NAME

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

SYNOPSIS

       mkfs.fat [OPTIONS] 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.

       -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 is 0xF0 or 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.

       --invariant
           Use constants for normally randomly generated or time based data such as volume ID and creation time.
           Multiple runs of mkfs.fat on the same device create identical results with  this  option.   Its  main
           purpose is testing mkfs.fat.

       --help
           Display option summary and exit.

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

       The     home     for     the     dosfstools     project     is     its      GitHub      project      page
       ⟨https://github.com/dosfstools/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  Andreas  Bombe  ⟨aeb@
       debian.org⟩.