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Fundamentals of Computer Systems and Software

May 7, 2025

CAIE IGCSE ICT 0417 Theory

Types and Components of Computer Systems

Hardware & Software

Hardware

  • Definition: Physical components of a computer system, including input and output devices.
  • Internal Hardware Devices:
    • Central processing unit (CPU)
    • Processor
    • Motherboard
    • RAM & ROM (Internal Memory)
    • Graphics & Sound Cards
    • Storage: HDD, SSD
    • Network Interface Card (NIC)
  • External Hardware Devices:
    • Monitor, Keyboard, Mouse, Printer
    • External Storage Devices

Software

  • Definition: Programs and instructions that control computer functions.
  • Types of Software:
    • Application Software: For specific tasks (e.g., spreadsheets, databases)
    • System Software: Platform for applications (e.g., OS, compilers, linkers)

Analogue and Digital Data

  • Concept: Computers understand binary (0,1) digital data; real-world data is analogue.
  • Conversion: ADC (Analogue to Digital Converter), DAC (Digital to Analogue Converter)

Main Components of Computer Systems

Central Processing Unit (CPU)

  • Function: Executes hardware/software operations, known as a microprocessor.
  • Components:
    • Control unit: Manages I/O devices
    • ALU (Arithmetic and Logic Unit): Performs computations
    • Registers: Small memory regions

Internal Memory

  • RAM: Volatile, temporary, used for currently active data.
  • ROM: Non-volatile, stores permanent data (BIOS).
  • BIOS: Stores system configuration, powered by CMOS battery.

Input & Output Devices

  • Input Devices: Hardware for data entry (e.g., keyboard, mouse).
  • Output Devices: Display processed data (e.g., monitor, printer).

Backing and Secondary Storage

  • Purpose: Permanent data storage (e.g., HDD, SSD)
  • Comparison:
    • RAM/ROM: Temporary, smaller but faster
    • Backing Storage: Permanent, larger, cheaper

Operating Systems

  • Functions: Control operations, load/run programs, handle errors, maintain security.
  • User Interfaces:
    • CLI: Command Line Interface, direct communication with the computer.
    • GUI: Graphical User Interface, user-friendly with icons.
    • Dialogue-based: Voice commands
    • Gesture-based: Interacts with gestures

Types of Computers

Desktop Computers

  • Characteristics: Separate monitor, keyboard, portable.
  • Advantages: Easier to upgrade, stable internet.
  • Disadvantages: Not portable, desk clutter.

Mobile Computers

  • Laptops: Portable, single unit, long battery.
  • Smartphones: Apps, lightweight, internet access.
  • Tablets: Bigger than smartphones, touch screen.
  • Phablets: Hybrid of smartphones and tablets.

Impact of Emerging Technologies

Artificial Intelligence (AI)

  • Applications: Autonomous vehicles, face recognition, data analysis.
  • Negative Impacts: Unemployment, de-skilling.

Extended Reality (XR)

  • Augmented Reality (AR): Merges virtual and real-world.
  • Virtual Reality (VR): Creates entirely new environments.