README_HW1

ReadMe for HW1

Exercise 1:
	For the CyclicBarrier class, only Semaphores were used as a synchronization primitive. 
	This class has three semaphores: One for blocking access to changing variables, 
	another as a method for forcing threads to wait at the barrier, and one which blocks when the last thread has reached the barrier.
	
	The reset method was implemented in a way which triggers a BrokenBarrier exception
	in any threads following the thread which called barrier.reset(). 
	Note: any threads already waiting will be released and also throw a BrokenBarrier exception.
	
	-CB:  Will run the original demo function provided in the skeleton
	
	-CB1: Will run demo2() method which tests the CyclicBarrier's reset method by creating four threads, 
		  having the third thread reset the barrier and displaying the exceptions thrown by the waiting threads and
		  any threads which try to call .await() on the broken barrier.
	
	-CB2: Will run demo3() method which demonstrates the CyclicBarrier's action being executed once the barrier is tripped.
	
	
	
Exercise 2:
	For the TaskManager class, Semaphores and locks were used as synchronization primitives.
	Demo methods were added as new options to ensure correction of program.
	
	-TM : 	Will run the original demo function provided in the skeleton
	
	-TM1: 	Will run method demo2() which creates tasks but one of them cancels the task inside doInBackground() method.
			This ensures that program handles canceled tasks as expected.
			
	-TM2:	Will run demo3() which creates two new tasks to be executed However the second task will create 20 more tasks onCompletion()
	
	-d T: 	Turn on 'T' flag to display the debug statements for TaskManager 

General Notes For Developers:
-Options.java stores the options to specify when the program is run. This is where you can add new tests.
Once the tests are added in Options.java, you can start them in Nachos.java.
-Debug.java allows you to add new debug flags to Nachos. To add new flags just specify them in Debug.println() method.
- -d followed by custom arguments will display debug info
- -CT/TM will run the CyclicBarrier and/or TaskManager demos
- Use -RY to turn random yield on, together with -rs <seed>
- Use -ps for preemptive scheduling. Preemptive scheduling allows for the scheduler to prioritize threads.
- Removing -ps allows the program to terminate.