ICT REVISION GUIDE

• Computer


  Processes data through a program
• Hardware


  Equipment like PCs, keyboards, monitors, and mice
• Types of computers


  • Desktop PCs
  • Laptops
  • Tablets
  • Supercomputers
• Data


  Raw information
• Information


  Data that people understand
• Data interpretation example


  • 30112012 can be a date or a sum of money
• Computer functions


  • Input
  • Process
  • Store
  • Output
• Types of computers


  • PCs
  • Mainframe computers
  • Minicomputers
  • Supercomputers
• Processor


  Microprocessor built into a microchip
• Processor performance


  Affected by speed and number of cores
• Processor choice


  Depends on intended use, like word processing or gaming
• Peripheral devices


  • Input devices
  • Output devices
  • Storage devices
• Input devices


  • Keyboards
  • Pointing devices (mice, joysticks, trackpads)
• Output devices


  • Monitors
  • Printers
  • Scanners
• Types of scanners


  • Hand-held
  • Flatbed
  • Sheet-fed
• Optical Mark Recognition (OMR)

  Reads marks on paper to input data without typing
• Optical Character Recognition (OCR)

  Converts printed or handwritten characters into text for processing
• Magnetic Ink Character Recognition (MICR)


  Reads specially shaped characters printed in magnetic ink
• OCR vs MICR


  OCR uses reflected light, while MICR uses magnetic field patterns
• Magnetic stripe cards


  Information stored on a magnetic stripe on a plastic card, can be input directly into a computer, used for access control, disadvantages include susceptibility to electromagnetic radiation and data copying/editing
• Smart cards


  Plastic card with a microprocessor chip, used for payments and cash withdrawals, more secure than magnetic stripe cards
• Digital cameras, digital video cameras, and webcams

  Digital cameras store pictures on memory cards, digital video cameras record moving images with sound, webcams used for remote viewing over the Internet, advantages include easier backup, sharing via email, and display on various devices, disadvantages include increased storage needs for high-quality files
• Biometric scanners


  Identify individuals based on unique physical characteristics, used for building access and car key replacements, minimize fraud and theft risks
• Sensors


  Used to input environmental data like light intensity and temperature, convert analogue voltage to digital signals for computer processing, widely used in weather stations and robotics for data logging and control
• Audio input devices and technologies


  • Touch-tone telephones
  • Microphones
  • Voice recognition software
  • Speech recognition
• Audio input


  Advantages include ease of use, disadvantages include the need for training and accuracy issues
• Remote control


  Uses infrared technology to control devices, handset emits coded pulses of infrared light, receiver in the controlled device processes commands
• LCD monitors


  More compact and consume less power than CRT monitors
• Monitor resolution


  Determined by the number of dots across and from top to bottom
• Graphics card


  Controls screen display quality
• Touch screen


  Used for both output and input, mainly with tablets and smartphones, no need for a keyboard but text input is slower
• Multimedia projector


  Projects computer screen images onto a larger screen for better visibility, used in classrooms and homes for movies and games
• Printer types


  • Dot-matrix
  • Inkjet
  • Laser
  • Thermal
• Print quality


  Measured by dpi (dots per inch), higher dpi means better quality
• Photo-printers


  Used for digital photographs, can print without a computer
• Advantages of printers


  Useful when no computer available
• Disadvantages of printers


  Slow and expensive compared to electronic communications, printed materials are bulky and deteriorate
• Plotters


  Draw lines on paper using colored pens, used in computer-aided design, more expensive but can print larger sheets
• Multi-function devices (MFD)


  Combine printer, scanner, and communications link, cost-effective and space-saving
• Speakers


  Used for sound output