What is bios routine?

The BiOS (Basic Input/Output System) routine is a firmware interface that initializes and tests hardware components during the boot process of a computer. It performs a Power-On Self Test (POST) to check the system's hardware integrity and then loads the operating system from a storage device. The BiOS also provides a set of low-level routines for managing hardware interactions, enabling communication between the operating system and the computer's hardware. It is essential for system startup and configuration.