Memory Models
Many programmers prefer to address memory such that there is no distinction between code space and data space (cf. above), as well as from physical and virtual memory (see below) — in other words, numerically identical pointers refer to exactly the same byte of RAM.
However, many early computers did not support such a flat memory model — in particular, Harvard architecture machines force program storage to be completely separate from data storage. Many modern DSPs (such as the Motorola 56000) have 3 separate storage areas — program storage, coefficient storage, and data storage. Some commonly-used instructions fetch from all three areas simultaneously — fewer storage areas (even if there were the same total bytes of storage) would make those instructions run slower.
Read more about this topic: Memory Address
Famous quotes containing the words memory and/or models:
“Within the memory of many of my townsmen the road near which my house stands resounded with the laugh and gossip of inhabitants, and the woods which border it were notched and dotted here and there with their little gardens and dwellings, though it was then much more shut in by the forest than now.”
—Henry David Thoreau (1817–1862)
“The greatest and truest models for all orators ... is Demosthenes. One who has not studied deeply and constantly all the great speeches of the great Athenian, is not prepared to speak in public. Only as the constant companion of Demosthenes, Burke, Fox, Canning and Webster, can we hope to become orators.”
—Woodrow Wilson (1856–1924)