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Some sample questions

Quiz 3, Friday, 24 February, will include some questions with a certain
amount of mathematics in them.   (Other questions will not involve
much/any math.)  We've talked about and worked out in class questions
involving math on several occasions since the start of the quarter
(look at the graph in the first readings), including last Friday.

In response to student requests for sample "math" problems, the following
collection is offered.  Select from them freely, but there is NO REASON
TO DO THEM ALL.  Many, Many are the same as others with slight changes.
Phrases like "Answer all the above assuming ..." are not intended literally.

Optional question:  How many questions are given below?

-- sdf
Stephen Franklin
ICS 1C Instructor

KB = Kilobytes; KB/sec = Kilobytes per second;

Question A0:
A web browser contacts a server and retrieves a 6KB document which includes
5 in-line images totaling 30KB (3 are less than 2KB, one is 8KB and one is
20KB).  Assuming that each document and each in-line image requires 2
seconds to request and that the server sends data to the client at 10KB/sec
with a minimum transmission time of 0.5 seconds, how long does it take to
retrieve and display the document including all the in-line images?

A1: In question A0, change the length of the original document to 26KB.
A2: In question A0, change "2 seconds" to "3 seconds"
A3: In question A0, double the transmission speed.
A4: In question A0, make the minimum transmission time 2 seconds.
A5: In question A0, change "5 in-line images totalling 30KB (...)"
    to "15 in-line images each 2KB in size"

Question B0:
Modify question A to assume 
  (1) all images are stored compressed by a factor of 4,
  (2) server decompression takes a 1 second per 4KB of compressed
      image or fraction thereof (that is, decompressing any image
      larger than 4KB and no larger than 8KB takes 2 seconds), and 
  (3) decompression by the browser is 3 times slower than on the server.
Answer A0-A5 assuming the server does all decompression.
Answer A0-A5 assuming the browser does all decompression.
Answer A0-A5 assuming that each decompression is done in such a way as
  to complete the display process in the minimum amount of time.
Answer all the above, assuming that the compression factor is 10.
Answer all the above assuming that browser decompression is 5 times
  slower than server decompression.

==================================================================
The following questions refer to the graphs at
  http://www.ics.uci.edu/~ics1c/doc/logbytepack.gif
See also http://www.ics.uci.edu/~ics1c/doc/netstats.html

Notation:  "[apples/oranges/pears]" means to choose one of the
  alternatives: apples, oranges, pears

For each service/protocol and each month, you should be able to tell
how many bytes and how many packets, were reported for that month.

What was the approximate average number of bytes in a packet in (pick a
month) for [ftp/gopher/www]?

Let X, Y, Z be 3 distinct choices from the list: ftp, gopher, www, Z39.50.
In what months (if any) did the SUM of X and Y traffic (measured
in [bytes/packets]) exceed Z traffic?

Let X and Y be 2 distinct choices from the list: ftp, gopher, www, Z39.50.
  In what months (if any) was X traffic 3 times that of Y?
Now replace "3" by any other positive number.

In what months (if any) was the number of [ftp/gopher/www] packets at
least 1 [million/billion] more than in the previous month?