INF5040 Open Distributed Systems Lucas Provensi provensiifiuiono Swati Sharma swatisifiuiono Department of Informatics University of Oslo September 4 2014 Initial Meeting Plan ID: 592568
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Slide1
Exercises Meetings
INF5040 (Open Distributed Systems)
Lucas Provensi (provensi@ifi.uio.no)Swati Sharma (swatis@ifi.uio.no)Department of InformaticsUniversity of OsloSeptember 4, 2014Slide2
Initial Meeting Plan
2
INF5040 - Group MeetingsDateTopic04.09.14
Overview and theoretical exercises
11.09.14
Theoretical exercises
18.09.14
First programming assignment
(introduction and specification)
25.09.14
TAs will be available for helping
you with
the 1
st
assignment
02.10.14
No meeting
09.10.14
Theoretical exercises and submission of 1
st
assignment
16.10.14
Second programming assignment
(introduction and specification)
23.10.14
TAs will be available for helping
you with
the 2
nd
assignment
30.10.14
Theoretical exercises
06.11.14
Third programming assignment
(introduction and specification) and submission of 2
nd
assignment
14.11.14
TAs will be available for helping
you with
the 3
rd
assignment
20.11.14
Theoretical exercises
27.11.14
Theoretical exercises
and
submission of the 3
rd
assignmentSlide3
Theoretical exercisesBased on the lectures and taken form the text books;
Group of students;Preparation time + discussion.Programming assignmentsTutorial lectures;
Reserved days for assisting students;All assignments are mandatory!Topics covered during meeting may be part of final exam!INF5040 - Group Meetings3ExercisesSlide4
Groups of 2 to 3 studentsAll assignments must be approved to be eligible to take the final exam
For those who took this subject last fall:If you were eligible to take the exam then, i.e., you got the programming assignments approved, you do NOT have to do them again this semester.
Preferences regarding group composition (if any) should be sent to:To: provensi@ifi.uio.no and swatis@ifi.uio.noDeliveries:https://devilry.ifi.uio.no/Regarding all assignments4INF5040 - Group MeetingsSlide5
Development of a simple object-based distributed applicationWill be described
18.09.14Related to the topic discussed on the
Object-based Distributed Systems lecture (17.09.14)Technologies and Tools: Java CORBA and RMI APIs.Preliminary Deadline: 09.10.14Assignment 15INF5040 - Group MeetingsSlide6
Development of a simple application based on group communicationWill be described
16.10.14Related to the topic discussed on the Replication in Distributed Systems
lecture (15.10.14)Technologies and Tools: Spread Toolkithttp://www.spread.org/Java APIPreliminary Deadline: 06.11.14Assignment 26INF5040 - Group MeetingsSlide7
Development of a simple peer-to-peer protocolWill be described
06.11.14Related to the topic discussed on the Peer-to-peer Systems
lecture (29.10.14)Technologies and Tools: PeerSim Simulatorhttp://peersim.sourceforge.net/Preliminary Deadline: 27.11.14INF5040 - Group Meetings7Assignment 3Slide8
Introduction to Distributed Systems
Coulouris ch. 1 and TvS
ch. 1Distributed systems: components located in a network that communicates and coordinates their actions exclusively by sending messages.Consequences of distributed systemsDistribution transparencyINF5040 - Group Meetings8Previous LecturesSlide9
We defined a DS as one in which hardware and software components located at networked computers communicate and coordinate their actions only by passing messages. What are the consequences of defining a DS in this manner?
(Coulouris
ch. 1 ex. 1.1)Explain what is meant by (distribution) transparency, and give examples of different types of transparency. (Tanenbaum ch. 1 ex. 4)Why is not always a good idea to aim at implementing the highest degree of transparency possible? (Tanenbaum ch. 1 ex. 6)Describe precisely what is meant by scalable system. (Tanenbaum ch. 1 ex. 8)Consider the implementation strategies for massively multiplayer online games. In particular, what advantages do you see in adopting a single server approach for representing the state of the game? What problems can you identify and how might they be resolved?
(
Coulouris
ch
. 1 ex. 1.3)
The INFO service manages a potentially very large set of resources, each of which can be accessed by users throughout the Internet by means of a key (a string name). Discuss an approach to the design of the names of the resources that achieves the minimum loss of performance as the number or resources in the service increases. Suggest how the service can be implemented so as to avoid performance bottlenecks when the number of users becomes very large.
(
Coulouris
ch
. 1 ex. 1.10)
INF5040 - Group Meetings
9
ExercisesSlide10
System Models for Distributed Systems
Coulouris ch. 2
Physical models: capture the hardware composition of a system in terms of computers and other devices and their interconnecting network;Architecture models: defines the components of the system, the way they interact, and the way they are deployed in a network of computersFundamental models: formal description of the properties that are common to all architecture modelsinteraction models and failure modelsINF5040 - Group Meetings10Previous LecturesSlide11
How is caching useful in placement strategies? What are its disadvantages?
(Coulouris ch. 2 ex. 2.7)
What are the two variants of the interaction model in distributed systems? On what point do they differ? (Coulouris ch. 2 ex. 2.13)Consider two communication services for use in asynchronous distributed systems. In service A, messages may be lost, duplicated or delayed and checksums apply only to headers. In service B, messages may be lost, delayed or delivered too fast for the recipient to handle them, but those that are delivered arrive with the correct contents. Describe the classes of failure exhibited by each service. Classify their failures according to their effects on the properties of validity and integrity. Can service B be described as a reliable communication service? (Coulouris ch. 2 ex. 2.14)
Classes of failure:
omission(fail-stop, crash, channel), arbitrary (byzantine), timing(clock, performance)
Validity:
Any message in the outgoing message buffer is eventually delivered to the incoming message buffer
Integrity:
The message received is identical to the one sent, and no messages are delivered twice.
INF5040 - Group Meetings
11
Exercises