You might have heard the terms BIOS and UEFI being used interchangeably by computer geeks. However, while both perform similar duties, they differ from one another in a number of ways. Here we’ll take an in-depth look at both and discuss the difference between BIOS and UEFI. We will also talk about their similarities and look at some of their advantages and disadvantages.
Both BIOS and UEFI are low-level motherboard firmware that connect the PC and its hardware components with the operating system. While the former is the traditional version that has been in use for decades, the latter is the more modern iteration that is found in newer and more expensive motherboards and computers. So let’s take a deep dive and know more about them and how they differ from one another.
- What is BIOS?
- What is UEFI?
- Similarities between BIOS and UEFI
- Difference Between BIOS and UEFI
- UEFI: Disadvantages and Criticisms
- How to Check Whether Your PC is Running BIOS or UEFI?
What is BIOS?
BIOS stands for ‘Basic Input-Output System‘ and is the embedded software on the controller chip on the computer’s motherboard. It acts as a bridge between a computer’s hardware components and the operating system. It helps in loading the bootloader that boots and initializes the OS on your system. Typical BIOS setup screen / Image Courtesy: Wikipedia
What is UEFI?
Short for ‘Unified Extensible Firmware Interface‘, UEFI is the newer of the two firmware interfaces for computers. It is a successor to the BIOS and aims to address the latter’s technical limitations. Like BIOS, it also acts as the middleman to connect a computer’s hardware components to its operating system. That said, it comes with a number advantages over the legacy technology. UEFI Setup Screen on an Asus Motherboard / Image Courtesy: Asus
As mentioned already, BIOS and UEFI are two types of motherboard firmware that boots the PC into the operating system when powered on. They define how a PC turns on, which drive it boots from, and what core hardware components the system recognizes.
What is the Difference Between BIOS and UEFI?
BIOS is legacy technology that goes back to the DOS era and is written in assembler, whereas the more modern UEFI is written in C. BIOS still works in 16-bit mode, which means it can only address 1MB of executable memory. This limits its ability to initialize multiple devices at once and leads to slower boot times.
UEFI: Disadvantages and Criticisms
One of the major disadvantages of UEFI is that the higher abstraction layer and the ability to run UEFI applications opens the door to rootkits and other malware. A joint research by Advanced Intelligence (AdvIntel) and Eclypsium recently discovered that the TrickBot malware has gained a UEFI attack capability that not only helps it stay undetected, but also makes recovery incredibly hard.
You can easily figure out whether your PC is running BIOS or UEFI by following a few simple steps.
