FILE_SYSTEM_RECOGNITION_STRUCTURE structure

Contains the on-disk file system recognition information stored in the volume's boot sector (logical disk sector zero).

This is an internally-defined data structure not available in a public header and is provided here for file system developers who want to take advantage of file system recognition. For more information, see File System Recognition.

Syntax

typedef struct _FILE_SYSTEM_RECOGNITION_STRUCTURE {
  UCHAR  Jmp[3];
  UCHAR  FsName[8];
  UCHAR  MustBeZero[5];
  ULONG  Identifier;
  USHORT Length;
  USHORT Checksum;
} FILE_SYSTEM_RECOGNITION_STRUCTURE;

Members

Jmp

The JMP instruction. This data member is not included in the value contained in the Checksum data member.

FsName

The file system name. This is a sequence of 8 ASCII characters that represents the nonlocalizable human-readable name of the file system the volume is formatted with.

This string is in the same place as the OEM file system name on a disk with a normal BIOS parameter block (BPB) structure.

MustBeZero

Reserved space that contains all zeros.

This data member overlaps what normally are the following data members in a BPB:

• BytesPerSector
• SectorsPerCluster
• ReservedSectorCount

Because these data members are set to zero, this should be sufficient to cause earlier OSs to conclude that this is not a valid BPB and therefore recognize the volume.

Identifier

A structure identifier. Must contain the value 0x53525346 arranged in little-endian byte order.

At this point in the structure, the data is aligned to 16 bytes.

Length

The number of bytes in this structure, from the beginning to the end, including the Jmp data member.

Checksum

A two-byte checksum calculated over the bytes starting at the FsName data member and ending at the last byte of this structure, excluding the Jmp and Checksum data members.

Requirements

See also

Computing a File System Recognition Checksum

File System Recognition

FILE_SYSTEM_RECOGNITION_INFORMATION

FSCTL_QUERY_FILE_SYSTEM_RECOGNITION