DVD has the following specifications,
compared with standard CD:
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CD DVD
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Disc Diameter 120 mm 120 mm
Disc Thickness 1.2 mm 1.2 mm
Disc Structure Single Substrate Two bonded 0.6 mm substrates
Laser Wavelength 780 nm 650 and 635 nm
Numerical Aperture 0.45 0.60
Track Pitch 1.6 um 0.74 um
Shortest pit/land length 0.83 um 0.4 um
Reference Speed 1.2 m/sec, CLV 4.0 m/sec, CLV
Data Layers 1 1 or 2
Data Capacity 680 megabytes Single layer: 4.7 gigabytes
Double layer: 8.5 gigabytes
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