Besides running Windows Vista programs, you can also enter commands and run programs written in MS-DOS. MS-DOS stands for Microsoft Disk Operating System. MS-DOS, or DOS, employs a command-line interface through which you must type commands at a command prompt to run different tasks. A character such as a > or $ appears at the beginning of a command prompt. Each DOS command has a strict set of rules called a command syntax that you must follow when expressing a command. Many commands allow you to include switches and parameters that give you additional control of the command.