File Allocation Table

FAT
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 (1977) with Standalone Disk BASIC-80
Partition IDsMBR/EBR:
  • FAT12: 0x01 e.a. (Extended Attribute)
  • FAT16: 0x040x060x0E e.a.
  • FAT32: 0x0B0x0C 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 FAT32[1]
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 LFN[nb 1]
Features
Dates recorded
  • Modified 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 resolution
  • 2 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
Transparent
compression
Transparent
encryption
  • FAT12/FAT16: Per-volume only with DR-DOS
  • FAT32: No

File Allocation Table (FAT) is a file system developed for personal computers and was the default filesystem for the MS-DOS and Windows 9x operating systems.[citation needed] Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. The increase in disk drive capacity over time drove modifications to the design that resulted in versions: FAT12, FAT16, FAT32, and exFAT. FAT was replaced with NTFS as the default file system on Microsoft operating systems starting with Windows XP.[3] Nevertheless, FAT continues to be commonly used on relatively small capacity solid-state storage technologies such as SD card, MultiMediaCard (MMC) and eMMC because of its compatibility and ease of implementation.[4]

  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. ^ "Comparing NTFS and FAT file systems". Microsoft. Archived from the original on 2016-06-20. Retrieved 2014-01-27.
  4. ^ "A brief introduction to FAT (File Allocation Table) formats". www.wizcode.com. Archived from the original on September 25, 2015. Retrieved September 24, 2015.


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