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DISK_GEOMETRY_EX structure (ntdddisk.h)

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The DISK_GEOMETRY_EX structure is an arbitrary-length structure composed of a DISK_GEOMETRY structure followed by a DISK_PARTITION_INFO structure followed, in turn, by a DISK_DETECTION_INFO structure.

Syntax

typedef struct _DISK_GEOMETRY_EX {
  DISK_GEOMETRY Geometry;
  LARGE_INTEGER DiskSize;
  UCHAR         Data[1];
} DISK_GEOMETRY_EX, *PDISK_GEOMETRY_EX;

Members

Geometry

See DISK_GEOMETRY for a description of this member.

DiskSize

Contains the size in bytes of the disk.

Data[1]

Beginning of the data block, starting with a DISK_PARTITION_INFO structure followed by a DISK_DETECTION_INFO structure.

Remarks

DISK_GEOMETRY_EX is used in conjunction with the IOCTL_DISK_GET_DRIVE_GEOMETRY_EX and the IOCTL_DISK_GET_MEDIA_TYPES IOCTLs, in order to retrieve information about the geometry of a physical disk (media type, number of cylinders, tracks per cylinder, sectors per track, and bytes per sector).

Because the partition and detect information are not at fixed locations within the DISK_GEOMETRY_EX structure, ntdddisk.h provides two macros for accessing this information. Both macros take a pointer to a structure of type DISK_GEOMETRY_EX as an argument:

#if (NTDDI_VERSION < NTDDI_WS03)
#define DiskGeometryGetPartition(Geometry)\
                        ((PDISK_PARTITION_INFO)((Geometry)+1))

#define DiskGeometryGetDetect(Geometry)\
                        ((PDISK_DETECTION_INFO)(((PBYTE)DiskGeometryGetPartition(Geometry)+\
                                        DiskGeometryGetPartition(Geometry)->SizeOfPartitionInfo)))
#else
#define DiskGeometryGetPartition(Geometry)\
                        ((PDISK_PARTITION_INFO)((Geometry)->Data))

#define DiskGeometryGetDetect(Geometry)\
                        ((PDISK_DETECTION_INFO)(((ULONG_PTR)DiskGeometryGetPartition(Geometry)+\
                                        DiskGeometryGetPartition(Geometry)->SizeOfPartitionInfo)))
#endif

Requirements

Requirement Value
Header ntdddisk.h (include Ntdddisk.h, Ntddk.h, Ntdddisk.h)

See also

DISK_DETECTION_INFO

DISK_GEOMETRY

DISK_PARTITION_INFO

IOCTL_DISK_GET_DRIVE_GEOMETRY

IOCTL_DISK_GET_MEDIA_TYPES