ExFAT

Infobox filesystem
name = exFAT
developer = Microsoft
full_name = Extended File Allocation Table
introduction_date = November 2006
introduction_os = Windows Embedded CE 6.0
partition_id = 0x07 (MBR)
EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (GPT)
directory_struct = Table
file_struct = bitmap, Linked list
bad_blocks_struct = Cluster tagging
max_file_size = 16 Exabytes
max_files_no =
max_filename_size =
max_volume_size =
filename_character_set =
dates_recorded =
date_range = January 1, 1980 - December 31, 2107
date_resolution =
forks_streams =
attributes = Read-only, hidden, system, volume label, subdirectory, archive
file_system_permissions = No
compression =
encryption =
OS = Windows Embedded CE 6.0 (Embedded)
Windows Vista SP1 & later (Desktop)
Windows Server 2008 RTM (Server)

exFAT (Extended File Allocation Table, aka FAT64) is a proprietary file system suited especially for flash drives, introduced by Microsoft for embedded devices in Windows Embedded CE 6.0 and in their desktop operating system, starting with Windows Vista Service Pack 1 [cite web
url=http://windowsvistablog.com/blogs/windowsvista/pages/windows-vista-service-pack-1-beta-whitepaper.aspx#_Toc175944550
title=Vista SP1 Whitepaper
date=2007-08-28
accessdate=2007-08-28
author=Brandon LeBlanc
publisher=Microsoft] . exFAT can be used where the NTFS file system is not a feasible solution, due to data structure overhead.

The advantages over previous File Allocation Table (FAT) file system versions include:
* Scalability to large disk sizes
* Theoretical file size limit of 2⁶⁴ bytes (16 Exabytes), limit raised from 2³² bytes (4 Gigabytes in FAT16)
* Cluster size of up to 2²⁵⁵ sectors, implementation limit of 32MB
* Free space allocation and delete 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) [ [http://www.anandtech.com/systems/showdoc.aspx?i=3233&p=4 Anandtech - Second Shot: Windows Vista SP1] ]
* Support for Transaction-Safe FAT File System (TFAT) (optionally WinCE activated function)
* Provision for OEM-definable parameters to customize the file system for specific device characteristics

The disadvantages compared to previous FAT versions include:
* Devices using exFAT will not be able to use Windows Vista's ReadyBoost capability. [cite web|url=http://www.tech-recipes.com/rx/2801/exfat_versus_fat32_versus_ntfs
title=exFAT Versus FAT32 Versus NTFS
accessdate=2008-07-06]
* Licensing status is unclear. However, Microsoft has previously patented portions of the FAT file system. [cite web
url=http://www.computerworld.com/softwaretopics/software/story/0,10801,107640,00.html?source=NLT_PM&nid=107640
title=Microsoft FAT patents upheld
date=2006-01-11
accessdate=2008-02-22
author=Elizabeth Montalbano
publisher=Computerworld]
* Not available for previous versions of Microsoft Windows. [ [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] ]
* Not currently available as an open source implementation.

ee also

* List of file systems

References

External links

* [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] (Microsoft PowerPoint presentation)
* [http://msdn2.microsoft.com/en-us/library/aa915463.aspx TFAT Overview]
* [http://msdn2.microsoft.com/en-us/library/aa914353.aspx Extended FAT File System]