3 - 3
Item
Disc diameter
Storage capacity
Thickness of disc
Rewritable number
of times
Reflectance ratio
Track width
Recording/playback
laser wavelength
DVD-RW
12cm
4.7GB/side
1.2mm
At least 1000
18% - 30%
0.74um
635nm/650nm
DVD-R
12cm
4.7GB/side
Impossible (only additional
writing is possible)
45% - 85%
12cm
4.7GB/side
Impossible
3-2 Description of Newly Adapted Technology
3-2-1 Features and Format of DVD-RW
(1) Features of DVD-RW
1) Rewriting at least 1000 times is possible.
2) The recording mode (VF mode conforming to DVD video format or VR mode conforming to DVD
video recording format) can be selected.
(2) Format of DVD-RW
DVD-RW (DVD-ReWritable) is a DVD format that adds a rewritable function to DVD-R: The format
is certified by the DVD Forum.
The format of DVD-RW attaches a high value to compatibility of playback on DVD recorders/
players, DVD-ROM drives, etc. in the same way as with DVD-R: Here it is the same as that of one-
layer DVD-ROM and DVD-R, except for the reflectance ratio.
Information:
From the viewpoint of format, DVD-R and DVD-RW (recorded in the DVD video format) will be
equivalent once they are finalized. However, since the reflectance ratio is different, a device that
can play the DVD-R may not be able to play DVD-RW.
Table3-2-1 Comparison of DVD disc
: Same as on left
Description of Operation > Description of Newly Adapted Technology
2-layer
DVD-ROM
12cm
4.25GB/layer
18% - 30%
8cm
1.46GB/side
8cm
1.46GB/side
1-layer
DVD-ROM
