Surely it depends on your real time needs, real time doesn't mean fast, or even necessarily regular, just that your processing need is serviced in a "timely" ma

Surely it depends on your real time needs, real time doesn't mean fast, or even necessarily regular, just that your processing need is serviced in a "timely" manner. If that meant I need something checked at least once every 5 minutes then statistically the chances of not being serviced must approach 1/infinity? In Functional Safety the concept is know as "Process Safety Time"and is the time the controller and associated sensors and equipment has to sense and act to avert an unwanted event. In practice for industrial plant this ranges from maybe 3 seconds to half an hour, though extremes outside this exist either side, but anything that involves a valve or a contactor does not get much faster. So what kind of "real time" are you talking about?