Air Bearing Interface Characteristics of Opposed Asymmetric Recording Head Sliders Flying on a 1 in. Titanium Foil Disk

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
James White
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Hard Disk ◽  
Titanium Foil ◽  
Operating Conditions ◽  
Storage Device ◽  
Air Bearing ◽  
Mechanical Shock ◽  
Recording Head ◽  
Disk Interface

The current effort was motivated by the increasing appearance of data storage devices in small portable and mobile product formats and the need for these devices to deliver high storage capacity, low power requirements, and increased ruggedness. In order to address these requirements, this work considered the storage device to utilize a 1 in. titanium foil disk and a pair of opposed femtosized zero-load recording head sliders with asymmetrically configured air bearing surfaces. A titanium foil disk, due to its reduced thickness and relatively low mass density, requires less operational energy than a hard disk while providing storage densities and data transfer rates typical of a hard disk. The zero-load sliders were chosen in order to make negligible the air bearing interface normal force acting on the disk surface that can lead to high speed disk instability. The asymmetry of the slider air bearing surfaces, together with the disk dynamic flexibility, greatly improves the ability of the slider-disk interface to absorb substantial mechanical shock and other dynamic effects without the associated contact and impact typically observed with a hard disk. The current project evaluated the characteristics of this slider-disk air bearing interface for both static and unsteady operating conditions. Time dependent studies included a numerical simulation of the dynamic load process and the response to mechanical shock. A comparison with the performance of a hard disk interface was also included.

Air Bearing Slider-Disk Interface for Single-Sided High Speed Recording on a Metal Foil Disk

2007 ◽  
Vol 129 (3) ◽  
pp. 562-569 ◽  
Author(s):  
James White
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Flying Height ◽  
Metal Foil ◽  
Air Bearing ◽  
Recording Head ◽  
Disk Interface ◽  
Air Bearing Slider

There are disk-drive data storage applications best served by single-sided recording configurations. These include situations where (i) storage requirements can be achieved on a single side of a disk and (ii) dimensional constraints on the disk drive prohibit the presence of a recording head and its associated mounting device on each side of the disk. Even if dimensional requirements are not a concern, the most cost-effective and operationally efficient slider-disk air-bearing interface for single-sided recording is one that does not include an air-bearing slider, pressure pad, or other air-bearing structure on the nondata side of the disk. A metal foil disk offers some of the best characteristics of both the hard disk and floppy disk for digital data storage. It offers hard disk recording densities, increased shock resistance, reduced manufacturing cost, and requires less operational energy than a hard disk. However, use of a conventional recording head slider assembly without opposing air-bearing support for single-sided recording on a high-speed metal foil disk presents a fundamental problem because the air-bearing surface of the slider produces a net transverse force to the disk. This force causes the disk to deflect and can result in flying height and stability problems at the slider-disk interface. The current work describes an air-bearing interface for low flying height single-sided recording on a high-speed metal foil disk that minimizes disk deflection and instability without the presence of air-bearing components on opposing sides of the disk. The new interface utilizes a vacuum cavity-type air-bearing with little or no preload. Examples will be presented and discussed for the new interface that illustrate the flying characteristics of a picosized slider on a 1.8in. stainless steel disk with thickness of 25.4μm.

The Gas Bearing Interface of Opposed Recording Heads in a Disk Drive Utilizing Helium and Thin Titanium Foil Disks

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
James White
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Hard Disk ◽  
Disk Drive ◽  
Titanium Foil ◽  
Metal Foil ◽  
Mechanical Shock ◽  
Disk Interface ◽  
Recording Heads ◽  
Gas Bearing

Increased storage capacity and decreased power consumption are two key motivations in the development of hard disk drive (HDD) storage products. Two ideas that address these areas have recently received attention in the literature. These are (1) the use of helium instead of air as the working gas in the drive and (2) the incorporation of a thin metal foil as the disk substrate, replacing the much thicker aluminum or glass substrate of the hard disk (HD). The work that has been previously reported considered either the use of helium or thin foil substrates, but not both. This paper does consider both. It reports dynamic gas bearing simulation results for the helium filled interface between opposed recording heads and a disk whose substrate is a thin titanium foil. Motivation for the selection of titanium as the foil material is described in the paper. The thickness of the foil is chosen so as to achieve an optimal combination of centrifugal force and bending force that will provide required disk flatness and stability during high-speed rotation. Large-scale dynamic simulation is used to track the response of the recording head slider-foil disk interface due to mechanical shock in the vertical, pitch, and roll directions. Results are described and compared with those of the configuration that includes helium and a HD. Attention is focused on response to off-design conditions that can create head crash with the HD.

