Memory address

In computing, memory address is a data concept used at various levels by software and hardware to access the computer's primary storage memory. Memory addresses are fixed-length sequences of digits conventionally displayed and manipulated as unsigned integers. Such numerical semantic bases itself upon features of CPU (such as the instruction pointer and incremental address registers), as well upon use of the memory like an array endorsed by various programming languages.

Types of memory addresses

There are many types of memory addresses. In other words, a computer, and even one program may have several different memory address spaces.

A digital computer's memory, more specifically main memory, consists of many memory locations, each having a physical address, a code, which the CPU (or other device) can use to access it. Generally only system software, i.e. the BIOS, operating systems, and some specialized utility programs (e.g., memory testers), address physical memory using machine code operands or processor registers, instructing the CPU to direct a hardware device, called the memory controller, to use the memory bus or system bus, or separate control, address and data busses, to execute the program's commands. The memory controllers' bus consists of a number of parallel lines, each represented by a binary digit (bit). The width of the bus, and thus the number of addressable storage units, and the number of bits in each unit, varies among computers.