[$] Moving physical pages from user space

Processes in a Linux system run within their own virtual address spaces.Their virtual addresses map to physical pages provided by the hardware, butthe kernel takes pains to hide the physical addresses of those pages;processes normally have no way of knowing (and no need to know) where theirmemory is located in physical memory. As a result, the system calls formemory management also deal in virtual addresses. Gregory Price iscurrently trying to create an exception to this rule with aproposal for a new system call that would operate on memory using physicaladdresses.