BIOS is integrated to the motherboard on a non-volatile memory chip.
A computer is made up of components -- the video card, memory, sound card, hard drive and so on. You'll no doubt have noticed that your monitor and other components are activated before the operating system (such as Windows) has booted up. If Windows is not activating these devices, what is? It's the BIOS, which stands for Basic Input/Output System, and is pronounced bye-oss, not bee-oss. It is a software program stored in the hardware of your computer.
Function
The primary role of the BIOS is to boot up the operating system. When it receives the request to turn on, it checks for custom settings, loads the basic device drivers, performs the POST (Power-On Self Test; a quick check to see if components are working), locates boot-able media, then loads the operating system in line with how it has been configured to do so. Usually, you can see status reports from the BIOS on-screen as the computer boots up.
Location
The BIOS is stored in a flash memory chip, somewhere on your computer's motherboard. Flash memory is of the ROM (read-only memory) type, which is different from the normal memory (RAM -- random access memory) in that it is not wiped when the computer is turned off. If you are able to access your computer's internal components, you will be able to see where the BIOS is -- it may be clearly labeled with something like "AMIBIOS."
Configuration
During the BIOS start-up sequence, you will be given a way to enter its configuration menu. This is usually displayed with a message like "Press F2 to enter setup." The key is usually "F1," "F2," "Del," or "Esc." Once inside, you'll see a basic menu allowing you to change the BIOS configuration. Only make changes if you know what you are doing. A common use of this is to choose which device the BIOS boots from first -- for example, you might give priority to a USB slot or the DVD drive over the hard drive.
BIOS Vs. EFI
Although BIOS is in widespread use, even in new machines, it is beginning to be supplanted by EFI (Extensible Firmware Interface). BIOS was primarily used in older 16-bit and 32-bit machines, plus some 64-bit machines, while EFI, despite not being commonplace as yet, is replacing BIOS on some 32-bit and 64-bit machines. EFI is generally superior, allowing quicker boot times and configuration options.
Tags: operating system, your computer, 64-bit machines, hard drive, memory chip