ICT

• Computers can only understand data in the form of binary digits (0,1); this is commonly known as digital data. However, data in the real world is analogue, not limited to two specific values.
• Analogue data


  Data forms smooth curves
• Digital data


  Data changes in discrete steps
• ADC (analogue to digital converter)


  Hardware that converts analogue data to digital data

  
• DAC (digital to analogue converter)


  Hardware that converts digital data to analogue data
• Central Processing Unit (CPU)


  • It is a single integrated circuit at the core of most PCs and is also present in many household gadgets and equipment where some control or monitoring is required
  • It consists of a control unit (CU) that manages the input and output devices, an arithmetic and logic unit (ALU) that performs computations and makes logical judgments, and tiny memory regions known as registers
• Random access memory (RAM)

  Temporary memory storage, lost after power is shut down, performs read and write functions, is used to store data that are currently in use, and can be increased in size to improve operational speed
• Read-only memory (ROM)


  Permanent memory storage, non-volatile, can only be read from, used to store computer's configuration data, such as BIOS
• BIOS (basic input/output system)

  Stores the date, time and system configuration on a non-volatile chip called a CMOS (complementary metal oxide semiconductor) – this is usually battery powered
• Differences between RAM and ROM

  • RAM is a temporary memory device, ROM is a permanent one
  • RAM is volatile, ROM is non-volatile
  • RAM can be written to and from, but ROM can only be read from
  • RAM is used to store data, files, programs, and parts of OS that are currently in use, ROM is used in storing start-up data
• Input devices


  Pieces of hardware that allow users to enter data into computers
• Output devices


  Displays the computer's output in a human-readable format
• Differences between input and output devices

  • An input device can only send data, an output device can only receive data
  • Input devices are necessary for a computer to receive commands from the user for processing to be permitted, output devices are needed in order to display the outcome of the processing that took place to the user
  • Input devices are complex as they must ensure proper communication between the computer and the user, output devices are simpler as they only need to display the finale
• Backing and Secondary Storage

  Required to store significant amounts of data permanently, most commonly in the form of Hard disk drives and Solid-state drives
• Differences between internal memory and backing storage

  • RAM contents are lost when power is lost, ROM is read-only, and backing storage is permanent even without power
  • RAM and ROM are much smaller than backing storage
  • RAM and ROM are significantly faster in accessing data than backing storage
  • Backing storage is much cheaper than internal memory
  • Internal memories are fixed, and backing storage can be fixed or portable
  • Internal memories can be directly read by the CPU, while backing storage needs to be moved into the RAM before being read by the CPU
• Operating Systems


  • Controls operation of input, output & backing storage
  • Supervises loading, running & storage of application programs
  • Deals with errors in application programs
  • Maintains security of the whole computer system
  • Maintains a computer log
• Types of user interfaces

  • Command line interface
  • Graphical user interface
  • Dialogue-based user interface
  • Gesture-based user interface
• Command line interface


  User needs to type in commands to communicate with the computer, not restricted to pre-defined options, possible to alter computer configuration settings, needs to learn many commands for basic operations, all commands need to be typed in, which is time-consuming, very error prone, as commands must have correct format, spelling etc.
• Graphical user interface


  Uses WIMP (windows icons menu and pointing device), the user does not need to learn any commands, it is more user-friendly, icons are used to represent applications, a pointing device is used to click on an icon to launch the application, this is simpler than typing in commands, this type of interface uses up considerably more computer memory than a CLI interface, the user is limited to the icons provided on the screen, needs a more complex operating system
• Dialogue-based user interface


  Use the human voice to give commands to a computer system, no need for a driver to take their hands off the steering wheel, in a home, it is especially useful for people with disabilities because many tasks can be carried out by the spoken word only, possible to use it as a security feature because voice recognition could be used to identify a person, still unreliable, with many commands not being recognized or needing to be repeated several times (especially if there is background noise), can be quite complex to setup, user needs to know which commands can be used
• Gesture-based user interface


