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Linux 2.6 - man page for mkfs.vfat (linux section 8)

MKDOSFS(8)									       MKDOSFS(8)

NAME
       mkdosfs - create an MS-DOS file system under Linux

SYNOPSIS
       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	[
       block-count ]

DESCRIPTION
       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.

OPTIONS
       -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
	      ignored.

       -b sector-of-backup
	      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.

       -f number-of-FATs
	      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.

       -F FAT-size
	      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.

       -h number-of-hidden-sectors
	      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.

       -i  volume-id
	      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.

       -l filename
	      Read the bad blocks list from filename.

       -m message-file
	      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.

       -n volume-name
	      Sets the volume name (label) of the file system.	The volume name can be up  to  11
	      characters long.	The default is no label.

       -r root-dir-entries
	      Select  the  number of entries available in the root directory.  The default is 112
	      or 224 for floppies and 512 for hard disks.

       -R number-of-reserved-sectors
	      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-
	      tor).

       -s sectors-per-cluster
	      Specify the number of disk sectors per cluster.  Must be a power of 2, i.e.  1,  2,
	      4, 8, ... 128.

       -S logical-sector-size
	      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.

BUGS
       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 ;)

AUTHOR
       Dave Hudson - <dave@humbug.demon.co.uk>;  modified  by  Peter  Anvin  <hpa@yggdrasil.com>.
       Fixes and additions by Roman Hodek <roman@hodek.net> for Debian/GNU Linux.

ACKNOWLEDGMENTS
       mkdosfs	is based on code from mke2fs (written by Remy Card - <card@masi.ibp.fr>) which is
       itself based on mkfs (written by Linus Torvalds - <torvalds@cs.helsinki.fi>).

SEE ALSO
       dosfsck(8), dosfslabel(8), mkfs(8)

Version 2.x				    5 May 1995				       MKDOSFS(8)


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