Software & Apps Windows 569 569 people found this article helpful What Is BIOS (Basic Input Output System)? Everything you need to know about BIOS by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on February 26, 2020 reviewed by Michael Barton Heine Jr Lifewire Tech Review Board Member Michael Heine is a CompTIA-certified writer, editor, and Network Engineer with 25+ years' experience working in the television, defense, ISP, telecommunications, and education industries. our review board Article reviewed on Apr 15, 2020 Michael Barton Heine Jr Windows The Ultimate Laptop Buying Guide Tweet Share Email BIOS, which stands for Basic Input Output System, is software stored on a small memory chip on the motherboard. It's BIOS that's responsible for the POST and therefore makes it the very first software to run when a computer is started. The BIOS firmware is non-volatile, meaning that its settings are saved and recoverable even after power has been removed from the device. BIOS is pronounced as by-oss and is sometimes referred to as the System BIOS, ROM BIOS, or PC BIOS. However, it's also incorrectly referred to as the Basic Integrated Operating System or Built-In Operating System. What Is the BIOS Used For? Lifewire BIOS instructs the computer on how to perform basic functions such as booting and keyboard control. BIOS is also used to identify and configure the hardware in a computer such as the hard drive, floppy drive, optical drive, CPU, memory, and related equipment. How to Access BIOS The BIOS is accessed and configured through the BIOS Setup Utility. The BIOS Setup Utility is, for all practical purposes, the BIOS itself. All available options in BIOS are configurable through the BIOS Setup Utility. Unlike an operating system like Windows, which is often downloaded or obtained on a disc and needs to be installed by the user or manufacturer, BIOS comes installed from the moment the machine is manufactured. The BIOS Setup Utility is accessed in various ways depending on your computer or motherboard make and model. Here Are 3 Easy Steps to Access BIOS BIOS Availability All modern computer motherboards contain BIOS software. BIOS access and configuration on PC systems are independent of any operating system because the BIOS is part of the motherboard hardware. It doesn't matter if a computer is running Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, Linux, Unix, or no operating system at all—BIOS functions outside of the operating system environment and is no way dependent upon it. Popular BIOS Manufacturers The following are some of the more popular BIOS vendors: Phoenix TechnologiesIBMDellGatewayBYOSOFTAmerican Megatrends (AMI)Insyde Software Award Software, General Software, and Microid Research were BIOS manufacturers acquired by Phoenix Technologies. How to Use BIOS BIOS supports several hardware configuration options that can be changed through the setup utility. Saving these changes and restarting the computer applies the changes to the BIOS and alters the way BIOS instructs the hardware to function. Here are some common things you can do in most BIOS systems: Change the Boot OrderLoad BIOS Setup DefaultsFlash (Update) BIOSRemove a BIOS PasswordCreate a BIOS PasswordChange the Date and TimeChange Floppy Drive SettingsChange Hard Drive SettingsChange CD/DVD/BD Drive SettingsView Amount of Memory InstalledChange the Boot Up NumLock StatusEnable or Disable the Computer LogoEnable or Disable the Quick Power On Self Test (POST)Enable or Disable the CPU Internal CacheEnable or Disable the Caching of BIOSChange CPU SettingsChange Memory SettingsChange System VoltagesEnable or Disable RAIDEnable or Disable Onboard USBEnable or Disable Onboard IEEE1394Enable or Disable Onboard AudioEnable or Disable Onboard Floppy ControllerEnable or Disable Onboard Serial/Parallel PortsEnable or Disable ACPIChange the ACPI Suspend TypeChange the Power Button FunctionChange Power-on SettingsChange Which Display is Initialized First on Multi-Display SetupsReset Extended System Configuration Data (ESCD)Enable or Disable BIOS Control of System ResourcesChange Fan Speed SettingsView CPU and System TemperaturesView Fan SpeedsView System Voltages How to Access CPU and Memory Timing Settings in the BIOS More Information on BIOS Before updating BIOS, check what version is currently running on your computer. When configuring updates, verify that you've downloaded the right file for your motherboard and that the computer not be shut down part way through or the update canceled abruptly. Interruptions could brick the motherboard and render the computer unusable, making it difficult to regain functionality. One way to avoid this problem is to use what's called a "boot lock" section of the BIOS software which gets updated on its own apart from the rest so that if corruption ensues, a recovery process prevents damage. BIOS might check if the full update has been applied by verifying that the checksum matches up with the intended value. If it doesn't, and the motherboard supports DualBIOS, that BIOS backup can be restored to overwrite the corrupted version. The BIOS in some of the first IBM computers were not interactive like modern-day implementations but instead only served to display error messages or beeps codes. Any custom options were instead made by modifying physical switches and jumpers. It wasn't until the 1990s that the BIOS Setup Utility (also known as the BIOS Configuration Utility, or BCU) became common practice. However, nowadays, BIOS has slowly been being replaced by UEFI (Unified Extensible Firmware Interface) in newer computers, which offers benefits like a better user interface and a built-in, pre-OS platform for accessing the web.