AB
Developer(s)Microsoft, NCR, SCP, IBM, Compaq, Digital Research, Novell, Caldera
Full nameFile Allocation Table
Variants8-bit FAT, FAT12, FAT16, FAT16B, FAT32, exFAT, FATX, FAT+
Introduced1977 with Standalone Disk BASIC-80
Partition IDsMBR/EBR:• FAT12: 0x01 e.a. (Extended Attribute)
• FAT16: 0x04 0x06 0x0E e.a.
• FAT32: 0x0B 0x0C e.a.
• BDP : EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
Structures
Directory contentsTable
File allocationLinked list
Bad blocksCluster tagging
Limits
Max volume size• FAT12: 32 MB (256 MB for 64 KB clusters)
• FAT16: 2 GB (4 GB for 64 KB clusters)
• FAT32: 2 TB (16 TB for 4 KB sectors)
Max file size4,294,967,295 bytes (4 GB − 1) with FAT16B and FAT321
Max no. of files• FAT12: 4,068 for 8 KB clusters
• FAT16: 65,460 for 32 KB clusters
• FAT32: 268,173,300 for 32 KB clusters
Max filename length8.3 filename, or 255 UCS-2 characters when using LFN2
Features
Dates recorded• Modified date/time, creation date/time (DOS 7.0 and higher only),
• access date (only available with ACCDATE enabled), 3
• deletion date/time (only with DELWATCH 2)
Date range1980-01-01 to 2099-12-31 (2107-12-31)
Date resolution• 2 seconds for last modified time,
• 2 seconds for creation time,
• 1 day for access date,
• 2 seconds for deletion time
ForksNot natively
AttributesRead-only, hidden, system, volume, directory, archive
File system
permissions
• FAT12/FAT16: File, directory and volume access rights for read , write , execute , delete only with DR-DOS , PalmDOS , Novell DOS , OpenDOS , FlexOS , 4680 OS , 4690 OS , Concurrent DOS , Multiuser DOS , System Manager , REAL/32 : execute with only FlexOS, 4680 OS, 4690 OS; individual file / directory passwords not with FlexOS, 4680 OS, 4690 OS; world/group/owner permission classes only with multiuser security loaded
• FAT32: Partial, only with DR-DOS, REAL/32 and 4690 OS
Transparent
compression
• FAT12/FAT16: Per-volume, SuperStor , Stacker , DoubleSpace , DriveSpace
• FAT32: No
Transparent
encryption
• FAT12/FAT16: Per-volume only with DR-DOS
• FAT32: No

FAT

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Footnotes

  1. “File Systems”. Microsoft TechNet. 2001. Archived from the original on 2011-08-12. Retrieved 2011-07-31.

  2. Since Windows 2000, Microsoft Windows uses UTF-16 instead of UCS-2 for the internal “Unicode”. In UTF-16, a “character” (code point) may take up two code units.

  3. Microsoft (2006-11-15). Windows 95 CD-ROM CONFIG.TXT File Archived 2020-07-31 at the Wayback Machine Article 135481, Revision: 1.1, retrieved 2011-12-22: “For each hard disk, specifies whether to record the date that files are last accessed. Last access dates are turned off for all drives when your computer is started in safe mode, and are not maintained for floppy disks by default. Syntax: ACCDATE=drive1+|- [drive2+|-]...