BIOS

Short for Basic Input/Output System, the BIOS, ROM BIOS, or System BIOS is a chip located on all motherboards that contain instructions and setup for how your system should boot and how it operates. In the picture to the right, is an example of what a BIOS chip may look like on your computer motherboard. In this example, this is a picture of an AMIBIOS, a type of BIOS manufacturered by the AMI another good example of a BIOS manufacturer is Phoenix.
The BIOS includes instructions on how to load basic computer hardware and includes a test referred to as a POST (Power On Self Test) that helps verify the computer meets requirements to boot up properly. If the computer does not pass the POST, you will receive a combination of beeps indicating what is malfunctioning within the computer.
In most PCs, the BIOS has 4 main functions as mentioned below.

1. POST - Test the computer hardware and make no errors exist before loading the operating system. Additional information on the POST can be found on our POST and Beep Codes page.
2. Bootstrap Loader - Locate the operating system. If a capable operating system is located, the BIOS will pass control to it.
3. BIOS drivers - Low level drivers that give the computer basic operational control over your computer's hardware.
4. BIOS or CMOS Setup - Configuration program that allows you to configure hardware settings including system settings such as computer passwords, time, and date.