Cassette to CD

Double layer (DL) media have two independent data layers separated Cassette to CD by a semi-reflective layer. Both layers are ready from the same side, but bid the optics to paper money the laser's focus. Traditional single layer (SL) writable media are produced with a spiral groove molded in the sheltering polycarbonate layer (not in the data recording layer), to head and synchronize the speed of recording head.

Because fit a constant transfer rate for the whole disc is not so important in most contemporary CD uses, to keep the rotational speed of the disc safely beneath while maximizing data rate, a pure CLV approach needed to be abandoned. Some drives muscle in partial CLV (PCLV) scheme, by switching from CLV to CAV only when a rotational confines is reached.