mkdosfs - create an MS-DOS file system under Linux
mkdosfs|mkfs.msdos|mkfs.vfat [ -a ] [ -A ] [ -b sector-of-backup ] [ -c ] [ -l filename ]
[ -C ] [ -f number-of-FATs ] [ -F FAT-size ] [ -h number-of-hidden-sectors ] [ -i volume-
id ] [ -I ] [ -m message-file ] [ -n volume-name ] [ -r root-dir-entries ] [ -R number-of-
reserved-sectors ] [ -s sectors-per-cluster ] [ -S logical-sector-size ] [ -v ] device [
mkdosfs is used to create an MS-DOS file system under Linux on a device (usually a disk
partition). device is the special file corresponding to the device (e.g /dev/hdXX).
block-count is the number of blocks on the device. If omitted, mkdosfs automatically
determines the file system size.
-a Normally, for any filesystem except very small ones, mkdosfs will align all the
data structures to cluster size, to make sure that as long as the partition is
properly aligned, so will all the data structures in the filesystem. This option
disables alignment; this may provide a handful of additional clusters of storage at
the expense of a significant performance degradation on RAIDs, flash media or
large-sector hard disks.
-A Use Atari variation of the MS-DOS file system. This is default if mkdosfs is run on
an Atari, then this option turns off Atari format. There are some differences when
using Atari format: If not directed otherwise by the user, mkdosfs will always use
2 sectors per cluster, since GEMDOS doesn't like other values very much. It will
also obey the maximum number of sectors GEMDOS can handle. Larger file systems are
managed by raising the logical sector size. Under Atari format, an Atari-compati-
ble serial number for the file system is generated, and a 12 bit FAT is used only
for file systems that have one of the usual floppy sizes (720k, 1.2M, 1.44M,
2.88M), a 16 bit FAT otherwise. This can be overridden with the -F option. Some PC-
specific boot sector fields aren't written, and a boot message (option -m) is
Selects the location of the backup boot sector for FAT32. Default depends on number
of reserved sectors, but usually is sector 6. The backup must be within the range
of reserved sectors.
-c Check the device for bad blocks before creating the file system.
-C Create the file given as device on the command line, and write the to-be-created
file system to it. This can be used to create the new file system in a file instead
of on a real device, and to avoid using dd in advance to create a file of appropri-
ate size. With this option, the block-count must be given, because otherwise the
intended size of the file system wouldn't be known. The file created is a sparse
file, which actually only contains the meta-data areas (boot sector, FATs, and root
directory). The data portions won't be stored on the disk, but the file neverthe-
less will have the correct size. The resulting file can be copied later to a floppy
disk or other device, or mounted through a loop device.
Specify the number of file allocation tables in the file system. The default is 2.
Currently the Linux MS-DOS file system does not support more than 2 FATs.
Specifies the type of file allocation tables used (12, 16 or 32 bit). If nothing
is specified, mkdosfs will automatically select between 12, 16 and 32 bit, whatever
fits better for the file system size.
Select the number of hidden sectors in the volume. Apparently some digital cameras
get indigestion if you feed them a CF card without such hidden sectors, this option
allows you to satisfy them. Assumes '0' if no value is given on the command line.
Sets the volume ID of the newly created file system; volume-id is a 32-bit hexadec-
imal number (for example, 2e24ec82). The default is a number which depends on the
file system creation time.
-I It is typical for fixed disk devices to be partitioned so, by default, you are not
permitted to create a filesystem across the entire device. mkdosfs will complain
and tell you that it refuses to work. This is different when using MO disks. One
doesn't always need partitions on MO disks. The file system can go directly to the
whole disk. Under other OSes this is known as the 'superfloppy' format.
This switch will force mkdosfs to work properly.
Read the bad blocks list from filename.
Sets the message the user receives on attempts to boot this file system without
having properly installed an operating system. The message file must not exceed
418 bytes once line feeds have been converted to carriage return-line feed combina-
tions, and tabs have been expanded. If the filename is a hyphen (-), the text is
taken from standard input.
Sets the volume name (label) of the file system. The volume name can be up to 11
characters long. The default is no label.
Select the number of entries available in the root directory. The default is 112
or 224 for floppies and 512 for hard disks.
Select the number of reserved sectors. With FAT32 format at least 2 reserved sec-
tors are needed, the default is 32. Otherwise the default is 1 (only the boot sec-
Specify the number of disk sectors per cluster. Must be a power of 2, i.e. 1, 2,
4, 8, ... 128.
Specify the number of bytes per logical sector. Must be a power of 2 and greater
than or equal to 512, i.e. 512, 1024, 2048, 4096, 8192, 16384, or 32768.
-v Verbose execution.
mkdosfs can not create boot-able file systems. This isn't as easy as you might think at
first glance for various reasons and has been discussed a lot already. mkdosfs simply
will not support it ;)
Dave Hudson - <email@example.com>; modified by Peter Anvin <firstname.lastname@example.org>.
Fixes and additions by Roman Hodek <email@example.com> for Debian/GNU Linux.
mkdosfs is based on code from mke2fs (written by Remy Card - <firstname.lastname@example.org>) which is
itself based on mkfs (written by Linus Torvalds - <email@example.com>).
dosfsck(8), dosfslabel(8), mkfs(8)
Version 2.x 5 May 1995 MKDOSFS(8)