BIOSPARAMETERBLOCK

BIOS Parameter Block

Type

USHORT   usBytesPerSector;
BYTE     bSectorsPerCluster;
USHORT   usReservedSectors;
BYTE     cFATs;
USHORT   cRootEntries;
USHORT   cSectors;
BYTE     bMedia;
USHORT   usSectorsPerFAT;
USHORT   usSectorsPerTrack;
USHORT   cHeads;
ULONG    cHiddenSectors;
ULONG    cLargeSectors;
BYTE     abReserved[6];
USHORT   cCylinders;
BYTE     bDeviceType;
USHORT   fsDeviceAttr;

C Declaration Method

typedef struct

Fields

usBytesPerSector

Number of bytes per sector

bSectorsPerCluster

Number of sectors per cluster

usReservedSectors

Number of reserved sectors

cFATs

Number of FATs

cRootEntries

Number of root directory entries

cSectors

Number of sectors

bMedia

Media descriptor

usSectorsPerFAT

Number of secctors per FAT

usSectorsPerTrack

Number of sectors per track

cHeads

Number of heads

cHiddenSectors

Number of hidden sectors

cLargeSectors

Number of large sectors

abReserved[6]

Reserved

cCylinders

Number of cylinders defined for the physical device

bDeviceType

Physical layout of the specified device

0 48 TPI low-density diskette drive

1 96 TPI high-density diskette drive

2 Small (3.5-inch) 720KB drive

3 8-inch single-density diskette drive

4 8-inch double-density diskette drive

5 Fixed disk

6 Tape drive

7 Other (includes 1.44MB 3.5-inch diskette drive)

8 R/W optical disk

9 3.5-inch 4.0MB diskette drive (2.88MB formatted)

fsDeviceAttr

A bit field that returns flag information about the specified drive

Bit 0 Removable Media flag

0 Media is removable

1 Media cannot be removed

Bit 1 Changeline flag

0 The physical device driver returns the value 0, Unsure if media has changed, from the Media Check function

1 Device support determines that the media was removed since the last I/O operation.