Types of DOS commands

The command generally means an instruction written in computer language that user types to execute a specific operation on the DOS prompt. The specific operations on the DOS prompt. The command interpreter accepts our input in a specific form. This specification is known as the syntax and the output is known as DOS command.

The two types of commands:-

1.           Internal commands

2.           External commands

Internal Commands:-

Internal commands are those commands that are loaded automatically in the memory when dos are loaded into memory during booting process. These commands are easier to learn and use and require no eternal files for their storage as in case of external commands. These commands are always available at the console of the user and are executed must faster than external commands. The internal commands are used for common jobs such as copying, erasing and renaming files. Some common internal commands are copy, dir, cd, copy con, time etc. In other words, those commands which are frequently used and stored in the resident portion of the memory of the computer are called internal commands.

           External Commands:-

The external commands are used less frequently and are stored  in  some external files which are in some secondary storage device.  Whenever an external command is to be executed the external file in which that particular command is stored in transferred from the secondary storage i.e. disk to main memory i.e. RAM.

All executable files with extensions .com, .exe, and .bat are the external commands. These commands are used for relatively jobs like comparing two files, formatting disk etc. For using external commands we need to use corresponding command file available in DOS.