Magnetic disk device and its error data correction device and error data correction method

摘要

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk apparatus and an error correction method for a magnetic disk apparatus, and aims at correcting error data caused by thermal asperity.;Means for comparing the reproduction signal with the threshold value signal, and generating an error signal from the output of the comparison means and reproduction data, and immediately correcting or selecting soft ECC according to the error signal to perform error correction. The generation of the error signal can also be a run length restriction of the data.