BIOS Full Form

Introduction of BIOS

The BIOS Full Form is a Basic Input Output System.

  • The basic input/output system is boot firmware, designed to be the first code run by a PC when powered on. The initial function of the BIOS is to identify, test, and initialize system devices such as video display cards, hard disks, floppy disks, and other hardware.
  • basic input/output system consists of low-level software that controls the system hardware.
  • BIOS acts as an interface between the operating system(OS) and the hardware.
  • The basic input/output system sets the machine hardware into a known state so that software stored on compatible media can be loaded, executed, and given control of the PC.
  • BIOS is a link between hardware and software in a system.
  • It is preloaded into read-only memory or ROM, and some are loaded into RAM from disk.

What is BIOS?

It is built-in software that determines what your computer can do without accessing programs.

It is the first software run by a PC when it is powered on.

Typically this program is housed in Read-Only Memory (ROM) and is placed on the motherboard.

On some computers, you may have seen system checks running on the screen before the OS welcome screen appears. Those checks are what the BIOS does.

Evolution of BIOS

Early BIOS

In the early days of personal computers, BIOS was stored on a ROM (Read-Only Memory) chip on the computer’s motherboard. It was relatively simple and had limited capabilities. Users had little control over the settings, and updating it was challenging.

Expansion of Features

Over time, as computers became more sophisticated, BIOS evolved to include more features. Users gained the ability to configure hardware settings and set boot options, such as choosing between different devices to boot from (e.g., hard drive, CD-ROM, USB).

UEFI (Unified Extensible Firmware Interface)

One significant evolution in BIOS technology was the development of UEFI to replace traditional BIOS. UEFI offers a more flexible and feature-rich interface for managing hardware settings and the boot process. It supports larger hard drives, faster boot times, and improved security features.

Secure Boot

Secure Boot is a feature introduced with UEFI that helps protect the computer from malware by verifying the integrity of the operating system during startup.

Legacy Support

Despite the transition to UEFI, many computers still offer legacy BIOS support to ensure compatibility with older hardware and software.

Customization and User-Friendly Interfaces

Modern UEFI implementations often include user-friendly graphical interfaces, making it easier for users to navigate and configure settings.

Remote Management

Some UEFI implementations include remote management capabilities, allowing IT administrators to configure and monitor systems remotely.

BIOS Updates

Manufacturers release basic input/output system updates to fix bugs, improve compatibility, and enhance security. Users can now easily update their BIOS through various methods, including USB drives and within the UEFI interface.

The evolution of the basic input/output system has been driven by the need for greater functionality, improved security, and better user experiences.

POST (power on self-test)

The POST tests your computer’s processor, memory, chipset, video adapter, disk controller, disk drives, keyboard, and other crucial components.

The principal duties of the main BIOS during POST are as follows:

  • Verify CPU registers
  • Verify the integrity of the BIOS code itself
  • Verify some basic components like DMA, timer, interrupt controller
  • Find, size, and verify the system’s main memory
  • Initialize basic input/output system 
  • Beep Codes: If something is wrong, a basic input/output system might make beep sounds to tell you what’s not working.
  • Importance: POST is crucial because it ensures your computer is in good shape before it starts doing its work.
  • If It Fails: If POST finds a problem, your computer might not start properly, and you might need to fix the issue before it can run smoothly.
  • identify, organize, and select which devices are available for booting.

Types of BIOS

BIOS has the following types:

Traditional BIOS

This is the original type of basic input/output system that was commonly used in older computers. It is based on the BIOS firmware stored on a ROM (Read-Only Memory) chip on the computer’s motherboard.

Traditional BIOS provides basic hardware initialization and startup functions for the computer. It typically has a text-based interface for configuring settings and handling the boot process.

While still found in some older computers, it has largely been replaced by more advanced types.

UEFI (Unified Extensible Firmware Interface)

UEFI is the modern successor to traditional BIOS.

It offers a more flexible and feature-rich firmware interface. UEFI systems store firmware in flash memory instead of a ROM chip, which allows for easier updates.

UEFI provides a graphical user interface (GUI) for configuring hardware settings and managing the boot process.

