Introduction to BIOS and UEFI

BIOS (Basic Input/Output System)

• Startup Role: Initializes the computer and loads the operating system.
• Types of BIOS
  • System BIOS
  • ROM BIOS (Read Only Memory)
  • Flash Memory BIOS
• Initialization Process:
  • Initializes memory and CPU.
  • Executes BIOS code.
  • Conducts POST (Power-On Self Test)
    • Checks existence of memory, CPU, video, and input devices (keyboard/mouse).
  • Identifies boot drive and boot loader to start the operating system.

Flash Memory in BIOS

• Storage: Modern BIOS configurations are stored in flash memory on the motherboard.
• Dual BIOS Configurations:
  • Main BIOS
  • Backup BIOS
  • Allows BIOS upgrades and reversion if upgrade fails.

Legacy BIOS

• Features:
  • Text-based interface.
  • Interaction with hardware.
  • Basic configuration changes.
  • Limited capabilities (no driver additions or capability upgrades).
• History: Used for 25+ years in older computers.

UEFI (Unified Extensible Firmware Interface)

• Introduction: Standardized form of BIOS replacing legacy BIOS.
• Standardization: Created as EFI (Extensible Firmware Interface) by Intel.
  • Ensures consistency across manufacturers.
• Capabilities:
  • Main: View system info, modify date/time, and perform diagnostics.
  • Security: Set user/admin passwords.
  • Advanced: Change boot options.
  • UEFI Drivers: Install additional hardware drivers.
• Example Interface: Categories include Main, Security, Advanced, and UEFI Drivers.
  • Provides extensive configuration and diagnostic options.