In the future, the schedulers will also be loadable modules. Figure 1 illustrates real-time fifos. The example program will simply loop, reading data from the device, writing the data to an RT-fifo, and waiting for a fixed amount of time. All modules must contain an initialization routine. In this case, the argument is a fixed descriptor for a real-time fifo.
Periodic scheduling means the task is scheduled to run at certain intervals in time units.
The alternative is to make the task run only when an interrupt causes it to become active. This function is needed in any module. For a real-time task, we want to make sure a dead task is no longer scheduled. That's the end of the module. We also need a program which runs as an ordinary Linux process.