How do Real Time Operating Systems work?

Question

I mean how and why are realtime OSes able to meet deadlines without ever missing them? Or is this just a myth (that they do not miss deadlines)? How are they different from any

Answer 1

They actually don't guarantee meeting deadlines; what they do that makes them truly RTOS is to provide the means to recognize and deal with deadline overruns. 'Hard' RT systems generally are those where missing a deadline is disastrous and some kind of shutdown is required, whereas a 'soft' RT system is one where continuing with degraded functionality makes sense. Either way an RTOS permits you to define responses to such overruns. Non RT OS's don't even detect overruns.