US Patent 7280295 Method to improve data reliability on hard disk drive systems

A method for storing user data on a hard disk drive system comprises distributing user data across a plurality of independent data sectors, with each data sector including a first header having a first preamble field and a first sync mark field, and a second header having a second preamble field and a second sync mark field. The method performs a first timing recovery phase for recovering signal amplitude by acquiring phase and frequency lock from at least one of the preamble fields, and performs a subsequent frame synchronous detection phase by acquiring a corresponding sync mark field.