Data storage device with re-allocation processing

Abstract

Embodiments of the invention improve the security of data written on a magnetic disk by performing re-allocation processing starting from a sector whose defect is large in automatic re-allocation processing. According to one embodiment of the present invention, after the reliability of each of data sectors that have been read out from a magnetic disk according to a read command is determined, re-allocation processing on the data sectors is performed in the order of increasing reliability. As a result, within a limited period of time, it is possible to replace by priority a data sector where there is a high possibility that data recovery will be unable to be achieved. This makes it possible to increase the security of data and the reliability of the HDD. The reliability of each data sector is determined on the basis of the number of bytes corrected by ECC.

Dependencies are inferred from the claim text.