Re:CPU Clocks and Clock Interrupts, and Their Effects on Sch...
by zepearl on Tuesday February 12, 2019 @09:02PM
(#19149698)
Thx but well, this kind of goes frontally against the other 2 answers I got (I understood that nothing ever gets explicitly terminated by the OS and I felt happy with that approach as it kind of made sense to me, but some now strong doubts are coming back again...).
Re:CPU Clocks and Clock Interrupts, and Their Effects on Sch...
by gizmo686 on Tuesday February 12, 2019 @09:52PM
(#19149945)
Realtime doesn't mean error free. A realtime OS might provide some form of a watchdog feature where it can detect when a program fails to meet its deadline. Think of it like a segfault in a traditional system. If everyone did their job correctly, it would never come up, but people make mistakes and it is better to detect them and fail in a controlled manner than it is not notice and fail in unpredictable ways.
Re:CPU Clocks and Clock Interrupts, and Their Effects on Sch...
by marcosdumay on Wednesday February 13, 2019 @06:05AM
(#19152138)
Oh, I've read them now. There are some answers about something we used to call "soft real time". Those OSes (Linux was one, for a while, it's not anymore) will have some processes marked as real time, and change the scheduling so that they will execute right at the correct moments. The gotcha is that there can not be many real time processes, since the OS has no way to resolve a conflict between them.
What I described is called "hard real time". It is indeed a very different thing. Both kinds of OSes are in current use, on different niches.
The OSes also take into their hands to enforce that the tasks will finish at the time they asked for. What means that they either terminate by themselves, or the OS will terminate them, again with some explicit error.