Jeff,i’ve been learning about the NT kernel which Microsoft uses for almost all its OS’s and found out that the kernel was originally designed for a two-ring system (the kernel ring and the application ring) thus the other two rings were practically left idle.I would like to know if this two-ring system is still being used i.e with Vista.If so ,how will the other two rings when implemented improve system performance (thinking of a well structured preemptive kernel).Please fill me in. 