Homework 1 -- Solutions

The assignment:

• Ch. 1, exercises 1-5

The solutions:

• Ch.1, Ex. 1 - asks you to read up on iostat , use it to report disk input every 5 seconds, and to compute the utilization of each disk. -- See the iostat man page for details.
• Ch.1, Ex. 2 - - asks you to use the "Performance Tool" on Windows NT, Windows 2000, or Windows XP.
• Ch.1, Ex. 3 -

  	2 days    24 hrs   60 min   
                 *  ------ * ------ =  2880 min
                     day       hr   
  
  
  	12 + 1 + 5 + 10 + 6 = 34 min
  
                          2880 - 34 
          availability = --------- = 98.8% availability
                          2880
  
  

• Ch.1, Ex. 4 -

  	2 days    24 hrs   60 min   
                 *  ------ * ------ =  2880 min
                     day       hr   
  
  
  	15 + 2 + 3 + 8 + 6 = 34 min
  
                          2880 - 34 
           availability = --------- = 98.8% availability
                           2880
  
  

  ... but in question 3 the downtimes were during off-hours rather than prime-time and so likely had less adverse impact than the downtimes in question 4.
• Ch.1, Ex. 5 - For example, consider an HCI project in which the response time must be kept within acceptable limits for humans.