1.2.2. Secondary Storages

• What is the purpose of secondary storages?


  Keeping data long term once power is turned off.
• How do magnetic storages store data?


  They use the direction of magnetism to represent 1 and 0.
• What are the advantages of magnetic storages?


  • Large capacity
  • Cheap cost per MB
• What are the disadvantages of magnetic storages?


  • They aren't portable - they can be damaged when moved
  • Slow file access speed
  • Uses more energy and are heavier
• What's a reason why magnetic storages aren't portable?


  They have moving internal parts, meaning that they can be damaged easily when moved.
• What is an example of a magnetic storage?

  Hard drives.
• What is a typical use of magnetic storages?


  Storing lots of files when you don't need to carry them around.
• How do optical storages store data?


  They use laser to burn disc surfaces - laser can read flat or dipped area as 1 or 0.
• What are the advantages of optical storages?


  • Thin and light (portable)
  • Can easily be mass produced - cheap to make
• What are the disadvantages of optical storages?

  • Small capacity
  • Can easily be scratched and damaged
• What are some examples of optical storages?


  CD-ROM / CD-RW, DVD-ROM / DVD-RW, and Blu ray.
• What are the typical uses of optical storages?


  Distributing software, games, films, and music.
• How do solid state storages store data?


  They trap electrons in a gate to represent 1s - no electrons mean 0.
• What are the advantages of solid state storages?


  • Fast access speed
  • Reliable
  • Portable - no internal moving parts, and lightweight
  • Produces less heat and uses less energy
• What are the disadvantages of solid stage storages?


  • Small capacity compared to magnetic
  • Expensive cost per MB
• What are examples of solid state storages?

  Solid state drives, memory sticks, and SD cards.
• What are the typical uses of solid state storages?


  Carrying files around - used in portable devices.
• What are the storage characteristics?


  • Capacity
  • Speed
  • Portability
  • Durability
  • Reliability
  • Cost
• What is storage capacity?


  How much data they can hold.
• What is storage speed?


  How quickly data is accessed.
• What is storage portability?


  How easily device can be moved around.
• What is storage durability?


  How easily device could be broken.
• What does storage reliability mean?


  How long device will last for.
• What is storage cost?


  How much it costs per MB.