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.