MSFT_Disk class

Article
01/09/2023

Represents a Windows disk.

A MSFT_Disk object models the Windows operating system's concept of a disk device. The disk may be directly attached to the computer system, or it may be a virtual disk exposed to the system through the use of a Storage Management Provider.

The following syntax is simplified from Managed Object Format (MOF) code.

Syntax

class MSFT_Disk : MSFT_StorageObject
{
  String  Path;
  String  Location;
  String  FriendlyName;
  String  UniqueId;
  UInt16  UniqueIdFormat;
  UInt32  Number;
  String  SerialNumber;
  String  FirmwareVersion;
  String  Manufacturer;
  String  Model;
  UInt64  Size;
  UInt64  AllocatedSize;
  UInt32  LogicalSectorSize;
  UInt32  PhysicalSectorSize;
  UInt64  LargestFreeExtent;
  UInt32  NumberOfPartitions;
  UInt16  ProvisioningType;
  UInt16  OperationalStatus;
  UInt16  HealthStatus;
  UInt16  BusType;
  UInt16  PartitionStyle;
  UInt32  Signature;
  String  Guid;
  Boolean IsOffline;
  UInt16  OfflineReason;
  Boolean IsReadOnly;
  Boolean IsSystem;
  Boolean IsClustered;
  Boolean IsBoot;
  Boolean BootFromDisk;
};

Members

The MSFT_Disk class has these types of members:

Methods
Properties

Methods

The MSFT_Disk class has these methods.

Method	Description
Clear	Removes partition information and uninitializes a disk, returning it to a RAW state.
ConvertStyle	Converts the partition style of an already initialized disk.
CreatePartition	Creates a partition on a disk.
Initialize	Initializes a RAW disk with a particular partition style.
Offline	Takes the disk offline.
Online	Brings the disk online.
Refresh	Refreshes the cached disk layout information.
SetAttributes	Sets the disk's attributes and properties.

Properties

The MSFT_Disk class has these properties.

AllocatedSize

Data type: UInt64

Access type: Read-only

Qualifiers: Required, Units (Bytes)

The amount of space, in bytes, that is currently used on the disk.

BootFromDisk

Data type: Boolean

Access type: Read-only

TRUE if the computer is configured to start from this disk. On computers with BIOS firmware, this is the first disk that the firmware detects during startup. On computers that use EFI firmware, this is the disk that contains the EFI System Partition (ESP). If there are no disks, or if there are multiple disks with an ESP partition, this property is not set for any disk.

BusType

Data type: UInt16

Access type: Read-only

The I/O bus type used by the disk.

Value	Meaning
Unknown 0	The bus type is unknown.
SCSI 1	SCSI
ATAPI 2	ATAPI
ATA 3	ATA
1394 4	IEEE 1394
SSA 5	SSA
Fibre Channel 6	Fibre Channel
USB 7	USB
RAID 8	RAID
iSCSI 9	iSCSI
SAS 10	Serial Attached SCSI (SAS)
SATA 11	Serial ATA (SATA)
SD 12	Secure Digital (SD)
MMC 13	Multimedia Card (MMC)
Virtual 14	This value is reserved for system use.
File Backed Virtual 15	File-Backed Virtual
Storage Spaces 16	Storage spaces
NVMe 17	NVMe

FirmwareVersion

Data type: String

Access type: Read-only

A string representation of the disk's firmware version.

FriendlyName

Data type: String

Access type: Read-only

Qualifiers: Required

A user-friendly, display-oriented string to identify the disk.

Guid

Data type: String

Access type: Read-only

If the PartitionStyle is GPT, this property contains the GUID for the disk. This property will be NULL for all other disk types.

HealthStatus

Data type: UInt16

Access type: Read-only

The health status of the disk device.

Value	Meaning
Healthy 0	The disk is functioning normally.
Warning 1	The disk is still functioning, but has detected errors or issues that require administrator intervention.
Unhealthy 2	The volume is not functioning, due to errors or failures. The volume needs immediate attention from an administrator.

IsBoot

Data type: Boolean

Access type: Read-only

TRUE if the disk contains the boot partition.

IsClustered

Data type: Boolean

Access type: Read-only

TRUE if the disk is used in a clustered environment, or FALSE otherwise.

