Could not make out the difference between the Technical Terms

Recently I faced a small test in which there was a question which asked me to give the difference between multiprogramming, multitasking, multithreading. I could not give an exact answer to this question. I want to have the knowledge to this question at least now. Someone help me out.

These are common terms which are very much used in the context of operating system. Multiprogramming is one in which several programs run at the same time in a single processor. In an operating system context multitasking is allowing a user to perform more than one task at a time. Though the concept of multithreading would look similar outwardly to multitasking and multiprogramming they vary. Multithreading is the ability of a operating system to manage more than one user at a time or even to manage multiple requests by a single user. These are done by using the concept of threads.

Multiprogramming is a rudimentary form of parallel processing in which several programs are run at the same time on a uniprocessor.Since there is only one processor, there can be no true simultaneous execution of different programs. Instead, the operating system executes part of one program, then part of another, and so on. To the user it appears that all programs are executing at the same time.

Multitasking, in an operating system, is allowing a user to perform more than one computer task (such as the operation of an application program) at a time. The operating system is able to keep track of where you are in these tasks and go from one to the other without losing information

Multithreading is the ability of a program or an operating system process to manage its use by more than one user at a time and to even manage multiple requests by the same user without having to have multiple copies of the program running in the computer