1.02.2 Install and configure motherboards, central processing units (CPUs), and add-on cards - BIOS

Introduction 

Imagine that you’ve just finished building a new computer. After assembling all the components—motherboard, CPU, RAM, GPU, and storage—you press the power button. The fans start spinning, and the power light turns on, but nothing appears on the monitor. Now, you might be wondering how to boot the system before installing the operating system. In this lesson, we’ll explore the BIOS (Basic Input/Output System) and UEFI (Unified Extensible Firmware Interface), their features, and their functions. 

BIOS 

What is BIOS? BIOS stands for Basic Input/Output System

and has four functions. 

  • Power-on self-test (POST) 

  • Bootstrap Loader 

  • BIOS Drivers 

  • CMOS Setup (Complementary Metal-Oxide Semiconductor) 

The BIOS is like an orchestra conductor, performing checks (POST) to ensure all hardware is ready, selecting the right boot drive, starting the system (loading the OS), and adjusting (configuring settings) for smooth operation. 

Power-on Self-test (POST):

  • POST (Power-On Self-Test) runs diagnostic checks on essential hardware. 

  • Ensures CPU, memory, and storage are functioning correctly. 

  • Alerts with error messages or beep codes if issues are detected.

  • Occurs before the system fully starts up. 

Bootstrap Loader:

  • Locates and loads the operating system from the bootable device. 

  • Initiates the boot process by transferring control to the OS. 

  • Determines the correct boot drive based on BIOS settings. 

BIOS Drivers: 

  • Provides basic drivers for essential hardware (keyboard, display, storage). 

  • Enables communication between the CPU and hardware during startup. 

  • Operates before the operating system's drivers take over.

CMOS:

CMOS (Complementary Metal-Oxide-Semiconductor) refers to a chip of a small amount of memory on the computer’s motherboard that stores BIOS settings.  These settings include system time, date, hardware configurations, and boot sequence preferences. 

Have you ever wondered how your computer remembers the time and date even when it’s turned off? Or how it retains certain settings between restarts? The answer lies in a small but crucial component: the CMOS battery.  CMOS is powered by a small, coin-shaped battery which allows the settings to be preserved even when the computer is turned off.  When the battery dies, the CMOS resets to its default settings, and users may need to reconfigure their system’s BIOS. 

UEFI BIOS 

UEFI BIOS (Unified Extensible Firmware Interface) is the modern version of BIOS used in today’s systems. It was created to be a standard, offering the same features across all devices. UEFI improves on the old BIOS with faster boot times, better security, support for larger disks, and a user-friendly interface. 

Accessing the BIOS 

You can access the BIOS during startup by pressing a specific key. Common keys include F1, F2, Ctrl-S, or Ctrl-Alt-S, but it can vary by system. If you're unsure, a quick web search can help you find the right key for your device. 

Boot Options 

In the BIOS, you can: 

  • Select the Boot Drive: Choose the storage device where your operating system is installed to ensure the computer boots correctly. 

  • Control Hardware Features: Enable or disable hardware, like USB ports, to increase security. 

  • Customize Performance: Adjust settings like fan speed for better cooling or quieter operation, depending on your preference. 

What is Secure Boot? 

Secure Boot is a security feature in modern computers that helps protect your system from malware during the boot process. It ensures that only trusted software, like your operating system, can load when you start your computer. 

Why Use Secure Boot? 

You would use Secure Boot to prevent unauthorized or malicious software from taking control of your computer when it turns on. This helps keep your system secure, especially against boot-level attacks. 

How Does Secure Boot Work? 

When your computer starts, Secure Boot checks the digital signatures of the software trying to load. If the software has a trusted signature, it’s allowed to run. If not, Secure Boot blocks it, preventing potentially harmful software from compromising your system. 

What is a Boot Password? 

A Boot Password is a security feature that requires you to enter a password before your computer starts up. This adds an extra layer of protection by preventing unauthorized users from accessing your system. 

Summary:

  • BIOS Functions:

    • Performs hardware checks (POST).

    • Loads the operating system.

    • Manages hardware settings. 

  • UEFI BIOS:  

    • Modern version of BIOS.

    • Offers faster boot times, better security, and a user-friendly interface

  • Accessing BIOS: Press a specific key during startup (e.g., F1, F2, Ctrl-S).  

  • In BIOS, You Can:

    • Select the boot drive

    • Control hardware features (e.g., enabling/disabling USB ports)

    • Customize performance (e.g., adjusting fan speeds)

  • Security Features:

    • Secure Boot: Protects against malware by ensuring only trusted software loads

    • Boot Password: Requires a password before starting the system, adding extra protection