BIOS
BIOS (Basic Input Output System) Bios or the basic input output system is a set of programs stored inside a PROM chip and put on the motherboard. The main job of the program stored into this ROM is, as its name suggests is to provide the computer user the set of standard routines, to take care of input/output from the front input, output and the storage devices connected to the computer. This BIOS ROM is always available in the computer. So any user program can access these routines for their input/output requirements. The first PC BIOS was made by IBM for their PC range of computers. A PC system can be described as a series of layers-some hardware and some software-that interface with each other. Figure shows the four layers in a typical PC. The purpose of the layered design is to enable a given operating system and applications to run on different hardware. Fig shows how two different machines with different hardware can each use different sets of drivers (BIOS) to interf