Lecture Notes: Computer Startup and BIOS

Introduction to BIOS

• BIOS: Basic Input Output System.
  • Software that initiates when the computer is powered on.
  • Displays initial boot sequence information on the screen.
  • Also known as firmware of the system.
  • Stored in flash memory, not ROM (Read-Only Memory) in modern systems.

Functionality of BIOS

• Initialization: Powers on memory and CPU, executes BIOS code.
• POST (Power On Self Test):
  • Checks for essential hardware components: memory, CPU, video, input devices (keyboard/mouse).
  • Not a comprehensive hardware diagnostic tool.
• Boot Process:
  • Determines boot drive based on configurations.
  • Searches for boot loader to start operating system.

Motherboard and BIOS Configurations

• BIOS configurations stored on motherboard.
• Dual BIOS Configurations:
  • Main BIOS and backup BIOS.
  • Allows for system recovery if BIOS upgrade fails.

Legacy BIOS

• Characteristics:
  • Text-based, used in older computers for about 25 years.
  • Basic configuration changes possible.
  • Limited in upgrading capabilities, adding drivers, or extending functionalities.

UEFI BIOS

• UEFI (Unified Extensible Firmware Interface):
  • Replaces Legacy BIOS in modern computers.
  • Developed by Intel (EFI standard).
  • Standardized across different manufacturers.
• Features:
  • Main, Security, Advanced, and UEFI Drivers sections.
  • System information, date/time settings, diagnostics.
  • Security features such as user/administrator passwords.
  • Advanced settings for boot options.
  • UEFI Drivers tab for installing additional hardware drivers.