What is BIOS?
- Basic Input Output System is a non volatile firmware used to perform hardware initialization during the booting process.
- It is pre-installed on a flash memory fixed to the system's mother board.
What does a BIOS do?
- The BIOS includes instructions on how to load basic computer hardware and includes a test referred to as a POST (Power On Self Test) that helps verify the computer meets requirements to boot up properly.
- If the computer does not pass the POST, we will receive a combination of beeps indicating what is malfunctioning within the computer.
Functions of BIOS
POST ( Power On Self Test ) :
Tests all the computer hardware like keyboard, RAM, disk drivers and other hardware components.
Setup :
Enables to configure hardware settings including system settings like date and time of the system.
BIOS drivers :
Collection of actual drivers which acts as basic interface between the OS and the hardware.
Bootstrap Loader :
To load the OS from hard disk into the computer's main memory ( RAM ).
What is ROM shadowing?
The BIOS is copied from ROM to RAM each time the computer is booted because the RAM is faster than ROM. This is called shadowing.