IsOffline

Data type: Boolean

Access type: Read-only

TRUE if the disk is offline, or FALSE otherwise.

IsReadOnly

Data type: Boolean

Access type: Read-only

TRUE if the disk is read-only, or FALSE if it is read/write.

IsSystem

Data type: Boolean

Access type: Read-only

TRUE if this disk contains the system partition, or FALSE otherwise.

LargestFreeExtent

Data type: UInt64

Access type: Read-only

Qualifiers: Units (Bytes)

The largest contiguous block of free space on the disk. This is also the largest size of a partition that can be created on the disk.

Location

Data type: String

Access type: Read-only

A string that contains the PnP location path of the disk. The format of this string depends on the bus type. If the bus type is SCSI, SAS, or PCI RAID, the format is AdapterPnpLocationPath#BusType(PPathIdTTargetIdLLunId). If the bus type is IDE, ATA, PATA, or SATA, the format is AdapterPnpLocationPath#BusType(CPathIdTTargetIdLLunId). See the following Remarks section for a table that lists the parts of this string.

Note

For Hyper-V and VHD images, this property is NULL, because the virtual controller does not return the location path.

For more information about this property, see the following Remarks section.

LogicalSectorSize

Data type: UInt32

Access type: Read-only

Qualifiers: Units (Bytes)

The logical sector size of the disk, in bytes. For example, a 4K native disk will report 4096, while a 512 emulated disk will report 512.

Manufacturer

Data type: String

Access type: Read-only

A string representation of the disk's hardware manufacturer.

Model

Data type: String

Access type: Read-only

A string representation of the disk's model number.

Number

Data type: UInt32

Access type: Read-only

The operating system's number for the disk. Disk 0 is typically the boot device. Disk numbers may not necessarily remain the same across restarts.

NumberOfPartitions

Data type: UInt32

Access type: Read-only

The number of partitions that have been created on the disk.

OfflineReason

Data type: UInt16

Access type: Read-only

If IsOffline is TRUE, this property contains the reason for the disk being offline.

One of the following values.

Value	Meaning
Policy 1	The user requested the disk to be offline.
Redundant Path 2	The disk is used for multi-path I/O.
Snapshot 3	The disk is a snapshot disk.
Collision 4	There was a signature or identifier collision with another disk.
Resource Exhaustion 5	There were insufficient resources to bring the disk online.
Critical Write Failures 6	There were critical write failures on the disk.
Data Integrity Scan Required 7	A data integrity scan is required.

OperationalStatus

Data type: UInt16

Access type: Read-only

The operational status of the disk device.

Value	Meaning
Unknown 0	The operational status is unknown.
Other 1	A vendor-specific OperationalStatus has been specified by setting the OtherOperationalStatusDescription property.
OK 2	The disk is responding to commands and is in a normal operating state.
Degraded 3	The disk is responding to commands, but is not running in an optimal operating state.
Stressed 4	The disk is functioning, but needs attention. For example, the disk might be overloaded or overheated.
Predictive Failure 5	The disk is functioning, but a failure is likely to occur in the near future.
Error 6	An error has occurred.
Non-Recoverable Error 7	A non-recoverable error has occurred.
Starting 8	The disk is in the process of starting.
Stopping 9	The disk is in the process of stopping.
Stopped 10	The disk was stopped or shut down in a clean and orderly fashion.
In Service 11	The disk is being configured, maintained, cleaned, or otherwise administered.
No Contact 12	The storage provider has knowledge of the disk, but has never been able to establish communication with it.
Lost Communication 13	The storage provider has knowledge of the disk and has contacted it successfully in the past, but the disk is currently unreachable.
Aborted 14	Similar to Stopped, except that the disk stopped abruptly and may require configuration or maintenance.
Dormant 15	The disk is reachable, but it is inactive.
Supporting Entity in Error 16	This status value does not necessarily indicate trouble with the disk, but it does indicate that another device or connection that the disk depends on may need attention.
Completed 17	The disk has completed an operation. This status value should be combined with OK, Error, or Degraded, depending on the outcome of the operation.
Online 0xD010	In Windows-based storage subsystems, this indicates that the object is online.
Not Ready 0xD011	In Windows-based storage subsystems, this indicates that the object is not ready.
No Media 0xD012	In Windows-based storage subsystems, this indicates that the object has no media present.
Offline 0xD013	In Windows-based storage subsystems, this indicates that the object is offline.
Failed 0xD014	In Windows-based storage subsystems, this indicates that the object is in a failed state.

