What is BIOS?
BIOS (Basic Input Output System) is the firmware on x86 PCs. The acronym coincides with an ancient Greek word written “bios” in the Latin alphabet, meaning “life”. This is not a coincidence; it indicates that the BIOS is bringing the computer to life.
BIOS starts the hardware components after the computer is switched on, i.e. when the system is started. The process is called power-on-self-test (POST). It creates ACPI tables with which the operating system later controls the energy management of the hardware. The BIOS also has the configuration and hardware information. The BIOS determines the time parameters of the memory modules, as well as the clock frequency and operating voltage of the main processor. The BIOS then starts the operating system and then no longer plays a role.
Starting the operating system is called booting. During the boot process, the hardware is configured using the settings in the BIOS. The parameters (addresses, IRQ, slot, etc.) are completely or partially taken over by the operating system and managed independently.