Le 14/09/2010 16:21, Jeff Angielski a écrit :
On 09/14/2010 05:44 AM, Robert Schwebel wrote:
On Tue, Sep 14, 2010 at 11:24:21AM +0200, Raz wrote:
anyone can say preempt rt is hard real time?
Hard realtime has something to do with how you define "missing the
deadline". If somebody cuts the cable of your roboter controller in the
factory hall, the system misses the deadline. So it is all about
probabilities: hard realtime systems have a very, very low probability
of missing the deadline. However, in real life systems, it is> 0%.
So yes, if you talk about real world, it is hard realtime.
No. Preempt rt it's not hard realtime.
Hi Jeff,
I agree with you.
Saying just realtime makes confusion because people often think hard
realtime in this case. They can also have surprises with they use a soft
realtime OS in this case.
But most people/companies who think they need hard realtime really
don't. They can live with soft realtime and have a really low
probability of missing deadlines and having long latencies. For these
people, the preempt rt is adequate.
Yes. The reflexion to have is: I need realtime. Does my process to
control need hard realtime requirements or just soft realtime is enough?
Can my process to control support to miss some events sometime or not?
Patrice
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