CP1610: Introduction to Computer Components

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CP1610Introduction to Computer Components

• Archival Storage Devices

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What is Archival Storage?

• Similar to secondary storage.
• Typically more durable.
• Used for long-term or permanent storage
• Data backups from hard disks
• Permanent storage of data that will not be
  changed (ex music or movies)

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Common Archival Storage Media

• Optical Storage
• Flash Memory
• Magnetic Storage

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Optical Storage

• Use light (lasers) to read and write data.
• Not subject to data loss or corruption.
• Compact Discs (CDs)
• Digital Video Disks (DVDs)

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How Optical Storage Works

• Light is used to burn a series of pits (dark
  spots) on a disk.
• Dark spots and light spots are read as 0s and
  1s (binary).
• Re-writable discs use Phase technology
• Special dyes are used that react to the laser
• The Phase of the dyes can be changed to change
  the data.

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Data Storage on Optical Media

• CD-ROM drives
• Use CDFS (Compact Disc File System) or UDF
  (Universal Disk Format)
• Hold about 780 MB of data.
• DVD drives
• Use only UDF
• Uses the MPEG-2 encoding standard
• Standard hold about 4.5 GB of data.
• Dual-layered DVDs can hold up to 8.5 GB of data.

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• Optical discs have tracks and sectors, just like
  magnetic disks.
• Tracks and sectors are arranged in a spiral,
  instead of concentric circles.

Floppy Disk
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Flash Memory

• Also called solid-state storage.
• No moving parts (Data on the media is altered
  using electrical signals).
• Relatively high memory capacity.
• Commonly used for
• USB drives
• MP3 players
• Digital camera memory
• Mobile phone and PDA memory

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Multimedia Compression Standards

• MPEG-1 standard
• Image compression for business/home applications
• MPEG-2 standard
• Video film compression on DVD-ROM
• MPEG-3 standard
• Audio compression
• MPEG-4 standard
• Video transmissions over the Internet

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Magnetic Storage

• Like a cross between a floppy or hard disk, and
  an audio cassette.
• Stores data by aligning magnetic particles on a
  tape.
• Magnetic particles are read as 0s or 1s
  (binary).

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Advantages of Magnetic Storage

• Advantages
• Inexpensive and convenient
• Large capacity
• Several types and formats
• Disadvantage
• Sequential access

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Other Archival Storage Media

• ZIP Disks (By Iomega) and SuperDisks (by
  Imation).
• Similar to 3.5 inch floppy disks, but bigger,
  with more capacity.
• Never became popular because of CDs and DVDs