What is BIOS? The Basic Input/Output System

The BIOS is an essential part of computer history. The term was first used back in the 1970s as part of the CP/M (Control Program for Mi­cro­com­puters) operating system developed by Gary Kildall. But the BIOS is still in use today. However, suc­ceed­ing tech­no­lo­gies are now in­creas­ingly used in modern computers.

What is the meaning of a BIOS? The term is an acronym for Basic Input/Output System which describes a firmware that is stored as non-volatile memory on a computer’s mother­board. In contrast to normal working storage, the ROM component on which the BIOS is installed, is not deleted after the PC is switched off and, therefore, remains available im­me­di­ately upon start-up. When the user switches on a x64/x86 PC, the BIOS is auto­mat­ic­ally loaded. In contrast to an operating system, it doesn’t require in­stall­a­tion, but is already included in the computer’s hardware.

The BIOS presents the core functions of the computer and assesses them after every single start-up. It de­term­ines whether important parts of the memory, the CPU, and other hardware com­pon­ents are op­er­a­tion­al. This is referred to as power-on self test (POST).

The BIOS solves a core problem in most computers. Every software initially has to boot the main memory in order to start-up. This process requires ad­di­tion­al software which tells the system where a specific program or component – for example, the operating system – is located. This is where the BIOS comes in to act as a signpost. At the same time, it functions as a trans­mit­ter between the CPU and software. The BIOS creates a level of ab­strac­tion, the so-called hardware ab­strac­tion layer (HAL), which leads to the software being able to respond to the hardware in a stand­ard­ised manner.

Over the last few decades, the functions of the BIOS have been con­tinu­ously expanded. Besides POST, it also plays an important role in the power man­age­ment of a computer because it generates the necessary ACPI (Advanced Con­fig­ur­a­tion and Power Interface) tables which control how much power each device receives.

In addition, it monitors the func­tion­al­it­ies of in-built hard drives as well as ex­tern­ally connected com­pon­ents such as external hard drives or UBS sticks. Users can also adjust the order in which storages devices are activated via the BIOS. This is useful if, for example, a new operating system is being loaded from a DVD or a USB storage device.

The BIOS provides users with an op­por­tun­ity to make broad changes to the con­fig­ur­a­tion of the hardware. But beware, making changes to the BIOS should only be done by ex­per­i­enced users. Its interface is not very user-friendly and any mistakes made could affect the entire operating system.

But there are some instances when it may become necessary to make changes to the BIOS. These include instances where an operating system can no longer be launched during start-up. In this case, a closer look at the BIOS may reveal errors in the system. Users who are trying to boost the per­form­ance of their computers beyond those con­figured by the man­u­fac­turer can access the BIOS to overclock the CPU, for example. Users can also adapt the settings to reduce energy usage of their systems.

Where a user wants to replace specific hardware com­pon­ents, as is the case when in­stalling a new processor, for example, sometimes the BIOS no longer re­cog­nises the new component and then fails to load the operating system. If that’s the case, you’ll need to update the BIOS. Follow our simple step-by-step guide to update the BIOS yourself.

At the core, the BIOS has been hardly modified since the 1980s and, therefore, fails to meet the demands of modern hardware. But its suc­cessors are already in place. The Ex­tens­ible Firmware Interface (EFI) was developed in the 1990s and the Unified Ex­tens­ible Firmware Interface (UEFI) followed in 2005. As of 2010, the UEFI has become a standard among 64-bit computers due to its improved functions and more com­fort­able usability compared to the BIOS.

The UEFI includes a graphic user interface which can be navigated using the computer mouse and keyboard. In this way, network com­pon­ents can be accessed without system start-up using the internet. One of the main dif­fer­ences to the BIOS is that UEFI relies on a secure boot­load­er which prevents the start-up of un­li­censed operating systems and sus­pi­cious software improving the systems’ cyber security pro­tec­tion.