Network, Computer and Programming Resources
Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_BootSig [Offset=38, Size=1]Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_DrvNum [Offset=36, Size=1]Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_FilSysType [Offset=54, Size=8]Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_Reserved1 [Offset=37, Size=1]Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_VolID [Offset=39, Size=4]Boot Sector and BPB Structure[Fat12 and Fat16]-> BS_VolLab [Offset=43, Size=11]Boot Sector and BPB Structure[Fat32]-> BPB_BkBootSec [Offset=50, Size=2]Boot Sector and BPB Structure[Fat32]-> BPB_ExtFlags [Offset=40, Size=2]Boot Sector and BPB Structure[Fat32]-> BPB_FATSz32 [Offset=36, Size=4]Boot Sector and BPB Structure[Fat32]-> BPB_FSInfo [Offset=48, Size=2]Boot Sector and BPB Structure[Fat32]-> BPB_FSVer [Offset=42, Size=2]Boot Sector and BPB Structure[Fat32]-> BPB_Reserved [Offset=52, Size=12]
Fat32 - Boot Sector and BPB Structure[Fat32]-> BPB_ExtFlags [Offset=40, Size=2]
This field is only defined for FAT32 media and does not exist on FAT12 and FAT16 media.Bits 0-3 -- Zero-based number of active FAT. Only valid if mirroring is disabled.Bits 4-6 -- Reserved.Bit 7 -- 0 means the FAT is mirrored at runtime into all FATs. -- 1 means only one FAT is active; it is the one referenced in bits 0-3.Bits 8-15 -- Reserved.