map

n 1: a diagrammatic representation of the earth's surface (or

part of it)

2: a function such that for every element of one set there is a

unique element of another set [syn: {mapping}, {correspondence}]

v 1: make a map of; show or establish the features of details of:

"map the surface of Venus"

2: explore or survey for the purpose of making a map; "We

haven't even begun to map the many galaxies that we know

exist"

3: locate within a specific region of a chromosome in relation

to known DNA or gene sequences; "map the genes"

4: plan, delineate, or arrange in detail; ""map one's future"

[syn: {map out}]

5: depict as if on a map; "sorrow was mapped on the mother's

face"

6: to establish a mapping (of mathematical elements or sets)

[syn: {represent}]

mmap

The {Unix} {system call} which establishes a mapping between a

range of addresses in a user process's address space and a

portion of some "memory object" (typically a file, one of the

special "devices" /dev/mem or /dev/kmem or some

{memory-mapped} peripheral). This allows the process to

access a file at random byte offsets without using the seek

{system call} or to access physical addresses or {kernel}'s

{virtual address} space. It can also be used as an

alternative to writing a {device driver} since it is usually

simpler to code and faster to use.

(1995-02-14)