US Patent 7610589 Using helper drivers to build a stack of device objects

A method, used while building in processor memory a stack of device objects (DOs) representing a device, there being a multi-role driver for a plurality of roles at least one of which corresponds to the device, may include: registering a plurality of helper drivers so as to uniquely correspond to the plurality of roles, respectively, each helper driver mapping uniquely to one of the multiple roles of the multi-role driver, respectively; and indirectly specifying a corresponding one of the multiple roles of the multi-role driver by specifying the helper driver mapped thereto. A related apparatus and machine-readable medium bearing machine-readable instructions may include features similar to elements of the method.