Some categories of UEFI drivers do not require the use of these data structures. If a UEFI driver only produces a single protocol, or it manages, at most, one device, the techniques presented here are not required. An initializing driver does not produce any services and does not manage any devices, so it does not use this technique. A service driver that produces a single protocol and does not manage any devices does not likely use this technique. A root bridge driver that manages a single root bridge device does not likely use this technique, but a root bridge driver that manages more than one root bridge device may use this technique.