面向大数据应用的大容量全息光存储技术研究进展

随着信息时代全球数据量爆发式增长，需要存储的数据量与日俱增。面对大数据存储的挑战，全息光存储技术将信息以数据页的形式并行记录在体全息介质中，可以实现大容量数据的存储与高速读写，具有独特优势。本文从全息存储的原理和关键技术入手，详细介绍了面向商业化应用的全息光存储系统和全息光存储介质的研究现状，探讨了实现大容量和长寿命数据存储的技术途径。     

蓝光存储——信息化的核心技术

信息化的核心是数字化,数字化的基础是存储。蓝光存储是目前容量最大、最安全、成本最低的存储技术。本文通过蓝光与红光之间的技术比较、蓝光技术具体应用,介绍了蓝光光盘技术及其发展概况,回顾了中国前三代光存储技术产业的发展历程,分析了中国企业冲击第四代、第五代光存储技术的条件和实力。     

CD-RW刻录机的原理使用维护

随着数据库和多媒体技术的发展,越来越多的数据需要进行移动存储和交换。目前,大容量移动存储设备可分为三类：大容量软盘（Zip及LS-120）、移动硬盘(Jaz)和光存储设备（包括MO、PD、DVD-RAM及CD-R/RW等）。从容量、兼容性、存取速度及可靠性等综合指标来看,CD-RW（Compact Disc-ReWritable）刻录机占有明显优势。这种刻录机不但兼容CD-ROM驱动器和CD-R刻录机的功能,同时又可以对特殊的CD-RW盘片重写上千次,克服了普通光盘不能反复存取的缺点。尽管CD-RW刻录机的出现只有几年时间,但它很可能会取代CD-ROM和CD-R…     

采用不同中间夹层的双记录层磁光光盘热光特性比较

磁光存储技术是一种颇受关注的下一代光存储技术.为提高单个磁光光盘的存储容量,途径之一是采用多值存储、多波长读出技术,实现所谓三维磁光存储.通常使用不同波长的蓝光来实现信号的读写操作.如果不同波长的激光在磁光存储多层膜中产生热场分布的差异较大,将有利于提高读出信号的信噪比.本文结合光学矩阵法及有限元方法分析了中间夹层分别为SiN、GaP时,磁光存储多层膜的热光特性.结果表明在蓝光波段,用GaP层替代传统的SiN中间夹层,将使磁光光盘具有更好的热光特性.     

模块化蓝光光存储性能静态测试系统

蓝光光存储是信息存储领域发展的一个重要方向。测试系统是研究蓝光光存储材料的必备条件，为建立蓝光光存储研究平台，设计和搭建了一套模块化蓝光光存储性能静态测试系统。激光工作波长为406．7nm。系统采用调制解调技术降低系统噪声，提高测量粘度：采用光点移动模式降低对样品尺寸的要求；采用纳米平台提高记录点的反复定位性能。实验结果证明测试系统性能良好，可以满足蓝光光存储性能静态测试要求。     

高密度蓝光存储的写策略

蓝光存储技术被认为是第三代光存储的主流技术．在蓝光存储技术中,由于数据传输速度的提高,特别是在高倍速蓝光光盘中记录数据,需要光盘和刻录机之间非常精密的配合,因此对写策略提出了更高的要求．介绍了用于蓝光存储的写策略的研究现状,并对其发展前景进行了展望．     

国际要闻

TDK推出200G蓝光存储光盘据EETimes网站报道:日本TDK近期研发成功了存储能力达到200G的单面可记录蓝光光盘,超过现有存储能力达到25G的单层蓝光光盘和50G的双层光盘。公司表示,200G的存储能力是TDK现有100G蓝光原型产品的2倍,可以存储大约18h的高精度视频。TDK走在了蓝光光盘媒体研发的最前沿,已于4月份开始交货25G可重复读写光盘。公司的100G光盘采用了四层25G存储层以达到其存储能力。对于200G光盘,TDK采用了蓝光光盘格式物理极限,在每层存储层上进行33.3G的数据存储,同时还要满足蓝光特征还原的最小容差。据Dow Corning Cor…     

超高密度数字光存储新技术的研究进展

信息技术的发展要求存储器件必须具备超高存储密度、超快存取速率以及长的存储寿命，而传统的数字光存储的存储密度已经接近其物理极限。因此探索新的存储理论、技术和材料，已成为目前数字光存储领域的急迫任务。简要综述了超高密度数字光存储新技术，介绍了近年来该领域研究的新进展。     

TDK研制出容量200GB的蓝光光盘

近日，TDK宣布开发出容量达200GB的蓝光光盘，使TDK现有100GB的存储容量增加了1倍。一张这样的蓝光光盘可以存储长达18小时的高清视频（24Mbit／s）。 最初的蓝光光盘标准容量是单层25GB，双层50GB。然而，最新的信号处理技术突破了光学介质的物理限制，实现了6层每层33．3GB的存储能力，这种200GB的蓝光光盘属于单面型。     