PartitionStyle

Data type: UInt16

Access type: Read-only

Qualifiers: Required

The partition style used by the disk.

Value	Meaning
Unknown 0	The partition style is unknown.
MBR 1	Master Boot Record (MBR)
GPT 2	GUID Partition Table (GPT)

Path

Data type: String

Access type: Read-only

Qualifiers: Required

A path that can be used to open an operating system handle to the disk device.

PhysicalSectorSize

Data type: UInt32

Access type: Read-only

Qualifiers: Units (Bytes)

The physical sector size of the disk, in bytes. For example, both 4K native disks and 512 emulated disks will report 4096.

ProvisioningType

Data type: UInt16

Access type: Read-only

The provisioning type of the disk device.

Value	Meaning
Unknown 0	The provisioning scheme is unspecified.
Thin 1	The storage for the disk is allocated on-demand.
Fixed 2	The storage is allocated when the disk is created.

SerialNumber

Data type: String

Access type: Read-only

A string representation of the disk's serial number.

Signature

Data type: UInt32

Access type: Read-only

If the PartitionStyle is MBR, this property contains the MBR partition signature. This property will be NULL for all other disk types.

Size

Data type: UInt64

Access type: Read-only

Qualifiers: Required, Units (Bytes)

Total size of the disk, in bytes.

UniqueId

Data type: String

Access type: Read-only

The disk identifier. This contains the VPD Page 0x83 information that uniquely identifies this disk. The following types are accepted (in order of precedence):

8 (SCSI Name String)
3 (FCPH Name)
2 (EUI64)
1 (Vendor Id)
0 (Vendor Specific)

If the disk is an exposed virtual disk, the UniqueId is used to map the association between the two objects.

UniqueIdFormat

Data type: UInt16

Access type: Read-only

Qualifiers: Values ( "Vendor Specific", "Vendor Id", "EUI64", "FCPH Name", "SCSI Name String" ), ValueMap ("0", "1", "2", "3", "8")

The format of the disk identifier. This property contains the VPD Page 0x83 descriptor type that was used to set the UniqueId property.

Remarks

The following table lists the parts of the location path string used in the Location property.

Location path part	Description
AdapterPnpLocationPath	The adapter's PnP location path. This is retrieved by calling the SetupDiGetDeviceProperty function, passing &DEVPKEY_Device_LocationPaths for the PropertyKey parameter.
BusType	The bus type: ATA, RAID, SAS, or SCSI. Note: If the bus type is IDE, PATA, or SATA, it appears as ATA in the location path string. If it is PCI RAID, it appears as RAID.
PathId	The number of the bus. This is the value of the PathId member of the SCSI_ADDRESS structure that is returned by the IOCTL_SCSI_GET_ADDRESS control code.
TargetId	The number of the target device. This is the value of the TargetId member of the SCSI_ADDRESS structure that is returned by the IOCTL_SCSI_GET_ADDRESS control code.
LunId	The number of the LUN. This is the value of the Lun member of the SCSI_ADDRESS structure that is returned by the IOCTL_SCSI_GET_ADDRESS control code.

The following table contains examples of location paths.

Bus type	Example location path
ATA	PCIROOT(0)#PCI(0100)#ATA(C01T03L00)
RAID	PCIROOT(0)#PCI(0200)#PCI(0003)#PCI(0100)#RAID(P02T00L00)
SAS	PCIROOT(1)#PCI(0300)#SAS(P00T03L00)
SCSI	PCIROOT(0)#PCI(1C00)#PCI(0000)#SCSI(P00T01L01)

Starting in Windows 10: MSFT_Disk derives from MSFT_StorageObject. It now inherits the property ObjectId, which was formerly a property of MSFT_Disk.

Requirements

Requirement	Value
Minimum supported client	Windows 8 [desktop apps only]
Minimum supported server	Windows Server 2012 [desktop apps only]
Namespace	Root\Microsoft\Windows\Storage
MOF	Storagewmi.mof

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MSFT_Disk class

Syntax

Members

Methods

Properties

Remarks

Requirements

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