Spatial distribution of overwrite interference on film disks

A method is described for distinguishing the type of overwrite mechanism present in recording media and for determining the spatial distribution across the track. Measurements were made on ferrite, thin-film, and metal-in-gap (MIG) ferrite heads on thin-film and particulate disks using this method. Depending upon the overwrite conditions, the overwrite interference may be uniformly distributed across the track or may be concentrated at the track-edges. The method is useful at high track densities where the track edge interference may be significant. All three heads show the same general behavior, the differences reflecting the greater effectiveness in overwriting by the lower-flying thin-film and MIG heads