CS 3733 Operating Systems, Spring 2007 Assignment 4 Comments

This assignment was graded on a basis of 30 points.

• In the C code, rand must be protected also.
  This is not the case in the Java code.
• In part 2, don't print the results if a mutex error occurs.
• There is adifference between:
  public synchonized void addToSum(double c);
  and public static synchonized void addToSum(double c);
  
• Suppose Part3Tester has a synchronized run method.
  What is the difference in Part3Tester between:
      Part3Tester extends thread: new Part3Tester
      Part3Tester implements Runable: new Thread(this)
• If you synchronize the run method:
  either it does nothing (if each thread uses its own object)
  or it makes the code completely serial.
• What is the difference between:
      pthread_mutex_lock(&lock);
      sum += sin(x) * sin(x);
      pthread_mutex_unlock(&lock);
  and
      w = sin(x) * sin(x);
      pthread_mutex_lock(&lock);
      sum += w;
      pthread_mutex_unlock(&lock);