Patent ID: 7969679

Claim:
A servo area testing method for a magnetic recording medium of ε discrete track system, a magnetic recording medium of a bit pattern system or a magnetic recording medium having a recording layer of uneven pattern, comprising the steps of positioning a magnetic head in a DC erased designated track of the rotating magnetic recording medium, moving the magnetic head in a radial direction of the magnetic recording medium across a plurality of DC erased tracks including the designated track and reading a signal for one track round by the magnetic head according to a read start signal corresponding to respective moving position in the radial direction, A/D converting the read signal for the one track round to a digital value and storing the digital value in a memory correspondingly to the respective moving positions in the radial direction, obtaining the read signal for the revolution of a plurality of the tracks from the memory and canceling jitter in the track direction of each of the read signals corresponding to the respective servo areas of one track revolution in the read signals for the plurality of track revolutions, binary-coding the read signal for each track revolution, jitter of which is cancelled, by a designated slice level and generating a binary image data an image of which has one axis corresponding to the moving position in the radial direction and the other axis corresponding to a circumferential direction of the magnetic recording medium, detecting, from the binary image data, a position of the track number in each servo area, and testing each servo area by judging a defect of the servo area on the basis of the read signal in the radial direction stored in the memory corresponding to the least significant bit of at least the track number in the position of the track number in each servo area.