It offers features like secure boot, which enhances system security by verifying the integrity of the operating system during startup.

Legacy BIOS

Many modern computers with UEFI firmware also include a “Legacy” or “Compatibility Support Module (CSM)” option.

This allows users to enable a compatibility mode that emulates the behavior of a traditional basic input/output system. Legacy BIOS is included for backward compatibility with older operating systems and hardware that may not fully support UEFI.


Coreboot is an open-source firmware project that aims to provide an alternative to traditional BIOS and UEFI. It is designed to be lightweight, fast, and highly customizable.

Coreboot is often used in embedded systems and specific hardware configurations.

Open Firmware

Open Firmware is a firmware standard commonly used in Apple Macintosh computers, and it’s also found in some other systems.

It’s known for its user-friendly boot menu and a command-line interface. Open Firmware is highly extensible and open source.

Custom Firmware

Some specific computer manufacturers create their own customized firmware that is tailored to their hardware and needs. These custom firmware types may have unique features and configurations.

The type of basic input/output system used in a computer depends on the motherboard and firmware chosen by the manufacturer.

Most modern computers come with UEFI firmware, which offers advanced features, security enhancements, and user-friendly interfaces.

BIOS Functions

BIOS Functions
BIOS Functions

Hardware Initialization – BIOS makes sure all your computer’s parts, like the CPU and RAM, are ready to work.

System Configuration – It checks how everything is set up and decides which devices should run.

Boot Order – The basic input/output system decides where your computer should look to start the operating system, like from the hard drive or a USB drive.

Date and Time – It keeps track of the current date and time, which is important for various tasks on your computer.

Password Security – Some basic input/output system versions let you set a password to protect your computer from unauthorized access.

BIOS boot process

If the system has just been started (cold boot) the full POST will run.

But if the reset button is pressed then the warm boot-specific flag value is detected in memory and BIOS does not run POST.

This saves time in testing all the memories.

The basic input/output system begins its POST when the CPU is reset.

A little-known feature of the original IBM BIOS versions is the attempt to load a program through the keyword port.

BIOS Setup

Main Menu in BIOS Setup

1. System Time and Date: In this section, you can set the current date and time. It might seem simple, but these settings play a crucial role in file time stamps and system logs.

2. Language Settings: The basic input/output system setup isn’t always in English. You can change the language to one you’re more comfortable with. This is especially handy if you’re navigating through BIOS settings for any reason.

3. Drive Configuration: Here, you can get a glimpse of the hard drives and storage devices your computer recognizes. It’s where you can check if your hard drive is detected properly.

4. Boot Sequence: This is an essential setting. It decides the order in which your computer looks for devices to boot from. For example, if your hard drive isn’t working correctly, you can set the BIOS to boot from a USB drive as a temporary fix.

Advanced Menu in BIOS Setup

1. CPU Settings: Here, you can tweak settings related to your computer’s processor. You might find options to enable or disable features like Hyper-Threading or Turbo Boost, which can influence your computer’s processing power. Additional settings may include:

  • Overclocking options for boosting CPU performance.
  • Multiplier and voltage settings for fine-tuning clock speed.
  • CPU thermal management to control heat and fan speeds.

2. Virtualization Support: This setting is crucial if you want to run virtual machines. Enabling virtualization support allows you to use programs like VMware or VirtualBox more efficiently. Additional settings may include:

  • Nested virtualization support.
  • VT-d (Virtualization Technology for Directed I/O) settings.
  • VT-x (Virtualization Technology) options for advanced virtualization tasks.

3. Integrated Peripherals: These settings control the behavior of various hardware components on your motherboard. You can enable or disable onboard devices like audio, LAN (Local Area Network) controllers, and USB controllers. Additional settings may include:

  • Integrated GPU (Graphics Processing Unit) configuration.
  • Audio and network adapter settings.
  • SATA controller modes for hard drive management.

4. USB Configuration: This section allows you to manage USB-related settings. You might find options to enable USB legacy support or control USB ports’ power. Additional settings may include:

  • USB port wake-up functions.
  • USB selective suspend settings.
  • USB 3.0 or 3.1 controller configurations.