  Relies on human interaction by the moving of hands, head or even feet, replaces mechanical input devices, no physical contact is required, very natural interface for a human operator, no training is needed to interface with the computer, it is possible for unintentional movement to be picked up, only works near the camera or sensor (maximum of 1.5 meters), may only accept a limited number of movements (for example, it may take several attempts to determine exactly what finger movements are recognized)
• Desktop Computers


  • Made up of a separate monitor, keyboard, mouse, and processor unit, not very portable
  • Uses: office and business work, educational use, general entertainment, gaming device
  • Advantages: easier and less costly to upgrade and expand, spare parts are standardized, better specifications for a given price, no critical power consumption, less likely to be damaged or stolen, more stable internet access
  • Disadvantages: not particularly portable, more complicated due to wiring, files must be copied to another portable storage device to take work elsewhere
• Laptop Computers


  • Monitor, keyboard, pointing device and processor are all together in one unit, extremely portable, lightweight, low power consumption and heat output
  • Uses: office and business work, educational use, gaming, general entertainment
  • Advantages: portability, no trailing wires and desk clutter, take up less room, take advantage of Wi-Fi
  • Disadvantages: easier to steal, limited battery life, awkward keyboards and pointing devices, not easy to upgrade
• Smartphones


  • Allow normal phone calls, have an operating system allowing them to run computer applications, communicate with the internet using Wi-Fi or mobile networks
  • Uses: send/receive emails, use apps, use camera, use MP3/4 player
  • Advantages: very small and lightweight, connect to internet on the move, can be used almost anywhere, have apps that can tell instant location, reasonable battery life
  • Disadvantages: small screens and keyboards, web browsing and photography can drain battery, limited memory, not all website features are compatible, easier to lose or be stolen, slower data transfer than Wi-Fi
• Tablets


  • Work similarly to smartphones but are somewhat bigger in size
  • Uses: send/receive emails, use apps, use camera, use MP3/4 player
  • Advantages compared to laptops: very fast to switch on, fully portable, touch screen technology, not much heat, longer battery life
  • Disadvantages compared to laptops: tend to be expensive, limited memory/storage, slow and error-prone typing, support fewer file formats
• Phablets


  • Hybrid between a tablet and a smartphone, have much larger screens than a smartphone but are smaller than a tablet
  • Uses: entertainment, gaming, camera/video, internet use, email, GPS, calendar, telephone banking, voice over IP, social networks, instant messaging, office and business management, education, remote control

  
• Laptops are the most expandable, smartphones are the most portable, tablets and phablets fall somewhere in between, the choice of device will depend on your specific needs and use case
• Artificial Intelligence (AI)


  A machine or application which carries out a task that requires some degree of intelligence, such as using language, recognizing faces, operating machinery, analyzing data to predict outcomes
• Everyday uses of AI include autonomous (driverless) vehicles, we already have driverless trains and autopilots on airplanes, but driverless cars are still being developed
• Artificial Intelligence (AI)


  A machine or application which carries out a task that requires some degree of intelligence
• Everyday uses of AI

  • Autonomous (driverless) vehicle
  • Robotic research to help amputees and people with disabilities
  • Robots to help carry out dangerous or unpleasant tasks
• Negative impacts of AI

  • Unemployment
  • Dependency on technology
  • De-skilling
• Extended reality


  Real and virtual combined environments
• Augmented reality (AR)


  A merger between the virtual and physical (real) world; it lays objects onto pre-existing objects
• Virtual reality (VR)


  Enables an entirely new world to be created, unlike AR, which has no link to the actual surroundings of the user
• Input device


  Any hardware device that allows a user to enter data or instructions into a computer directly
• An input device can send data to another device, but it cannot receive data from another device
• Input devices are necessary for a computer to receive commands from its users and data to process
• Input devices


  • Keyboards
  • Numeric keypads
  • Mouse
  • Touchpad
  • Tracker ball
  • Remote Control
  • Joysticks
  • Driving wheel
  • Touch screen
  • Scanners
  • Digital Cameras
  • Microphones
  • Sensors
  • Light pens
• Keyboards


  • Fast entry of new text into a document
  • Well-known method
  • Easy to use for most people
  • Easier to do verification checks as data is entered