Re: Why is Linux not RTOS?
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Hi, Why is Linux kernel considered a (hard) realtime OS? I already
Linux kernel is never considered a real time OS.A real time OS should be predictable.The general linux kernel is not predictable because of many reasons. A few are it uses virtual memory. when there is virtual memory there will be page swaps which are un predictable.
And the linux scheduler is not a deterministic one.There is a scheduler project which provides a deternistic behaviour to the scheduler.This scheduler is called O(1) scheduler. This gives a constant scheduling latency. This is used in many embedded linux to make it a real time OS. Ex: motavista
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
An RTOS is just a facilitator to build Real time systems. A Real time system developer should analyse a RTOS wether is will be useful for his system. If some body is holding spin lock and making it non-preemptive its a bad design. So even a RTOS linux has spin locks. Its the designer who should take care.
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 ?? 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.htmlPlease read the FAQ at http://www.linux-learn.org/faqs
- 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