STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR structure (winioctl.h)

Used in conjunction with the IOCTL_STORAGE_QUERY_PROPERTY control code to retrieve the storage access alignment descriptor data for a device.

Syntax

typedef struct _STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR {
  DWORD Version;
  DWORD Size;
  DWORD BytesPerCacheLine;
  DWORD BytesOffsetForCacheAlignment;
  DWORD BytesPerLogicalSector;
  DWORD BytesPerPhysicalSector;
  DWORD BytesOffsetForSectorAlignment;
} STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR, *PSTORAGE_ACCESS_ALIGNMENT_DESCRIPTOR;

Members

Version

Contains the size of this structure, in bytes. The value of this member will change as members are added to the structure.

Size

Specifies the total size of the data returned, in bytes. This may include data that follows this structure.

BytesPerCacheLine

The number of bytes in a cache line of the device.

BytesOffsetForCacheAlignment

The address offset necessary for proper cache access alignment, in bytes.

BytesPerLogicalSector

The number of bytes in a logical sector of the device.

BytesPerPhysicalSector

The number of bytes in a physical sector of the device.

BytesOffsetForSectorAlignment

The logical sector offset within the first physical sector where the first logical sector is placed, in bytes.

Example: Offset = 3 Logical sectors

+---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|LBA      |##|##|##|00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|
+---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|Physical |                       |                       |                ...
|Sector   |           0           |           1           |           2
+---------+-----------------------+-----------------------+---------------

In this example, BytesOffsetForSectorAlignment = 3 * BytesPerLogicalSector.

Requirements

See also

Disk Management Structures

IOCTL_STORAGE_QUERY_PROPERTY