Messages in this thread |  | | | Date | Wed, 19 Jul 2000 17:26:50 -0500 | | From | Ron Flory <> | | Subject | Re: An important fact about real time computing |
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Jesse C Cronce wrote:
> I thought that the point of RT sched. was that in a soft real time > environment, given an expected amount of faults and a certain sys. > load you can expect a certain failure rate, and in a hard real time > environment given an expected number of faults and a sys. load you > can guarantee that if you add another task to the current set of tasks > it will (under most circumstances) succeed.
Although there are many different genre of 'realtime', the fundamental factor is deterministic behavior such that a running thread or process shall not be pre-empted except by an interrupt, or a higher priority thread/process being marked 'runnable' (generally by an ISR via semaphore/mutex release). This is vital to ensure a system can keep up with hardware and data flow that cannot be allowed to 'miss' a critical timing deadline.
Everything else just boils down to implementation differencess.
Fault tolerance is another issue entirely...
bye-
ron
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