An approach to a reduced-head hard disk drive (HDD) involves an actuator elevator subsystem that includes a ball screw cam assembly with a hybrid permanent magnet (PM)-variable reluctance (VR) stepper motor disposed therein, to rotate the cam screw, which vertically translates an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. A suitably configured hybrid stepper motor can provide 200 full steps/rev for a 3.8 mm translation. Thus, to meet or surpass a step resolution of 6 m/step or 0.5625/step, the hybrid stepper motor would only need to be operated at 4 micro-step mode in order to achieve a 0.45/step or 0.00475 mm/step, which enables a smoother motion since the available holding torque at the 4.sup.th micro-step provides sufficient torque margin to overcome load torque, frictional torque, and detent torque.

A data storage device is disclosed comprising a head actuated over a disk surface, wherein the head comprises a plurality of elements including a write assist element. A bias signal applied to the write assist element is controlled such that the write assist element is substantially unprotruded, and while the write element is substantially unprotruded, an air bearing resonant frequency (ABRF) of the head and disk surface is measured. The bias signal applied to the write assist element is controlled such that the write assist element protrudes toward the disk surface, and while the write assist element protrudes toward the disk surface, the head is excited at the measured ABRF and the head touching down onto the disk surface is detected.

According to one embodiment, a head gimbal assembly includes a suspension and a magnetic head supported by the suspension via a gimbal portion. The magnetic head includes a slider and a head portion provided in the slider. The slider includes an air bearing surface, a pair of side surfaces, a leading-side end surface, and a trailing-side end surface. The slider includes a deep groove which is formed between the leading-side step portion and the trailing-side step portion and is open to the air bearing surface and the pair of side surfaces, and a pair of partition walls which extends from the trailing-side step portion toward the leading-side step portion along the pair of side surfaces to close at least a portion of a side surface opening of the deep groove.

According to one embodiment, a head gimbal assembly includes a suspension and a magnetic head supported by the suspension via a gimbal portion. The magnetic head includes a slider and a head portion provided in the slider. The slider includes an air bearing surface, a pair of side surfaces, a leading-side end surface, and a trailing-side end surface. The slider includes a deep groove which is formed between the leading-side step portion and the trailing-side step portion and is open to the air bearing surface and the pair of side surfaces, and a pair of partition walls which extends from the trailing-side step portion toward the leading-side step portion along the pair of side surfaces to close at least a portion of a side surface opening of the deep groove.

The present embodiments relate to magneto-resistive read heads that can utilize read shields to maintain a reference layer magnetization. A magneto-resistive head can include a first shield and a second shield disposed adjacent to the first shield, with a distance between the shields forming a read gap. The magneto-resistive head can also include a first spacer layer disposed in the read gap. The magneto-resistive head can also include a first reference layer disposed in the read gap adjacent to the first spacer layer. A first reference layer magnetization direction can be set based at least by a first shield magnetization direction. The magneto-resistive head can also include a sense layer disposed in the read gap between the first spacer layer and the second shield.

A storage device includes a storage controller that controls a writer to generate a magnetic field at an air-bearing surface (ABS) of a storage medium and to selectively alter a strength of the magnetic field by a predetermined amount when writing data to select data tracks on the storage medium.

A storage device includes a storage controller that controls a writer to generate a magnetic field at an air-bearing surface (ABS) of a storage medium and to selectively alter a strength of the magnetic field by a predetermined amount when writing data to select data tracks on the storage medium.