How can I modify windbg is using ring0 on single pc?

if you are ruuning XP, latest windbg allows local kernel debugging.

Select Local tab in Kernel Debugging Dialog.

Hope it helps

Visu

well it is still stactic all you can do with local kernel debugging is watch
read and write to user and kernel memory that is all
no dynamic commands like t,p,g , no break points bp etc are avl
in xp too that means it is of practically not much usefull

well if that is what you would like to then livekd does that for you in w2k too
and even older versions of windbg is sufficient

Thats right. However, I am just wondering, why livekd can offer debugging with one PC and Microsoft can't. Since livekd internally uses Microsoft kd or windbg, I am sure there has to be some (hidden??) interface for live debugging or probing. Anyone knows how livekd works?

Visu

read some microsoft.public.kernel or microsoft.public.windbg

livekd instalss a driver and fools the os to think it as a crashdump file
and fakes some context structures and redirects the ioctl to read the kernel memory

and the ms guys picked it upon that idea and implemented it in xp
as Local Kernel Debugging so it is a reversers contribution in some twisted
context

but in xp they dont fake context structures and such because they had the complete source code for thier os as well as russinovichs app