Description of the FAT32 File System in Windows XP
This article was previously published under Q310525
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This article describes the FAT32 file system that is included with Microsoft Windows XP.
Windows XP includes an updated version of the FAT file system. This updated version is called FAT32. The FAT32 file system allows for a default cluster size as small as 4 KB, and includes support for EIDE hard disk sizes larger than 2 gigabytes (GB).
Note the following:
FAT32 FeaturesFAT32 provides the following enhancements over previous implementations of the FAT file system:
FAT32 Compatibility ConsiderationsTo maintain the greatest compatibility possible with existing programs, networks, and device drivers, FAT32 was implemented with as little change as possible to the existing Windows architecture, internal data structures, Application Programming Interfaces (APIs), and on-disk format. However, because 4 bytes are now required to store cluster values, many internal and on-disk data structures and published APIs have been revised or expanded. In some cases, existing APIs will not work on FAT32 drives. Most programs will be unaffected by these changes. Existing tools and drivers should continue to work on FAT32 drives. However, MS-DOS block device drivers (for example, Aspidisk.sys) and disk tools will need to be revised to support FAT32 drives.
All of the Microsoft bundled disk tools have been revised to work with FAT32. In addition, Microsoft is working with leading device driver and disk tool manufacturers to support them in revising their products to support FAT32.
NOTE: A FAT32 volume cannot be compressed by using Microsoft DriveSpace or DriveSpace 3.
Dual-Boot ComputersWindows XP, Windows 2000, Windows Me, Windows 98, and Windows 95 OSR2 can access FAT32 volumes. MS-DOS, the original version of Windows 95, and Windows NT 4.0 do not recognize FAT32 partitions, and are unable to boot from a FAT32 volume. Also, FAT32 volumes cannot be accessed properly if the computer is started by using another operating system (for example, a Windows 95 or MS-DOS boot disk).
Creating FAT32 VolumesThe Disk Management snap-in in Windows XP is a tool for managing your hard disks and the volumes or partitions that they contain. Use Disk Management to create new FAT32 volumes, or format an existing volume to use the FAT32 file system. You can format basic and dynamic volumes to use FAT32.
Create a FAT32 Partition or Logical DriveTo create a new FAT32 partition or logical drive in Windows XP, follow these steps:
Format an Existing Volume to Use FAT32To format a volume, follow these steps:
Support BoundariesFor legacy (older) programs that cannot be installed on a FAT32 volume, or do not properly save files or read them, contact program manufacturer.
NOTE: Although the FAT32 file system supports hard disks up to 2 terabytes in size, some hard disks may not be able to contain bootable partitions that are larger than 7.8 GB because of limitations in your computer's basic input/output system (BIOS) INT13 interface. Please contact your hardware manufacturer to determine if your computer's BIOS supports the updated INT13 extensions.
For additional information about the FAT16 and the FAT32 file systems, click the following article numbers to view the articles in the Microsoft Knowledge Base:
184006 (http://support.microsoft.com/kb/184006/) Limitations of FAT32 File System
310561 (http://support.microsoft.com/kb/310561/) Maximum Partition Size Using the FAT16 File System in Windows XPFor additional information about how to convert a FAT16 or a FAT32 volume to NTFS, click the following article numbers to view the articles in the Microsoft Knowledge Base:
307881 (http://support.microsoft.com/kb/307881/) HOW TO: Convert a FAT16 or FAT32 Volume to NTFS in Windows XP
140365 (http://support.microsoft.com/kb/140365/) Default Cluster Size for FAT and NTFSFor additional information about dynamic disk and basic disk storage, click the following article number to view the article in the Microsoft Knowledge Base:
175761 (http://support.microsoft.com/kb/175761/) Dynamic vs. Basic Storage in Windows 2000For additional information about how to use Disk Management, click the following article numbers to view the articles in the Microsoft Knowledge Base:
309000 (http://support.microsoft.com/kb/309000/) HOW TO: Use Disk Management to Configure Basic Disks in Windows XP
308424 (http://support.microsoft.com/kb/308424/) HOW TO: Use Disk Management to Configure Dynamic Disks in Windows XP