Midterm review questions

Midterm review questions
EEE466 fall 2012
The following questions will help you review for the midterm examination. I'm not promising that
any of these exact questions will actually be on the midterm, but I do promise that if you understand
the core concepts underlying these questions and their answers, you will be well prepared
to write the examination.
Short answer questions
• Define network delay (latency, lag), jitter, and bandwidth. Give sample units for each measure.
• Node A sends a message of length x to node B across a network with effective bandwidth
w. What is the elapsed time from the first bit of the message leaving A to the last bit of the
message arriving at B?
• What are the differences between a synchronous distributed system and an asynchronous
distributed system? Which of these is more common in real systems and why?
• Is it possible to construct a reliable distributed system on top of an unreliable network channel?
If no, why not? If yes, what kinds of techniques can be used to accomplish this?
Chapter 2 questions: 2.2, 2.6, 2.11, 2.13, 2.14, 2.15, 2.17
Chapter 3 questions: 3.5, 3.7, 3.8
Chapter 4 questions: 4.2, 4.7, 4.10, 4.11, 4.18
Chapter 5 questions: 5.5, 5.6, 5.7, 5.8, 5.10, 5.15, 5.22
Design question
You are designing a client-server system that uses a request-reply protocol. The server is responsible
for storing an ordered list of strings. The stored strings may include any character except a
line feed.
Operations
• The client can ask the server to add a string to the end of the list. The server's response
must indicate success or failure of the operation.
• The client can request a string at a given list index. The server must return the string or signal
an error (e.g., if the list index is out of bounds).
• The client can request the complete list of strings. The server must return all strings in the
list, in order.
Socket-based implementation
Define a protocol specification that will allow the operations described above. See lab 3 for an
example protocol specification.
Provide a pseudo-code implementation of the server side of this system, assuming the implementation
would be in Java.
Provide a pseudo-code implementation of the client side of this system, assuming the implementation
would be in Java.
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Challenge. Provide a protocol specification for a similar system in which the stored strings may
include any characters at all. (Hint, look at the ways this problem is addressed in the HTTP protocol
and in email message formats.)
Java RMI-based implementation
Define an appropriate Java remote interface for the operations described above.
Define a Java class that appropriately implements your remote interface.
Describe the steps required to instantiate the server.
Describes the steps required to instantiate the client.
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