http://valinet6l6tq6d5yohaa6gdsf2ho4qcqcxyj2nahp5kd4z7nsa6ycdqd.onion/2024/07/23/Proper-and-easy-RAM-reservation-for-embedded-devices-running-Linux.html
Or such designs forgo Linux entirely and run a single binary bare metal, especially when running real time is a goal. Anyway, the point is, the “coordinating” app is mostly the single process running for the entire lifetime of the system.