Spring 2012-2013 : Quiz-2 and Midsem Solutions




  • Quiz-2 2013 Problems and solutions
    • Quiz 2- question 1
      Consider a server which runs a script when a
      request arrives. The script runs the following pseudocode:

      do {
      useCPU(); // uses CPU for exactly 3 ms
      useIO(); //does I/O for Uniform(0,10) ms
      while (B)

      Suppose the probability of the boolean statement B being true is 0.9.
      Suppose the server is a single threaded server. An arriving request
      that finds the server busy is queued in a buffer. Assume infinite
      buffer. Arrivals are Poisson and the rate is 10 requests per
      second. What is the average response time of requests?
  • Solution




  • Quiz 2 - question 2
    • Consider the following navigation pattern of faculty on
      asc.iitb.ac.in. From the home page, they go to ``view course
      feedback'' with prob 0.4, to ``student transcripts'' with prob
      0.6. From ``course feedback'' page they go to ``home page'' with
      prob 0.9. and to ``student transcripts'' with prob 0.1. From
      ``transcripts'' they go to home page with prob 0.8 and to ``course
      feedback'' with prob 0.2. Assume these are the only 3 web-pages on
      this web-site. Out of 1000 URLs received in a particular time-period
      in steady state, how many are expected to be for ``student
  • Solution