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BIOS (Basic Input/Output System)
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A firmware interface that initializes and tests hardware, loads the operating system, and manages system settings.
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Functions of BIOS
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(a) POST (Power-On Self-Test): Runs hardware diagnostics. (b) Bootstrap Loader: Loads the OS from the bootable device. (c) BIOS Drivers: Provides basic drivers for keyboard, display, and storage. (d) CMOS Setup: Stores system settings like time and hardware configurations.
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Power-On Self-Test (POST)
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Performs diagnostics on essential hardware (CPU, memory, storage). Provides error messages or beep codes if issues are detected.
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Bootstrap Loader
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Locates the operating system on the boot device and initiates the boot process by transferring control to the OS.
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BIOS Drivers
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Provides basic drivers for keyboard, display, and storage, allowing communication between hardware and the CPU during startup.
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CMOS (Complementary Metal-Oxide-Semiconductor)
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A chip that stores BIOS settings like system time and hardware configurations. Powered by a small battery to retain data when the computer is off.
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CMOS Battery
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A coin-shaped battery that powers CMOS memory, allowing settings to be preserved when the computer is turned off.
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UEFI BIOS (Unified Extensible Firmware Interface)
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A modern version of BIOS with faster boot times, support for larger disks, better security, and a user-friendly interface.
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Accessing BIOS
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Press a key during startup (e.g., F1, F2, Ctrl-S) to access BIOS settings.
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BIOS Boot Options
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In BIOS, you can: Select the boot drive. Control hardware features (enable/disable USB ports). Adjust performance settings (fan speed, etc.).
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Secure Boot
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A UEFI (Unified Extensible Firmware Interface) feature that ensures only trusted software loads during startup, protecting against malware and unauthorized software.
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How Secure Boot Works
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Checks the digital signatures of software trying to load. Only software with a trusted signature is allowed to run.
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Boot Password
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A security feature that requires a password before the system starts, preventing unauthorized users from accessing the computer.
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Summary of BIOS Functions
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(a) Performs POST checks. (b) Loads the operating system. (c) Manages hardware settings.
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Summary of UEFI BIOS
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(a) Faster boot times. (b) Enhanced security features. (c) User-friendly interface.