"Audio playbacks are mechanisms which read data from a storage medium and produce commands and signals which an audio system turns into music. Playbacks are constantly changed to meet market demands, requiring that the control software be updated quickly and fficiently.

Playbacks execute typical commands known to all users of modern audio devices, such as: load, eject, play, stop/pause, scan, fast forward/reverse, seek up/down (track and/or folder), and options such as shuffle. The functionalities which are evoked in response to these commands are called behaviors. In event-driven radio applications it is possible to receive the request for execution of new behavior before the completion of the previous behavior. The priority and interaction of behaviors can be quite complex, and in many cases depends on specific customer requirements. Handling the execution sequence falls to a task “operation layer” which describes what is being commanded by the user or the OS. The behaviors themselves are collected in the task “functional layer”. Finally, a task “communication layer” handles two-way interface between the playback and the radio’s main board.

 http://delphi.com/pdf/techpapers/2007-01-0783.pdf

With regard to the above link....all I can tell you at this point ...e.Digitals method of switch interface through microcontroller to os and aooscated API are patented layers.

With regard to " The OS was and-written for this project, based loosely on the MicroOS™ (Digital Corporation) specifications."

I have no idea what that means or who "Digital Corporation" is...lol

 doni

 P.S. Tedstriker....I'd like to say I have an answer to your patent question a bit back....I have the file saved, however,  I've not had the time to go through it yet.