What Is BIOS?

Written by Coursera Staff • Updated on

Every time your computer boots up, it relies on BIOS to ensure everything is working properly. Learn more about this firmware and what you can do with BIOS.

[Featured image] A person in a gray hoodie sits at their desk and launches BIOS on their desktop computer.

Basic input/output system (BIOS) is a type of firmware that usually comes installed on a computer and provides it with instructions to boot up when turned on. Firmware is a form of software or a program embedded in hardware, and in the case of BIOS, it's a memory chip embedded in your motherboard. 

When you turn on your computer, BIOS runs a set of diagnostic tests to make sure everything works properly. The initial test is the power on self-test (POST), and if the computer fails, the system will not boot correctly. This tests peripheral devices like disk drives, video cards, the keyboard, and the mouse, to see if they work properly. After POST, the bootstrap loader searches the computer for a functioning operating system (OS), like Windows, and if it finds one, it turns control of the hardware over to the OS. 

BIOS has two other functions: BIOS drivers and BIOS setup. The drivers give your computer control over its hardware, while setup allows you to make configurations to the computer's hardware, like adjusting the time or changing system settings.  

What are some things you can do with BIOS?  

BIOS setup allows you to make changes to your computer's hardware. Some of the things you can do with it include: 

  • Changing the boot order

  • Changing system voltages 

  • Changing the date and time on your computer

  • Changing your CPU settings

  • Enabling or disabling POST

  • Changing the power button function

  • Enabling or disabling onboard audio

  • Enabling or disabling your computer's logo

  • Changing your memory settings and viewing the amount of memory you have installed

  • Changing the settings on your DVD/CD drive 

  • Creating or removing a BIOS password 

To access BIOS, power on your computer. As it comes on, you'll see a message that says "Press F1 to enter BIOS setup" or something similar, depending on the computer you have. You may see a different message, but it will usually ask you to press a certain key to enter BIOS. Once you see the message, press the suggested key as quickly as possible.  

Can you upgrade or change your BIOS? 

Whether you can upgrade your current BIOS chip will depend on your specific device. If you are unable to upgrade but want more memory, you can replace it with a more advanced option. However, if you have a flash BIOS chip, you can update it. Flash BIOS allows you to boot your computer with a special disk or unique set of instructions, and it's not usually found on older hardware.  

Get started in IT support 

Ready to start or continue an exciting career in IT? Consider earning Google's IT Support Professional Certificate on Coursera. The certificate takes about six months to earn, and you do not need a degree or experience to start. Learn about BIOS and other IT skills, how to provide customer support, how to perform day-to-day IT tasks, and much more. 

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