Multitasking Vs Multithreading Vs Multiprocessing

Question

Possible Duplicate:
Difference between multitasking, multithreading & multiprocessing?

What is the real differences & Similarities between Multitasking, Multiprocessing & Multithreading.

Answer 1

From Wikipedia:

multiprogramming is the allocation of a computer system and its resources to more than one concurrent application, job or user ("program" in this nomenclature).

Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system.

As multitasking greatly improved the throughput of computers, programmers started to implement applications as sets of cooperating processes (e. g., one process gathering input data, one process processing input data, one process writing out results on disk). This, however, required some tools to allow processes to efficiently exchange data.