System tolerance of 64-mm-diameter magneto-optical disks with a 4.7-Gigabyte capacity

We observed sufficiently wide detection tolerances in a magneto-optical (MO) drive system based on the domain-wall-displacement detection (DWDD) method. Those DWDD disks had a capacity of 4.7 Giga-byte on 64 mm diameter substrates optimized for land and groove (L/G) recording. Addressing was performed with the assistance of a one-side-wobbled groove. We investigated two types of DWDD disks i.e. the anneal-less type and the sidewall-annealed type.