In both MS-DOS and Windows, there are two different ways commands can be executed. They could either be executed internally or externally. In real-time computing, there is no difference between an internal command and an external command. We would, however, consider the slight differences that they have.
Simply put, an internal command is a command that is always available to the user. Internal commands are stored in the system’s memory and can be executed from the command processors. In MS-DOS, the command processor is command.com, while in Windows, it is cmd.exe.
In contrast, external commands are not usually stored on the system’s memory. Instead, they require a separate system file to operate. Some examples of internal commands include copy, del, cd, and dir, while some external commands are edit.com, scandisk.exe, defrag.exe, and fdisk.exe.
To help you grasp the picture more clearly, let us say your computer does not have the defrag.exe file. You attempt executing the defrag.exe command, and you will receive an error message which could either be “bad command” or “bad file name.” This is because defrag.exe is an external command, and it can only be executed when the defrag.exe file is present.
However, as far as your computer is running, the internal commands stored on its memory are readily available to be executed. They do not require another separate system file to run them.
Running an Internal Command
Provided you can open a command line and run any of the internal commands available on your MS-DOS or Windows version.
Why are Internal Commands Needed?
Internal commands are important because they are needed to run the MC-DOS and Windows operating systems effectively. Having being stored on the command processor, they are easily accessible and always available when required.
Listing of Internal Commands
Let us now consider some more examples of internal commands available on most MC-DOS and Windows versions. They include Assoc, Break, Call, CD, Cls, Color, Copy, Date, Echo, Erase, Exit, For, GoTo, If, Lock, Move, Path, Pause, Ren, Set, Shift, Switch, Time, Title, Type, Unlock, Verify, Vol, etc.