Optical Storage Devices

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  • Topic: Compact Disc, Optical disc, DVD
  • Pages : 2 (283 words )
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  • Published : December 19, 2011
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Optical Storage Devices

• An optical disk is a high-capacity storage medium.
An optical drive uses reflected light to read data.
• To store data, the disk's metal surface is covered with tiny dents (pits) and flat spots (lands), which cause
light to be reflected differently.
• When an optical drive shines light into a pit, the light cannot be reflected back. This represents a bit value
of 0 (off). A land reflects light back to its source,
Representing a bit value of 1 (on)

• In PCs, the most commonly used
Optical storage technology is called
Compact Disk Read-Only Memory (CD-ROM).
• A standard CD-ROM disk can store up to 650
MB of data, or about 70 minutes of audio.
• Once data is written to a standard CD-ROM which causes light to be reflected differently. Disk, the data cannot be altered or overwritten.

Optical Storage Devices - DVD-ROM
• A variation of CD-ROM is called Digital Video Disk
Read-Only Memory (DVD-ROM), and is being used
in place of CD-ROM in many newer PCs.
• Standard DVD disks store up to 9.4 GB of data—
enough to store an entire movie. Dual-layer DVD
disks can store up to 17 GB.
• DVD disks can store so much data because both sides
of the disk are used, along with sophisticated data compression technologies.

CD-Recordable (CD-R)
This drive lets you record your
own CDs, but data cannot be overwritten once it is
recorded to the disk.

CD-Rewritable (CD-RW)
This drive lets you record a
CD, then write new data over the already recorded

Photo CD
This technology is used to store digital photographs.
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