mkdosfs

Syntax:

mkdosfs [-lMp] [-C|c size] [-e number]
        [-F type] [-f number] [-h number] 
        [-I vol_id] [-L vol_label] [-m media] 
        [-O oem_label] [-R|r] [-S size] [-s size] 
        device | mountpoint | file

Runs on:

QNX Neutrino

Options:

-C size

The minimum default cluster size. Don't specify both -C and -c.

-c size

The cluster size for the filesystem; the default is determined by disk geometry. Don't specify both -c and -C.

-e number

The number of root directory entries (FAT12/16 only); the default is 512.

-F type

The FAT type (12, 16, or 32).

-f number

The number of FAT tables to write; the default is 2.

-h number

The number of “hidden sectors”; the default is determined by disk geometry.

-I vol_id

The volume ID/serial number; the default is based on the current time.

-L vol_label

Specify a volume label; the default is none.

-l

Make a LOST.DIR directory (for use by chkdosfs when repairing a filesystem).

-M

Don't mirror FAT (FAT32 only).

-m media

Media descriptor byte; the default is 0xF0 or, if there are hidden sectors, 0xF8.

-O oem_label

Set the OEM label; the default is:

MSDOS5.0: For a FAT12/FAT16 filesystem.
MSWIN4.1: For a FAT32 filesystem.

-p

(QNX Neutrino 6.6 or later) Update the partition descriptor on unmounted device targets.

-R

Preserve the size and content of existing reserved sectors (reformat).

-r

The number of “reserved sectors”; the default is determined by FAT type.

-S size

Sector size for the filesystem; the default is determined by disk geometry.

-s size

Set the size (number of sectors) in the filesystem; the default is determined by disk geometry.

device

The device name to host the DOS filesystem (e.g., /dev/hd0t11).

mountpoint

The mountpoint of the DOS filesystem (e.g., /fs/hd0-dos).

file

A regular file to contain the DOS filesystem image.

Description:

The mkdosfs utility formats a DOS filesystem on the specified target (typically a disk device or partition).

If you don't specify essential user options such as FAT type and cluster size, mkdosfs formats the DOS filesystem using the most suitable options for the size and disk geometry of the host. You can override this default auto-configuration and force a particular format to be used by setting the options you need.

Summary of filesystem commands

The following table shows the shared objects and related commands for the filesystems:

Partition type	Filesystem	Shared object	Initialize with:	Check with:
1, 4, or 6	DOS	fs-dos.so	mkdosfs	chkdosfs
7	Windows NT^a	fs-nt.so	N/A	N/A
11, 12, or 14	FAT32	fs-dos.so	mkdosfs	chkdosfs
77, 78, or 79	QNX 4	N/A	N/A	N/A
131	Linux (Ext2)	fs-ext2.so	N/A	N/A
175	Apple Macintosh HFS or HFS Plus^a	fs-mac.so	N/A	N/A
177, 178, or 179	Power-Safe	fs-qnx6.so	mkqnx6fs	chkqnx6fs^b
185	QNX Trusted Disk	fs-qtd.so	mkqfs	N/A

^a Read-only.

^b Not usually necessary.

For more information, see the Filesystems chapter of the System Architecture guide.

Examples:

mkdosfs /dev/hd0t6

Format complete: FAT16 (4096-byte clusters), 201888 kB available.

Exit status:

0: The filesystem was constructed without error.
1: The filesystem wasn't constructed. This may be due to an error or inconsistency with the user options or because of a nonrecoverable error, such as disk I/O or insufficient memory.

Contributing author:

Robert Nordier

License:

This utility is based on software from Robert Nordier; for licensing information, see “Licensing information” in Typographical Conventions, Support, and Licensing.

Caveats:

The mkdosfs utility destroys or overwrites any existing filesystem on the target.