ICT 1.2

• Central Processing Unit (CPU)


  The computer's "brain" responsible for processing instructions entered into the computer
• CPU Functions


  1. Fetches instructions from memory

  2. Decodes the instructions to determine the required operation

  3. Executes the operation

  4. Stores the result back in memory or sends it to an output device
• CPU Components


  • Arithmetic Logic Unit (ALU)
  • Control Unit (CU)
  • Registers
• ROM (Read-Only Memory)


  Non-volatile (retains data when powered off), read-only (data cannot be modified), stores essential instructions (e.g. BIOS)
• RAM (Random Access Memory)


  Volatile (loses data when powered off), read-write (data can be modified), stores data and instructions in use by CPU
• ROM is non-volatile, while RAM is volatile
• ROM is read-only, while RAM is read-write
• ROM stores essential instructions, while RAM stores data and instructions currently in use
• Input Devices


  • Allow users to enter data or instructions into a computer system
• Input devices


  Send data or instructions to the computer
• Output devices


  Receive data from the computer
• Input Devices vs Output Devices


  • Input devices are used for user interaction and data entry, while output devices display or produce the results of data processing
• Direct Data Entry Devices


  • Magnetic Stripe Reader
  • Chip and PIN Reader
  • RFID Reader
  • OMR (Optical Mark Recognition)
  • OCR (Optical Character Recognition)
  • Barcode Reader
  • QR Scanner
• Direct Data Entry Devices


  • Allow for fast and accurate data capture from physical sources
• Output Devices


  • Display or produce the results of data processing from a computer system
• ER


  • Large display, good for presentations
  • Requires darkened room, expensive bulbs
• Laser Printer


  • Printing high-quality text and graphics quickly
  • Fast, high-quality prints, lower cost per page
  • Expensive initial cost, limited to flat surfaces
• Inkjet Printer


  • Printing text and graphics using liquid ink
  • Lower initial cost, high-quality prints
  • Slower, higher cost per page, ink may smudge
• Dot Matrix Printer


  • Printing text and simple graphics using a print head that strikes an ink-soaked ribbon
  • Low cost, can print multi-part forms
  • Noisy, low print quality
• Plotter


  • Creating large-format graphics, such as architectural plans and engineering designs
  • High accuracy, can print on various materials
  • Slow, expensive, large size
• 3D Printer


  • Creating three-dimensional objects by adding material layer by layer
  • Customisable designs, rapid prototyping
  • Limited materials, slow process
• Speaker


  • Converting digital audio signals into sound
  • Range of sizes and power outputs, immersive audio
  • Can be power-hungry, the sound quality varies
• Actuator


  • Converting electrical signals into physical movement, e.g., motors and valves in robotics
  • Precise movement, programmable
  • Requires power, potential mechanical wear
• Holographic imaging


  • A technique that creates three-dimensional images by recording and reconstructing light waves
  • These images provide a realistic and immersive visual experience
• Holographic imaging could be used in medicine to create


  • MRI scan images
  • Ultrasound images
  • 3D views of our internal organs
• Numeric keypad


  A device used to input a pin
• Interpreter


  Analyses and executes a program line by line
• 3D printer


  Produces output in the form of solid objects
• Speaker


  Produces output in the form of sound
• Backing storage is typically slower than internal memory but has a larger capacity
• Backing storage is non-volatile, meaning it retains data when the computer is powered off
• Examples of backing storage


  • Hard disk drives (HDD)
  • Solid-state drives (SSD)
  • USB flash drives
  • Optical discs (CDs, DVDs)
• Backing storage


  Long-term storage used to store data, files, and programs when not in use
• Internal memory


  Temporary storage of data and essential instructions while the computer is running
• Examples of internal memory


  • RAM
  • ROM
• Differences between backing storage and internal memory


  • Function
  • Speed
  • Capacity
  • Volatility
• Storage media


  • Magnetic drives
  • Optical discs
  • Solid-state media
• Magnetic drives


  • Long-term data storage, backup, and archiving
  • High capacity, low cost per GB
  • Slower access time, moving parts, susceptible to magnets
• Optical discs


  • Data storage, audio, video, and software distribution
  • Portable, durable, low cost
  • Limited capacity, susceptible to scratches
• Solid-state media


  • Fast data storage for portable devices and modern computers
  • Fast access time, no moving parts
  • More expensive, limited write cycles