Sony DVD Rom/DVD Video - Manual (Page 6)

06
WHAT’S NEW
From CD to DVD
DVD Types and Formats
A DVD consists of two halves, where each half disc
is 0.6 mm thick, holding one or two layers of informa-
tion. The DVD format provides multiple configurations
of data layers. Each layer provides additional data
capacity.
DVD, which stands for Digital Versatile
Disc, is the next generation of optical disc
storage technology. It is essentially an
optical disc that can hold video as well as
audio and computer data. This new
optical disc can reach a capacity of up to
24 times the capacity of a CD-ROM and
encompasses pre-recorded read only
discs like DVD-Video, DVD-ROM,
DVD-Audio, SACD as well as recordable
formats like DVD-R, DVD-RAM,
DVD+RW and DVD-R/W.
For movie applications, a DVD can
store full length movies in a high-quality
digital video with surround sound in
several languages and a wide range of
interactivity as well as subtitles. All DVD
players and DVD-ROM drives are
equipped with an additional laser diode or
a special lens for playback capability of
existing Audio CDs and CD-ROMs.
Format and
Specifications
The DVD standard defines a disc
that maintains the overall dimensions
of the current Compact Disc.
Therefore the backwards compatibility
with existing Audio CDs and CD-ROMs
was easier to realize. The table on the
right demonstrates similarities and
differences of CDand DVD.
Disc Type Capacity 12 cm
DVD-5 single sided, single layer 4.7 GB
DVD-9 single sided, dual layer 8.5 GB
DVD-10 double sided, single layer 9.4 GB
DVD-18 double sided, dual layer 17.1 GB
Mini DVD DVD
Disc diameter 80 mm 120 mm
Disc thickness 1.2 mm 1.2 mm
Disc structure two bonded two bonded
0.6 mm substrates 0.6 mm substrates
Laser wavelength 650/635 nm 650/635 nm
Numerical aperture 0.6 0.6
Track pitch 0.74 µm 0.74 µm
Shortest pit/land 0.4 µm 0.4 µm
lenght
Data layers up to 2 up to 4
Data capacity 1.46 GB–2.66 GB 4.7 GB–17.1 GB