Method of testing magnetic disc device
A write head, which is positioned by reading a servo pattern with a read head, writes data on even tracks of a magnetic disc, and then writes data on odd tracks. Then a read head is positioned on a read position and sequentially reads all the written data. As a result, it is decided whether a read error has occurred. Further, positional deviation of the tracks, in which the read error occurs, is measured.
1. A method for testing a magnetic disc device, comprising at least:
writing data on every other track of the magnetic disc according to a servo pattern;
writing data on the rest of the tracks;
reading data from all tracks in which data are written;
determining whether a read error occurs;
determining a track having a deviation of a track pitch based on the read error;
arranging that data is written on a track in which a read error occurs, and no data is written on tracks surrounding the track in which the read error occurs;
starting reading of data from a position away from one side of the track, and sequentially reading data at some positions, each of which is gradually closer to the track;
obtaining a first position where an error rate of reading the data reaches a predetermined error rate;
starting reading of data from a position away from the other side of the track, and sequentially reading data at some positions, each of which is gradually closer to the track; and
obtaining a second position where an error rate of reading the data reaches a predetermined error rate, wherein
a position of the track is calculated based on the first position and the second position.