present invention during a physical re read operation the hard disk drive can selectively retain the most reliable signal segments from among multiple read operations in one exemplary embodiment a reliability metric is used to identify the most reliable signal segments a reliability metric can be assigned to each signal segment for multiple read operations and the more reliable signal segments are selected by comparing the reliability metric values of each segment in this manner the present invention selectively retains signal segments based on a signal quality or reliability value assigned to each segment for example a signal segment may comprise n samples of the y signal such as n equal to 32 or 16 samples according to one exemplary hard disk format the number of samples per sector is on the order of 5 000 fig2 is a schematic block diagram of an exemplary ldpc based iterative hard disk drive 200 incorporating features of the present invention the analog front end 210 soft channel detectors 220 230 memories 240 250 and lpdc decoder 260 operate in a similar manner to the corresponding elements in fig1 discussed above as shown in fig2 the iterative hard disk drive 200 also includes a multiplexer 270 controlled by a selection signal generated by a selection.