Re: Why is Linux not RTOS?
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On 4/4/07, John Anthony Kazos Jr. <jakj@xxxxxxxxxxx> wrote:
> Why is Linux kernel considered a (hard) realtime OS? I already > understand the basic reason is that the linux kernel does not > guarantee that a task will be completed on time. But I would > appreciate answers in terms of more of kernel jargons. > > What stops us from classifying kernel as hard RTOS? Is it because at > times the kernel is non-preemptive (for e.g. while holding spinlocks)? > Has it got something to do with interrupt latency / scheduling latency > etc? > > Is the behaviour of the kernel (when it is preemptive) similar to hard > real time OS ?? From what I've read, the preemption in the kernel is mostly a hack because nobody's found a way to reduce the latency of certain long functions yet. And there is a separate RTOS version called Real-Time Linux or RTL...I think. Try googling. It's used in life-support machinery and so forth.
Yes, I'm aware that there are quite a lot of different patches / projects aimed at giving better RTOS behaviour ... but my question was aimed at vanilla kernel. Thanks, Rick - To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs