• Title, Summary, Keyword: Hard Disk Drive

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Numerical Prediction of Flow Field in a Hard Disk Drive (하드 디스크 드라이브 내부의 유동장에 관한 수치적 연구)

  • Lee, Jae-Heon;Back, Y.R.;Kim, K.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.3 no.3
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    • pp.206-214
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    • 1991
  • Flow field in a hard disk drive has been predicted numerically. Theoretical model was constructed based on a commercially available hard disk drive with 40 Mega byte capacity. Since the gap between disk tip and shroud is not homogeneous in real hard disk drive, three kinds of gap size have been tested as computational model. The discussion has been made on the circumferential velocity, radial velocity, and pressure fields. As a result, the average shear stress on the disk surface was reduced as the gap size decreased. This means that the shroud should be designed compactly to reduce power consumption of the spindle motor.

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Effects of Smooth and Textured Disks on Particle Generation in a Hard Disk Drive (하드 디스크 드라이브에서 Smooth 디스크와 LZT 디스크가 입자 발생에 미치는 영향)

  • Lee, Dae-Young;Huh, Sun-Young;Kang, Pil-Sun;Hwang, Jung-Ho;Cho, Keung-Youn;Kang, Tae-Sik
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.2
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    • pp.123-129
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    • 2006
  • The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated ill HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted particles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

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Effects of Smooth and Textured Disks on Particle Generation in a Hard Disk Drive (하드디스크 드라이브에서 Smooth 디스크와 LZT 디스크가 입자 발생에 미치는 영향)

  • Lee Dae-Young;Huh Sun-Young;Kang Pil-Sun;Hwang Jungho;Cho Keung-Youn;Kang Tae-Sik
    • 정보저장시스템학회:학술대회논문집
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    • pp.88-95
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    • 2005
  • The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated in HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted panicles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

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Shock Response Analysis of 2.5in Hard Disk Drive Supported by Rubber Mounts (고무 마운트로 지지된 2.5인치 하드디스크 드라이브의 충격 응답 해석)

  • seol Woong;Chang Young-Bae;Park No-Cheol;Park Young-Pil
    • 정보저장시스템학회:학술대회논문집
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    • pp.215-216
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    • 2005
  • Nowadays, mobility as well as basic performances has been the important performance index of hard disk drive, It makes a system unstable to satisfy mobility, huge storage capacity and high transfer rate. Shock and vibration analysis has been important because hard disk drive could be exposed by external shock and vibration. The probability of this situation has been increasing. In this research, each component and the whole system of 2.5in HDD are made to a finite element model. Results of finite element analysis are compared with the results of experimental modal analysis. Shock analysis is executed for 2.5in hard disk drive.

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Investigation of Particle Generation in a Hard Disk Drive During the Start/Stop Period (구동 및 정지시 하드 디스크 드라이브 내 입자 발생 특성에 관한 실험적 연구)

  • Park, Hee-Sung;Yoo, Yong-cheol;Bae, Gwi-Nam;Hwang, Jung-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.6
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    • pp.744-752
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    • 1999
  • Particle contamination in a hard disk drive has been recognized as an important issue because particles can significantly affect the reliability of the drive. In this study, characteristics of the particle generation in a hard disk drive during the start/stop period were investigated. The number of particles generated in the drive was measured at 5 locations by using condensation nucleus counters(CNC) with sampling probes. It was found that most of particles were generated whenever the drive started or stopped. The number of particles detected by the condensation nucleus counter depended on sampling parameters including sampling location, shape of sampling probe, and sampling velocity.

Stiction and AE Characteristics of Hard Disk Drive under Various Environmental Conditions (환경 조건에 따른 하드디스크의 Stiction 및 AE 특성)

  • 박용식;성인하;김대은
    • Tribology and Lubricants
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    • v.17 no.1
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    • pp.1-9
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    • 2001
  • Hard disk drives operate in various environmental conditions. Thus, it is necessary to assess the reliability of the head/disk interface under these conditions. In this work, stiction and acoustic emission signals were investigated under different temperature, humidity, and ambient pressure conditions. Also, track average amplitude was observed for disk failure in N$_2$environment. It is shown that failure of the head/disk interface occurs more readily at high temperature and low ambient pressure conditions.

Investigation of Head-Disk Impact for Development of Ultra-Low Flying HDI (극저부상 HDI 개발을 위한 Head-Disk Impact 연구)

  • 조언정;박노열
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.122-126
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    • 2001
  • Magnetic hard disk drive is continually being pushed to reduce head-disk spacing for higher recording densities. The current minimum spacing between the air-bearing slider and disk has been reduced to under 15 nm. In this work, it was investigated if flying height could be lowered under the height of laser bumps. With the reduction of the spinning speed, the flying height was decreased under the height of laser bumps. When a head swept between landing zone and data zone, the head-disk impact was monitored using AE and friction signals. It is demonstrated that magnetic hard disk drive could be operated without tribological failures under the height of laser bumps.

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Effect of Disk Rotational Speed on Contamination Nano Particles Generated in a Hard Disk Drive (하드 디스크 드라이브 회전수 변화가 드라이브 내 나노 오염 입자 발생에 미치는 영향)

  • Lee, Dae-Young;Hwang, Jung-Ho;Bae, Gwi-Nam
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.8
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    • pp.976-983
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    • 2004
  • In high-density hard disk drives, the slider should be made to fly close to the magnetic recording disk to generate better signal resolution and at an increasingly high velocity to achieve better data rate. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation. Contamination particles in the hard disk drive can cause serious problems including slider crash and thermal asperities. We investigated the number and the sizes of particles generated in the hard disk drive, operating at increasing disk rotational speeds, in the CSS mode. CNC (condensation nucleus counter) and PSS (particle size selector) were used for this investigation. In addition, we examined the particle components by using SEM (scanning electron microscopes), AES (auger electron spectroscopy), and TOF-SIMS (time of flight-secondary ions mass spectrometry). The increasing disk rotational speed directly affected the particle generation by slider disk interaction. The number of particles that were generated increased with the disk rotational speed. The particle generation rate increased rapidly at motor speeds above 8000 rpm. This increase may be due to the increased slider disk interaction. Particle sizes ranged from 14 to 200 nm. The particles generated by slider disk interaction came from the lubricant on the disk, coating layer of the disk, and also slider surface.

A Study on Fuzzy Expert System for the Fault Diagnosis of Hard Disk Drive Test System (Hard Disk Drive 검사 시스템의 고장 전단용 퍼지 전문가 시스템에 관한 연구)

  • Mun, Un-Cheol;Gwon, Hyeon-Tae;Nam, Chang-U
    • Proceedings of the KIEE Conference
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    • pp.625-628
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    • 2003
  • This paper proposes a fuzzy expert system for the fault diagnosis of Hard Disk Drive(HDD) test systems. The purposes of this system are diagnosis of HDD test systems, detection of system faults using test history, and presentation of the way of repair. Proposed Expert system is designed with Fuzzy logic and Binary Logic to present the way of repair using HDD tort result, HDD test history. The proposed system is simulated with actual data from SAMSUNG HDD product line in KUMI, KOREA, and show effective results.

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An Expert System using Fuzzy and Binary logic for the Fault Diagnosis of Hard Disk Drive Test System (Hard Disk Drive 검사시스템의 고장 진단을 위한 퍼지-이진 논리 결합형 전문가 시스템에 관한 연구)

  • 문운철;이승철;남창우
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.6
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    • pp.457-464
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    • 2004
  • Hard Disk Drive (HDD) test system is an equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD production line, KUMI, KOREA, and shows satisfactory results.