硬盘固件区虚拟技术的原理与实用性分析

为提高硬盘固件修复成功率,简化硬盘固件修复的工作流程,分析了硬盘固件的基本工作原理与硬盘固件区的基本结构,介绍了包括固件模块替换法、备用固件区替换法、固件模块重定位法和热交换法在内的传统硬盘固件修复技术的概念,阐述了硬盘固件区虚拟技术的实现原理以及操作细节,并在此基础之上将该技术与传统硬盘固件修复技术进行了全方位的比较,通过一系列对比实验表明了该技术在日常数据恢复工作中的优势和实用价值.     

先软后硬 为SSD硬盘“延寿”

SSD固态硬盘虽然具备极致的读写速度,但闪存颗粒存在写入次数的极限值,因此SSD的寿命总会随频繁的使用而折损。如果你想尽可能延长SSD的使用寿命,不妨从软硬两个方面下手优化。可读不可写的SSD SSD的物理特性决定了其怕写(入)不怕读(取),想延长SSD寿命自然就要落实到如何尽可能减少硬盘的写入数据量。而影响硬盘写入数据的操作主要在于硬盘索引、预读取、系统还原和Windows事件记     

浅析PCI3000数据库功能

PC-3000 for Windows作为俄罗斯ACELAB公司推出的商用硬盘修复工具,是一项对受损硬盘驱动进行数据恢复的技术方案。它专为小型商业开发,不需要使用无尘室,硬盘复写器或其他昂贵设备。该软件具有人性化设计的硬盘驱动器固件信息数据库,允许维修人员在数据库快速搜索硬盘驱动器资源,避免了必须花费大量精力查找匹配固件的毛病。     

基于EDK2平台的数据备份与恢复技术

针对文件分配表文件系统数据的安全保障需求,基于符合统一可扩展固件接口(UEFI)规范的EFI开发套件2(EDK2)开源环境,提出一种固件层数据备份与恢复技术。利用EDK2提供协议接口读取硬盘分区数据,将获取的文件及目录信息备份为EFI镜像文件格式,数据恢复时反向写入目标分区。实验结果表明,该技术可解决传统数据备份对操作系统的过度依赖问题,其在固件层实现数据备份,实用性更强。     

提升固态存储设备读取性能的方法

针对不带大容量缓存的固态存储设备随机读取性能差的问题,提出预取和压缩用户热数据映射表的算法,来提升热数据的访问速度.该算法包括把顺序写入的数据和随机写入的数据分开存储、压缩连续物理地址映射、后台预取热数据映射表等方法,这些方法提升了热数据的映射命中率,减少了闪存的访问次数,达到了改善系统读取性能的目的.实验结果表明,该方法能减少将近一半的随机读取延时,读取速度在原来的基础上翻倍.该算法能显著改善那些不带大容量缓存的移动存储设备及消费级固态硬盘使用者的用户体验.     

计算机硬盘数据恢复的技术分析

硬盘是计算机系统中最主要的外部存储设备,硬盘上存储的数据会因为各种原因遭到损坏或丢失,数据恢复是将硬盘上损坏或丢失的数据重新找回来,还原为正常可用数据的过程。该文主要分析了硬盘文件存储和读取的原理,以及数据恢复的原理,论述了硬盘数据损坏或丢失的原因和类型,以及相应的恢复方法。     

《深度剖析—硬盘固件级数据恢复》

出版社:电子工业出版社出版时间:2013-1SBN:9787121191640内容简介:本书是为数据恢复爱好者撰写的一本参考书。作者根据长期的实际工作经验,对于带有固件故障的硬盘,如何进行数据恢复进行了深度剖析,其内容包括各个硬盘系列的固件结构及特点、故障分析、     

基于文件操作阻断的系统安全加固技术

尽管危害系统安全的程序的作用机理和实现方法差异很大,但在实现过程中,它们最底层的攻击行为统一表现为对系统文件的读取或写入.该文通过对系统非法文件的读取访问和写入访问的严密控制,提出了一种基于文件操作阻断的系统安全加固防护技术,分析了文件操作阻断技术的防护范围、防护时机、防护策略以及防护效果评估,建立起本地计算机系统的最终安全防线.     

全程图解迈拓硬盘 “换头术”

迈拓硬盘在读取固件区时．只有一个磁头上的固件为活动固件区（我们必须清楚．数据区有多个工作磁头．但读取固件区时只有一个特定的磁头为其活动区域。比如一个80G的金钻九代．主头是3头．读取固件时只能由3头进行；数据区工作时则有2头和3头组成。这里必须说明．迈拓磁头分布不是由0开始排列的．一般是由2开始）。重定义主头就是重新定义在读取固件区时的工作磁头。比如由左图中的3头定义为2头读取固件。     

强悍随机性能 影驰Thunder GT 128 Pro固态硬盘

影驰Thunder GT 128 Pro固态硬盘采用了JMicron JM667H主控芯片,定位设置在Laser系列之上(Laser系列均采用SandForce2281)。产品最大的特点在于4KB随机文件读写性能强劲,官方连续读写速度高达480MB/s(读取)、300MB/s(写入),而最大随机读写效率则为70000IPOS(读取)/58000IPOS(写入)。JMF667H是JMicron今年所推出的第四代SSD主控,它是一颗32Bit的ARM9架构处理器,内置3     

Poisson disk sampling through disk packing

Computational Visual Media - Poisson disk sampling is an important problem in computer graphics and has a wide variety of applications in imaging, geometry, rendering, etc. In this paper, we...     

