What types of OS feature descriptors are supported by Windows?
Any information to be stored as a feature descriptor must comply with one of the standard formats that Microsoft has defined. Additional feature descriptors cannot be defined or implemented without Microsoft consent. Microsoft has defined the following feature descriptors. Extended Compat ID Windows uses class and subclass codes to help locate the appropriate default driver for a USB device. However, the USB Device Working Group must allocate these codes. This means that devices that implement new types of features often do not yet have appropriate class and subclass codes, so Windows cannot use the codes to select a default driver. IHVs can circumvent this problem by storing the information in firmware as an extended compat ID OS feature descriptor. Windows can then retrieve this information when the device is plugged in and use it to help determine which default driver to load. For details, see “Extended Compat ID OS Feature Descriptor Specification,” which is included in this packag
