OS X and iOS Kernel Programming

Object Relationship

As we have seen, there are two important classes for an I/O Kit driver, one being the superclass that the main driver class inherits from and the other being the provider class that the driver uses to access its hardware. This design means that the functionality that the driver implements is separate from the way in which the driver's hardware device connects to the computer. For example, a driver that supports a PCI sound card and a driver that supports a USB audio output device will both inherit from the same IOAudioDevice superclass, and the operating system will interface to both drivers by making the same calls to each driver. After all, the operating system's audio subsystem shouldn't need to care how an audio output ...