深入分析S.M.A.R.T技术

读者和用户对硬盘数据存储可靠性的关注逐渐升温，由此在本刊论坛上引发了一场关于S.M.A.R.T技术的激烈讨论。为让更多读者深入了解这项已为我们服务了长达9年的技术，我们仔细筛选出具有针对性的问题，并在希捷硬盘工程师的大力协助下，将一直工作于系统后台的S.M.A.R.T技术提到前台，旨在深入，详细地分析关于它的方方面面。     

“聪明”的硬盘——谈S.M.A.R.T.技术

在硬盘厂商的广告中,已经越来越多地提到了S.M.A.R.T.技术。关于S.M.A.R.T.,人们只知道它是“自我监督分析与报告技术”的缩写,那么,到底它是一种什么样的技术呢? S.M.A.R.T.技术从本质上是一种可靠性预测技术,它通过预测硬盘的故障提醒系统或用户备份数据,防止故障。S.M.A.R.T.是由Compaq及IBM领导,业界几家最大的厂商如Seagate、IBM、Quantum及Western Digital等组成     

S.M.A.R.T的可靠性有多高？

S.M.A.R.T是英Self-Monitoring，Analysis and Reporting Technology的缩写，即自检、分析和报告技术。顾名思义，这是用来对硬盘自身进行监测，并向用户提供分析结果的一项自诊断技术。自ATA-3以后，S.M.A.R.T技术已经成为IDE硬盘必备的规范。现在，无论是IDE产品还是SCSI产品，几乎所有市售硬盘都支持S.M.A.R.T功能，但要使用这个功能，必须具备相应的BIOS和专门的应用程序。     

自修复磁盘阵列技术研究

以数据为中心的计算模式对数据的可靠性提出新的需求,高可靠存储设备成为高性能计算的基础.自从Xiotech公司提出ISE结构并取得成功后,关注磁盘失效之前的征兆而不是失效后的具体处理的"自修复"概念已成为磁盘阵列设计新的指导思想之一.提出存储系统可靠性系数的概念,分析单个磁盘可靠性与磁盘阵列可靠性关系,选择合适的磁盘S.M.A.R.T属性结合磁盘当前利用率和历史信息建立评定磁盘状态的T~2US算法,接着介绍RAID 5结合T2US监测的高可靠、自修复的RAID 5T结构,说明RAID 5T结构的运行方式和磁盘不符合T~2US监测标准时数据迁移策略,最后对结构的可靠性利用存储系统可靠性系数和MTTF分别进行了分析.     

基于智能预警的自恢复存储系统研究

为提高磁盘阵列存储的可靠性,提出一种基于智能预警的自恢复存储系统。在对磁盘S.M.A.R.T信息实时监测采集的基础上,利用机器学习方法对磁盘故障进行预测,对于预警磁盘采取以数据为中心的自修复迁移保护策略。分析结果表明,该系统能提高存储可靠性,数据迁移过程对用户透明,可用性较强。     

用好S.M.A.R.T技术

电脑性能曾经是大家最为关注的焦点，但是目前来看，似乎性能显得并不那么重要，反而电脑数据的安全性一直是大家所关注的，所以不少用户部给电脑安装硬盘保护程序。不过遗憾的是，一旦硬盘瘫痪了硬盘数据还是会丢失。因此，为了尽可能减少因硬盘数据丢失带来的损失，做好硬盘安全的预防工作尤为重要。然而大家又是否想到，其实硬盘S．M．A．R．T技术可以自我监测、分析及报告硬盘的故障，从而让用户提早备份并修复硬盘，降低用户的经济损失。[编者按]     

Active SMART，拉响硬盘崩溃前的警报

Active SMART是一个硬盘状态监测软件，它利用S．M．A．R．T技术来对硬盘进行监测。那么，什么是S．M．A．R．T技术呢?S．M．A．R．T(Self Monitoring Analysis and Reporting Technology自动监视分析与报告技术)是在ATA-3标准中正式提出的一项技术，由Quantum和Compaq公司联合开发，用于     

IBM PC SERVER技术连载（五）

IBM的硬盘驱动器(三) IBM 3.5英寸Ultrastar系列硬盘驱动器采用了第三代PRML(Partial Response Maximum Likelihood)技术,它对通过磁盘的数据波形进行取样,并据此构造数据流。该技术进一步提高了有效存储容量和数据吞吐率。 IBM的S.M.A.R.T技术可对硬盘故障预警,防患于未然。该技术结合IBM的预测失效分析(PFA)技术,可有效地     

数据的金刚罩——硬盘安全技术全接触

随着硬盘容量的不断增大,数据安全性也越来越受人关注。针对硬盘的安全问题,众硬盘厂商无不使出浑身解数,研发各种数据保护技术。今天,笔者将带您认识这些技术,看看这些技术如何保护您的劳动成果。万物之本—S.M.A.R.TS.M.A.R.T全称为“Self-Monitoring,AnalysisandReportingTe     

5种现象预示硬盘将要出现故障

1．出现S．M.A.R．T故障提示。S．M．A．R．T．即“自我监测、分析及报告技术”。它可以监控磁头、磁盘、电机、电路等部件,由硬盘的监测电路和主机上的监测软件对被监对象的运行情况与历史记录和预设的安全值进行分析、比较,一旦出现安全值范围以外的情况,     

A variational approach to multi-phase motion of gas, liquid and solid based on the level set method

We propose a simple and robust numerical algorithm to deal with multi-phase motion of gas, liquid and solid based on the level set method [S. Osher, J.A. Sethian, Front propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulation, J. Comput. Phys. 79 (1988) 12; M. Sussman, P. Smereka, S. Osher, A level set approach for capturing solution to incompressible two-phase flow, J. Comput. Phys. 114 (1994) 146; J.A. Sethian, Level Set Methods and Fast Marching Methods, Cambridge University Press, 1999; S. Osher, R. Fedkiw, Level Set Methods and Dynamics Implicit Surface, Applied Mathematical Sciences, vol. 153, Springer, 2003]. In Eulerian framework, to simulate interaction between a moving solid object and an interfacial flow, we need to define at least two functions (level set functions) to distinguish three materials. In such simulations, in general two functions overlap and/or disagree due to numerical errors such as numerical diffusion. In this paper, we resolved the problem using the idea of the active contour model [M. Kass, A. Witkin, D. Terzopoulos, Snakes: active contour models, International Journal of Computer Vision 1 (1988) 321; V. Caselles, R. Kimmel, G. Sapiro, Geodesic active contours, International Journal of Computer Vision 22 (1997) 61; G. Sapiro, Geometric Partial Differential Equations and Image Analysis, Cambridge University Press, 2001; R. Kimmel, Numerical Geometry of Images: Theory, Algorithms, and Applications, Springer-Verlag, 2003] introduced in the field of image processing.     

A DAFT DL_POLY distributed memory adaptation of the Smoothed Particle Mesh Ewald method

The Smoothed Particle Mesh Ewald method [U. Essmann, L. Perera, M.L. Berkowtz, T. Darden, H. Lee, L.G. Pedersen, J. Chem. Phys. 103 (1995) 8577] for calculating long ranged forces in molecular simulation has been adapted for the parallel molecular dynamics code DL_POLY_3 [I.T. Todorov, W. Smith, Philos. Trans. Roy. Soc. London 362 (2004) 1835], making use of a novel 3D Fast Fourier Transform (DAFT) [I.J. Bush, The Daresbury Advanced Fourier transform, Daresbury Laboratory, 1999] that perfectly matches the Domain Decomposition (DD) parallelisation strategy [W. Smith, Comput. Phys. Comm. 62 (1991) 229; M.R.S. Pinches, D. Tildesley, W. Smith, Mol. Sim. 6 (1991) 51; D. Rapaport, Comput. Phys. Comm. 62 (1991) 217] of the DL_POLY_3 code. In this article we describe software adaptations undertaken to import this functionality and provide a review of its performance.     

基于小波系数的双变量模型中医诊断图像处理方法

中医四诊即望、闻、问、切,是中医用于诊断疾病的四个基本方法,它们是中医正确辨证和有效治疗的前提.对中医诊断图像进行去噪可以提高医学图像的信息利用率,小波变换是目前最新的时频分析工具,是医学图像去噪的强有力处理工具.提出了一种基于层内和层间相关性的双变量模型小波收缩图像处理方法.实验证明,该图像处理方法能有效去除中医诊断图像中的噪声.     

