What exactly is BIOS?
The abbreviation BIOS means “Basic Input/Output System”. It is the firmware of a PC – A software which is built integrated into the hardware. The BIOS is stored on a small chip in the mainboard of the computer and is always preinstalled. There are motherboards, which also have a second chip, that acts as backup. The BIOS is the link between the software (OS) and hardware components such as hard drives, keyboard, mouse and printer. The navigation in BIOS is only possible with a keyboard.
And what is this UEFI?
The new version of BIOS is called UEFI, which means unified extensible firmware interface. UEFI looks like an operating system, can be controlled by mouse and is capable of executing programs.
What is BIOS responsible for?
The main tasks of the BIOS are a self-test and the initialization of the hardware as well as the communication between the operating system and other components. When a computer is turned on, the BIOS starts and prepares the PC for booting. First it performs the power-on self-test (POST). The computer checks one by one whether the basic hardware components such as CPU and RAM are working properly. If errors are found, the BIOS displays them by specific sounds or on screen, if the graphics have already been tested successfully.
Following this self-test, the booting process starts. For this, the hardware must know from which component it should boot the operating system. The BIOS searches the operating system in the available devices (hard drives, USB, DVD) following a specific order. As soon as it finds software, the PC is booting automatically. The order of the drives, on which to search for the operating system, can be set in the BIOS. For instance if you want to delete the existing OS and install a new one via DVD, it is necessary to set “CDROM” as first boot device. Other tasks of the BIOS are managing date and time as well as the temperature monitoring of the processor and the mainboard.
How do I get into the BIOS?
To enter the BIOS, a certain key must be pressed (multiple times!) right after turning on the PC and even before the operating system is booted. It depends on the manufacturer which key: usually - and also at all spo-books – the BIOS is accessed by pressing the key "F2" or "Del".