. Stands for Basic Input Output System.
    . It is program that computer's processor uses to get started as soon as we turn it on.
    . When we turn on computer, BIOS enables computer to perform certain operations.
    . It manages data flow between computer's OS and attached devices like mouse, keyboard etc.
    . Its primary job is to govern early stages of start-up process, ensuring OS is correctly loaded into memory.
     . Dual BIOS system has Main bios and Back up bios to ensure that if one bios is failed, board boots from the second one.

  POST - Power On Self Test:

     . Firstly, it checks computer's hardware in order to ensure that it is able to complete start-up process.


     . It attempts to load OS through bootstrap loader in to memory.


     . Bios play a role in computer security.
     . We have options to setup password to set up in bios settings.

  BIOS setting:

     . BIOS itself resides on ROM or flash memory chip attached to computer motherboard.
     . When we restart computer, it shows option to BIOS setting by pressing F2 key.