AIFFWriter is a sample sound output device component; that is, it is a sound component that takes input data from the Apple Mixer component and sends output data to a sound output device. This sample code is useful if you want to support a new sound output device, since it shows how to manage the link between the Apple Mixer component and your custom sound-producing hardware.
Note, however, that AIFFWriter doesn't actually communicate with a real hardware device; instead, it writes its output data into a file (you can consider the file to be a "virtual" sound output device). The source code is written, however, so that you can easily replace the file-writing code by code that sends the data to buffers on your custom sound-producing device. In AIFFWriter, hardware interrupts from your device are simulated using interrupts generated by the Time Manager. Look in the file AIFFHardware.c for the routines you need to modify to support an actual hardware device.
For complete information on sound output device components, see the chapter "Sound Components" in the book Inside Macintosh: Sound.
