Microsoft DOS fdisk command

Updated: 05/21/2018 by Computer Hope

About fdisk

Fdisk is used to delete and create partitions on the hard drive in earlier versions of MS-DOS and Windows.


The fdisk command is an external command that is available in the below Microsoft operating systems. With MS-DOS 3.3x and below was used as the external file. MS-DOS 4.x and later including versions of Windows that support the command use fdisk.exe as the external file.

Tip: How do I set up a hard drive in Windows?

Fdisk syntax

Configures a hard disk for use with MS-DOS.


/STATUS Displays partition information.
/X Ignores extended disk-access support (will not use LBA support). Use this switch if you receive one of the below symptoms.

Unable to access a drive from DOS versions that predate version 7.
Disk access messages.
Stack overflow messages.
High amounts of data corruption.
Extra drive letters

Secret fdisk switches

Disclaimer: Below is a listing of secret or undocumented MS-DOS fdisk commands and switches. Use these commands at your risk.

Command Information
FDISK /MBR Command used to rewrite the Master Boot Record. Additional information about fdisk /mbr.
FDISK /CMBR <DISK> Recreates the Master Boot Record on the specified disk. Performs the same functions as FDISK /MBR except can be used on other disk drives.
FDISK 1/PRI:100 Creates a 100 MB DOS partition on the hard drive.
FDISK 1/EXT:500 Creates a 500 MB meg extended DOS partition on the hard drive.
FDISK 1/LOG:250 Creates a 250 MB logical drives on the hard drive.
FDISK /Q Prevents fdisk from booting the system automatically after exiting fdisk.
FDISK /STATUS Shows you the current status of your hard drives.
FDISK /ACTOK Makes fdisk not check the disk integrity allowing the drives to be created faster.
FDISK /FPRMT Prevent the prompt for FAT32 support and allows FDISK to be forced into using FAT32 on drives smaller than 540 MB. By default, FDISK does not use FAT32 on any drive smaller than 540 MB. Finally, this command can only be used with FDISK that supports FAT32.

Fdisk examples


Open the fdisk option screen that you can see in the fdisk simulation.

Note: If any partition is deleted everything within that partition will be erased.

See the fdisk simulation for additional information and examples.

Additional information

Fdisk script file - Fdisk has the capability of being run from an external file, allowing you to quickly create and delete partitions through fdisk. To do this, create a file from the DOS edit command. Below are the steps required for generating this file.

Edit fdisk.scr - In the edit screen, enter the commands you want to be run in fdisk. For example, if you want to run fdisk and display the partition information, you would enter 4.

Because fdisk requires you to press Enter after a selection, press Ctrl+P and then press Ctrl+M to create a music symbol, which acts as a carriage return.

If you need to press the Esc key, you would use Ctrl+P and then press Esc, which would be represented as a backward arrow.

When doing the commands to run FDISK, all these must be on one line; do not place each command on separate lines.

Once you have created the script file, you can then type fdisk < fdisk.scr that will then execute the script file. If the script file encounters an error during its process, you need to recreate the script file where the mistake occurred.

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