A disk file allocation system from Microsoft that uses 32-bit values for FAT entries instead of 16-bit values used by the original FAT system, enabling partition sizes up to 2TB (terabytes). FAT32 first appeared in Windows 95B and is also found in Windows 98 and Windows NT 5.0.
In order to overcome the volume size limit of FAT16 while still allowing memory-constrained DOS real-mode code to handle the format, Microsoft decided to implement a newer generation of FAT, known as FAT32, with 32-bit cluster numbers, of which 28 bits are currently used.
In theory, this should support a total of approximately 268,435,438 (< 228) clusters, allowing for drive sizes in the range of 2 terabytes. However, due to limitations in Microsoft's scandisk utility, the FAT is not allowed to grow beyond 4,177,920 (< 224) clusters, placing the volume limit at 124.55 gigabytes, unless "scandisk" is not needed. Windows 2000 and XP placed a limit on the size of FAT32 partitions they can create at 32 GB, Microsoft says this is by design but does not explain why, and those versions of Windows are quite capable of reading and writing larger FAT32 partitions created by other means. FAT32 was introduced with Windows 95 OSR2. The many changes it incorporated made it a major improvement.
The maximum possible file size for a FAT32 volume is 4 GB minus 1 byte (232-1 bytes). For most users, this has become the most nagging limit of FAT32 as of 2005, since video capture and editing applications can easily exceed this limit, as can the system swap file.
32-bit File Allocation Table File System Not the same as VFAT or FAT, which are both 16-bit file systems.