WHAT IS A BIOS?

BIOS(Basic Input Output System)


1.Basic Input Output System (BIOS) is the first program which runs when we power on 

our personal computer. This is a small  program normally stored in a non-volatile 

memory(like ROM).

2.In earlier days BIOS softwares are loaded from a disk. But now a days ROM are 

already integrated to mother board and BIOS program are loaded to ROM .

3.This is a program which test all the peripherals and necessary condition so that 

OS can be loaded,this is known as power-on self-test.
Power-on self-test
The BIOS software is built into the PC, and is the first code run by a PC 

when powered on ('boot firmware'). When the PC starts up, the first job for 

the BIOS is the power-on self-test, which initializes and identifies system devices 

such as the CPU, RAM, video display card, keyboard and mouse, hard disk drive, 

optical disc drive and other hardware.

 
The BIOS then locates boot loader software(bootstrap) held on a peripheral device 

(designated as a 'boot device'), such as a hard disk or a CD/DVD, and loads 

and executes that software, giving it control of the PC 

LINKS

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1.MORE ON BIOS