Slide 1

Data Storage Device CD & DVDPrepared By:-Jerin ChackoVyas PratikAP

Index History Manufacturing Types Difference between CD & DVD Limits the Data on a CD/DVD HD-DVD v/s Blue Ray DVD

First public demonstration of CD is in 1976 By Sony. High Quality Audio CDs have been commercially available from October 1982 By Philips The VCD standard was created in 1993 by Sony, Philips, Matsushita.

History

Manufacturing of CD/DVD

TypesCD (Compact Disc)DVD (Digital Video Disc)HD-DVD (High Defination Digital Video Disc)BD (Blue ray Disc)

CD12 cm disk with plastics substrate, aluminum coating and plastic cover0.83 micron wide pits, 1.6 micron spacingData storage capacity 700 MB

Overall CD

DVD12 cm disk with plastics substrate, aluminum coating and plastic cover0.4 micron wide pits, 1.2 micron spacingData storage capacity 4.7 GBTwo sided, 2 levels/side top level partially reflectingIncrease to 8.5 GB (2 sided), 17 GB (2 levels, 2 sided)

Two levels of DVD

DiffrenceCDDVDCapacity: 700 MBCapacity: 4.7 GBData Tran. Rate: 1.4-1.6 MB/SecData Tran. Rate: 11 MB/SecPits Length: 0.83 MicronPits Length: 0.4 MicronDistance b/w Disc Sur.-Data Sur: 1.1mmDistance b/w Disc Sur.-Data Sur: 0.6mmDisc Thickness: 1.2 mmDisc Thickness: 1.2 mm

Note:-This is the Optic which help to write data on CD/DVD

Limits the Data on a CD/DVDEach pit is one bit (0 or 1) of dataHow fast the CD turns (1.4 m/sec for single speed)Rotation speed limit: about 52x (72.8 m/sec)Problem is lifetime of Blue laser approaching 1000 hrs

HD-DVD v/s Blue Ray DVDNext generation DVD format has two competitorsHD-DVD: Toshiba, NEC, Microsoft, entertainment industryBlue Ray (BD): Sony, Hatachi, Panisonic, Apple etcBlue Ray higher capacity (25 GB) vs HD (15 GB)Hence shorter pits: Blue ray 0.16 m, HD 0.205 mProblem is that Blue ray is much nearer the surface (0.1 mm)Blue ray can have 8 layers, up to 200 GB, HD 4 layers, 60 GBSept 2008 Blue ray only 8% of market, DVD 92%

Reference Sites:-www.wikipedia.orgwww.digicom.com

Thank you.