Sample Quiz 1 Questions
For the quiz, you may bring the class notes, the papers that were
assigned, your writing assignments, the presentation you prepared, and
the text book (assuming it arrives...)
In Ethernet: Distributed Packet Switching for Local Computer
Networks, the author describes a link-layer protocol used to send
packets around a local computer network. The physical medium for this
network is a coax cable (like the kind you get cable TV from). The
communicating computers are connected to the same cable at the same
Q1: When two computers try to inject a message into the cable
at the same time, the messages collide. What does the Ethernet
Protocol say the computers should do to try to get their respective
Q2: You are getting bad performance on your local
Ethernet network. A little investigation shows that your nemesis, Net
Vader, is watching lots of videos - and he's sharing the same Ethernet
cable as you! To retaliate, you decide to create a rogue Ethernet
card that gives preference to your packets over NV's during a
collision. What will your card do different when a collision is
detected? Be concrete.
Q3: The paper describes the use of a packet
transceiver for connecting two coax cables into what looks like a
single cable. Describe how such a system should handle
collisions. (Hint: Consider two cases: A collision on one cable but
not the other, a collision on both cables at the same time)
Q4: Do you think the tranceiver setup described in Q3 would
scale out to hundreds of cable segments connected together? Briefly
describe why you think it would or would not.
In Disk System Architectures for High-Performance Computing,
you learned about the 5 RAID levels. Suppose you are configuring a
service like photo.net with three RAIDs. In the questions below, make
sure you explain your choice and list the key assumptions you used to
choose the RAID you think is most appropriate.
Q5: You must first configure a RAID for photo.net's swap file.
Given your knowledge of virtual memory, what RAID level is most
appropriate? (assume photo.net has enough main memory to prevent
Q6 Now, you must configure a RAID for photo.net's JPG files.
These are the photo files that Philip or users upload. Assume there
are 50,000 JPG files on photo.net and that 250 jpg files are uploaded
each day. Also assume that photo.net must serve several requests for
distinct JPG files at any one time, all day long. What RAID level is
Q7 Finally, you must configure the RAID for the Oracle database
files. Like the JPG case, there are many more reads than writes.
Unlike the JPG case, Oracle uses only a handful of very large files.
Most of the time, the same file is being read or written. What RAID
level is most appropriate?