While most portions of an operating system are maintained and developed by individuals who specialize in a given operating system, device drivers are unique: They’re maintained by a much broader spectrum of developers. Some device driver authors have extensive experience with a particular operating system, while others have detailed knowledge of specific hardware components and are tasked with maintaining device drivers for those components across multiple systems. Too, device drivers are often somewhat self-contained, so that a developer can maintain a device driver while viewing other parts of the system as a black box.

Of course, that black box still has an interface, and each operating system provides its own set of interfaces to device ...