What does USB legacy support mean in BIOS?

Traditional USB support means enabling USB devices during power-on self-test. Usually, it is set to enable, and it is also enabled by default.

After this option is turned on, you can use the mouse in the DOS system (for example, you can only use the keyboard to move when restoring the system with GHSOT, and you can click with the mouse after starting this function), and you can also allow users to use the USB keyboard, mouse or hub connected to the USB port when the system is started or in the application or utility program of the operating system that does not support USB devices (such as Microsoft DOS). There is also an important function, which allows the USB keyboard to press DEL to directly enter the BIOS settings. If it is not turned on, the keyboard of USB interface will not run, and it will enter the interface of BIOS settings.

Extended data

The concept of BIOS

It is a set of programs solidified on a ROM chip on the computer motherboard, which stores the most important basic input and output programs of the computer, self-checking programs after startup and self-starting programs of the system. It can read and write specific information of system settings from CMOS. ? Its main function is to provide the lowest and most direct hardware setting and control for the computer. In addition, the BIOS also provides some system parameters to the operating system. The change of system hardware is hidden by BIOS, and the program uses BIOS function instead of directly controlling the hardware. Modern operating system ignores the abstraction layer provided by BIOS and directly controls hardware components.

References:

Baidu encyclopedia -BIOS