Each class object includes a list of class_device descriptors, each of which represents a single logical device belonging to the class. The class_device structure includes a dev field that points to a device descriptor, thus a logical device always refers to a given device in the device driver model. However, there can be several class_device descriptors that refer to the same device. In fact, a hardware device might include several different sub-devices, each of which requires a different User Mode interface.
