Hardware Reference
In-Depth Information
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DVD-10 (9.4GB double-side, single-layer)
—A DVD-10 is constructed of two
stamped substrates bonded together back to back. The recorded layer (Layer 0 on
each side) usually is coated with aluminum. Note that these discs are double-sided;
however, drives have a read laser only on the bottom, which means the disc must be
removed and flipped to read the other side.
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DVD-18 (17.1GB double-side, dual-layer)
—A DVD-18 combines both double lay-
ers and double sides. Two stamped layers form each side, and the substrate pairs
are bonded back to back. The outer layers (Layer 0 on each side) are coated with
semitransparent gold, whereas the inner layers (Layer 1 on each side) are coated with
aluminum.Thereflectivityofasingle-layerdiscis45%-85%,andforadual-layerdisc
the reflectivity is 18%-30%. The automatic gain control (AGC) circuitry in the drive
compensates for the different reflective properties.
Figure 11.11
shows the construction of each of the DVD disc types.
Figure 11.11
DVD disk types and construction.
