Re: An important fact about real time computing

From: Ron Flory (ron.flory@adtran.com)
Date: Wed Jul 19 2000 - 17:26:50 EST


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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Jul 23 2000 - 21:00:12 EST