System creates illusion of large contiguous memory space(s) for each process.
Relevant portions of VM are loaded automatically and transparently.
Address map translates virtual addresses to physical addresses.

Single-Segment Virtual Memory :

one area of 0..n-1 words

divided into fix-size pages

Multiple-Segment Virtual Memory :

multiple areas of up to 0..n-1 (words)

each holds a logical segment (function, data structure)

each is contiguous or divided into pages