Method and device for testing units for processing magnetic disks, modified disk therefor and device for recording that disk

摘要

The method of testing units for the processing of magnetic disks comprises the insertion of a modified disk into the testing unit and the reading of this disk when operations controlled by a testing programme are carried out. The modified disk has a plurality of concentric tracks (36, 37, 38....; 36, 35,34....) recorded on one or both sides in such a way that the distance between two tracks is slightly greater than the distance between the tracks of standard disks. Only the central track (36) coincides exactly with the corresponding central track of standard disks. After the modified disk has been inserted in the testing unit, the magnetic head (126) is firstly positioned on the central track (36) of the disk and then moved inwardly and outwardly until end tracks are found at which a specified degree of cross-talk occurs. The head misalignment is calculated as the distance (d) between te axis of the base track (36) and the axis of a hypothetical track centred between the inner and outer end tracks. Eccentricity errors are measured by comparing the number of sectors in which errors occur in adjacenttracks around the end tracks.