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What is BIOS? What is Legacy BIOS and UEFI BIOS?


Excerpt: Students who enjoy reinstalling Windows operating system probably know word BIOS, but what is a BIOS? If you still do not know about BIOS, then this Big Eye Boy article will tell you very simply. There are currently two types of BIOS, one is traditional BIOS and other is mainstream UEFI BIOS. What is BIOS? The BIOS calculates...

What is BIOS?

BIOS is an important part of computer history. The term was first used in 1970s as part of CP/M (Microcomputer Control Program) operating system developed by Gary Kildall. But BIOS is still in use today. However, successful methods are now increasingly used in modern computers.

What is BIOS? What is Legacy BIOS and UEFI BIOS?


BIOS: Decades old definition of a term

What does BIOS mean? The term is an abbreviation for Basic Input/Output System, which describes firmware stored on a computer's motherboard as non-volatile memory. Unlike normal working storage, ROM components that have BIOS installed are not removed when computer is turned off, and therefore are still available immediately after startup. The BIOS is automatically loaded when user turns on x64/x86 computer. Unlike an operating system, it does not need to be installed and is already included in computer hardware.

HistorySome have pointed out that word BIOS in Greek means "bios", which means "life". In other words, BIOS is software that brings your computer to life.

Basic BIOS tasks

The BIOS provides access to main functions of computer and evaluates them after each boot. It determines whether important parts of memory, processor, and other hardware components are functioning. This is called a power-on self-test (POST).

NOTEIf BIOS detects an error during POST, it will emit one or more beeps through system speaker. Depending on computer manufacturer, individual beeps may emit specific error codes that indicate a problem. For example, for a graphics card issue, IBM BIOS error code is one short beep followed by two long beeps.

The BIOS solves a major problem with most computers. Each software must initially be loaded into main memory in order to work. This process requires additional software to tell system where a particular program or component (such as an operating system) is located. This is what BIOS does, it's a pointer. At same time, it functions as a transmitter between CPU and software. The BIOS creates an abstraction layer, called Hardware Abstraction Layer (HAL), that allows software to respond in a standardized way to hardware.

Additional BIOS Features

Over past few decades, BIOS capabilities have continued to expand. In addition to POST, it also plays an important role in computer power management as it generates necessary ACPI (Advanced Configuration and Power Interface) tables that control how much power each device receives.

It also controls functionality of internal hard drive as well as external components such as external hard drives or UBS devices. Users can also configure mass storage activation sequence through BIOS. This is useful, for example, when booting a new operating system from a DVD or USB stick.

Changing and updating BIOS

The BIOS provides user with ability toIt is possible to make significant changes to hardware configuration. Please note, however, that BIOS modifications should only be made by advanced users. Its interface is not very user friendly and any mistake can affect entire operating system.

However, BIOS modification may be required in some cases. These situations include cases where operating system can no longer be started at boot time. In this case, a thorough review of BIOS may reveal errors in system. The BIOS is accessed by users who are trying to increase performance of their computer beyond what manufacturer configures, such as overclocking processor. Users can also adjust settings to reduce system power consumption.

TipsTo change BIOS configuration, you must first launch BIOS interface. In most cases, you will need to hold down a certain key or key combination at startup in order to activate it. Click to view BIOS shortcuts

When a user wants to replace a certain hardware component, such as installing a new processor, sometimes BIOS no longer recognizes new component and cannot load operating system. In this case, you need to update BIOS.

Alternative and subsequent technologies: EFI and UEFI

Basically, BIOS hasn't changed much since 1980s and therefore can't meet needs of today's hardware. However, his successor is already in place. The Extensible Firmware Interface (EFI) was developed in 1990s, followed by Unified Extensible Firmware Interface (UEFI) in 2005. Since 2010, UEFI has become standard for 64-bit computers because it is more functional and easier to use than BIOS.

UEFI includes a graphical user interface that can be navigated using a computer mouse and keyboard. Thus, network components can be accessed via Internet without booting system. One of main differences from BIOS is that UEFI uses Secure Boot, which prevents unlicensed operating systems and questionable software from loading, increasing system protection against cyber threats.

FactAlthough many new computers use Unified Extensible Firmware Interface, many people still refer to it as system BIOS. To differentiate them, some people refer to BIOS as Legacy BIOS and UEFI as UEFI BIOS.

What are advantages of traditional BIOS and UEFI

UEFI has following advantages over BIOS:

  1. UEFI allows users to work with drives larger than 2TB, while old legacy BIOS version cannot handle large drives.
  2. UEFI supports more than 4 primary partitions using GUID partition table.
  3. Computers using UEFI firmware have a faster boot processzky than BIOS. Various UEFI optimizations and improvements can help your system boot faster than ever before.
  4. UEFI supports secure boot, which means that validity of operating system can be checked to ensure that no malware has interfered with boot process.
  5. UEFI supports UEFI firmware networking feature, which is useful for remote troubleshooting and UEFI configuration.
  6. UEFI has a simpler graphical user interface and richer setup menus than a traditional BIOS.

After reading above, you may find that UEFI has many advantages over BIOS. It is because of these advantages that UEFI is considered successor to BIOS.

However, not all computers or devices support UEFI. To use UEFI firmware, hardware on drive must support UEFI. Also, your system drive must be a GPT drive. If not, you can use a professional disk management tool to convert an MBR disk to a GPT disk. So you can successfully boot your computer in UEFI mode.

Today, UEFI is gradually replacing traditional BIOS on most modern PCs as many major hardware manufacturers have switched to using UEFI. To boot from a GPT disk and take advantage of UEFI, you may need to convert your legacy BIOS to UEFI.

  • What is difference between UEFI and BIOS?
  • BIOS and UEFI are two firmware interfaces through which computer boots operating system. The BIOS uses Master Boot Record (MBR) to store information about hard drive data, while UEFI uses GUID Partition Table (GPT). Compared to BIOS, UEFI is more powerful and has more advanced features. This is latest method of starting a computer to replace BIOS. In short, UEFI is successor to BIOS.

  • Which is better to use: UEFI or BIOS?
  • Today, UEFI is gradually replacing traditional BIOS on most modern PCs because it includes more security features than traditional BIOS mode and boots faster than traditional systems. If your computer supports UEFI firmware, you should convert your MBR disk to a GPT disk to use UEFI boot instead of BIOS. However, if you are booting from network with BIOS only, you will need to boot in Legacy BIOS mode.

  • What is UEFI Boot Mode?
  • UEFI boot mode is boot process used by UEFI firmware. UEFI stores all initialization and boot information in .efi files stored in a special partition called EFI System Partition (ESP). During POST, UEFI firmware scans all bootable storage devices attached to system for validth GUID Partition Table (GPT).

    The UEFI firmware scans GPT for an EFI service partition to boot. If no EFI boot partition is found, firmware may fall back to old legacy boot method. If both UEFI boot and legacy boot fail, you may receive a disk boot error message.

  • What are benefits of UEFI booting?
  • UEFI booting has many advantages over BIOS mode. For example, UEFI supports unlimited partitions and supports drives larger than 2TB. Computers running UEFI firmware can boot faster than BIOS due to any magic code that needs to run during boot. UEFI also has more advanced security features such as secure boot that help make your computer even more secure.