5. Trusted Computing: If your computer supports a Trusted Platform Module (TPM) or other security features, you can configure them here. These settings enhance the security of your system. Additional settings may include:

  • TPM version and activation.
  • Secure Boot settings for enhanced OS security.
  • Data encryption and decryption settings.

6. Power Management: This is where you control how your computer manages power. You can set options for sleep mode, hibernation, and power-saving features. Additional settings may include:

  • ACPI (Advanced Configuration and Power Interface) options.
  • Power profiles for different usage scenarios.
  • Wake timers and alarm settings.

Boot Menu in BIOS Setup

1. Boot Device Priority: This is where you decide the order in which your computer looks for devices to boot from. For instance, if you want your computer to start from a USB drive or a DVD, you can set that preference here. Additional settings may include:

  • Prioritizing specific hard drives.
  • Specifying boot devices for different scenarios, like first boot, second boot, etc.
  • Network boot options for remote installations.

2. Hard Drive Order: Here, you can see a list of the hard drives and storage devices that your computer recognizes. You can check if your hard drive is detected properly and, if not, troubleshoot any issues. Additional settings may include:

  • Disk information and capacity.
  • SMART (Self-Monitoring, Analysis, and Reporting Technology) status for drive health.
  • Drive-specific settings for advanced users.

3. Boot Mode (Legacy or UEFI): You might encounter an option to choose between Legacy and UEFI boot modes. This setting determines how your computer’s firmware interacts with the operating system. UEFI is the newer, more versatile option, while Legacy mode is older and less secure. Additional settings may include:

  • Enabling or disabling CSM (Compatibility Support Module) for legacy compatibility.
  • Secure Boot options for enhanced security.
  • Booting from external devices in UEFI mode.

4. Secure Boot: Secure Boot is a feature that helps protect your system from unauthorized or malicious code. You can enable or disable it in this section. Additional settings may include:

  • Managing Secure Boot keys.
  • Customizing secure boot configurations.
  • Secure Boot troubleshooting options.

5. Fast Boot: Fast Boot can significantly reduce your computer’s startup time. It’s like taking the express lane on a highway. In this section, you can enable or disable Fast Boot and configure its settings. Additional settings may include:

  • Fast Boot-related timings and delays.
  • Managing Fast Boot for specific devices.
  • Compatibility with other boot-related settings.

Security Menu in BIOS Setup

1. Administrator/User Passwords: This is your first line of defense. You can set passwords to restrict access to the BIOS setup or even booting from certain devices. Additional settings may include:

  • Changing or resetting passwords.
  • Configuring password requirements.
  • Enabling or disabling password prompts.

2. Device Security: This section allows you to manage the security of individual hardware components. For example, you can lock down USB ports to prevent unauthorized data transfers. Additional settings may include:

  • Setting up security for specific hardware components.
  • Configuring device permissions.
  • Blocking or allowing certain hardware functions.

3. Trusted Platform Module (TPM): If your computer supports TPM, you can configure its settings in this section. TPM provides hardware-based security features like encryption and secure boot. Additional settings may include:

  • Enabling or disabling TPM.
  • Managing TPM version and specifications.
  • Configuring TPM for data protection and system integrity.

4. Secure Boot Configuration: Secure Boot is a feature designed to ensure that only trusted and signed software can run during the boot process. You can manage its settings in this section. Additional settings may include:

  • Enabling or disabling Secure Boot.
  • Managing Secure Boot keys and certificates.
  • Customizing the Secure Boot process for added security.

5. Password Policies: This area allows you to set policies for BIOS and system passwords. You can define password requirements like length and complexity. Additional settings may include:

  • Specifying password expiration and renewal policies.
  • Configuring account lockout settings.
  • Setting up password recovery options.

6. Data Encryption and Decryption: In some basic input/output system versions, you can configure settings related to data encryption and decryption. This adds an extra layer of security to your storage devices. Additional settings may include:

  • Managing encryption algorithms and keys.
  • Configuring encryption modes and settings for specific drives.
  • Handling secure data wipe procedures.

