===============
Synchronisation
===============

Race condition
	A situation where multiple threads may manipulate data in such a way that the outcome depends on the execution order.
Critical Section
	A section of code that manipulates shared data.
Mutual Exclusion
	Making sure that only one thread can be executing in a critical section at once.
Deadlock
	When two or more processes are waiting for something that can only be provided by one of the waiting processes.

Semaphores
==========

- Two operations on a shared value:
	
	P(s)
		::
		
			while (s <= 0) {}
			s--;
	V(s)
		::
		
			s++;

- Don't busy wait; give up the cpu.


Java
====

wait()
	Give up the lock, and yield to another thread, waiting for something to call notify.
notify()
	Yield to a waiting thread.
notifyAll()
	Wake up all waiting threads.