Physical Address Space

Physical Address Space

Physical addresses are used to select RAM, ROM, device registers, and bus attachments. Physical addresses start at 0 and can (in some systems) go as high as 240. This range includes 1.1e12 unique numbers, or 1,024 gigabytes (GB), or 1 terabyte (TB).

Software never uses physical addresses directly. Kernel-level software can access physical memory and devices using indirect addressing discussed later.

Device Addresses
Memory Addresses