Method and apparatus for writing scrambled multi-value data to a physical
media and for reading scrambled multi-value data from a physical media,
are disclosed. The physical media can be an optical disk. The scrambling
can be performed by a multi-valued LFSR scrambler and the descrambling
can be performed by a multi-valued LFSR descrambler. Further, the
multi-valued data that is scrambled can include synchronization data
and/or user data. Error correction coding can be used during the writing
process and processing to correct for errors can be used during the
reading process. Also, methods and apparatus for synchronizing
multi-valued data written to and read from physical media are disclosed.
Multi-value correlation methods and apparatus are also disclosed.