BIOS
BIOS stands for Basic Input Output System. BIOS is a hardware-bound core of an operating system. This ROM component is loaded immediately after the computer is started. BIOS has the task all to test the installed hardware components and to initialize them if necessary.
Each time the computer is started, the BIOS automatically carries out a self-test. Then use the calculator the BIOS to start the operating system and the flow of data between the hard disk, graphics card, mouse and keyboard and printers until the operating system does the job for him.