Ms-Dos stands for “Microsoft Disk Operating System” which is marked by Microsoft Corporation form U.S.A. It is single user and single tasking operating system. It is command based operating system.


There are two types of command in Ms-Dos: -

Ø Internal Command

Ø External Command 


Internal Command: -These commands are loaded in the computer system is called Internal Command.


There are many type of internal command:-

Ex à copy con, CLS, type, time, date, DIR, REN, VOL, VER, MK DIR, PATH, RMDIR, Exit, for, go to etc.


External Command: - This command not built into the system because those command are after between the versions of ms-dos.


                   When you type on built external command than you have to define the path of external command. This command loaded into hard disk.


There are many types of external command:-

Ex à EDIT, ATTRIB, CHKDSK, APP end, label etc.


How to start MS - DOS if your operating system is windows 7: -

1.     First of all boot the system.

2.     Then click on start button.

3.     Click on all program.

4.     Click on Accessories.

5.     Click on Command Prompt.


1.     Press start button + R (run)

2.     Type CMD or Command

3.     Click on OK