What is BIOS?

• A BIOS (Basic Input/Output System) is an electronic set of instructions that a computer uses to successfully start operating. 
• The BIOS is located on a chip inside of the computer and is designed in a way that protects it from disk failure.
• A main function of the BIOS is to give instructions for the power-on self test (POST).
• This self test ensures that the computer has all of the necessary parts and functionality needed to successfully start itself, such as use of memory, a keyboard and other parts. 
• If errors are detected during the test, the BIOS instructs the computer to give a code that reveals the problem. 
• Error codes are typically a series of beeps heard shortly after startup.
• The BIOS also works to give the computer basic information about how to interact with some critical components, such as drives and memory, that it will need to load the operating system. Once the basic instructions have been loaded and the self-test has been passed, the computer can proceed with loading the operating system from one of the attached drives.