Difference Between Legacy BIOS and UEFI BIOS | What is BIOS?

Summary

This video explains the difference between Legacy Boot and UEFI, two methods used to boot computers. It explores how BIOS (Basic Input/Output System) works in both processes, highlighting UEFI's modern advantages like faster boot times, enhanced security features like secure boot, and a more flexible, graphical user interface. UEFI uses the GUID Partition Table (GPT) for larger disks and multiple partitions, while Legacy Boot relies on the older Master Boot Record (MBR). The video emphasizes UEFI's superior performance, security, and extensibility, positioning it as the standard for modern computing.

Takeaways

• 😀 Legacy Boot and UEFI are two methods for initializing computer hardware and booting the operating system, with UEFI being the more modern and advanced method.
• 😀 BIOS (Basic Input/Output System) is the firmware responsible for initializing hardware components and starting the boot process when a computer is powered on.
• 😀 The BIOS performs a Power-On Self Test (POST) to check hardware components such as the processor, memory, and storage devices for issues before booting the system.
• 😀 In Legacy Boot, the BIOS loads the Master Boot Record (MBR) from the bootable device to start the operating system, whereas UEFI uses the EFI System Partition (ESP) to load boot loaders.
• 😀 UEFI offers a more advanced boot process, including hardware initialization, execution of drivers, and better management of boot devices.
• 😀 UEFI supports the GUID Partition Table (GPT) for partitioning, allowing for larger disks (over 2.2TB) and more partitions, while Legacy BIOS uses the older Master Boot Record (MBR) system with limitations.
• 😀 UEFI includes advanced security features such as Secure Boot, which helps prevent unauthorized operating systems or malware from running during the boot process, while Legacy BIOS lacks these features.
• 😀 UEFI typically offers faster boot times due to parallel hardware initialization, while Legacy BIOS often experiences slower boot times due to sequential initialization processes.
• 😀 The UEFI interface is more user-friendly, offering a graphical interface with mouse support, while the Legacy BIOS provides a simpler, text-based interface that requires keyboard navigation.
• 😀 UEFI is modular and extensible, allowing for easy updates and the addition of new drivers, whereas Legacy BIOS is less flexible and requires extensive firmware updates for new functionality.

Q & A

What is BIOS and what role does it play in the boot process?

BIOS (Basic Input/Output System) is software stored on a small chip on the motherboard that initializes and tests the hardware components during the boot process. It checks essential hardware like the CPU, memory, and storage devices, then configures the system before handing over control to the operating system.

What is the difference between Legacy Boot and UEFI?

Legacy Boot uses the older BIOS system and the Master Boot Record (MBR) to initialize and load the operating system. UEFI (Unified Extensible Firmware Interface) is a more advanced system that uses the EFI System Partition (ESP) and provides enhanced features like secure boot, faster boot times, and greater flexibility.

How does BIOS perform the Power On Self Test (POST)?

When the computer is powered on, BIOS runs the POST to check the functionality of essential hardware components like the processor, memory, and storage devices. If any issues are found, error messages are displayed to alert the user.

What is the Master Boot Record (MBR) and how does it function in the Legacy Boot process?

The MBR is a small section of the boot device where the boot loader is stored. In Legacy Boot, BIOS reads the MBR to locate and execute the boot loader, which loads the operating system into memory.

What is UEFI's role in the boot process?

UEFI initializes the hardware components, loads UEFI drivers for system devices, and selects the boot device using the EFI System Partition (ESP). It then hands control over to the operating system's boot loader, allowing the operating system to start.

What are some key security features in UEFI that are not present in Legacy Boot?

UEFI includes advanced security features like Secure Boot, which ensures that only trusted software signed with a recognized certificate can run during the boot process, protecting against malware and unauthorized operating systems. Legacy Boot lacks such advanced security mechanisms.

How does UEFI improve boot times compared to Legacy Boot?

UEFI offers faster boot times because it can initialize hardware components in parallel, whereas Legacy Boot initializes them sequentially, resulting in slower boot times.

What is the difference in partitioning schemes between UEFI and Legacy Boot?

UEFI uses the GUID Partition Table (GPT), which supports larger disks (greater than 2.2TB) and allows up to 128 primary partitions. Legacy Boot uses the MBR partitioning scheme, which supports disks up to 2.2TB and a maximum of 4 primary partitions.

How does UEFI's user interface differ from BIOS?

UEFI typically offers a graphical user interface with mouse support, making it more user-friendly and easier to navigate. In contrast, BIOS provides a text-based interface that requires keyboard navigation, which can be less intuitive.

How does UEFI handle error recovery compared to Legacy Boot?

UEFI provides more advanced error handling and recovery options due to its modular design and access to more system resources during the boot process. Legacy Boot has more limited error handling and recovery capabilities.

Why is UEFI considered more extensible than Legacy Boot?

UEFI is modular and extensible, allowing new drivers and applications to be added without replacing the entire firmware. This makes it easier to update and add new functionality. Legacy Boot is less flexible and requires more extensive firmware modifications for updates.