Starting Multiple Schedulers

• the FRS controller has enqueued all the activity processes to their minor frames

• all the enqueued processes have done their own initial setup and have joined.

Each FRS controller tells its Frame Scheduler that it has enqueued all activities by calling frs_start(). Each activity process tells its Frame Scheduler that it is ready to begin real-time processing by calling frs_join().

A Frame Scheduler is ready when it has received one or more frs_enqueue() calls, an appropriate number of frs_join() calls, and an frs_start() call. Each synchronized Frame Scheduler tells the master Frame Scheduler when it is ready. When all the schedulers are ready, the master Frame Scheduler gives the downbeat, and the first minor frame begins.