What is Multithreading?

Multithreading is a feature provided by the operating system that enables your application to have more than one execution path at the same time. We are all used to Windows' multitasking abilities, which allow us to execute more than one application at the same time. Just right now I am writing the 14th lesson of the Programmers Heaven's VB.NET School in Microsoft Word, listening to my favorite songs in WinAmp and downloading a new song using the Internet Download Manager. In a similar manner, we may use multithreading to run different methods of our program at the same time. Multithreading is such a common element of today's programming that it is difficult to find windows applications that don't use it. For example, Microsoft Word takes user input and displays it on the screen in one thread while it continues to check spelling and grammatical mistakes in the second thread, and at the same time the third thread saves the document automatically at regular intervals. In a similar manner, WinAmp plays music in one thread, displays visualizations in the second and takes user input in the third. This is quite different from multitasking as here a single application is doing multiple tasks at the same time, while in multitasking different applications execute at the same time.