Method for optimizing viterbi detector threshold values

摘要

A magnetic disk drive apparatus adopting a PRML (Partial Response Maximum Likelihood) optimizes a Viterbi detector threshold value in order to optimize a read channel. The apparatus includes the steps of setting an average range of Viterbi detector threshold values for each head and storing the average range. The apparatus additionally includes the steps of writing and reading test data by using Viterbi detector threshold values within the average range of the Viterbi detector threshold values with respect to corresponding zones of the head, so as to evaluate minimum error rates for the respective zones of the head; setting the Viterbi detector threshold values corresponding to the minimum error rates for the respective zones of the head, as optimal Viterbi detector threshold values of the corresponding zones, and storing the optimal Viterbi detector threshold values into a storage; and storing the optimal Viterbi detector threshold values into a maintenance area of a disk.