Design of the FAT file system

FAT
Developer(s)Microsoft, SCP, IBM, Compaq, Digital Research, Novell, Caldera
Full nameFile Allocation Table:
FAT12 (12-bit version),
FAT16 (16-bit versions),
FAT32 (32-bit version with 28 bits used),
exFAT (64-bit versions)
Introduced1977 (Standalone Disk BASIC-80)
FAT12: August 1980 (SCP QDOS)
FAT16: August 1984 (IBM PC DOS 3.0)
FAT16B: November 1987 (Compaq MS-DOS 3.31)
FAT32: August 1996 (Windows 95 OSR2)
exFAT: November 2006 (Windows Embedded CE 6.0)
Partition IDsMBR/EBR:
FAT120x01 e.a.
FAT160x040x060x0E e.a.
FAT320x0B0x0C e.a.
exFAT0x07 e.a.
BDP:
EBD0A0A2-B9E5-4433­87C0-68B6B72699C7
Structures
Directory contentsTable
File allocationLinked list
Bad blocksCluster tagging
Limits
Max volume sizeFAT12: 32 MB (256 MB for 64 KB clusters)
FAT16: 2 GB (4 GB for 64 KB clusters)
FAT32: 2 TB (16 TB for KB sectors)
Max file size4,294,967,295 bytes (4 GB - 1) with FAT16B and FAT32[1]
Max no. of filesFAT12: 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 LFN
Features
Dates recordedModified date/time, creation date/time (DOS 7.0 and higher only), access date (only available with ACCDATE enabled),[2] deletion date/time (only with DELWATCH 2)
Date range1980-01-01 to 2099-12-31 (2107-12-31)
Date resolution2 seconds for last modified time,
10 ms 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 right only with 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

The FAT file system is a file system used on MS-DOS and Windows 9x family of operating systems.[3] It continues to be used on mobile devices and embedded systems, and thus is a well-suited file system for data exchange between computers and devices of almost any type and age from 1981 through to the present.

  1. ^ Cite error: The named reference GB4 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Microsoft_2006_ACCDATE was invoked but never defined (see the help page).
  3. ^ Bhat, W. A. (2010). "Review of FAT data structure of FAT32 file system". S2CID 58178285. {{cite web}}: Missing or empty |url= (help)