osdev-notes/Physical & Virtual Memory.md

Most processes are not permitted to directly access physical memory. Access is mediated transparently through the MMU (Memory Management Unit). Even the kernel's memory access is mediated through the MMU, so that it can account for all the allocated physical memory, and so that it doesn't overwrite its own address space.

Physical Memory

Physical memory on x86 is divided into "Page Frames". A Page Frame is a strictly physical concept.