Editing Protected mode (section)

=== Privilege levels ===
{{details|Ring (computer security)}}
[[File:Priv rings.svg|thumb|right|300px|Example of privilege ring usage in an operating system using all rings]]

In protected mode, there are four privilege levels or [[ring (computer security)|ring]]s, numbered from 0 to 3, with ring 0 being the most privileged and 3 being the least. The use of rings allows for system software to restrict tasks from accessing data, [[call gate]]s or executing privileged instructions.<ref name="Rings">{{ cite book | title = Intel 64 and IA-32 Architectures Software Developer's Manual Volume 1: Basic Architecture | publisher = [[Intel]] | at = Section 6.3.5 Calls to Other Privilege Levels |date=May 2019 | url = https://software.intel.com/en-us/download/intel-64-and-ia-32-architectures-software-developers-manual-volume-1-basic-architecture }}</ref> In most environments, the operating system and some [[device driver]]s run in ring 0 and applications run in ring 3.<ref name="Rings"/>