Developing control applications in RT-Linux

Developing control applications in RT-Linux usually requires splitting the application into two parts. Both parts can be communicated using a special device called RT-fifos.

Tasks with hard real-time constraints: they are programmed and executed as RT-tasks at kernel level.

Tasks with soft or no real-time constraints: they are executed as "conventional" Linux user processes. Unlike RT-tasks, the graphical system and the networking support are available for these tasks, so those parts of an application that need these resources have to be executed as Linux processes.

The execution of RT-tasks is done using the Linux facility to dynamically load new kernel modules. RT-tasks are dynamic kernel modules. Even RT-Linux is a set of kernel modules (scheduler, fifos, ?) that need to be dynamically loaded.