On 02/11/11 8:39 AM, m.roth at 5-cent.us wrote: > They have*everything* to do. Look, I*said* this is OT, but since you > insist, the overwhelmingly*bad* design decision was to put the GUI into > ring 0, instead of the way Windows 3, and X on*Nix, and *everybody* else > did, resulting in a GUI error bringing down the*entire* system. the "GUI" is a fairly nebulous term. The graphics display driver is indeed at ring zero for performance (in fact in early versions of NT, it ran in ring 1 or 2, but the performance hit of the ring transitions to access IO ports on early graphics cards was overwhelming so in NT4 it was moved to ring0). However, the GDI, User (window manager), desktop, and about everything else are in ring3 user space.