| 摘要 |
A magnetic disk for a computer disk drive system is recorded in the format appropriate to the system with at least two special tracks. The first track has known data recorded therealong but to a narrowe width (T/2) than the normal track width (T) for the format. Upon reading data from the track (28) the signal obtained is little dependent on head alignment and a poor signal-to-noise ratio can be assessed as being due to deficiency elsewhere in the system. The second track (30) has known data recorded therealong and is flanked on each side by a track (29:31) containing an interference signal content and spaced from the second track by a void space (38:40). The combination provides a test band so that upon reading the second track (30), the signal-to-noise ratio between the data signal and the interference signal is a function of head alignment. In each case signal-to-noise is measured in terms of the error rate between the data read and the known data recorded. Further first tracks may be provided of differing widths to provide differing read signal amplitudes for signal-to-noise ratio assessment. Further test bands may be provided with differing void space widths to provide assessment for differing degrees of head misalignment. |
