They load dynamically into memory as needed The audio, MCI, and joystick extensions might use special hardware to enhance basic Windows functionality. Audio device drivers might support audio hardware that adds improved fidelity or MIDI capabilities. MCI devices drivers might support hardware to control auditorium lighting or control the hardware in an audiovisual presentation. Joystick device drivers might support new hardware such as an airplane control wheel for a flight simulator.
Audio devices (waveform and MIDI), joysticks, and MCI devices are Windows installable device drivers. These device drivers have the following characteristics:
They load dynamically into memory as needed
They use a standard set of entry points to handle messages
They handle unrecognized messages with default processing