<P> BIOS (/ ˈbaɪɒs / BY - oss; an acronym for Basic Input / Output System and also known as the System BIOS, ROM BIOS or PC BIOS) is non-volatile firmware used to perform hardware initialization during the booting process (power - on startup), and to provide runtime services for operating systems and programs . The BIOS firmware comes pre-installed on a personal computer's system board, and it is the first software to run when powered on . The name originates from the Basic Input / Output System used in the CP / M operating system in 1975 . Originally proprietary to the IBM PC, the BIOS has been reverse engineered by companies looking to create compatible systems . The interface of that original system serves as a de facto standard . </P> <P> The BIOS in modern PCs initializes and tests the system hardware components, and loads a boot loader from a mass memory device which then initializes an operating system . In the era of MS - DOS, the BIOS provided a hardware abstraction layer for the keyboard, display, and other input / output (I / O) devices that standardized an interface to application programs and the operating system . More recent operating systems do not use the BIOS after loading, instead accessing the hardware components directly . </P> <P> Most BIOS implementations are specifically designed to work with a particular computer or motherboard model, by interfacing with various devices that make up the complementary system chipset . Originally, BIOS firmware was stored in a ROM chip on the PC motherboard . In modern computer systems, the BIOS contents are stored on flash memory so it can be rewritten without removing the chip from the motherboard . This allows easy, end - user updates to the BIOS firmware so new features can be added or bugs can be fixed, but it also creates a possibility for the computer to become infected with BIOS rootkits . Furthermore, a BIOS upgrade that fails can brick the motherboard permanently, unless the system includes some form of backup for this case . </P>

What do today's computers use to access the bios firmware interface