Even Though Both CD And DVD Disks Have The Samemedia Size And Shape, The Things They Have In Common Ends There. There Are Many Differentthings Between The Two, Such As What They Holdand How Much They Hold. Data Pits And LasersA Disc Has Microscopic Grooves That Will Movealong In A Spiral Around The Disc. CDs And DVDs Both Have These Grooves, With Laser Breamsapplied To Scan These Very Grooves.As You May Know, Digital Information Is Representedin Ones And Zeroes. Inside Of These Discs, Verytiny Reflective Bumps Known As Lands And Nonreflective Holes Known As Pits, Which Can Befound Beside The Grooves, Reflect Both The Onesand The Zeroes Of Digital Information.By Reducing The Wave Length Of The Laser To 625mmor More Infrared Light, DVD Technology Has Managed To Write In Smaller Pits When Comparedto The Standard Technology Of CD. This Will Allow For A Greater Amount Of Data Per Trackon The DVD. The Minimum Length Allowed For A Pit In A Single Layer DVD-R Is .4 Micron, Whichis Obviously More Than The .0834 Micron That ACD Offers.The Tracks Of A DVD Are Narrower As Well, Whichallows For More Tracks Per Disc, Which Alsotranslates Into More Capacity Than A CD. Theavaerage Single Layer DVD Holds 4.5 GB Of Data,while A CD Holds A Mere 700 MB.LayersAs Stated Above, A DVD Has Smaller Pits And Thelasers Need To Focus On Them. This Is Actuallyachieved By Using A Thinner Plastic Substratethan In A CD, Which Means That The Laser Needsto Pass Through A Thinner Layer, With Lessdepth To Reach The Pits. It's This Reduction Inthickness That's Responsible For The Discs That Were Only 0.6mm Thickness - Which Is Halfthat Of A CD.Data Access SpeedDVDs Will Access Data At A Much Faster Rate Thana CD Can. The Average 32X CD-ROM Drive Readsdata At 4MB A Second, While A 1X DVD Drive Readsat 1.38MB A Second. This Is Even Faster Than An 8X CD Drive.Universal Data FormatThe Recording Formats Of CDs And DVDs Are Quitedifferent, As DVDs Use UDF, Or The UniversalData Format. This Format Allows Data, Video,audio, Or Even A Combination Of All Three Tobe Stored In A Single File Structure. The Advantage To This Is Any File Can Be Accessedby Any Drive, Computer, Or Even Consumer Video.CDs On The Other Hand Aren't Compatible Withthis Format. (word Count 427)PPPPP
