Difference Between BIOS and UEFI

Jan 25,2024
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BIOS and UEFI are the basic input and output systems. Both of them are similar in action, having the POST (Power-on-self-test) procedure before starting up the system.

What is BIOS?

BIOS being abbreviated as Basic Input Output System, which is stored in a special type of ROM called EPROM (Electronically Programmable ROM). This EPROM enables the manufacturer to push out new firmware updates.

Generally, one can access BIOS by pressing DEL, F2, F12 etc though it completely depend from manufacturer to manufacturer. The basic function of the BIOS is to load booting information from Boot sector to main memory.

What is UEFI?

UEFI stands for Unified Extensible Firmware Interface, it does the same job as BIOS. The basic difference between the both is UEFI stores the booting information in a .efi file instead of the firmware.

EFI file is stored on a hard partition called EFI System Partition (ESP), along with the .efi file, EFI partition also contains the Bootloader.

Advantages of UEFI Over BIOS

There some limitations of BIOS which UEFI rectifies, hence giving it an edge over BIOS systems:

UEFI provides a faster booting time.
UEFI has driver support which makes it easier to get updated.
There is security enhancements support with UEFI system such as Secure Boot.
UEFI has capabilities to run in 32 and 64-bit mode, whereas BIOS can only run in 16 Bit mode.
UEFI being running on 32-bit provides GUI (Graphics User Interface) support.
With UEFI you can add up to 9 ZB (ZettaByte) of drive storage whereas with BIOS you can add up to 2.2 TB of drives.
UEFI supports GPT partitioning scheme.