- File Allocation Table (FAT) is a computer file system architecture and a family of industry-standard file systems utilizing it. The FAT file system is a legacy file system which is simple and robust. It offers good performance even in light-weight implementations, but cannot deliver the same performance, reliability and scalability as some modern file systems. It is, however, supported for compatibility reasons by nearly all currently developed operating systems for personal computers and many mobile devices and embedded systems, and thus is a well-suited format for data exchange between computers and devices of almost any type and age from 1981 up to the present.
File system creation
To create a FAT filesystem, install .
mkfs.fat supports creating FAT12, FAT16 and FAT32, see Wikipedia:File Allocation Table#Types for an explanation on their differences.
mkfs.fat will select the FAT type based on the partition size, to explicitly create a certain type of FAT filesystem use the
-F option. See for more information.
Format a partition to FAT32:
# mkfs.fat -F 32 /dev/partition
mkfs.vfatis a symlink to
mkfs.fat, they are the same utility.
Here is an example of the default mount configuration in the kernel:
$ zgrep -e FAT -e DOS /proc/config.gz | sort -r
# DOS/FAT/NT Filesystems CONFIG_FAT_FS=m CONFIG_MSDOS_PARTITION=y CONFIG_FAT_FS=m CONFIG_MSDOS_FS=m CONFIG_VFAT_FS=m CONFIG_FAT_DEFAULT_CODEPAGE=437 CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1" CONFIG_NCPFS_SMALLDOS=y
A short description of the options:
- Language settings:
- All filenames to lower letters on a FAT partitions if enabled:
- Enables support of the FAT file systems:
- Enables support of a FAT partitioned harddisks on 86x PCs:
If the partition type detected by mount is VFAT then it will run the
#!/bin/bash #mount VFAT with full rw (read-write) permissions for all users #/usr/bin/mount -i -t vfat -oumask=0000,iocharset=utf8 "$@" #The above is the same as mount -i -t vfat -oiocharset=utf8,fmask=0000,dmask=0000 "$@"
Writing to FAT32 as normal user
To write on a FAT32 partition, you must make a few changes to the fstab file.
/dev/sdxY /mnt/some_folder vfat user,rw,umask=000 0 0
user flag means that any user (even non-root) can mount and unmount the partition
rw gives read-write access;
umask option removes selected rights - for example
umask=111 remove executable rights. The problem is that this entry removes executable rights from directories too, so we must correct it by
dmask=000. See also Umask.
Without these options, all files will be executable. You can use the option
showexec instead of the umask and dmask options, which shows all Windows executables (com, exe, bat) in executable colours.
For example, if your FAT32 partition is on
/dev/sda9, and you wish to mount it to
/mnt/fat32, then you would use:
/dev/sda9 /mnt/fat32 vfat user,rw,umask=111,dmask=000 0 0
Now, any user can mount it with:
$ mount /mnt/fat32
And unmount it with:
$ umount /mnt/fat32
Detecting FAT type
If you need to know which type of FAT file system a partition uses, use the file command:
# file -s /dev/partition
/dev/partition: DOS/MBR boot sector, code offset 0x3c+2, OEM-ID "mkfs.fat", sectors/cluster 4, root entries 512, sectors 4096 (volumes <=32 MB), Media descriptor 0xf8, sectors/FAT 3, sectors/track 32, heads 64, serial number 0x5bc09c21, unlabeled, FAT (12 bit)
Alternatively you can use minfo from thepackage:
# minfo -i /dev/partition ::
device information: =================== filename="/dev/partition" sectors per track: 32 heads: 64 cylinders: 2 media byte: f8 mformat command line: mformat -t 2 -h 64 -s 32 -i "/dev/partition" :: bootsector information ====================== banner:"mkfs.fat" sector size: 512 bytes cluster size: 4 sectors reserved (boot) sectors: 1 fats: 2 max available root directory slots: 512 small size: 4096 sectors media descriptor byte: 0xf8 sectors per fat: 3 sectors per track: 32 heads: 64 hidden sectors: 0 big size: 0 sectors physical drive id: 0x80 reserved=0x0 dos4=0x29 serial number: 5BC09C21 disk label="NO NAME " disk type="FAT12 "