Extended Capacity and High Speed Magnetic Field Modulation Recording for 3.5" Magnetooptical Disk

The authors attempted recording by magnetic field modulation overwriting with a flying magnetic head, using a (1,7) RLL code, mark-edge recording, write precompensation, equalization, and the ZCAV format. A flying magnetic head for high-speed magnetooptic recording was developed. It was confirmed that the magnetic head has a magnetic efficiency of 1.38 Oe/mA at a spacing of 18 ¿m and a modulation frequency of 8.16 MHz. Under these conditions, a linear recording density of 0.55 ¿m/bit and an overwrite power margin in excess of ±25% were achieved. A 3.5" magnetooptic disk drive with a storage capacity greater than 300 MB and a high data transfer rate of 2.7 MB/s at the outermost track was realized.