• Transactions of the Society of Information Storage Systems
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• v.7 no.2
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• pp.65-69
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• 2011

Head Disk Interface (HDI) in a Hard Disk Drive (HDD) has decreased to achieve high areal density. Thus, the contact between a slider and a disk becomes more important. The contact between the slider and the disk can cause severe wear and damage of both the slider and the disk. Especially, Touch Down (TD) that the contact occurs continuously and repeatedly is extremely dangerous. Therefore, it is necessary to analyze the unstable bouncing vibration of the slider in head-disk interface. In this paper, we investigate the characteristic and causes of the Touch Down.

• Tribology and Lubricants
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• v.16 no.5
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• pp.395-402
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• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider and a laser-textured disk was studied. Particles of different concentrations, materials and sizes were injected to the head-disk interface (HDI), consisting of disks with various textures, at the same speed. In a contaminated environment, durability of head-disk interface gradually decreased as the particle concentration increased. Large particles caused HDI failure early and resulted in an extensive damage to the slider and disk surfaces. Hard particles also caused HDI failure earlier and damages more extensive than soft ones. Based on the test results, mechanisms of HDI failure with picoslider were presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.340.2-340
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• 2002

A practical implementation method of squeeze-film aeroelastic disk vibration damping and its practical design performance are presented to provide a solution method to meet the tight TMR(Track Mis-Registration) design budget of high-TPI HDDs. Most previous research results are mainly based on the component-level study in the 'open-cover state' which is far from the realistic operations HDD condition. (omitted)

• The Journal of the Acoustical Society of Korea
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• v.14 no.4
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• pp.5-11
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• 1995

In this paper, we design the new high-speed seek algorithm which can access the data of disk (in 3.5-inch optical disk drive). When seek the target track on optical disk in high-speed using the ref-T. E(Reference Tracking Error) and sample pulse signal, it's always possible high-speed seek without re-check and compensation for error by the ref_T. E and sample pulse signal. The performance test result is represented as follow ; it is satify the average seek time of 28mses.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.10-21
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• 2003

During seek operation in disk drives, the recording head is moved toward desired track by seek servo controller and then is settled onto the center of the desired track by settling servo controller. If the head speed at the start of settling servo control is not slow, it may produce overshoot relative to the center of track and thus extend the settling time. The degradation in settling performance will be more severe as the track width becomes smaller for higher density of data storage. We design a new settling servo controller for minimizing settling time based on the pole-zero cancellation. In order to cancel slow poles in settling response, we apply discrete pulse signals to the system in addition to the state feedback control. For exact pole-zero cancellation, we consider the dynamics of power amplifier used for actuator current regulation and the effects of delay in control action. In addition, we present system parameter identification algerian for the robustness of our controller to system parameter variation. In order to demonstrate the practical use of our controller, we present experimental results obtained by using a commercially available disk drive.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.94-101
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• 2007

In the Hard Disk Drive(HDD) production, the detect pattern or defective HDD set is important information to diagnosis of defective HDD set. This paper proposes a pattern recognition neural network for the defect distribution of HDD. In this paper, 5 characteristics are determined for the classification to six standard defect pattern classes. A multi-layer perceptron is trained for the pattern classification the inputs of which are 5 characteristic values and the 6 outputs are the nodes of standard patterns. The experiment with proposed neural network shows satisfactory results.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.683-688
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• 1999

This paper describes design of equalizer chips of the read channel for high-density hard-disk drives. In order to meet increasing need of hard-disk drives, the read channel incorporates various PRML schemes. They require proper equalization to implement the efficient hardware of Viterbi decoders. This paper describes EPR-IV equalization for the read channel and a 200MHz analog FIR filter chip is presented which utilizes the sampled analog signal processing efficiently.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.159-167
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• 1999

A digital tracking controller is proposed for a precise positioning control under a large repetitive and/or non repetitive disturbances. The proposed control system. Numerical Examples are illustrated for a precise head positioning of optical disk drives regardless of a torque disturbance and/or output disturbance.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.109-116
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• 2021

Since RDF (Resource Description Framework) triples are modeled as graph, we cannot directly adopt existing solutions in relational databases and XML technology. In order to store, index, and query Linked Data more efficiently, we propose a convergence indexing method combined R*-tree and K-dimensional trees. This method uses a hybrid storage system based on HDD (Hard Disk Drive) and SSD (Solid State Drive) devices, and a separated filter and refinement index structure to filter unnecessary data and further refine the immediate result. We perform performance comparisons based on three standard join retrieval algorithms. The experimental results demonstrate that our method has achieved remarkable performance compared to other existing methods such as Quad and Darq.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.130-137
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• 2006

The HDD(hard disk drive) using Load/unload(L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop(CSS). It has been widely used in portable hard disk drive and will become the key technology for developing the small form factor hard disk drive. The main objects of L/UL are no slider-disk contact or no media damage. For realizing those, we must consider many design parameters in L/UL system. In this paper, we focus on lift-off force. The 'lift-off' force, defined as the minimum air bearing force, is another very important indicator of unloading performance. A large amplitude of lift-off force increases the ramp force, the unloading time, the slider oscillation and contact-possibility. To minimize 'lift-off' force we optimizes the slider and suspension using the integrated optimization frame, which automatically integrates the analysis with the optimization and effectively implements the repetitive works between them. In particular, this study is carried out the optimal design considering the process of modes tracking through the entire optimization processes. As a result, we yield the equation which can easily find a lift-off force and structural optimization for suspension.