> Well, this is VERY offtopic, but i wonder:
> Is Linux a real-time os just like Qnx?
Linux is not a realtime OS and has no claims of being one. Arguably a full
QNX system is not fully realtime either (it has a filesystem, which is a
hard thing to deal with in realtime).
RT-Linux is a realtime kernel that runs regular Linux as a low-priority
process.
Linux has so-called "soft realtime" scheduling classes, that allow you to
mark a process to be run before normal timeshare processes, but there are
no guarantees on scheduling latencies.
IMO, the whole realtime thing is drastically overblown. There are not many
things that need to be realtime that can't be adequately accomplished
inside a normal operating system's driver framework, assuming it has a low
enough interrupt latency. Unfortunately, the concept of realtime and the
distinction between it and normal systems is subtle and is poorly
understood by people who haven't done OS work, so it often ends up as a
system requirement where it isn't really needed.
-- "Love the dolphins," she advised him. "Write by W.A.S.T.E.."
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