ExFAT: Difference between revisions

exFAT
Developer(s)	Microsoft
Full name	Extended File Allocation Table
Introduced	March 2008 with Windows Vista SP1
Structures
Directory contents	Table
File allocation	bitmap
Bad blocks	Cluster tagging
Limits
Max file size	16 Exabytes
Features
Date range	January 1, 1980 - December 31, 2107
Attributes	Read-only, hidden, system, volume label, subdirectory, archive
File system; permissions	No
Other
Supported; operating systems	Windows Embedded CE 6.0; Windows Vista SP1

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Revision as of 19:21, 3 May 2008

exFAT (Extended File Allocation Table, aka FAT64) is a proprietary file system suited especially for flash drives, introduced by Microsoft in Windows Embedded CE 6.0. exFAT can be used where the NTFS file system is not a feasible solution, due to data structure overhead. Windows Vista Service Pack 1 also adds support for exFAT.^[1]

The advantages over previous File Allocation Table (FAT) file system versions include:

theoretical file size limit of 2⁶⁴ bytes (16 Exabytes), limit lifted from 2³² bytes (4 Gigabytes)
cluster size of up to 2²⁵ bytes, implementation limit of 32MB
free space allocation performance improved due to introduction of a free space bitmap
support for more than 1000 files in a single directory
support for access control lists (not supported yet in Windows Vista SP1) ^[2]
support for Transaction-Safe FAT File System (TFAT) (optionally WinCE activated function)

The disadvantages compared to previous FAT versions include:

Devices using exFAT will not be able to use Windows Vista's ReadyBoost capability.^{[citation needed]}
Licensing status is unclear. However, Microsoft has previously patented portions of the FAT file system.^[3]
Not available for previous versions of Microsoft Windows. ^[4]
Not currently available as an open source implementation.

^ Brandon LeBlanc (2007-08-28). "Vista SP1 Whitepaper". Microsoft. Retrieved 2007-08-28. {{cite web}}: Check date values in: |date= (help)
^ Anandtech - Second Shot: Windows Vista SP1
^ Elizabeth Montalbano (2006-01-11). "Microsoft FAT patents upheld". Computerworld. Retrieved 2008-02-22. {{cite web}}: Check date values in: |date= (help)
^ [http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/STO072_WH06.ppt Personal Storage: Opportunities and challenges�for pocket-sized storage devices in the Windows world]

@@ Line 8: / Line 8: @@
 | partition_id =
 | directory_struct = Table
-| file_struct = [[Linked list]]
+| file_struct = [[bitmap]]
 | bad_blocks_struct = Cluster tagging
 | max_file_size = 16 [[Exabyte]]s