Introduction
BIOS stands for Basic Input / Output System. The BIOS, or ROM BIOS, is software that is burned into a ROM chip on the motherboard. It serves two basic functions:
The POST, or Power On Self Test, is run as soon as you start your computer. The POST checks all major components of the computer hardware to ensure they are functioning correctly. If any of the tested components fail the POST, the computer will either display an error message or emit an audible error code made up of a series of beeps. If all tests pass, the computer emits one single beep.
The BIOS also contains the basic startup programs and drivers needed for the operating system to communicate with the major hardware components upon initial startup.
CMOS and BIOS are often interchanged terms although they are different things. Think of the BIOS as the skeleton frame upon which the CMOS settings hang.
Manufacturers
There are two primary BIOS manufacturers today:
- AMI
- Phoenix
Award Software, maker of the Award BIOS products, merged with Phoenix Technologies in 1998. Information regarding Award products can be found at the Phoenix web site.
A Word of Caution
Note that the BIOS can be upgraded in most computers by a process called flashing the ROM, or flashing the BIOS. You should not attempt to upgrade your BIOS unless you really know what you are doing. If you make a mistake, you can permanently disable your computer! For more information, see our article on ROM.