A basic input/output system (BIOS) is an electronic set of instructions that a personal computer (PC) uses to successfully boot. It is located on a chip on a computer’s motherboard and is designed to be protected against disk failure. While it can be updated, this must be done carefully to avoid damaging your computer or preventing it from booting. Certain computer manufacturers, such as Apple™, use other systems such as Open Firmware.
A screenshot of a BIOS setup screen.
The function of the BIOS
One of the main functions of the BIOS is to provide instructions for the Power-On Self Test (POST). This self-test ensures that the computer has all the parts and functionality it needs to start up successfully, such as using memory, keyboard, and other components. If errors are detected during the test, the computer provides code that reveals the problem. Error codes are typically presented as a series of beeps heard shortly after startup.
A computer motherboard.
The BIOS also works to provide the computer with basic information on how to interact with some critical components, such as hard drives and memory, needed to load the operating system (OS). After the basic instructions have loaded and the self-test has passed, the computer can proceed with loading the operating system from one of the connected drives. The functions and control of the hardware within the computer are then transferred to the OS, which later controls the system.
A CMOS chip, which contains the information the BIOS needs to start.
How is it stored on a computer
Traditional BIOS firmware is included on the computer’s motherboard as read-only memory (ROM). This means that the system is accessible, but not dynamically recorded in the same way as a computer’s hard drive during operation. A battery on the motherboard keeps the data on it intact, even when the computer is turned off while not in use. Although it is sometimes confused with a Complementary Metal Oxide Semiconductor (CMOS), the BIOS refers to the firmware on the motherboard, while the CMOS is the physical location where the date and system configuration data is stored.
A BIOS chip allows a computer to correctly boot the boot process.
Many PC manufacturers today use flash memory to maintain this system, which allows users to more easily upgrade it on computers. This can resolve issues with the original BIOS or add new functionality to it. Users can periodically check for new versions, as some vendors release multiple updates over the life of a product. To find an update, users should check the motherboard manufacturer. These updates should be done with care, as incorrect versions or corrupted software can make your computer impossible to start.
Configuring and controlling the BIOS
PC users can make certain system adjustments through a configuration screen on the computer. The setup screen is normally accessed with a special key sequence during the first few moments of boot, usually “Delete” or a function key. This configuration screen allows users to change the order in which the drives are accessed during startup, monitor the temperatures of computer components, and control the functionality of various devices. Most computer users never need access to these systems on their computer, although many fixes for simple errors may require tweaking.
Updating a BIOS chip requires professional-level knowledge to prevent damage to the machine.