BIOS stands for basic input/output system, which consists of low-level software that controls the sys- tem hardware and acts as an interface between the operating system and the hardware.

The BIOS itself is software running in memory that consists of all the various drivers that interface the hardware to the operating system. The BIOS is unique compared to normal software in that some of it is preloaded into read-only memory (or ROM), and some is loaded into RAM from disk.