What is UEFI and BIOS? What is difference between UEFI and BIOS?


When you start your PC or laptop before loading OS (Operating system) a software runs that software we called it as a BIOS (Basic Input Output System). It also starts even if you don't have a storage device or Operating system installed in the PC/Laptop.

How does BIOS Works?

  1. The first thing BIOS does is it check all the parts of the computer whether they are working or not properly.
  2. The basic check of hardware done by BIOS is called a POST ( Power n Self Test).
  3. If any hardware fails to start up it will show the pop-up on to the screen.
  4. After the POST the BIOS to the storage device to get the bootloader so by that it can run operating system
BIOS software has it chip on the motherboard you will find it when you remove the case of CPU.

There are two different kinds of BIOS

1. Legacy BIOS

1. Legacy BIOS is the old BIOS it is old about 25 years old. When you start your PC or working on your PC you might know the BIOS screen and its all text. From this option, it helps you to do the setting of your hardware

2. Previously most of the operating system communicates with the hardware through the BIOS without accessing directly.

3. But there are some issues with the legacy BIOS such as it only supports limited hardware devices and for BIOS to identify the network card it becomes difficult, so to rectify that again you need to download the file or by using the internet because there is no other way to do in the Legacy BIOS inside.


1.  In the latest motherboard, we find a UEFI BIOS  (UNIFIED EXTENSIBLE FIRMWARE INTERFACE)

2.  Most of the manufacturers have taken the standard of UEFI BIOS so it should be specific to the hardware and with that, they also keep in mind it should be used universally in the world. 

3. UEFI BIOS is effectively replacing the Legacy BIOS

4. In all the Motherboard, UEFI BIOS is not taken place and eliminated the usage of Legacy BIOS.

UEFI Advantages

1. The big advantage of the UEFI BIOS it helps to boot a larger storage device i.e. up to 2.2 TB hard disk, removable storage devices and also it supports FAT system.

2. UEFI also supports the GUID partition table (GPT) 

3. It also has a  pre-boot environment.
    -  UEFI is not an operating system.
    -  Has it own application, driver and shell.
    -  Back up the storage, browse the internet.
    -  Remote Diagnostics even without having an OS.

Non - Volatile BIOS Memory

When you are configuring a BIOS setting it to need to be stored so this activity is done by  Non - Volatile BIOS Memory. It takes all the setting and keeps saved inside the computer.

CMOS (Complementary Metal Oxide Simulator)

CMOS is (Complementary Metal Oxide Simulator) it helps to save the setting data of BIOS memory. This day we are not using CMOS memory rather than that we are using flash memory.
The disadvantages of the CMOS is that you must have always some type of power to always keep your configuration actively inside of the memory. If you lost power you lose your all setting you made it in the computer.

Nowadays CMOS battery is not needed there place are taken by flash memory.

CMOS now only be seen in the old motherboard and to save the date and time setting.

CMOS helps to reset the BIOS configuration by just removing the battery.

Flash Memory

CMOS place nowadays is taken by flash memory. To save the configuration it does not need any type of electrical power. It is so much reliable and flexible to store the BIOS configuration. BIOS configuration is stored in a reliable.

Tags: bios,computer,computer bios,computers,tutorial,setup bios of all computers,bios (software genre),how to update your computer bios,bios setup,motherboard bios,computer basics,gaming computer,setup bios of all computers to setup windows,computer (industry),personal computer,computer hardware,set up new computer,learn computers,basic computers,how to update your bios windows 10 every computer,computers in hindi,pc