Chapter6 - Philips CDD522 Operating Instructions Manual

It doesn't even have a groove or tracks (although it does contain
- apre-groove).
The reader should. see this Orange disk as a "Chameleon'-disk
that, when recorded onto, becomes Red, Yellow or Green after
"Finalization", a special recording operation.
FIG. 5
OPERATING SYSTEM
This paper will describe the CD System, starting at the surface of
the disk where the data is encoded in pits and moving up
through the six layers to the carrier unit, the disk.
The complete logical data-structure above the level this paper
ends with, is described in Part Two.
The six layers this paper will guide the reader through, are:
Layer One : Physical structure.
LayerTwo — : EFM Structure.
Layer Three : Subcode Structure.
Layer Four — : Sector Structure.
Layer Five : Track Structure.
Layer Six : Session Structure.
Chapter 1. Layer One: The Physical Structure
All Compact Disks have the same physical structure. They are
made of poly-carbonate and have a diameter of 12 cm.
The information is placed between two plastic layers. The layer
at the read-out side is the thickest. This explains why,
contradictorily,
the side most sensitive to mechanical
mistreatment is the label-side, since it has the information layer
directly beneath it and is very thin.
ATS