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:
“Our children evaluate themselves based on the opinions we have of them. When we use harsh words, biting comments, and a sarcastic tone of voice, we plant the seeds of self-doubt in their developing minds.... Children who receive a steady diet of these types of messages end up feeling powerless, inadequate, and unimportant. They start to believe that they are bad, and that they can never do enough.”
—Stephanie Martson (20th century)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didnt make a turning point of it, we were assigned to the humanities, to poetry, philosophy, paintingthe nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)
“A good memory is not as good as a ragged pen.”
—Chinese proverb.
“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 (18171862)