Fixed-priority pre-emptive scheduling

Fixed priority pre-emptive scheduling is commonly used in real-time systems. With fixed priority pre-emptive scheduling, the scheduler ensures that at any given time, the processor executes the highest priority task of all those tasks that are currently ready to execute.

The pre-emptive scheduler has a clock interrupt task that can provide the scheduler with options to switch after the task has had a given period --- the time slice. This scheduler system has the advantage of making sure no task hogs the processor for any time longer than the time slice. Most RTOS’s have pre-emptive schedulers. Also turning off Time Slicing effectively gives you the non- pre-emptive RTOS.