How is Dos used?

Every time when we type anything at the Dos prompt, and press enter, we are telling Dos to run a program. Also, it will first look to see if there is an internal command program which has that name, and if it does not find one, then it will look to see if there is a file on disk with that name. When we finds an external file with the extension. COM ( command), or EXE (executable), then the program is loaded and run. In this case Dos looses control of the computer until the program has ended.