Computer Science

• What is an input device?

  A device that allows data to be entered into a computer system

  eg. keyboard, mouse, microphone, sensor, touch screen
• What is an output device?

  A device that allows the user to view/hear the data that has been entered into a computer system

  eg. speaker, headphones, printer, monitor
• How sensors and microprocessors are used:

  • Sensor sends signal to micoprocessor
  • Signal is analogue and is converted to digital
  • Data is compared to stored value
  • If data does not match, counter is incremented by 1
  • Continuous process
• Advantages of high-level language:

  • Closer to human language
  • Easier to understand
  • Easier to debug
  • Less likely to make errors
• Why use lossless compression:

  • Deleted parts can be recovered
  • Lossy would remove data
  • Lossless does not remove data
  • Can be restored to original state
  • ..otherwise files will not work correctly
• How checksum detects error:

  • Sending device creates value from calculation on data
  • Value is transmitted with data
  • Receiving device performs same calculator
  • Values are compared after transmission
  • If no match, an error is detected
• USB:

  • Universal Serial Bus
  • Data transmission method
  • Uses serial transmission
  • Universal standard
• MAC address:

  • Media Access Control
  • Used to identify a device
  • Unique address
  • Does not change
  • Set by manufacturer
  • First part: Manufacturer ID
  • Second part: ID
• Uses of hexadecimal:

  • MAC addresses
  • Error messages
  • IP addresses
  • URL