Physical Organization of CD-ROM III
Given this scheme, it is not possible to have 2 adjacent 1s: 1s are always separated by 0s. As a matter of fact, because of physical limitations, there must be at least two 0s between any pair of 1s.
Raw patterns of 1s and 0s have to be translated to get the 8-bit patterns of 1s and 0s that form the bytes of the original data.
EFM encofing (Eight to Fourteen Modulations) turns the original 8 bits of data into 14 expanded bits that can be represented in the pits and lands on the disk.
Since 0s are represented by the length of time between transition, the disk must be rotated at a precise and constant speed. This affects the CD-ROM drive’s ability . to seek quickly.