Apparatus and method for processing events in a digital versatile disc (dvd) system using system threads and separate dormant/awake counter threads and clock driven semaphores

Abstract

A multi-threaded digital versatile disc system which is controlled by a system thread includes an independent counter thread for controlling the counter parameters. Only the counter thread (and not the system thread) increments and decrements the counter parameters based on an input from the system clock. Counter parameters can be attached, or associated, with the counter thread and all associated counter parameters are incremented together by the thread. The counter thread has a semaphore and a queue associated with it and the counter thread remains dormant until woken up by the semaphore. The semaphore queue receives periodic messages from the system clock via a conventional operating system mechanism and periodically increments and decrements its associated counter parameters. Other threads, originating from this system or from another system, can also communicate with the counter thread by means of the queue by directing an event message to the operating system which places the message in the queue.