Servo pattern enhancements for high areal density hard disk drives

To achieve the areal density goal in hard disk drives of 1Tbit∕in.2 the minimum physical spacing or flying height (FH) between the read/write element and disk must be reduced to ∼2nm. A brief review of several FH adjustment schemes is first presented and discussed. Previous research showed that the actuation efficiency (defined as the ratio of the FH reduction to the stroke) was low due to the significant air bearing coupling. In this paper, an air bearing surface design, Slider B, for a FH control slider with a piezoelectric nanoactuator is proposed to achieve virtually 100% efficiency and to increase dynamics stability by minimizing the nanoscale adhesion forces. A numerical study was conducted to investigate both the static and dynamic performances of the Slider B, such as uniformity of gap FH with near-zero roll over the entire disk, ultrahigh roll stiffness and damping, low nanoscale adhesion forces, uniform FH track-seeking motion, dynamic load/unload, and FH modulation. Slider B was found to exhibit an overall enhancement in performance, stability, and reliability in ultrahigh density magnetic recording.

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Effect of Non-Operational Shock on Interaction Between Suspension Lift-Tab and Load/Unload Ramp

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-63558 ◽

2005 ◽

Author(s):

Aravind N. Murthy ◽

Eric M. Jayson ◽

Frank E. Talke

Keyword(s):

Hard Disk Drive ◽

Failure Modes ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Disk Drive ◽

Disk Drives ◽

Head Disk Interface ◽

Disk Interface ◽

Operational Shock

Most hard disk drives manufactured in the last few years have Load/Unload (L/UL) technology. As opposed to the Contact Start/Stop (CSS) technology, L/UL technology has the advantage of improved areal density because of more disk space availability and better shock performance. The latter characteristic has significant benefits during the non-operational state of the hard disk drive since head/disk interactions are eliminated and the head is parked on a ramp adjacent to the disk. However, even if head/disk interactions are absent, other failure modes may occur such as lift-tab damage and dimple separation leading to flexure damage. A number of investigations have been made to study the response of the head disk interface with respect to shock when the head is parked on the disk ([1], [2]). In this paper, we address the effect of non-operational shock for L/UL disk drives.

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Magnetic Tape: The Challenge of Reaching Hard-Disk-Drive Data Densities on Flexible Media

MRS Bulletin ◽

10.1557/mrs2006.102 ◽

2006 ◽

Vol 31 (5) ◽

pp. 404-408 ◽

Cited By ~ 16

Author(s):

Richard H. Dee

Keyword(s):

Data Storage ◽

Magnetic Tape ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Operating Conditions ◽

Magnetic Data ◽

Disk Drives ◽

Placement Problem ◽

The Future

AbstractBy the end of 2006, the areal density of magnetic recording on tape will approach that seen in hard disk drives of the early to mid-1990s.These operating conditions are reviewed in relation to the operating conditions deemed necessary for the future of magnetic data storage on tape.What results is a clear set of tasks, encompassing both materials and systems architecture issues, to achieve very high-density data storage on magnetic tape, leading to 10 Tbyte tape cartridge capacities and higher.The key to achieving on tape the areal densities of tens to hundreds of Gbit in.2, common in hard disk drives (HDDs), lies primarily in the properties of the medium itself.As for volumetric density of the storage entity, HDDs and tape cartridges are roughly equivalent.The mechanical dimensional uncertainties that accompany the use of flexible, as opposed to rigid, media means that both the mechanical and magnetic properties of materials play a key role in the future of tape.The need for new architectures to overcome the track placement problem that results from increasing track density on flexible media are reviewed, as well as the “particles in a binder” concept that has served so well as the physical basis of tape media over the past 50 years.

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On the quasi-rigid body motion of the head actuator assembly in hard disk drives

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/095440602321029490 ◽

2002 ◽

Vol 216 (12) ◽

pp. 1259-1262

Author(s):

S Zeng

Keyword(s):

Rigid Body ◽

Vibration Mode ◽

Hard Disk Drives ◽

Hard Disk ◽

Areal Density ◽

Body Motion ◽

Fe Model ◽

Disk Drives ◽

Rigid Body Mode ◽

Set Up

A quasi-rigid (QR) vibration mode between 3 and 5 kHz is common in current hard disk drives (HDDs), which hinders servo bandwidth improvement and thus limits growth in the areal density (numbers of bits that can be stored per unit area) of HDDs. In this paper, a finite element (FE) model of a head actuator assembly (HAA) is developed and an experimental set-up is established to study the quasi-rigid body mode. The FE model result is compared with the experimental data. It is found that the quasi-rigid body mode is in fact a butterfly-like mode, which integrates the flexibility of the pivot assembly as well as the flexibility and the mass of the whole head actuator body.

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