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Optical Storage Devices

Group 6:Pham Van HungNguyen Van KienNguyen Thanh Tung

Duong Viet Duc

Computer Architecture Project1

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1. Introduction

2. Optical Device Storage

3. Data Marks and Spaces

4. Write and Read Mechanism

5. Trending

Contents

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1. Introduction

Definition

Data Storage : is a device for recording(storing) information(data).

Computer data storage : Memory  – Fundamental computer component

Fundamental Storage Technologies

 – Semiconductor  – Semiconductor-based intergrated circuits

 – Magnetic  – patterns of magnetization on a magneticaly coated surface

 – Paper  – Punching Holes in paper or cardboard

 – Uncommon  – Vacuum tube, Molecular, Electro-acoustic(sound wave),..

 – Optical  – An electro-mechanical unit that can write and readinformation on a special disc medium using a laser light

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2. Optical Device Storage

Definition• Optical storage is any storage method in which data is written and

read with a laser for archival or backup purposes.

• Optical media is more durable than tape and less vulnerabletoenvironmental conditions.

• Optical disc storage is non-volatile  

• The deformities may be permanent (read only media ), formedonce (write once media) or reversible (recordable or read/writemedia).

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2.1 Classification

• 5 types of optical devices.

• Classified by the usage and disc size.

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2.1 Classification (cont.)

A, Legacy Optical Devices:

• No longer in productions: : Laser disc, Sega's GD-Rom, Sony'sMiniDisc and SuperAudio-CD….. 

B, (CD) Compact Disc:

• Released in 1982, offered digital sound. In 1990, released CD-R tocreate optical discs at home.

• Using red wavelength laser, average size is 700 MB.

C, DVD (Digital Versatile/Video Disc)

• Released in late 1990s, offered digital movie format. Used redwavelength laser like CD.

• Allows 4.7 GB and up to 8.5 GB (dual-layer). DVD-Audio discs are usedin studio.

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2.1 Classification (cont.)

D, HD DVD (High Definition DVD)

• Released by Toshiba, offered space for HD movies on a single disc.

• Using a blue wavelength laser, capability of holding 15 GB per layer.

• No longer continued

E, Blu-ray

• The newest optical format, offers a HD movie on one disc.

Becoming common in home computers.• Developed by Sony, offers 25 GB per layer. Using the same type of

laser as HD-DVD drives.

• Have a protective coating that makes disc durable.

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3.Data Marks and Spaces

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Parameters of optical disk products

Parameter Units CD DVD Blu-ray

Wave-length micrometer 0.78 0.65 0.405

NA 0.45-0.5 0.6-0.65 0.85

Track Pitch micrometer 1.6 0.740 0.320

Shortest Pit micrometer 0.831 0.399 0.138

Density Gb/in^2 0.4 2.8 15.9

Capacity GB 0.65 4.7 27

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4.Write and Read Mechanism

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4.1 Write Mechanism

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4.1 Write Mechanism

Encoding Technique

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4.2 Read Mechanism

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4.2 Read Mechanism (cont.)

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5. Trending

-Use high NA and shorter lambda in order to obtainsmaller spot size and higher data density.

- Orientate to 4th generation of optical storagedevices with two promising technologies: near-fieldoptics and magnetically amplifying magneto-opticalsystem.

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1. Introduction

2. Optical Device Storage

3. Data Marks and Spaces

4. Write and Read Mechanism

5. Trending

Summary

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