In computing, BIOS is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process. The BIOS firmware comes pre-installed on an IBM PC or IBM PC compatible's system board and exists in some UEFI-based systems to maintain compatibility with operating systems that do not support UEFI native operation. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS originally proprietary to the IBM PC has been reverse engineered by some companies looking to create compatible systems. The interface of that original system serves as a de facto standard.

Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices such as a monitor, mouse, keyboard, and speakers.