Novel control and peripheral technologies proposed for future hard disk drives

New technologies of discrete track recording (DTR), bit patterned media (BPM) and thermally assisted magnetic recording (TAMR) have been proposed for next generation hard disk drives. To realize these technologies, there are other big challenges required for head positioning in order to follow eccentricity of recording tracks to the center of spindle motor, for read write clock synthesis synchronous to the eccentricity and platter warpage, and for high frequency signal transfer in GHz band. This paper proposes novel solutions of an actuator control method with a voltage driver and an over sampled local feedback, an eccentricity analysis algorithm for discrete tracks without referring to embedded servo patterns, a phase locked loop clock synthesizer with a variable loop counter, and a super wide band flexible cable with new materials. The performances are evaluated and demonstrated on a head-media test system and this paper reports the result and proposes the applications for future hard disk drive products.