I think what the original poster said about different rotation speeds is correct. He's not saying that different parts of the disk spin at different speeds at the same time (which would obviously break it), but that the whole disk spins at different speeds depending on which part of the disk is being read at the time.
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Rotation speed
I think what the original poster said about different rotation speeds is correct. He's not saying that different parts of the disk spin at different speeds at the same time (which would obviously break it), but that the whole disk spins at different speeds depending on which part of the disk is being read at the time.