exFAT
From Wikipedia, the free encyclopedia
| exFAT | |
|---|---|
| Developer | Microsoft |
| Full name | Extended File Allocation Table |
| Introduced | November 2006 (Windows Embedded CE 6.0) |
| Partition identifier | 0x07 (MBR) EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (GPT) |
| Structures | |
| Directory contents | Table |
| File allocation | bitmap |
| Bad blocks | Cluster tagging |
| Limits | |
| Max file size | 16 Exabytes |
| Max number of files | |
| Max filename length | |
| Max volume size | |
| Allowed characters in filenames | |
| Features | |
| Dates recorded | |
| Date range | January 1, 1980 - December 31, 2107 |
| Date resolution | |
| Forks | |
| Attributes | Read-only, hidden, system, volume label, subdirectory, archive |
| File system permissions | No |
| Transparent compression | |
| Transparent encryption | |
| Supported operating systems | 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 [1]. 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 lifted from 232 bytes (4 Gigabytes)
- Cluster size of up to 2255 bytes, 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) [2]
- 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.[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.
[edit] See also
[edit] References
- ^ Brandon LeBlanc (2007-08-28). Vista SP1 Whitepaper. Microsoft. Retrieved on 2007-08-28.
- ^ Anandtech - Second Shot: Windows Vista SP1
- ^ Elizabeth Montalbano (2006-01-11). Microsoft FAT patents upheld. Computerworld. Retrieved on 2008-02-22.
- ^ Personal Storage: Opportunities and challenges�for pocket-sized storage devices in the Windows world
[edit] External links
- Personal Storage: Opportunities and challenges for pocket-sized storage devices in the Windows world (Microsoft PowerPoint presentation)
- TFAT Overview
- Extended FAT File System
