What is BIOS in computers & how does it work?

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BIOS means Basic Input Output System. That’s a lot more than the name suggests. You might think that the BIOS controls the input and output system. But BIOS does much more, and it is not possible for an operating system to continue without a real BIOS. Today we will see what BIOS is in computers.

BIOS has been there in our computers since the time of the DOS disk operating system…. even before the structured DOS created by Microsoft. It is one of the most important components of the computer, although it does not take credit for appearing regularly on your screen. This article also covers the most fundamental component of the computer and explains why it is necessary in computers to make them work.

What is BIOS

BIOS is firmware, in short. It is stored on a chip on the motherboard of the computer and is essentially a set of instructions that help load the operating system. Your operating system wouldn’t load if it wasn’t for the BIOS!

When you turn on the computer, the BIOS commands are issued. These instructions check your computer’s memory and processor (for errors).

  1. It lists the memory by checking each compartment to see if they all work.
  2. After checking the RAM and processor, the system searches for other devices connected to the computer
  3. It detects all devices, including the keyboard and mouse, and then checks the boot options
  4. The boot options are checked in the order configured in the BIOS: boot from CD-ROM, boot from hard disk, boot from local network, etc.
  5. The system searches the bootstraps on the devices in the order in which you or the machine tool manufacturer configured the BIOS.
  6. It transmits control of the computer to the operating system by loading the essential parts of the operating system into the memory (RAM) reserved for the operating system once the bootstrap has been found.

This is not an exhaustive list of BIOS functions. It also checks CMOS and other chips to set the date and time on the computer and load device drivers into memory. It checks and loads the input and output interruptions (signals) into the working memory so that the operating system knows what is happening. For example, when a user presses a key, an interrupt request is created and transmitted to the BIOS which sends it to the operating system. The operating system then decides what to do, based on the programming.

The reason why the operating system cannot run without BIOS is that the first one is on the hard disk or on a removable disk. It is the BIOS that loads the drivers for the hard disks and removable media to run them. It then loads the primary parts of the operating system such as MBR, GPT, FAT, etc. into memory so that the operating system can continue to load itself.

Read : Check if your PC uses UEFI or BIOS.

Make changes to the BIOS

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It is easy to make changes to the BIOS if necessary. The most common change in the BIOS is the change of the BOOT ORDER. While the computer is booting, press the LED key on your keyboard to enter the BIOS. From there you can see different options under different headings. Use the tab and arrow keys to navigate. Sometimes the Page Up and Page Down buttons are needed to change the values of the essential elements. When you are finished, press F10 to save and exit the changes. Options are displayed at the right or bottom of the screen so you know which buttons to press to save or cancel changes. The options also determine which keys are used to change the values.

Read : Reset BIOS parameters to zero in Error.

How to update the BIOS

If the calculation scenario changes, new devices etc. are introduced. For a computer to work with these devices, the BIOS must be updated. If your operating system does not recognize a new device, it is possible because the BIOS does not know how to handle it. If you are facing such problems, you should check if BIOS updates are available.

You must first check the BIOS version. This can be done by entering the BIOS at boot time by pressing LED. Once you have the BIOS version of your computer to update the BIOS, visit your computer manufacturer’s website to see if an updated version of the BIOS is available. If so, download it and run it. The process usually erases all previous information on the BIOS chip and rewrites it with the new information.

Make sure you have a power fuse while upgrading the BIOS. Because if the computer shuts down during the process, the BIOS may be damaged and you need a technician to repair it. Your boot CD/DVD may or may not help, depending on the BIOS status after a power failure or sudden system shutdown when rewriting the BIOS.


If you need:

  1. Have you forgotten your BIOS password? Using PC-CMOS Cleaner
  2. You get the CMOS checksum error
  3. Reset BIOS password with CmosPwd.

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