I know that the first instruction stored in BIOS is "mapped" to memory address 0, and that a signal on the reset pin to the microprocessor causes this instruction to be fetched, beginning the POST and all the chain-loading involved in the boot process.
I also know that there is a Memory-Management Unit (MMU?) at the hardware level. Is it in charge of doing this redirect (away from DRAM to the BIOS firmware) so that the processor can interact with the memory of the computer in a blissfully naive way? If so, what other areas (in addition to BIOS) does the MMU map into the total address space?
I know that for modern operating systems with a GUI, the displays are "bitmapped". Does the MMU map a portion of the video RAM on the video card into the global address space as well?
What about virtual memory and paging? Does the hardware MMU have any intrinsic capabilities that facilitate the virtual memory feature provided by the OS?
I may be way off.