Originally posted by JoeRyan:

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49% of a DL disc is the "whole disc, one layer." That's why it looked as though the whole disc were burned when it was one entire layer up to the layer break. That assumes that you are recording to full capacity on the disc because each layer must be exactly the same size in terms of recorded capacity. (Recording only half a DL disc will show show a burned section about two-thirds of the way through the bottom of the disc's layer 0 and then two-thirds back to the hub area on layer 1. Why 2/3 instead of half? Area = pi times radius squared. The last "third" is equal to half the disc area.)

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