1.2.10

Examples of Optical Storage

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Examples of Optical Storage

There are three main types of optical storage in use today, although their use is declining:

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Compact Disk (CD)

  • CDs are the original optical media standard.
  • A single CD can store around 700 MB of data.
  • CDs are very cheap to produce.
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Digital Versatile Disk (DVD)

  • DVDs are often used to store games or standard-definition movies for home viewing.
  • A single DVD can store around 4.7 GB of data.
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Blu-Ray Disks (BD)

  • Blu-Ray disks are often used to store high definition movies or games.
  • A single Blu-Ray disk can store around 25 GB of data.

Types of Optical Disk

Each of the three optical media standards can come in any of the following forms:

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Read-Only Memory (ROM)

  • A CD-ROM, DVD-ROM, or BD-ROM is a disk which can be read only.
  • The manufacturer writes the initial data, and this cannot be changed.
  • This is often used in content distribution so that people cannot accidentally overwrite the content.
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Write-Once (R)

  • A CD-R, DVD-R, or BD-R is a disk which can be written once by the user at home.
  • Once the user has written data to the disk, they cannot overwrite it.
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Re-writable (RW)

  • A CD-RW, DVD-RW, or BD-RW is a disk which can be overwritten whenever the user would like to.
  • These are often used for backups which might need to be updated in the future.

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1Computer Systems

1.1Systems Architecture

1.2Memory & Storage

1.3Computer Networks, Connections & Protocols

1.4Network Security

1.5Systems Software

1.6Ethical, Legal, Cultural & Environmental Concern

2Computational Thinking, Algorithms and Programming

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