[cluda01]

I believe a more formal definition of realtime is: When missing a deadline constitutes a system failure. Given this definition realtime systems are not bucketed in such a way that they invite a false dichotomy. For instance on one end of the spectrum you would have hard realtime systems (e.g. a pacemakers) where missing a deadline means death of the patient or serious financial loss. On the other end of the spectrum you would have soft realtime systems (e.g. facebook) where missing a deadline of say displaying a web page in under a second would constitute a system failure (revenue/engagement decrease), but still be valuable (people will put up with slow page loads, look at reddit).