Segmentation

Segmentation

An important aspect of memory management that became unavoidable with paging is the separation of the user's view of memory and the actual physical memory.
The user's view of memory is not the same as the actual physical memory. The user's view is mapped onto physical memory.
This mapping allows differentiation between logical memory and physical memory.

http://siber.cankaya.edu.tr/ozdogan/OperatingSystems/ceng328/node188.html