Editing Memory protection (section)

=== Segmentation ===
{{main|Memory segmentation}}
[[Memory segmentation|Segmentation]] refers to dividing a computer's memory into segments.  A reference to a memory location includes a value that identifies a segment and an offset within that segment. A segment descriptor may limit access rights, e.g., read only, only from certain [[protection ring|rings]].

The [[x86]] architecture has multiple segmentation features, which are helpful for using protected memory on this architecture.<ref name="intel_3a_p1">{{cite book 
|     author = Intel
|      title = Intel 64 and IA-32 Architectures Software Developer's Manuals: Volume 3A: System Programming Guide, Part 1
|  publisher = Intel
|       date = July 2008
|        url = https://www.intel.com/design/processor/manuals/253668.pdf
| access-date = 2008-08-21
}}</ref> On the x86 architecture, the [[Global Descriptor Table]] and [[Local Descriptor Table]]s can be used to reference segments in the computer's memory. Pointers to memory segments on x86 processors can also be stored in the processor's segment registers. Initially x86 processors had 4 segment registers, CS (code segment), SS (stack segment), DS (data segment) and ES (extra segment); later another two segment registers were added &ndash; FS and GS.<ref name="intel_3a_p1"/>