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Understanding Computer Interfacing and BIOS❌

Jun 1, 2025

Lecture Notes on Computer Interfacing and BIOS

Key Concepts

  • Device Communication:

    • Programs execute from hard drive to CPU.
    • Input devices (e.g., mouse, keyboard) don't have instructions for CPU.
    • Devices use programs called services or drivers to communicate with CPU.
  • Drivers:

    • Contain instructions for CPU to understand devices like keyboards, webcams, printers.
  • BIOS (Basic Input Output Services):

    • Software that initializes hardware and boots operating systems.
    • Stored in ROM chip (non-volatile memory) on the motherboard.
    • Provides essential instructions before the operating system loads.
  • ROM vs RAM:

    • ROM is non-volatile; data is not erased when computer turns off.
    • RAM is volatile; data is erased when power is off.

UEFI (Unified Extensible Firmware Interface)

  • Modern replacement for traditional BIOS.
  • Better compatibility and support for newer hardware.
  • Expected to become the standard BIOS.

Power On Self Test (POST)

  • Test run by BIOS during boot-up to check hardware functionality.
  • Issues with hardware produce beep codes (Morse code-like series) instead of screen errors.
  • Beep codes vary by manufacturer.
  • Not all computers have built-in speakers for beep codes.

BIOS Settings and CMOS Chip

  • CMOS chip stores basic booting data (date, time, boot preferences).
  • Access BIOS settings via a specific key during boot-up.
  • Important for IT support roles to modify BIOS settings.

Re-imaging and IT Tasks

  • Re-imaging refers to wiping and reinstalling an operating system.
  • Performed using programs on external devices (USB, CD-ROM, network server).
  • BIOS settings must be modified to boot from an external device for re-imaging.