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Microkernel: Difference between revisions
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The memory manager *may* be implemented in userspace - doesn't have to be.
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(The memory manager *may* be implemented in userspace - doesn't have to be.) |
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== Design ==
[[Image:Microkernel.png|frame|right|Basic overview of a microkernel]]
A Microkernel tries to run most services - like networking, filesystem, etc. - as daemons / servers in user space. All that's left to do for the kernel are basic services, like physical memory allocation (
In theory, this concept makes the kernel more responsive (since much functionality resides in preemptible user-space threads and processes, removing the need for context-switching into the kernel proper), and improves the stability of the kernel by reducing the amount of code running in kernel space. There are also additional benefits for OS' that support multi-CPU computers (much simpler re-entrancy protection and better suitability for asynchronious functionality) and distributed OS' (code can use services without knowing if the service provider is running on the same computer or not). A drawback is the amount of messaging and Context Switching involved, which makes microkernels conceptually slower than monolithic kernels. (This isn't to say that a smartly designed microkernel could not beat a foolishly designed monolithic one.)
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