Design of Optimized Opposed Slider Air Bearings for High-Speed Recording on a Metal Foil Disk

2005 ◽  
Vol 128 (2) ◽  
pp. 327-334 ◽  
Author(s):  
James White
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Floppy Disk ◽  
Digital Data ◽  
Current Work ◽  
Flying Height ◽  
Metal Foil ◽  
Air Bearing ◽  
Mechanical Shock ◽  
Air Bearings

A metal foil disk offers some of the best characteristics of both the hard disk and floppy disk for digital data storage. The current work defines an opposed slider air-bearing arrangement that provides advantages when used with a high-speed metal foil disk in either a fixed or removable format. Use is made of the fact that the opposing sliders interact through their influence on the flexible disk that is sandwiched between them. Asymmetry of opposing air bearings is created by etching the air-bearing pad opposite the recording element pad to a depth sufficient that the flying height and air film stiffness of the opposing pad reach desired levels. The result is an air-bearing interface with low flying height and high stiffness over the recording element directly opposed by a high flying height and low stiffness on the other side of the disk. This air-bearing interface was found to provide an enhanced dynamic flexibility to the metal foil disk when it is subjected to mechanical shock. As a result, the opposed slider arrangement with metal foil disk is able to avoid contact and impact when subjected to substantial levels of mechanical shock. Thus, wear and damage to slider and disk surfaces are reduced as well as the possibility of lost recorded data. This should make the metal foil disk a strong candidate as a rotating storage medium for mobile and portable applications where a shock environment is common. Computer simulation of the new air-bearing configuration will be presented and discussed. The current work is related to but distinct from that reported recently by White (2005, ASME J. Tribol., 127, pp. 522–529) for a Mylar disk.

Optimization of Air Bearing Contours for Shock Performance of a Hard Disk Drive

2003 ◽  
Author(s):  
Eric M. Jayson ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Time Dependent ◽  
Air Bearing ◽  
Disk Interface ◽  
Shock Response ◽  
Shock Event

Hard disk drives must be designed to withstand shock during operation. Large movements of the slider during shock impulse can cause reading and writing errors, track misregistration, or in extreme cases, damage to the magnetic material and loss of data. The design of the air bearing contour determines the steady state flying conditions of the slider as well as dynamic flying conditions, including shock response. In this paper a finite element model of the hard disk drive mechanical components was developed to determine the time dependent forces and moments applied to the slider during a shock event. The time dependent forces and moments are applied as external loads in a solution of the dynamic Reynolds equation to determine the slider response to a shock event. The genetic algorithm was then used to optimize the air bearing contour for optimum shock response while keeping the steady flying conditions constant. The results show substantial differences in the spacing modulation of the head/disk interface after a shock as a function of the design of the air bearing contour.

Dynamic Analysis of Sliding Contacts at Head-Disk Interface

2002 ◽  
Author(s):  
T.-J. Chuang ◽  
S. M. Hsu
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Time History ◽  
Disk Drive ◽  
Element Model ◽  
Disk Surface ◽  
Magnetic Data ◽  
Head Disk Interface ◽  
Sliding Contacts ◽  
Disk Interface

As magnetic data storage technology moves towards higher areal data density with higher rotational speeds and lower flying heights, the propensity of severe sliding contacts at the head-disk interface is bound to increase. The tribological performance of the head-disk interface will have significant impact on the durability and service life of the hard disk drive (HDD). A 3D finite element model is constructed to simulate the high speed impact event of a slider on the disk surface. For a given design of the disk with known layer thicknesses and properties, as well as that of the slider with its surface texture, the model predicts contact zone, depth force and duration as well as time-history of energy transfer and its partition, substrate stress and plastic zone for a given impact velocity. The effects of the material properties and layer thicknesses on the performance of the HDD are investigated.

