Ict

• Hardware


  Physical components that make up the computer system
• Hardware

  • Each piece has a specific role in the computer system
  • Can be internal (fixed inside) or external
• Input devices


  Devices that input data into the computer system
• Input devices

  • Mouse
  • Keyboard
  • Microphone
  • Barcode scanner
• Output devices

  Devices that output data from the computer system
• Output devices

  • Monitor
  • Speakers
  • Printer
  • Projector
• External storage devices

  Provide external storage or backup solutions
• To run computer, system must consist of both hardware and software
• Software

  Programs for controlling the operation of the computer or processing electronic data
• Types of software

  • Application software
  • System software
• Application software


  Software with specific tasks (e.g. word processing, spreadsheets, databases, graphics editing, audio/video editing)
• System software


  Provides services for the computer to operate (e.g. operating system, device drivers, utility software)
• System software


  • Operating system
  • Antivirus
  • Performance utilities
• Applets are small computer programs that perform specific tasks within a larger program
• Applets


  Small computer program that performs a specific task within a larger program
• Creating content for presentation

  1. Use word processor to type up text

  2. Use spreadsheet software to create a graph

  3. Use graphic editing application to include pictures
• Producing menus for a restaurant

  1. Use word processing to include text and pictures

  2. Use spreadsheet software to calculate the cost of meals
• Control and measurement systems

  • Measure conditions to maintain an environment (e.g. temperature in a greenhouse)
  • Automatically take action to control the environment (e.g. turn on heater when temperature drops)
• Analog signal


  Continuous range of values collected by sensors
• Digital signal

  Discontinuous values converted from analog signals, understood by computers
• Analog to digital conversion

  Analog signals from sensors are converted to digital signals using an analog to digital converter so computers can understand them
• Measuring and control software

  • Measures conditions in an environment (e.g. temperature in a greenhouse)
  • Compares measurements to preset levels
  • Takes control actions (e.g. turn on heater) to maintain desired conditions
• Sensors placed in a river to check water level, if level rises above 5 meters a flood barrier is raised
• Sensor data


  Cannot be directly read by computer, requires analog to digital converter
• Measurement systems


  Take readings and store results, can detect changes in the environment
• Control systems


  Change the environment, compare sensor values to preset levels and take action accordingly
• Using computers and sensors to measure temperature has advantages over manual readings, including measurements taken outside school hours, more accurate and consistent readings, and continuous monitoring
• Devices used in control systems

  • Computer
  • Sensors
  • Analog to digital converter
  • Actuators (e.g. lights, heater, motor, pump)
• Operating systems


  Manage computer functions including hardware devices, input/output, and provide graphical user interface
• Utility software


  Maintain computer resources by running specific tasks, e.g. antivirus, performance optimization
• Device drivers


  Allow hardware devices to run on a computer
• Linkers and compilers


  Translate programs written in specific languages into executable files that can be run by the computer
• Examples of system software

  • Operating systems
  • Utility software (e.g. antivirus, device drivers)
• CPU


  The brain of the computer system, where all the calculating and decision making takes place
• CPU


  • Modern computers have dual or quad core processors which can process instructions simultaneously and independently
  • Allows an instruction or data to be processed, decoded and executed
• Processing an instruction


  1. Fetch data and instructions from main memory (RAM)

  2. Decode the instruction

  3. Execute the instruction
• Primary storage (main memory)


  Holds data, programs and instructions that are currently in use
• Primary storage


  • Random Access Memory (RAM)
  • Read Only Memory (ROM)
• Random Access Memory (RAM)


  Temporary storage for instructions being processed by the CPU, volatile (data lost when powered off)
• Read Only Memory (ROM)


  Holds boot up instructions, non-volatile (data not lost when powered off)