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by andruby
1013 days ago
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That not a stupid question. It's a bit (ha!) more complex. These are called pits and lands. > The pits and lands do not directly represent the 0s and 1s of binary data. Instead, non-return-to-zero, inverted encoding is used: a change from either pit to land or land to pit indicates a 1, while no change indicates a series of 0s. There must be at least two, and no more than ten 0s between each 1, which is defined by the length of the pit. This, in turn, is decoded by reversing the eight-to-fourteen modulation used in mastering the disc, and then reversing the cross-interleaved Reed–Solomon coding, finally revealing the raw data stored on the disc. https://en.wikipedia.org/wiki/Compact_disc#Physical_details These encoding types are used to improve the "tracking" of the laser head, and to keep the timing consistent. We want the medium to regularly have changes between pits and lands to synchronise the timing and speed of the disc. The encoding scheme enforces this. https://en.wikipedia.org/wiki/Non-return-to-zero#NRZI https://en.wikipedia.org/wiki/Eight-to-fourteen_modulation |
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It's wild it's as complex as it is! Though it makes sense it seems way more robust