Comparative aspects of AC bias recording

Experimental results are presented comparing the performance of various heads and disks for ac bias recording of data on rigid disks. Ferrite and thin film heads are included in the comparison as are particulate disks with normal and unusually thick coatings. The data indicate that thin film heads are preferable to ferrite for ac bias recording and that frequency response and overwrite performance are at most only slightly degraded by very thick disk coatings.