METHODS AND APPARATUS FOR SELECTIVELY RETAINING READ SIGNAL SEGMENTS BASED ON ASSIGNED RELIABILITY METRICS IN A HARD DISK DRIVE

摘要

provides methods and apparatus for improved physical re-reading operation from the hard disk drive . Method and apparatus disclosed herein may optionally maintain the data in the hard disk drive . Assigning a reliability metric to each of the plurality of segments of the read signal, and repeating the assigning step for a plurality of the read operation, the read signal from the repeat channel by keeping the segments selectively based on the assigned reliability metric is read. Read signal can be obtained by moving the transducer in a storage medium . Reliability metric may be based on the soft bit decision , the log likelihood ratio or the noise estimation of a given segment .