The Basic Input Output System (BIOS) is a non-volatile program burned into read-only memory (ROM). It is available as soon as the computer is powered on. It contains instructions for interfacing to the hardware peripherals as well as instructions for loading the operating system. The BIOS provides a low-level interface to hardware peripherals. The UEFI (Unified Extensible Firmware Interface) is a newer open source replacement for the BIOS. When the computer is powered on, all of its intelligence is in the BIOS or the UEFI. As part of the boot process, the operating system is loaded into RAM (random access memory) and executed by the BIOS or UEFI.