segmentatietabel

A segmentatietabel, or segmentation table, is a data structure used in computer systems, particularly in memory management, to track how a computer's memory is divided into segments. Each segment is a logical block of memory that can have a different size and protection attributes. The segmentation table stores information about each segment, including its starting address in physical memory and its length.

When a program tries to access a memory location, the system first looks up the corresponding segment in the segmentation table. It uses the segment number provided by the program to find the relevant entry in the table. From this entry, it retrieves the physical base address of the segment and its length. The system then calculates the actual physical address by adding the offset within the segment to the base address. If the calculated physical address falls outside the bounds of the segment (i.e., it is greater than the segment's length), a segmentation fault or error occurs, preventing unauthorized access or corruption of memory.

Segmentation tables allow for flexible memory allocation. Different segments can represent different logical parts of a program, such as code, data, or stack. This logical segmentation makes it easier for programmers to manage memory and for the operating system to enforce protection mechanisms, ensuring that one program cannot interfere with the memory of another. Some systems use a combination of segmentation and paging, known as paged segmentation, to further enhance memory management capabilities.