Patent ID: 7417816

Claim:
An inspection method for inspecting a defect of a magnetic disk in a magnetic disk drive comprising the magnetic disk and a head, said inspection method comprising: classifying the head as either a first group of heads having superior read performance or a second group of heads having read performance inferior to the read performance of the head in the first group; associating a head classified as the first group with a first error correction code having a first number of symbols, and associating a head classified as the second group with a second error correction code having a second number of symbols that is larger than the first number of symbols; writing to the magnetic disk, by the head, inspection data, and a third error correction code used to correct an error of the inspection data, said third error correction code having a specified number of symbols that is larger than the second number of symbols; if the head is classified as the first group, reading the inspection data by use of the first number of symbols that is part of the specified number of symbols of the third error correction code; and detecting a read error of the inspection data.