Patent ID: 7212000

Claim:
A method for detecting a defective disk for a hard disk drive, comprising: loading a disk that has a first side and a second side into a tester that has a first head located adjacent to the first side and a second head located adjacent to the second side; writing at least one test signal onto the first and second sides of the disk; reading and storing first data from the first side; reading and storing second data from the second side; loading the disk into the tester so that the second side is adjacent to the first head and the first side is adjacent to the second head; reading and storing third data from the first side; reading and storing fourth data from the second side; calculating a first area between a curve generated from the first data and a curve generated from the third data; calculating a second area between a curve generated from the second data and a curve generated from the fourth data; calculating the average of the first and second areas; and, determining whether the disk is defective using the calculated average.