Large Capacity Floppy Disk with New Servo System

Abstract

A floppy disk drive employing simplified continuous servo system with optical servo signal detector was developed. The servo detector consists of a couple of laser and photo diodes, and both of them are built in upper and lower conventional transducing heads, respectively. Trenches to prevent head floating from media surface were introduced at the slider surface. This enabled good read/write characteristics at the spindle rotational speed up to 2500 rpm. Barium ferrite media having dye layer between laminated base films was also developed and servo signal was written on the dye layer by using 830 nm laser beam. Using the barium ferrite of 1250 Oe coercive force and MIG head, 45 kFRPI D_<50> of the linear density was obtained. From these results, 128 MB large capacity of 3.5 inch floppy disk will be expected to realize for practical use.