- On the 80386 processor, there is a trick for mapping the page tables into memory: You set a slot in the top-level page directory to point to… the page directory itself. When you follow through this page directory entry, you end up back at the page directory, and the effect is that the process of mapping a linear address to a physical page ends one stop early. You end up pointing not at the destination page, but at the page table that points at the destination page. From the point of view of the address space, it looks like all of the page tables have been mapped into memory. This makes it easier to edit page directory entries because you can do it within the address space.
Anyone who is among the living has hope —even a live dog is better off than a dead lion!
Ecclesiastes 9:4 NIV