What is BIOS on a PC: Definition and Characteristics

What is BIOS How Does it Works
What is BIOS How Does it Works

We all know that PCs have a BIOS, that famous blue screen with yellow letters that is used to configure some PC parameters, but do you know what it is exactly? In this article we are going to tell you what the BIOS is, what its definition is, its characteristics and what its functions are exactly.

BIOS is a “concept” that is frequently referred to in the computer world, and although almost everyone has a vague concept of what it is and what it is for, few are those who know it exactly. So, below we are going to explain everything so that you can fully understand the concept.

What is BIOS?

BIOS stands for “Basic Input Output System“, which means something like “Basic input and output system.” It is a firmware installed in a ROM (non-volatile) memory of the computer, often on a dedicated chip. It is a fundamental element in starting a PC because it is the bridge between the hardware and the software of the system: essentially, it is what explains to the software how the hardware should work.

BIOS chip

Note: BIOS is pronounced as is in Spanish, but it is pronounced “by-os” in English. It should not be confused with other acronyms such as “Basic Integrated Operating System” or “Built-in Operating System”.

What is the BIOS for on a PC?

The BIOS takes care of very low-level functions on the PC, such as the boot sequence (what storage device is the operating system on and how to boot from it) or how to operate the keyboard.

bios interface

It also serves to identify and configure hardware components such as hard drives, external storage devices, the processor or RAM, and it is in fact from the BIOS where we can modify, for example, the operating parameters of the processor to deactivate cores, activate and disable HyperThreading / SMT, or modify its speed to Overclock or Underclock.

Main functions of the BIOS on a PC


In the BIOS of a PC we can modify a huge amount of hardware configuration options. As a general rule, you will only have to enter the BIOS, change the parameter, save the changes and restart the PC for them to take effect, since as we have mentioned before the BIOS affects the PC’s boot system and is the first thing that the hardware consults to know how to behave.

These are the main functions that you can modify:

  • Change the order of the boot sequence.
  • Load factory settings.
  • Update BIOS.
  • Create / change / deactivate the access password.
  • Change the date and time of the computer.
  • Change storage unit settings.
  • Change disc / optical drive settings.
  • View the amount of memory installed in the system.
  • Configure whether or not we want the numeric pad of the keyboard to be active at startup.
  • Enable or disable the motherboard manufacturer’s logo at boot.
  • Enable or disable POST (Power On Self Test).
  • Enable or disable the internal processor cache.
  • Change the options and behavior of the processor.
  • Change the options and the speed of the RAM memory.
  • Change the voltages.
  • Create RAID systems of storage devices.
  • Enable or disable IEE1394.
  • Enable or disable the onboard sound card.
  • Enable or disable the RS232 / LPT ports.
  • Enable or disable ACPI.
  • Change the behavior of the PC power button.
  • Change boot options.
  • Enable or disable multiple monitors at startup.
  • Change the behavior of the PWM fans.
  • Monitor PC temperatures.

How do I access to enter to configure the PC parameters?

As a general rule, as soon as you press the power button on the PC, you can access it by repeatedly pressing the DEL key on the keyboard, although on some computers this changes and the key is F2 (Insyde) or F1 (Microid). In many PCs we can also partially access specific BIOS functions, such as pressing F10 to simply select the storage device from which we want the system to boot.

How to enter BIOS