The Amiga system devices are software engines that provide access to the
Amiga hardware.   Through these devices, a programmer can operate a modem,
spin a disk drive motor, time an event, and blast a trumpet sound in
stereo.  Yet, for all that variety, the programmer uses each device in the
same manner.

 What is a Device?     Using A Device            Using An Exec Device 
 Accessing a Device    Devices With Functions    Function Reference