What is BIOS?


BIOS ( Basic Input Output System ) is an essential set of programs stored on a chip on the motherboard of a computer

   It acts an intermediary between computer hardware and its operating system without it , the PCs operating system cannot communicate with or take control of the hardware.

Difference between BIOS and UEFI


1.Windows blue screen

2.No animation

3.Can’t recognize Ethernet, WI-FI and Bluetooth

4.No remote diagnosis and repair support

5.No mouse support, keyboard only

6.No secure booting option

7.Firmware program in 16-bit assembly language

8.Supports 2.2 terabytes


1.User friendly graphical user interface

2.Multi colored with animations

3.Support Ethernet, WI-FI and Bluetooth connectivity

4.Support remote diagnosis and repair if the OS won’t boot

5.Keyboard and mouse support

6.Secure boot facility to stops loading malicious software

7.Firmware program in 64-bit c language

8.Supports drive sizes up to 9 zettabytes

Let see how works

4 main function of BIOS

  • Power on self-test (POST)
  • Bootstrap loader
  • Setup utility program
  • BIOS drivers

Functions of BIOS

Power on self-test:

Conducts power on self-test (post) a built- in diagnostic program that checks whether the computer has all of the necessary parts and functioning properly, such as memory and keyboard.

Bootstrap loader:

helps in loading the operating system

The program searches for any available operating system and if found, it loads the operating system into RAM of the computer.

Setup utility program:

A non-volatile memory (NVRAM) is used to store information about the computer system. During installation of a system, the user runs BIOS setup program and enters the correct parameters the setting of memory, disk types and other setting are stored in NVRAM.

BIOS driver:

It is collection of programs stored in one or more EPROM (Erasable programmable read-only me memory) or EEPROM (electrically Erasable programmable read only memory) chips, depending on the computer design, on the motherboard.

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