Free boundary problems in the theory of fluid flow through porous media: A numerical approach

In this paper we study from the numerical point of view elliptic free boundary problems in the theory of fluid flow through porous media by a new method. Research supported by C.N.R. in the frame of the collaboration between L. A. N. of Pavia and E. R. A. 215 of C. N. R. S. and of Paris University and carried out also with the cooperation of the Division C. E. T. I. S. of C.C.R. Euratom Ispra.     

A dependability model for TMR system

Much research has been done on the dependability evaluation of computer systems. However, much of this is gone no further than study of the fault coverage of such systems, with little focus on the relationship between fault coverage and overall system dependability. In this paper, a Markovian dependability model for triple-modular-redundancy (TMR) system is presented. Having fully considered the effects of fault coverage, working time, and constant failure rate of single module on the dependability of the target TMR system, the model is built based on the stepwise degradation strategy. Through the model, the relationship between the fault coverage and the dependability of the system is determined. What is more, the dependability of the system can be dynamically and precisely predicted at any given time with the fault coverage set. This will be of much benefit for the dependability evaluation and improvement, and be helpful for the system design and maintenance.     

A sampled normal form for feedback linearization

This paper discusses the problem of preserving approximated feedback linearization under digital control. Starting from a partially feedback linearizable affine continuous-time dynamics, a digital control procedure which maintains the dimension of the maximally feedback linearizable part up to any order of approximation with respect to the sampling period is proposed. The result is based on the introduction of a sampled normal form, a canonical structure which naturally appears when studying feedback linearization.This work was supported by an Italian 40% M.U.R.S.T. grant and a French M.E.N.-D.R.E.D. grant.     

Parallel S.O.R. iterative methods

New explicit group S.O.R. methods suitable for use on an asynchronous MIMD computer are presented for the numerical solution of the sparse linear systems derived from the discretization of two-dimensional, second-order, elliptic boundary value problems. A comparison with existing implicit line S.O.R. schemes for the Dirichlet model problem shows the new schemes to be superior (Barlow and Evans, 1982).     

QCDgrid: A Grid Resource for Quantum Chromodynamics

Quantum Chromodynamics (QCD) is an application area that requires access to large supercomputing resources and generates large amounts of raw data. The UK's national lattice QCD collaboration UKQCD currently stores and requires access to around five Tbytes of data, a figure that is growing dramatically as the collaboration's purpose built supercomputing system, QCDOC [P.A. Boyle, D. Chen, N.H. Christ, M. Clark, S.D. Cohen, C. Cristian, Z. Dong, A. Gara, B. Joo, C. Jung, C. Kim, L. Levkova, X. Liao, G. Liu, R.D. Mawhinney, S. Ohta, K. Petrov, T. Wettig and A. Yamaguchi, “Hardware and software status of QCDOC, arXiv: hep-lat/0309096”, Nuclear Physics. B, Proceedings Supplement, Vol. 838, pp. 129–130, 2004. See: http://www.ph.ed.ac.uk/ukqcd/community/qcdoc/; P.A. Boyle, D. Chen, N.H. Christ, M.A. Clark, S.D. Cohen, C. Cristian, Z. Dong, A. Gara, B. Joo, C. Jung, C. Kim, L.A. Levkova, X. Liao, R.D. Mawhinney, S. Ohta, K. Petrov, T. Wettig and A. Yamaguchi, “Overview of the QCDSP and QCDOC computers”, IBM Journal of Research and Development, Vol. 49, No. 2/3, p. 351, 2005] came into full production service towards the end of 2004. This data is stored on QCDgrid, a data Grid currently composed of seven storage elements at five separate UK sites.     

Dependable domestic systems design: A socio-technical approach

This paper describes a model that defines the attributes of domestic systems that lead to system dependability and a user-oriented specification method for support systems based on this model. We start by discussing technical dependability models and discuss how these have to be extended for use in a domestic context. We present an extended dependability model based on a socio-technical perspective. This extends the technical notion of dependability to take into account fitness for purpose, acceptability and adaptability. We then go on to discuss MDDS – a questionnaire-based method that reflects the socio-technical dependability model. It is intended for use by social care professionals who are specifying and designing support systems for older or disabled people. MDDS provides a basis for examining a design from a dependability perspective. We illustrate the use of the method and conclude with a discussion of its qualitative evaluation.