Please help

[Sheap]

As far as what runs in what ring, it isn't really that big a deal. First, most modern CPUs have only 2 rings, so if your OS is intended either for platform independence or targeted at a 2-ring CPU, you don't have a choice. This is pretty much everybody except Windows. Secondly, one of the reasons many CPU designs have only 2 rings, is because having extra rings isn't really all that useful. As evidence you can look at free Unix type systems, and note their great stability, yet they all run in 2 rings only. What should they be doing that they aren't, and how much real-world improvement would it give?