BIOS, short form for Basic Input/Output System is the very first piece of software run by computers when they are powered on. The BIOS firmware allows your computer to get started and communicate with the operating system and attached devices like hard disk, video adapter, keyboard, mouse, USB and printer.
Unlike the operating system which can be pre-installed by the manufacturer or the user, BIOS is an integral part of the computer and all computers ship with the BIOS located in a chip on their motherboards.
The Main Functions of BIOS
When you turn on the computer, BIOS performs a check on the computer’s hardware and attachments to make sure they are all in place and operational. It then loads the relevant portions of the operating system into the computer’s random access memory.
BIOS stores the exact details of a computer’s hardware components and devices, freeing the operating system from the task of understanding hardware and connected devices. When device details change, only the BIOS program needs to be updated, no need for the software to change or adapt to the revised devices.
BIOS is Getting Replaced By UEFI
Originally, BIOS was stored in a ROM chip on the PC motherboard which required the chip to be removed in order to update the firmware. Later on modern computer systems started using flash memory to store BIOS. This made it easy to push updates and fix bugs without removing the chip from the motherboard, but this also made the BIOS vulnerable to rootkit attacks by viruses.
As of 2014, newer computers are mostly using Unified Extensible Firmware Interface (UEFI) which address the technical shortcomings of BIOS