BIOS

1. 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 below, is an example of what a BIOS chip may look like on your computer motherboard. In this example, this is a picture of an early AMIBIOS, a type of BIOS manufactured 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.

The four main functions of a PC BIOS

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