Editing Memory segmentation (section)

===Segmentation without paging===
Associated with each segment is information that indicates where the segment is located in memory&mdash; the ''segment base''. When a program references a memory location, the offset is added to the segment base to generate a physical memory address.

An implementation of virtual memory on a system using segmentation without paging requires that entire segments be swapped back and forth between main memory and secondary storage. When a segment is swapped in, the operating system has to allocate enough contiguous free memory to hold the entire segment. Often [[fragmentation (computing)|memory fragmentation]] results if there is not enough contiguous memory even though there may be enough in total.