WIA Driver Components
The WIA minidriver can be viewed as two logical layers:
The WIA service interface layer
The device communication layer
The following diagram illustrates the logical breakdown of a WIA minidriver and its components.
WIA Minidriver Interfaces
A WIA minidriver is a COM object that implements the IUnknown COM interface and two WIA-specific COM interfaces: IStiUSD and IWiaMiniDrv. The WIA minidriver interface layer implements these interfaces and is the entry point into the WIA minidriver. Applications do not call the WIA minidriver interfaces directly; only the WIA service calls into these interfaces.
The device communication layer is responsible for low-level interactions with the still image device through a kernel-mode bus driver. All interactions with the device are sent through this layer. This layer is responsible for packaging data to be sent to the device into a format that the physical device can understand, and for unpackaging data received from the device into a format that the driver understands.
This sections provides additional information about the WIA minidriver and its components in the following areas: