MKDOSFS(8)						      System Manager's Manual							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 correspond-
       ing 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  for-
	      mat.  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-compatible 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 appropriate  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 cre-
	      ated 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 nevertheless 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  with-
	      out 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 hexadecimal 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 combinations, 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 sectors are needed, the default is 32. Otherwise the
	      default is 1 (only the boot sector).

       -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 dis-
       cussed 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)