CM_FLOPPY_DEVICE_DATA structure (wdm.h)
The CM_FLOPPY_DEVICE_DATA structure defines a device-type-specific data record that is stored in the \Registry\Machine\Hardware\Description tree for a floppy controller if the system can collect this information during the boot process.
Syntax
typedef struct _CM_FLOPPY_DEVICE_DATA {
USHORT Version;
USHORT Revision;
CHAR Size[8];
ULONG MaxDensity;
ULONG MountDensity;
UCHAR StepRateHeadUnloadTime;
UCHAR HeadLoadTime;
UCHAR MotorOffTime;
UCHAR SectorLengthCode;
UCHAR SectorPerTrack;
UCHAR ReadWriteGapLength;
UCHAR DataTransferLength;
UCHAR FormatGapLength;
UCHAR FormatFillCharacter;
UCHAR HeadSettleTime;
UCHAR MotorSettleTime;
UCHAR MaximumTrackValue;
UCHAR DataTransferRate;
} CM_FLOPPY_DEVICE_DATA, *PCM_FLOPPY_DEVICE_DATA;
Members
Version
The version number of this structure.
Revision
The revision of this structure.
Size[8]
The floppy disk density size.
MaxDensity
The maximum density.
MountDensity
The mount density.
StepRateHeadUnloadTime
The step rate head unload time in milliseconds.
HeadLoadTime
The head load time in milliseconds.
MotorOffTime
The motor off time in seconds.
SectorLengthCode
Indicates the sector size as an exponent in the formula ((2**code) * 128).
SectorPerTrack
The number of sectors per track.
ReadWriteGapLength
The read/write gap length, in bytes.
DataTransferLength
The data transfer length, in bytes, not including the synchronization field.
FormatGapLength
The format gap length, in bytes.
FormatFillCharacter
The format fill character.
HeadSettleTime
The head settle time in milliseconds.
MotorSettleTime
The motor settle time in milliseconds.
MaximumTrackValue
The maximum track number on the media. Track numbers are zero-based values.
DataTransferRate
The value written to the Datarate register before accessing the media.
Requirements
| Requirement | Value |
|---|---|
| Header | wdm.h (include Wdm.h, Ntddk.h, Ntifs.h) |