Supervisor Mode

What Does Supervisor Mode Mean?

Supervisor mode is a mode of execution in a device in which all instructions, including privileged ones, can be performed by the processor. It is thus capable of executing both input/output operations and privileged operations. The operating system of a computer usually operates in this mode. Supervisor mode helps in preventing applications from corrupting the data of the operating system.

Techopedia Explains Supervisor Mode

Supervisor mode mostly deals with interpreting different commands and is capable of executing privileged instructions. It has full access to all components of a system and is mostly reserved for the operating system (OS) since OS routines run in supervisor mode. Supervisor mode is the automatic mode selected when a computer is powered on. It allows the initial programs executed in the computer, mainly the bootloader, BIOS and OS, to have unlimited access to the hardware. It is also the mode selected by the OS kernel for low-level tasks that require unrestricted hardware access.

Supervisor mode may provide access to different peripherals, to memory management hardware or to different memory address spaces. It provides the much-needed protective barrier between applications. It is also capable of interrupt enabling, disabling, returning and loading of processor status. Supervisor mode can also change and create memory address spaces and also access the memory address spaces of other operations. It also has the ability to access the different data structures inside the OS.