Network, Computer and Programming Resources
Boot Sector and BPB Structure[Fat32]-> BPB_RootClus [Offset=44, Size=4]Boot Sector and BPB Structure[Fat32]-> BS_BootSig [Offset=66, Size=1]Boot Sector and BPB Structure[Fat32]-> BS_DrvNum [Offset=64, Size=1]Boot Sector and BPB Structure[Fat32]-> BS_FilSysType [Offset=82, Size=8]Boot Sector and BPB Structure[Fat32]-> BS_Reserved1 [Offset=65, Size=1]Boot Sector and BPB Structure[Fat32]-> BS_VolID [Offset=67, Size=4]Boot Sector and BPB Structure[Fat32]-> BS_VolLab [Offset=71, Size=11]Boot Sector and BPB Structure-> BPB_BytsPerSec [Offset=11, Size=2]Boot Sector and BPB Structure-> BPB_FATSz16 [Offset=22, Size=2]Boot Sector and BPB Structure-> BPB_HiddSec [Offset=28, Size=4]Boot Sector and BPB Structure-> BPB_Media [Offset=21, Size=1]Boot Sector and BPB Structure-> BPB_NumFATs [Offset=16, Size=1]
Fat32 - Boot Sector and BPB Structure[Fat32]-> BPB_RootClus [Offset=44, Size=4]
This field is only defined for FAT32 media and does not exist on FAT12 and FAT16 media. This is set to the cluster number of the first cluster of the root directory, usually 2 but not required to be 2. NOTE: Disk utilities that change the location of the root directory should make every effort to place the first cluster of the root directory in the first non-bad cluster on the drive (i.e., in cluster 2, unless it’s marked bad). This is specified so that disk repair utilities can easily find the root directory if this field accidentally gets zeroed.