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Qualifiers Specific to the WDM Provider

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The following qualifiers are used by the WDM Provider in device driver MOF files when they are extracting data from WNODEs to generate instances of WDM driver classes.

MissingValue

Data type: DWORD, array, uint8, uint16, uint32, sint8, sint16, or sint32.

Applies to: properties

A missing value for this property should be represented by NULL rather than 0 (zero).

WMIDataId

Data type: uint32

Applies to: properties

Index in the WNODE of the data for the property. The WDM provider uses this qualifier to determine how the data is formatted while extracting data from the WNODE and generating WMI classes. The starting value is 1.

WMIExpense

Data type: uint32

Applies to: classes

Indication of the resource cost to access the data block. For example, disk geometry information does not require a lot of resources to obtain because it is available in the device extension. Disk read/write performance is more resource-intensive because it requires extra work on each read/write operation. Therefore, the WMIExpense qualifier value is larger for disk read/write performance.

WMIMethodId

Data type: uint32

Applies to: methods

Index in the WNODE of the data for the property. The WDM provider uses this qualifier to determine how the data is formatted while extracting data from the WNODE and generating WMI classes. The starting value is 1.

Requirements

Requirement Value
Minimum supported client
 Windows Vista
Minimum supported server
 Windows Server 2008