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Lecture # 12 Optical Storage Devices Flowcharts

Lecture # 12 Optical Storage Devices Flowcharts. Optical Storage Devices. It is a storage medium that can be written to and read using a laser beam. Two Kinds of Optical Storage Devices. CD-ROM (compact disk read-only memory) DVD-ROM (digital video disk read-only memory).

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Lecture # 12 Optical Storage Devices Flowcharts

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  1. Lecture # 12Optical Storage DevicesFlowcharts

  2. Optical Storage Devices It is a storage medium that can be written to and read using a laser beam.

  3. Two Kinds of Optical Storage Devices • CD-ROM(compact disk read-only memory) • DVD-ROM(digital video disk read-only memory)

  4. Optical Storage Devices – How Optical Storage Works • 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).

  5. 1 0

  6. Optical Storage Devices – CD-ROM • 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 700 MB of data. • Once data is written to a standard CD-ROM disk, the data cannot be altered or overwritten.

  7. Optical Storage Devices – CD-ROM Speeds and Uses • Early CD-ROM drives were called single speed, and read data at a rate of 150 KBps. • CD-ROM drives now can transfer data at speeds of up to 7800 KBps. Data transfer speeds are getting faster. • CD-ROM is typically used to store software programs. CDs can store audio and video data, as well as text and program instructions.

  8. Optical Storage Devices - Other Optical Storage Devices • A CD-Recordable (CD-R) drive lets you record your own CDs, but data cannot be overwritten once it is recorded to the disk. • A CD-Rewritable (CD-RW) drive lets you record a CD, then write new data over the already recorded data.(100 times overwriting is possible) • PhotoCD technology is used to store digital photographs.

  9. Digital Video Disk (DVD) • 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. • Storage capacity ranges from 9.4 GB to 17 GB

  10. Optical Storage Devices - DVD-ROM • 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. • Dual-layer DVD disks can store so much data because both sides of the disk are used. • Device’s laser beam can read data from the first layer and then look through it to read from the second layer.

  11. Recordable Optical Technologies • DVD-Recordable (DVD-R) Record data onto a special recordable digital video disk using a special drive. • DVD-RAM Record, erase, re-record data.

  12. Flowcharts

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