Types of Memory Addresses
There are several 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.
A computer program uses memory addresses to execute machine code, store and retrieve data. Most application programs do not have a knowledge about physical addresses. Rather, they address logical addresses, or virtual addresses, using computer's memory management unit and operating system memory mapping; see below.
Read more about this topic: Memory Address
Famous quotes containing the words types of, types, memory and/or addresses:
“Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
—Talcott Parsons (1902–1979)
“... there are two types of happiness and I have chosen that of the murderers. For I am happy. There was a time when I thought I had reached the limit of distress. Beyond that limit, there is a sterile and magnificent happiness.”
—Albert Camus (1913–1960)
““I have done it,” says my memory. “I cannot have done it,” says my pride, refusing to budge. In the end—my memory yields.”
—Friedrich Nietzsche (1844–1900)
“The fable, which is naturally and truly composed, so as to satisfy the imagination, ere it addresses the understanding, beautiful though strange as a wild-flower, is to the wise man an apothegm, and admits of his most generous interpretation.”
—Henry David Thoreau (1817–1862)