FAT16 and FAT12 File Systems [Files]

The 12-bit cluster identifier that is used in the FAT12 file system limits a partition to storing a maximum of 2¹² (4096) clusters. Windows 2000 uses cluster sizes from 512 bytes to 8 KB, which limits a FAT12 file system volume size to 32 MB. Therefore, Windows 2000 uses the FAT12 file system as the format for all 5¼-inch and 3½-inch floppy disks that store up to 1.44 MB of data.

A FAT16 file system with a 16-bit cluster identifier can work with 2¹⁶ (65,536) clusters. On Windows 2000, cluster sizes range from 512 bytes (the sector size) to 64 KB, which limits volume sizes to 4 GB. The cluster size Windows 2000 uses depends on the size of a volume. If you format a volume that is less than 16 MB as a FAT file system by using the format command or the Disk Management snap-in, Windows 2000 uses the FAT12 file system format instead of the FAT32 file system format.

The following table identifies the default FAT16 file system cluster sizes.

The FAT file system allows file names of up to 255 characters, including the terminating null character. This is similar to the NTFS file system, which allows file names of up to 256 characters. The FAT file system also allows paths of up to 260 characters, including the terminating null character.