Segmentation
Segmentation is a memory management technique in which each job is divided into several segments of different sizes, one for each module that contains pieces that perform related functions. Each segment is actually a different logical address space of the program.
When a process is to be executed, its corresponding segmentation are loaded into non-contiguous memory though every segment is loaded into a contiguous block of available memory.
Segmentation memory management works very similar to paging but here segments are of variable-length where as in paging pages are of fixed size.
A program segment contains the program's main function, utility functions, data structures, and so on. The operating system maintains a segment map tablefor every process and a list of free memory blocks along with segment numbers, their size and corresponding memory locations in main memory. For each segment, the table stores the starting address of the segment and the length of the segment. A reference to a memory location includes a value that identifies a segment and an offset.
