ICT TEST 2

• Types of input devices

  • Keyboards
  • Pointing devices
  • Remotes
  • Joysticks
  • Driving wheel
  • Touchscreens
• Keyboard


  Most common input device on computers, used for inputting data into application software and typing in commands
• Types of keyboards


  • Standard keyboard
  • Concept keyboard
  • Numeric keypad
• Concept keyboard


  • Uses icons and phrases instead of standard letters, usually used in food restaurants
  • Fast data entry
  • Waterproof
  • Tamper resistant
• Numeric keypad


  • Used to enter numbers only
  • Faster than standard keyboards
  • Small keys make it difficult to input data
  • Order of numbers can sometimes be not intuitive
• Pointing device


  Allows the user to control the position of a pointer on the screen
• Types of pointing devices

  • Mouse
  • Touchpad
  • Trackball
• Mouse


  • Allows the user to control the position of the pointer by moving the mouse and select items by double clicking
  • Faster way to choose options
  • Difficult for people with restricted arm movement
  • Easy to damage
  • Doesn't need large desk area
• Touchpad


  • Same functions as a mouse
  • Difficult for people with restricted arm movement
  • More difficult to control than a mouse
  • More difficult to do functions such as drag and drop
• Trackball


  • Controls the pointer on the screen by rotating a ball
  • Doesn't need fine control
  • Easier to use than mouse
  • More accurate in positioning
  • More robust
  • Less desk space needed than mouse
• Remote


  Used to control operations of devices remotely through infrared signals
• Remote


  • Operated from any reasonable distance
  • Difficult for people with restricted arm movement
  • Very easy to block signal due to walls
• Joystick


  Allows the user to control movement by gripping the handle
• Joystick


  • Easier than a keyboard for video games and simulations
  • More difficult to control pointer in comparison to other devices
• Driving wheel


  Allows the user to simulate turning a wheel while driving
• Driving wheel


  • Easier than keyboard or joystick for video games and simulations
  • Expensive
  • Too sensitive and has no feedback to improve it
• Touchscreen


  Allows the user to select options and icons by simply touching the part of the screen where the wanted item is located
• Touchscreen


  • Fast data entry
  • Limited options
• A Network is two or more computers or other electronic devices connected together so that they can exchange data
• Stand-alone computer


  A computer that is not connected to a network
• Reasons for using a computer connected to a network

  • Easily share files and data
  • Share resources such as printer, scanner and internet connections
  • Communicate with other network users (email, video conferencing, chatting, etc)
  • Store data centrally (by using server) for ease of access and backup
  • Keep all of our settings centrally we can use any work station (PC)
• Reasons for using a computer connected to the internet

  • Make use of online services such as e-commerce (shopping), e-banking, etc
  • Get access to a huge range of information
  • Access forms of entertainment (games, music, videos, etc.)
  • Join online communities (e.g., Facebook, MySpace, etc.)
• Disadvantages of using a computer connected to a network

  • The computer is vulnerable to hackers
  • If the network breaks, many tasks become very difficult to perform
  • Your computer can more easily be attacked by a virus
  • We have to be careful about revealing personal information
  • We have to be careful to avoid suspect websites that might contain malware
  • We have to be aware that information found on the internet is not always accurate or reliable
• Client


  Client computers are the normal computers that user can use it to get their work done
• Server


  Servers are special, powerful computers that provide services to the client computers
• Services provided by servers

  • Providing a central, common file storage area
  • Sharing hardware, such as printers
  • Controlling who can or cannot have access to the network
  • Sharing internet connections
• Servers are more expensive than normal computers
• In a small network, one server might provide all of these services
• In a larger network, there might be many servers sharing the work
• Types of Networks


  • LAN – Local Area Network
  • WLAN – Wireless Local Area Network
  • WAN – Wide Area Network
• Local Area Network (LAN)


  • Usually within one building or not over a large geographical area
  • A LAN consists of a number of computers and devices, e.g., printers, which will be connected to hubs or switches
• Advantages of LAN


  • The sharing of resources (such as expensive peripherals and application software)
  • Communication between users
  • A network Administrator to control and monitor all aspects of networking (e.g., changing password, monitoring internet, etc.)
• Disadvantages of LAN


  • Easier spread of viruses through the whole network
  • The development of queues for printer, which can be frustrating
  • Slower access to networks, such as internet
  • Increased security risk as compared to stand alone computers
  • If the main server breaks down, in must cases, the network will no longer function
• Wireless Local Area Networks (WLANs)

  • Similar to LANs, but there are no wires or cables
  • They provide wireless network communication over very short distances (a few metres) usually radio or infra-red signals instead of cables
  • Devices known as access points are connected into the wired network, at fixed locations
  • Because of the limited range, most commercial WLANs need several access points, to permit uninterrupted wireless communication
  • The access point receives and transmits data between the WLAN and the wired network structure
• Advantages of WLANs


  • All computers can access the same services and resources (e.g., printers, scanners, internet access, etc.)
  • There is no cabling to individual computers and devices so safety is improved
  • The system is more flexible since, users can move their laptops from their desks
  • Adding new computers and devices is a very easy task and costs are reduced, since no extra cabling is needed
• Disadvantages of WLANs


  • Security is a big issue, since anyone with a WLAN enabled laptop or computer, can access a network if it can pick up a signal
  • There may be problems of interference, which can affect the signal
  • Data transfer is slower than LAN
• Wide Area Network (WAN)


  • A Wide Area Network is formed by a number of LANs being connected together through either a router or modem
  • Some companies setup private WANs, which is expensive but comes with an advantage of much enhanced security and speed
  • It is common to use an Internet Service Provider (ISP) for connections to the internet and communicate through this network system
• Advantages of WAN


  • A WAN is a network that extends over a large area
  • WAN can be connected using optical fibre cable, satellite link, radio signals, etc.
• Disadvantages of WAN


  • Very expensive
  • Limited access
  • Data access slows down if spread over huge area
• LAN


  Confined to a very small area