IOCTL_DISK_GET_DRIVE_GEOMETRY_EX IOCTL (ntdddisk.h)

Returns information about the physical disk's geometry (media type, number of cylinders, tracks per cylinder, sectors per track, and bytes per sector).

The difference between IOCTL_DISK_GET_DRIVE_GEOMETRY_EX and the older IOCTL_DISK_GET_DRIVE_GEOMETRY request is that IOCTL_DISK_GET_DRIVE_GEOMETRY_EX can retrieve information from both Master Boot Record (MBR) and GUID Partition Table (GPT)-type partitioned media, whereas IOCTL_DISK_GET_DRIVE_GEOMETRY can only read MBR-style media.

Major code

IRP_MJ_DEVICE_CONTROL

Input buffer

None.

Input buffer length

None.

Output buffer

The driver returns the DISK_GEOMETRY_EX data in the buffer at Irp->AssociatedIrp.SystemBuffer. The size of the output buffer may not be the same size as the input buffer.

Output buffer length

Parameters.DeviceIoControl.OutputBufferLength in the I/O stack location of the IRP indicates the size, in bytes, of the buffer, which must be at least (sizeof(DISK_GEOMETRY) + sizeof(LARGE_INTEGER)) and up to (sizeof(DISK_GEOMETRY) + sizeof(LARGE_INTEGER) + sizeof(DISK_PARTITION_INFO) + sizeof(DISK_DETECTION_INFO)).

Status block

The Information field is set to the size, in bytes, of the returned data.

The Status field returns one of the following values:

• STATUS_SUCCESS
• STATUS_UNRECOGNIZED_MEDIA
• STATUS_INVALID_PARAMETER
• STATUS_INVALID_DEVICE_REQUEST
• STATUS_INFO_LENGTH_MISMATCH
• STATUS_INSUFFICIENT_RESOURCES
• STATUS_BUFFER_TOO_SMALL

Remarks

Only callers above Partmgr.sys may call this IOCTL as it contains disk partition information.

This IOCTL uses IOCTL_DISK_GET_DRIVE_GEOMETRY to get the DISK_GEOMETRY structure and IOCTL_DISK_GET_LENGTH_INFO to get the GET_LENGTH_INFORMATION structure. Both of these IOCTL's are supported for use at the disk.sys level.

Requirements