Introduction to MS-DOS Commands

MS-DOS (Microsoft Disk Operating System) is a text-based operating system that was widely used before Windows became popular. Even today, understanding MS-DOS is essential for computer fundamentals, especially for students in India and across the globe.

One of the most common topics students encounter is the difference between Internal and External Commands of MS-DOS. In this article, we will cover this topic deeply, with clear definitions, examples, tables, and simple explanations.

What are MS-DOS Commands?

MS-DOS commands are instructions you type into the command prompt to perform specific tasks such as creating files, navigating folders, copying data, or even formatting a disk.

These commands are divided into two main types: 

• Internal Commands
• External Commands

Understanding the difference between them is important because they behave differently and are stored differently on your system.

Internal Commands: Definition & Examples

Definition:

Internal commands are built into the command.com file of the MS-DOS operating system. When your system boots up, these commands are automatically loaded into memory. That means you can use internal commands even without accessing any external file

Key Characteristics:

Loaded into memory during system boot

Faster to execute

Available at all times

Do not require any external file

List of Common Internal Commands:

Command Function

DIR Displays list of files and folders

COPY Copies files from one location to another

DEL Deletes files

CD Changes the directory

CLS Clears the screen

TYPE Displays content of a text file

REN Renames a file

VER Shows DOS version

DATE Displays or changes the date

TIME Displays or changes the time

Examples:

DIR: To list files in a folder

CD STUDY: To move into the STUDY folder

DEL NOTES.TXT: To delete the file named NOTES.TXT

External Commands: Definition & Examples

Definition:

External commands are not loaded into memory automatically. These are separate program files (usually with .exe, .com, or .bat extensions) stored on the hard disk or bootable media like a pen drive or floppy disk. You can use them only if the required files are present.

Key Characteristics:

Stored on disk, not in memory

Slower than internal commands

Require external program files

Used for more advanced or larger tasks

List of Common External Commands:

Command	File Type	Function
FORMAT	.EXE	Formats a disk
DISKCOPY	.EXE	Copies entire disk to another
XCOPY	.EXE	Copies folders and subfolders
TREE	.COM	Displays folder structure graphically
CHKDSK	.EXE	Checks disk status
LABEL	.EXE	Changes disk label
SYS	.COM	Transfers system files

Examples:

FORMAT A: – To format a floppy disk

XCOPY C:\DATA D:\BACKUP /S – To copy entire folder structure

CHKDSK – To check disk health

Key Differences Between Internal and External Commands

Feature	Internal Commands	External Commands
Stored in	Command.com (memory)	Separate files on disk
Load Time	Loaded at boot time	Loaded when called
Execution Speed	Faster	Slightly slower
File Dependency	No external file needed	Needs .EXE/.COM/.BAT file
Example Command	DIR, COPY, CD, DEL	FORMAT, XCOPY, CHKDSK
Availability	Always available	Only if file is present

Conclusion

MS-DOS may be old, but its command structure teaches the foundation of all modern operating systems. The difference between internal and external commands is simple but powerful. Once you master this, you’ll easily understand how command-line systems work.

Whether you are a student in India or anywhere else in the world, this guide is your complete answer key.

Stay curious, keep learning!

FAQs

Q1. What is an internal command in MS-DOS?

Ans: A command built into the command.com file and available at all times without needing any external file.

Q2. Is FORMAT an internal command?

Ans: No, FORMAT is an external command as it needs format.com to run.

Q3. Where are external command files stored?

Ans: Usually in the C:\DOS or system path folder.

Q4. What happens if an external command file is missing?

Ans: You will get the error: “Bad command or file name.”

Q5. How many internal commands are there?

Ans: There is no fixed number, but commonly around 15-20 depending on the version of MS-DOS.