Network, Computer and Programming Resources

Fat32 - Boot Sector and BPB Structure-> BPB_SecPerClus [Offset=13, Size=1]

Number of sectors per allocation unit. This value must be a power of 2 that is greater than 0. The legal values are 1, 2, 4, 8, 16, 32, 64, and 128. Note however, that a value should never be used that results in a “bytes per cluster” value (BPB_BytsPerSec * BPB_SecPerClus) greater than 32K (32 * 1024). There is a misconception that values greater than this are OK. Values that cause a cluster size greater than 32K bytes do not work properly; do not try to define one. Some versions of some systems allow 64K bytes per cluster value. Many application setup programs will not work correctly on such a FAT volume.