Predictions of Rotordynamic Performance for Electric Turbocompound

2012 ◽  
Author(s):  
Keun Ryu ◽  
Augustine Cavagnaro
Keyword(s):  
High Speed ◽  
Fuel Efficiency ◽  
Element Model ◽  
Operating Conditions ◽  
System Level ◽  
Engine Oil ◽  
Storage Device ◽  
Prototype Development ◽  
Linear And Nonlinear ◽  
Type Motor

An electric turbocompound (ETC) system for heavy duty diesel engines offers significant system level benefits, such as improved fuel efficiency and reduced NOx emissions with a lower CO2 footprint. Presently, a high speed switched reluctance type motor/generator is integrated into a turbocharger shaft between the turbine and compressor wheels. The motor assists rapid acceleration of the turbocharger shaft, thereby rendering faster transient response. At steady or over-boost operating conditions, the generator provides electric power which can be used directly or stored in an on-board storage device. ETCs operate at high rotational speeds and, if equipped with fluid film bearings, use pressurized engine oil to lubricate the bearings (journal and thrust). This paper presents comprehensive predictions of the linear and nonlinear shaft motions of an ETC supported on floating ring bearings. A rotor structural finite element model integrates the floating ring bearing model for prediction of the rotor-bearing system (RBS) linear and nonlinear forced responses under actual operating conditions. Predictions show a complex rotordynamic behavior of the RBS with large amplitude subsynchronous motions over a wide speed range. However, the subsynchronous whirl motions reach a limit cycle enabling continuous operation without system failure. Most importantly, stiffness of the lamination stack mounted on the shaft has a significant effect on the amplitude and frequency content of the shaft motion. The present analysis effectively aids to accelerate ETC prototype development with increased reliability and product troubleshooting.

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

MRS Bulletin ◽  
2006 ◽  
Vol 31 (5) ◽  
pp. 404-408 ◽  
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.

scholarly journals Data Mining for Information Storage Reliability Assessment by Relative Values

2018 ◽  
Vol 7 (4.7) ◽  
pp. 204 ◽  
Author(s):  
Iskandar N. Nasyrov ◽  
Ildar I. Nasyrov ◽  
Rustam I. Nasyrov ◽  
Bulat A. Khairullin
Keyword(s):  
Data Storage ◽  
Error Rate ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Careful Analysis ◽  
Information Storage ◽  
Storage Device ◽  
Relative Distribution ◽  
Solid State Drives ◽  
Reliability Indicators

The data ambiguity problem for heterogeneous sets of equipment reliability indicators is considered. In fact, the same manufacturers do not always unambiguously fill the SMART parameters with the corresponding values for their different models of hard disk drives. In addition, some of the parameters are sometimes empty, while the other parameters have only zero values.The scientific task of the research consists in the need to define such a set of parameters that will allow us to obtain a comparative assessment of the reliability of each individual storage device of any model of any manufacturer for its timely replacement.The following conditions were used to select the parameters suitable for evaluating their relative values:1) The parameter values for normally operating drives should always be greater or lower than for the failed ones;2) The monotonicity of changes in the values of parameters in the series should be observed: normally working, withdrawn prematurely, failed;3) The first two conditions must be fulfilled both in general and in particular, for example, for the drives of each brand separately.Separate averaging of the values for normally operating, early decommissioned and failed storage media was performed. The maximum of these three values was taken as 100%. The relative distribution of values for each parameter was studied.Five parameters were selected (5 – “Reallocated sectors count”, 7 – “Seek error rate”, 184 – “End-to-end error”, 196 – “Reallocation event count”, 197 – “Current pending sector count”, plus another four (1 – “Raw read error rate”, 10 – “Spin-up retry counts”, 187 – “Reported uncorrectable errors”, 198 – “Uncorrectable sector counts”), which require more careful analysis, and one (194 – “Hard disk assembly temperature”) for prospective use in solid-state drives, as a result of the relative value study of their suitability for use upon evaluating the reliability of data storage devices. 

Optimization of Air Bearing Contours for Shock Performance of a Hard Disk Drive

2005 ◽  
Vol 127 (4) ◽  
pp. 878-883 ◽  
Author(s):  
Eric M. Jayson ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Time Dependent ◽  
Air Bearing ◽  
Disk Interface ◽  
Shock Response ◽  
Shock Event

Hard disk drives must be designed to withstand shock during operation. Large movements of the slider during a shock impulse can cause reading and writing errors, track misregistration, or in extreme cases, damage to the magnetic material and loss of data. The design of the air bearing contour determines the steady-state flying conditions of the slider as well as dynamic flying conditions, including shock response. In this paper a finite element model of the hard disk drive mechanical components was developed to determine the time dependent forces and moments applied to the slider during a shock event. The time-dependent forces and moments are applied as external loads in a solution of the dynamic Reynolds equation to determine the slider response to a shock event. The genetic algorithm was then used to optimize the air bearing contour for optimum shock response while keeping the steady flying conditions constant. The results show substantial differences in the spacing modulation of the head-disk interface after a shock as a function of the design of the air bearing contour.

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