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STORAGE_ADAPTER_DESCRIPTOR structure (ntddstor.h)

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The STORAGE_ADAPTER_DESCRIPTOR structure is used in conjunction with the IOCTL_STORAGE_QUERY_PROPERTY request to retrieve the storage adapter descriptor data for a device.

Syntax

typedef struct _STORAGE_ADAPTER_DESCRIPTOR {
  ULONG   Version;
  ULONG   Size;
  ULONG   MaximumTransferLength;
  ULONG   MaximumPhysicalPages;
  ULONG   AlignmentMask;
  BOOLEAN AdapterUsesPio;
  BOOLEAN AdapterScansDown;
  BOOLEAN CommandQueueing;
  BOOLEAN AcceleratedTransfer;
#if ...
  BOOLEAN BusType;
#else
  UCHAR   BusType;
#endif
  USHORT  BusMajorVersion;
  USHORT  BusMinorVersion;
  UCHAR   SrbType;
  UCHAR   AddressType;
} STORAGE_ADAPTER_DESCRIPTOR, *PSTORAGE_ADAPTER_DESCRIPTOR;

Members

Version

Contains the version of the structure STORAGE_ADAPTER_DESCRIPTOR. The value of this member will change as members are added to the structure.

Size

Specifies the total size of the descriptor, in bytes.

MaximumTransferLength

Specifies the maximum number of bytes the host bus adapter (HBA) can transfer in a single operation.

MaximumPhysicalPages

Specifies the maximum number of discontinuous physical pages the HBA can manage in a single transfer (in other words, the extent of its scatter/gather support).

AlignmentMask

Specifies the HBA's alignment requirements for transfers. A storage class driver sets the AlignmentRequirement field in its device objects to this value. The alignment mask indicates alignment restrictions for buffers required by the HBA for transfer operations. The valid mask values are 0 (byte aligned), 1 (word aligned), 3 (DWORD aligned), and 7 (double DWORD aligned).

AdapterUsesPio

Indicates when TRUE that the HBA uses Programmed Input/Output (PIO) and requires the use of system-space virtual addresses mapped to physical memory for data buffers. When FALSE, the HBA does not use PIO.

AdapterScansDown

Indicates when TRUE that the HBA scans down for BIOS devices, that is, the HBA begins scanning with the highest device number rather than the lowest. When FALSE, the HBA begins scanning with the lowest device number. This member is reserved for legacy miniport drivers.

CommandQueueing

Indicates when TRUE that the HBA supports SCSI-tagged queuing and/or per-logical-unit internal queues, or the non-SCSI equivalent. When FALSE, the HBA neither supports SCSI-tagged queuing nor per-logical-unit internal queues.

AcceleratedTransfer

Indicates when TRUE that the HBA supports synchronous transfers as a way of speeding up I/O. When FALSE, the HBA does not support synchronous transfers as a way of speeding up I/O.

BusType

Specifies a value of type STORAGE_BUS_TYPE that indicates the type of bus to which the device is connected.

BusMajorVersion

Specifies the major version number, if any, of the HBA.

BusMinorVersion

Specifies the minor version number, if any, of the HBA.

SrbType

Specifies the SCSI request block (SRB) type used by the HBA. This member is valid starting with Windows 8.

Value Meaning
SRB_TYPE_SCSI_REQUEST_BLOCK The HBA uses SCSI request blocks.
SRB_TYPE_STORAGE_REQUEST_BLOCK The HBA uses extended SCSI request blocks.

AddressType

Specifies the address type of the HBA. This member is valid starting with Windows 8.

Value Meaning
STORAGE_ADDRESS_TYPE_BTL8 The HBA uses 8-bit bus, target, and LUN addressing.

Remarks

Storage class drivers issue a device-control request with the I/O control code IOCTL_STORAGE_QUERY_PROPERTY to retrieve this structure, which contains configuration information from the HBA for data transfer operations. The structure can be retrieved either from the device object for the bus or from a functional device object (FDO), which forwards the request to the underlying bus.

If excessive protocol errors occur on an HBA that supports synchronous transfers (AcceleratedTransfer is TRUE), the storage class driver can disable synchronous transfers by setting SRB_FLAGS_DISABLE_SYNCH_TRANSFER in SRBs.

Requirements

Requirement Value
Header ntddstor.h (include Ntddstor.h)

See also

IOCTL_STORAGE_QUERY_PROPERTY

IoBuildDeviceIoControlRequest

STORAGE_ADAPTER_DESCRIPTOR

STORAGE_BUS_TYPE

STORAGE_DESCRIPTOR_HEADER

STORAGE_DEVICE_DESCRIPTOR

STORAGE_DEVICE_ID_DESCRIPTOR