Evaluating disk idle behavior by leveraging disk schedulers

Disk idle behavior has a significant impact on the energy efficiency of disk storage systems. For example, accurately predicting or extending the idle length experienced by disks can generate more potential opportunities to save energy. This paper employs a trace driven simulation to evaluate the impacts of different disk schedulers and queue length thresholds on the disk idle behavior. Experimental results give three implications: (1) Position based schedulers and long queue length thresholds can significantly reduce the maximal queue length and the average queue length. (2) Position based schedulers and long queue length thresholds can generate more idle periods which are shorter than 1 s, but they do not affect those long idle periods contained in the modern server workloads. (3) Disk idle periods demonstrate both self-similarity and weak long-range dependence, and the disk schedulers and queue length thresholds do impact the Hurst parameter and the correlation behavior of the workloads. The analysis results in this paper provide useful insights for designing and implementing energy efficient policies for the disk drive based storage systems.     

基于第二磁盘的解决磁盘碎片的方案

针对Windows操作系统因磁盘碎片而导致性能下降的问题,提出了一种新的磁盘碎片问题解决方案.给计算机新添一个磁盘,给Windows操作系统添加一个文件系统过滤驱动,将容易产生碎片的目录转存到新的磁盘上,并定期对这个新增磁盘进行碎片整理,从而有效控制磁盘碎片数量.提出了优先地使用固态硬盘作为新增磁盘,将具有更大的优势.实验结果表明,这种新增磁盘的方案能大幅降低磁盘碎片,具有很好的实用价值.     

Optimal disk merge patterns

Our purpose is to study the optimal way to merge n initially sorted runs, stored on a disk like device, into a unique sorted file. This problem is equivalent to finding a tree with n leaves which minimizes a certain cost function (see Knuth [1]).We shall study some properties of those optimal trees, in the hope of finding efficient ways for constructing them.In particular, if all the initial runs have the same length, an algorithm for constructing the best merge pattern is described ; its running time is proportional to n ² and it requires space proportional to n.A special case is also analyzed in which the problem is solved in time and space proportional to n, and which provides some insight into the asymptotic behaviour of optimal merge trees.     

Attenuation of rotating disk vibrations with sector-shaped plates in disk storage devices

A parametric study has been conducted to understand the mass loading contribution to rotating disk vibrations in disk storage devices. With sector-shaped plates retaining air between the two plates and a rotating disk, results have shown frequency crossing of disk flutter modes with non-zero nodal diameters where significant modal pattern switching is observed. Extending the range of the analysis to sector geometries provides insight into the disk vibrations on the degree of frequency separation and mode switching as a span angle of the sector-shaped plates and disk rotating speed. Design guidelines are formulated to minimize this mode crossing phenomenon and thus minimize the number of spindle disturbances present during track follow or the servotrack writing process.     

Preplanning of disk merges

A method is presented for developing Runge-Kutta integration algorithms with built-in estimates of the accumulated truncation error. Several new 2-nd, 3-rd, and 4-th order algorithms are given. The computation per step of the new algorithms is identical to that of algorithms which provide only an estimate of the local truncation error. Numerical experimentation with the new algorithms shows that the estimated error compares very well with the true accumulated error. Further, the error is of the same order as that incurred using traditional Runge-Kutta algorithms.     

Reducing disk I/O times using anticipatory movements of the disk head

Finding a good rest position for the disk head is very important for the performance of a hard disk. It has been shown in the past that rest positions obtained through anticipatory movements of the disk head can indeed improve response time, but practical algorithms have not been described yet. In this paper we describe a software technique for perfoming anticipatory movements of the disk head. In particular, we show that by partitioning the disk controller memory into a part used for caching and a part used for predictive movements, lower I/O times as compared with the usual read-ahead cache configurations are obtained. Through trace-driven simulations we show in fact that significant improvements in the disk I/O times can be obtained as compared to standard disk caching. Since the technique should be realized at the firmware level in the disk controller and no hardware modifications are needed, the implementation cost is low.     

Effect of thermal pole tip protrusion and disk roughness on slider disk contacts

Ultra-high areal density for hard disk drives requires a stable head disk interface at a flying height lower than 8 nm. At such a low flying height, small flying height variations may cause slider/disk contacts. Slider/disk contacts can also occur when a write-current is applied to the write coil since the flying height between slider and disk can be affected by the thermal expansion of the pole tip. In this paper, we investigate the vibration characteristics of sliders during thermally induced contacts using laser Doppler vibrometry. We perform a parametric study of contact events using disks with different surface roughness and lubricant thicknesses, and analyze the slider motion statistically. For a given write current, we observe that the slider vibrations increase with disk roughness and lubricant thickness.     

Effect of disk rotational speed on contamination particles generated in a hard disk drive

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. Condensation nucleus counter (CNC) 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.This research was supported by CISD (Center for Information and Storage Device; Grant No. R11-1997-042-12001-0) and KOSEF (Korea Science and Engineering Foundation; Grant No. R01-2003-000-10142-0).