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How does Linux kernel detect and plug in your hardware?

Nov 18, 2011, 10:00 (1 Talkback[s])


Re-Imagining Linux Platforms to Meet the Needs of Cloud Service Providers

"Everything starts with at the Kernel. Operating systems are using Privilege Rings.

These rings are created by CPU and not by OS. Any OS kernel operates in Ring 0 which is most privileged level and can comunicate directly to the hardware and the CPU. Rings 1 and 2 are commonly used for device drivers. And ring 3 is used for user-space applications (media players, web servers and anything else user can communicate to directly). Device drivers are a „bridge" between user-space applications and hardware. You should note that in Linux rings 1 and 2 are NOT used (at least this is what I found out…), because Linux drivers are compilled directly into kernel or as a dynamic kernel modules (in both cases drivers appear in at a Ring 0).

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