A 'process' is an execution stream in the context of a 
particular process state. 
An execution stream is a sequence of instructions. 
Process state determines the effect of the instructions. It 
usually includes (but is not restricted to): 
Registers 
Stack 
Memory (global variables and dynamically allocated memory) 
Open file tables 
Signal management information 
*Key concept: processes are separated: no process can 
directly affect the state of another process. 
->Process is a key OS abstraction that users see - the 
environment you interact with when you use a computer is 
built up out of processes. 
The shell you type stuff into is a process. 
When you execute a program you have just compiled, the OS 
generates a process to run the program. 
 even Your WWW browser is a process.