NAME

       mkfs.fat - create an MS-DOS filesystem under Linux

SYNOPSIS

       mkfs.fat  [-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] [-D drive-number] [-M
       FAT-media-type] [-v] device [block-count]

DESCRIPTION

       mkfs.fat is used to create an MS-DOS filesystem under Linux on  a  device  (usually  a  disk  partition).
       device  is  the  special  file  corresponding to the device (e.g /dev/sdXX). block-count is the number of
       blocks on the device. If omitted, mkfs.fat automatically determines the filesystem size.

OPTIONS

       -a  Normally, for any filesystem except very small ones, mkfs.fat 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 filesystem. This is default if mkfs.fat 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, mkfs.fat 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 filesystems are managed by raising the logical sector size.  Under  Atari  format,  an  Atari-
           compatible  serial  number  for  the  filesystem  is  generated,  and  a  12 bit FAT is used only for
           filesystems 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 filesystem.

       -C  Create  the  file  given as device on the command line, and write the to-be-created filesystem to it.
           This can be used to create the new filesystem 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 filesystem 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 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.

       -D drive-number
           Specify the BIOS drive number to be stored in the FAT boot sector. This value  is  usually  0x80  for
           hard disks and 0x00 for floppy devices or partitions to be used for floppy emulation.

       -f number-of-FATs
           Specify the number of file allocation tables in the filesystem. The default is 2. Currently the Linux
           MS-DOS filesystem 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,
           mkfs.fat will automatically select between 12, 16 and 32 bit, whatever fits better for the filesystem
           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.

       -i volume-id
           Sets  the  volume  ID  of the newly created filesystem; volume-id is a 32-bit hexadecimal number (for
           example, 2e24ec82). The default is a number which depends on the filesystem 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. mkfs.fat 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
           filesystem  can  go  directly  to the whole disk. Under other OSes this is known as the 'superfloppy'
           format. This switch will force mkfs.fat 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  filesystem  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.

       -M FAT-media-type
           Specify the media type to be stored in the FAT boot sector. This value is usually 0xF8 for hard disks
           and has a value from 0xF9 to 0xFF for floppies or partitions to be used for floppy emulation.

       -n volume-name
           Sets the volume name (label) of the filesystem. 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

       mkfs.fat can not create boot-able filesystems. This isn't as easy as you might think at first glance  for
       various reasons and has been discussed a lot already. mkfs.fat simply will not support it ;)

SEE ALSO

       fatlabel(8)
       fsck.fat(8)

HOMEPAGE

       More      information      about      fsck.fat      and      dosfstools      can      be     found     at
       <http://daniel-baumann.ch/software/dosfstools/>.

AUTHORS

       dosfstools  were  written  by  Werner  Almesberger   <werner.almesberger@lrc.di.epfl.ch>,   Roman   Hodek
       <Roman.Hodek@informatik.uni-erlangen.de>,   and   others.   The  current  maintainer  is  Daniel  Baumann
       <mail@daniel-baumann.ch>.