What is BIOS? And How to Access It on Windows PCs

What is BIOS?

BIOS (Basic Input/Output System) is essential firmware that enables communication between the operating system and hardware components such as hard disks, keyboards, and display screens. It initializes hardware during the booting process and provides a runtime environment for the OS. BIOS also allows users to configure system settings and manage security features.

BIOS Full Form

BIOS stands for Basic Input/Output System. It is a fundamental component in computing that controls hardware initialization during the boot process and enables communication between the OS and system peripherals.

What is BIOS in Computer?

BIOS in a computer refers to the firmware embedded in the motherboard that manages system startup and hardware interactions. It ensures that all essential components function correctly before handing control to the operating system.

A Brief History of BIOS

BIOS was first introduced in 1975 by Gary Kildall for CP/M operating systems. IBM adopted it in 1981 for its PCs, making it a fundamental component of early computers. Over the years, BIOS evolved to meet modern computing needs, leading to the development of UEFI (Unified Extensible Firmware Interface) in the 2000s. UEFI replaced traditional BIOS by providing faster boot times, enhanced security, and support for larger storage devices.

How BIOS Works

When a computer is powered on, the BIOS performs the Power-On Self Test (POST) to check hardware functionality. It then identifies and initializes devices such as the CPU, RAM, and storage drives before handing control over to the operating system. BIOS assigns resources like memory addresses and interrupts to connected peripherals to ensure they function correctly.

Why is BIOS Important?

Without BIOS, a computer cannot boot or communicate with its hardware. It acts as a bridge between the hardware and software, ensuring all components work seamlessly. Additionally, BIOS settings allow users to customize system behavior, optimize performance, and enhance security.

The 4 Functions of BIOS

BIOS identifies, configures, tests, and connects computer hardware to the OS immediately after a computer is turned on. The combination of these steps is called the boot process.

These tasks are each carried out by BIOS’ four main functions:

• Power-on self-test (POST): This tests the hardware of the computer before loading the OS.
• Bootstrap loader: This locates the OS.
• Software/drivers: This locates the software and drivers that interface with the OS once running.
• Complementary metal-oxide semiconductor (CMOS) setup: This is a configuration program that enables users to alter hardware and system settings. CMOS is the name of BIOS’ non-volatile memory.

Accessing BIOS

With BIOS, the OS and its applications are freed from having to understand exact details, such as computer hardware addresses, about the attached I/O devices. When device details change, only the BIOS program needs to be changed. Sometimes, this change can be made during system setup.

Users can access BIOS and configure it through BIOS Setup Utility. Accessing BIOS Setup Utility varies somewhat depending on the computer being used. However, the following steps generally enable users to access and configure BIOS through Setup Utility:

1. Reset or power off the computer.
2. When the computer turns back on, look for a message that says “entering setup” or something similar. Accompanying that message will be a key that the user should press to enter system configuration. Here’s an example message a user might see: “Press [key] to enter BIOS setup.” Some keys often used as prompts are Del, Tab, Esc, and any of the function keys (F1-F12).
3. Upon seeing the prompt, quickly press the key specified.
4. Once in BIOS Setup Utility, users can change hardware settings, manage memory settings, change the boot order or boot device, and reset the BIOS password, among other configuration tasks.

BIOS Key: How to Enter BIOS

The BIOS key varies depending on the manufacturer of the motherboard. Some common BIOS keys include:

• Acer: F2 or DEL
• ASUS: F2 or DEL
• Dell: F2 or F12
• HP: ESC or F10
• Lenovo: F2 or Fn + F2
• MSI: DEL

If your computer boots too quickly, you can also use the Advanced Startup method in Windows to access the BIOS.

Transition to UEFI BIOS

UEFI (Unified Extensible Firmware Interface) is the modern replacement for traditional BIOS. It offers:

• Support for 64-bit architectures
• Faster boot times with optimized hardware initialization
• Secure Boot to prevent malware execution during startup
• Graphical user interfaces for easier configuration
• Support for larger hard drives (beyond 2TB) with GPT partitioning

Common BIOS Tasks and Customizations

Users can perform various tasks using BIOS settings, such as:

• Changing the boot order
• Loading default BIOS settings
• Updating BIOS firmware
• Configuring hard drive and optical drive settings
• Viewing installed memory and CPU information
• Adjusting system voltages and power settings
• Enabling/disabling BIOS control of system resources
• Modifying fan speed settings
• Monitoring CPU and system temperatures

BIOS Security: Protecting Your System

BIOS security is a somewhat overlooked component of cybersecurity; however, it should still be managed to prevent hackers from executing malicious code on the OS. Security group Cylance, in 2017, showed how modern BIOS security flaws could enable ransomware programs inside a motherboard’s UEFI and exploit other PC BIOS vulnerabilities.

BIOS Hacking Threats

BIOS attacks can allow hackers to install persistent malware that remains on the system even after the OS is reinstalled. Threat actors can exploit vulnerabilities to manipulate firmware, compromise system integrity, and steal sensitive data. Some notable BIOS-related threats include:

• Plundervolt Attack: This exploits voltage manipulation to bypass security features and alter data integrity.
• MoonBounce Malware: A UEFI bootkit that infects the BIOS to maintain persistence on the system.
• BIOS Rootkits: These allow attackers to gain deep control over system firmware, evading antivirus detection.

To protect against BIOS hacking, users should regularly update firmware, enable Secure Boot, and use manufacturer-recommended security patches.

BIOS Manufacturers

Some of the leading BIOS vendors include:

• Phoenix Technologies
• IBM
• Dell
• American Megatrends Inc. (AMI)
• Insyde Software
• Asus
• Foxconn
• Hewlett Packard (HP)
• Ricoh

Should You Update Your BIOS?

BIOS updates can improve system stability, enhance performance, and provide security patches. However, updating BIOS carries risks such as bricking the motherboard if done incorrectly. It is recommended to update BIOS only when necessary, such as fixing compatibility issues or addressing security vulnerabilities.

The Future of BIOS

With UEFI becoming the industry standard, traditional BIOS is gradually being phased out. Future advancements in firmware security, AI-driven diagnostics, and cloud-based BIOS management will further enhance system reliability and performance.

BIOS remains a crucial component of modern computing, ensuring hardware and software work harmoniously. Understanding its functionality, security measures, and customization options can help users optimize their systems for better efficiency and protection.

Frequently Asked Questions (FAQs)