ICT

• Computer


  An electronic and electromechanical device that can accept, process, store and retrieve data as well as output the result by following a set of instructions called a program
• Components of a computer system

  • Hardware
  • Software
• Computer hardware


  • The physical parts of the computer system that we can see and touch
• Parts of the computer hardware

  • System unit
  • Peripherals (keyboard, mouse, printer, etc.)
• System unit


  • Contains the central processing unit (CPU) and other electronic components
• Hardware components in the system unit

  • Arithmetic and Logic Unit (ALU)
  • Control Unit (CU)
  • Memory Unit
• RAM (Random Access Memory)

  Temporary and volatile memory
• ROM (Read Only Memory)


  Permanent and non-volatile memory
• Peripheral devices

  • Keyboard
  • Mouse
  • Scanner
  • Joystick
  • Monitor
  • Printer
  • Plotter
  • CD-Rom drives
  • USB flash drives
  • Uninterruptible Power Supply (UPS)
• Characteristics of a computer

  • Speed
  • Accuracy
  • Versatility
  • Reliability
  • Memory and storage
• Speed


  Computer processes data fast, measured in Megahertz (MHz)
• Computers now have very high speeds measuring up to 1,000 MHz and more
• Accuracy


  Computer gives accurate results as long as correct data is entered and there are no program errors or hardware faults
• Versatility


  Computer can be used to perform various kinds of jobs in almost all professions
• Reliability


  Computer can work for several hours producing good quality results without errors or getting tired, unlike humans
• Memory and storage


  Computer can store very large amounts of data, instructions and information
• EDVAC

  Electronic Discrete Variable Automatic Computer, a first generation computer with a single processing unit and simpler design than ENIAC
• UNIVAC

  Universal Automatic Computer, one of the first generation computers
• Desktop personal computer

  Personal small micro computer system that the user can place on the desk and work with
• Notebook computer

  Very small AC-/battery-powered computer that will fit inside a briefcase
• Palmtop computer

  Hand-held computer with no keyboard, using a stylus pen for input
• Types of input devices


  • Mouse
  • Keyboard
  • Scanner
  • Microphone
  • Card readers
  • Digital Camera
  • Joystick
• Mouse


  An input device that is used to control the movement of a pointer in a Graphical User Interface (GUI) environment
• Keyboard


  An input device for entering textual data, instructions/commands, and programs to the computer
• Scanner


  Input devices used for inputting images in the graphics formats into the computer
• Microphone


  An input device used to record sound into the computer
• Card readers


  Device used to read information that has been magnetically encoded on a plastic card such as the ATM card or an employee badge
• Digital Camera


  Device used to take pictures into the computer
• Joystick


  A joystick is used mostly for computer games
• Software


  A general term used to describe the set of instructions usually called a program, which controls the operations of a computer
• Program


  A sequence of instructions (steps) that computer follows to perform a task
• Data


  Representation of fact or a collection of facts, which the computer processes
• Application software


  Programs that enable computers to perform useful productive tasks
• System software


  Programs that direct and control the running of the computer's hardware and other connected devices
• Operating system


  A group of programs that manage the computer system resources
• File


  A named collection of related information. A file can be a program or a data file
• Memory


  The storage space where data and instructions are kept
• Response time


  The amount of time taken by the computer to respond when data/instructions are entered
• Utility Software


  Programs that maintenance computer's hardware, program and data. It is also known as service programs