Save and Exit Menu in BIOS Setup

1. Save Changes and Exit: This option allows you to save any modifications you’ve made in the BIOS setup and exit to restart your computer. It’s like locking in your changes. Additional settings may include:

  • Confirm your changes before saving.
  • Saving changes to a specific BIOS profile.
  • Rebooting your computer with saved settings.

2. Discard Changes and Exit: If you’ve made changes that you’re not satisfied with, this option allows you to discard them and exit without saving. It’s like hitting the reset button. Additional settings may include:

  • Confirming your decision to discard changes.
  • Discarding changes to specific BIOS profiles.
  • Exiting without saving and starting from the last saved state.

3. Restore Defaults: Sometimes, you might want to return everything to its original settings. This option allows you to reset the basic input/output system to its default configurations. Additional settings may include:

  • Confirming your decision to restore defaults.
  • Restoring defaults for specific basic input/output system profiles.
  • Clearing custom settings and reverting to factory defaults.

4. Load Optimized Defaults: This is a quicker way to reset your basic input/output system settings to a more optimized and performance-friendly configuration. It’s like starting with a clean slate for better performance. Additional settings may include:

  • Confirming your decision to load optimized defaults.
  • Loading optimized defaults for specific basic input/output system profiles.
  • Applying preset configurations for enhanced system performance.

5. BIOS Profiles: Some basic input/output system setups allow you to save and load different profiles with customized settings. This feature is like saving different configurations for different needs. Additional settings may include:

  • Naming and managing basic input/output system profiles.
  • Loading specific profiles for different purposes.
  • Saving profiles for specific use cases, such as gaming, work, or energy-saving.

What are the common BIOS Issues?

  • Boot Failure

    • Issue: Your computer may not start up, and you see error messages like “No bootable device
    • Solution: Check your boot order in the basic input/output system and ensure your boot device is correctly connected.
  • Password Problems

    • Issue: You forget your basic input/output system password, or it’s not working.
    • Solution: Contact your computer’s manufacturer for password reset instructions.
  • Hardware Not Recognized

    • Issue: Certain hardware components, like RAM or hard drives, may not be detected.
    • Solution: Re-seat or replace hardware components, check for loose connections and update BIOS if necessary.
  • Overheating and Fan Errors

    • Issue: Your computer may overheat, and you receive warnings about fan failure.
    • Solution: Clean dust from the computer’s interior, ensure fans are working, and monitor temperature settings in the basic input/output system.
  • Time and Date Errors

    • Issue: The system clock keeps resetting, leading to time and date discrepancies.
    • Solution: Replace the CMOS battery on your motherboard to maintain accurate time and date.


1. What is BIOS, and why is it essential for my computer?

  • Answer: BIOS stands for Basic Input/Output System. It’s a fundamental piece of software that resides on your computer’s motherboard.
  • BIOS is essential because it helps your computer start up and communicate with its hardware.
  • It contains instructions for initializing critical components like the CPU, RAM, and hard drive. Without BIOS, your computer wouldn’t know how to begin its operations.

2. How can I access the BIOS setup on my computer?

  • Answer: To access the BIOS setup, you typically need to press a specific key during the computer’s startup process. The key varies depending on your computer’s manufacturer but is often one of the F-keys (e.g., F2, F12), the Delete key, or the Escape key.
  • When you turn on your computer, look for an on-screen message that tells you which key to press to enter the BIOS setup. It’s usually displayed briefly, so be ready to press the key as soon as you start your computer.

3. Is it safe to make changes in the BIOS setup, and what settings can I modify?

  • Answer: Making changes in the BIOS setup is safe as long as you know what you’re doing. It’s a powerful tool for customizing your computer’s hardware settings. You can modify various settings, including boot device priority, CPU configurations, power management, and security features.
  • However, it’s crucial to be cautious and avoid changing settings you’re not familiar with, as misconfigurations could affect your computer’s performance or functionality.
  • Always document your changes and be prepared to restore default settings if needed.

Read more post: PC Full Form

Leave a Comment