4. List and describe the two common caching strategies (cache update policy) used in DFS.[6
marks]
5. Differentiate between subscription flooding and filter-based event routing models in a
publish-subscribe system. [6 marks]
6. Explain and describe Remote Procedure call (RPC).[5 marks]
7. List and explain the three Call semantics in Remote Procedure call (RPC).[6marks]
8. Discussthe functionality and significance of the RPC(Remote Procedure Call) Interface
Definition Language (IDL) like protocol buffer and compiler in facilitating distributed system
communications. [6 marks]
9. Present the architecture of a Google File System (GFS)[8 marks]
10. Discuss GFS high availability [3 marks]
11. Explain how a client read operation is performed in GFS(Google file Systems).[8 marks]
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SECTION B: 32 marks
• Answer all the questions in the provided booklet.
• The section consists of 4 questions.
1.
Discuss the key components and their roles in the Berkeley Algorithm, including
the master timekeeper and slave nodes. How do they cooperate to adjust system
clocks? [6 marks]
2.
Briefly explain the difference between logical and physical clocks. Why it is difficult
to synchronize physical clock? [2+3]
3.
Outline three techniques for synchronizing physical clocks. [12 marks]
4.
At 10:27:540 (hr, min, 1/100 sec.), server B requests time from the time-server A.
At 10:27:610, server B receives a reply from timeserver A with the timestamp of
10:27:375.
a) By using Cristian's algorithm, to what value should the time be set on the server
B clock? [5 marks]
b) Find out the drift of B's clock with respect to the time-server A's clock (assume
there is no processing time at the time-server for time service). [2 marks]
c) Is B's clock going too fast or too slow? If the answer is yes, by how much is the
clock going too fast or too slow? [2 marks]
**************************** Endof the Paper***********************************
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