Thread: Multi tasking, multi programming, multi threading

Hi. I want to know about what is Multitasking, multi programming, multi threading. It is very imp concept in operating system. Please give me some detailed information on it. It is very helpful for me.

Multi programming:

Multiprogramming is the method of running a number of programs at a time using timesharing. It allow a PC to do some things at the same time. Multiprogramming creates logical parallelism. The concept of multiprogramming is that the OS keeps a quantity of jobs in recall at the same time. The OS choose a job from the job pool and starts’ implement a job, when those jobs require before you for any I/O operation the CPU is switched to a different job. So the key idea here is that the CPU is in no way idle.

Multi tasking:

Multitasking is the logical extension of multiprogramming .The concept of multitasking is similar to multiprogramming but variation is that the change between jobs take places so frequently that the users can cooperate with every program while it is running. A time-shared Os uses CPU scheduling and multiprogramming to offer every user with a small PART of time-shared system.

Multi threading:

An application normally is executed as a separate process with a number of threads of control. In some conditions a single application possibly necessary to perform a number of similar tasks for example a web server accepts client requests for web pages, images, sound, and so forth. A busy web server may have a number of of clients at the same time as accessing it.