DEVICE_COPY_OFFLOAD_DESCRIPTOR structure (winioctl.h)

The DEVICE_COPY_OFFLOAD_DESCRIPTOR structure is one of the query result structures returned from an IOCTL_STORAGE_QUERY_PROPERTY request. This structure contains the copy offload capabilities for a storage device.

Syntax

typedef struct _DEVICE_COPY_OFFLOAD_DESCRIPTOR {
  DWORD     Version;
  DWORD     Size;
  DWORD     MaximumTokenLifetime;
  DWORD     DefaultTokenLifetime;
  DWORDLONG MaximumTransferSize;
  DWORDLONG OptimalTransferCount;
  DWORD     MaximumDataDescriptors;
  DWORD     MaximumTransferLengthPerDescriptor;
  DWORD     OptimalTransferLengthPerDescriptor;
  WORD      OptimalTransferLengthGranularity;
  BYTE      Reserved[2];
} DEVICE_COPY_OFFLOAD_DESCRIPTOR, *PDEVICE_COPY_OFFLOAD_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.

MaximumTokenLifetime

The maximum lifetime of the token, in seconds.

DefaultTokenLifetime

The default lifetime of the token, in seconds.

MaximumTransferSize

The maximum transfer size, in bytes.

OptimalTransferCount

The optimal transfer size, in bytes.

MaximumDataDescriptors

The maximum number of data descriptors.

MaximumTransferLengthPerDescriptor

The maximum transfer length, in blocks, per descriptor.

OptimalTransferLengthPerDescriptor

The optimal transfer length per descriptor.

OptimalTransferLengthGranularity

The granularity of the optimal transfer length, in blocks. Transfer lengths that are not an even multiple of this length may be delayed.

Reserved

Reserved.

Remarks

This structure is returned from a IOCTL_STORAGE_QUERY_PROPERTY request when the PropertyId member of STORAGE_PROPERTY_QUERY is set to StorageDeviceCopyOffloadProperty.

Requirements

   
Minimum supported client Windows 8 [desktop apps only]
Minimum supported server Windows Server 2012 [desktop apps only]
Header winioctl.h (include Windows.h)

See also

Disk Management Structures

IOCTL_STORAGE_QUERY_PROPERTY

STORAGE_PROPERTY_QUERY