基于光致变色原理的多阶存储实验研究

多阶存储是一种无需减小记录波长或增大数值孔径而显著提高光存储容量的新颖方法。对光致变色材料采用不同的光能量写人，读出时则具有不同的吸收率，该特性可用来实现多阶数据存储。在研究光致变色材料曝光特性的基础上，提出了基于光致变色原理的多阶存储数学模型，该模型反映了光致变色材料吸收率与曝光量之间的非线性关系，为光致变色材料的多阶存储写策略的优化提供了理论依据。在4阶和8阶静态存储实验结果中，各信号峰值之间有明显的阶次变化，且信号之间没有交叠现象，从而验证了利用该材料进行多阶存储的可行性。将该多阶技术应用在实际光盘存储中，可实现两至三倍于普通光盘容量的高密度存储。     

磁光阵列:一种新型数据存储模式的实现

介绍了一种磁盘与光盘融合数据安全存储的新模式,简称磁光阵列或ORAID（Optical Replicated Arrays of Independent Disks）。ORAID模式包括:将数据同时存储到磁盘模块和光盘模块中;可根据数据的属性信息从磁盘模块中读取数据,在目标磁盘无法被读取时,可根据数据在光盘模块中对应的位置信息,将存储有目标数据的光盘中的数据读入预设的数据缓冲区;将存储有目标磁盘数据的光盘中的数据存储到磁盘模块中更换后的新磁盘中。该模式在使用上像基于硬盘的系统一样方便,读写性能与RAID（Redundant Arrays of Independent Disks）一样;在数据安全方面,无论前端硬盘如何损坏数据都不会丢失,并且在硬盘坏损以及重建过程中保持数据的可提供性;ORAID具有物理层面上的合规性,所存的数据不可更改（WORM,Write Once Read Only）并可在无迁移的情况下长期保存50年以上;ORAID无须额外的备份系统。磁光阵列模式同样适用于固态硬盘与光盘的融合。     

Eco-Storage: A Hybrid Storage System with Energy-Efficient Informed Prefetching

In this paper, we present an energy-aware informed prefetching technique called Eco-Storage that makes use of the application-disclosed access patterns to group the informed prefetching process in a hybrid storage system (e.g., hard disk drive and solid state disks). Since the SSDs are more energy efficient than HDDs, aggressive prefetching for the data in the HDD level enables it to have as much standby time as possible in order to save power. In the Eco-Storage system, the application can still read its on-demand I/O reading requests from the hybrid storage system while the data blocks are prefetched in groups from HDD to SSD. We show that these two steps can be handled in parallel to decreases the system’s power consumption. Our Eco-Storage technique differs from existing energy-aware prefetching schemes in two ways. First, Eco-Storage is implemented in a hybrid storage system where the SDD level is more energy efficient. Second, it can group the informed prefetching process and quickly prefetch the data from the HDD to the SSD to increase the frequent HDD standby times. This will makes the application finds most of its on-demand I/O reading requests in the SSD level. Finally, we develop a simulator to evaluate our Eco-Storage system performance. Our results show that our Eco-Storage reduces the power consumption by at least 75 % when compared with the worst case of non-Eco-Storage case using a real-world I/O trace.     

蓝光盘作为存储介质在电视台的应用

通过比较DVD刻录盘、蓝光刻录盘、专业磁带、硬盘之间的优劣,结合镇江市广播电视台的实际情况,提出用蓝光刻录盘作为硬盘存储介质的补充,在编辑制作环节将需要离线保存的素材文件刻录保存到蓝光盘上,并将相关编目和索引说明编为二维码和条形码打印至光盘上,在媒资库通过扫描刻录光盘上的二维码和条形码来建立光盘检索数据库.在播出环节提出用SONY专业蓝光盘翻录电视剧来节省成本的方案.     

Partial-response coding, maximum-likelihood decoding: capitalizing on the analogy between communication and recording - [History of communications]

Signal processing and coding technology for digital magnetic recording is the core technology of the channel electronics module in a hard disk drive (HDD) that processes signals read from magnetic media. In this historical review I focus on what is now widely known as partial-response, maximum-likelihood (PRML) technology, which takes advantage of the inherent redundancy that exists in signals read out of magnetic media; its theoretical foundation goes back to 1970, and it capitalizes on the analogy between high-speed data transmission and high-density digital recording, and that between a convolutional code and a partial-response signal. The first PRML-based product was introduced by IBM in 1990, and PRML technology soon became the industry standard for all digital magnetic recording products, ranging from computers' HDDs and tape drives to micro hard discs used in PCs, mobile phones, and MP3 players; use of the PRML principle has recently been extended to optical recording products such as CDs and DVDs. Its improved version, called NPML (noise-predictive, maximum-likelihood), and variants have been adopted by the HDD industry since 2000. Today, a large number of communication and information theory researchers are investigating use of advanced techniques such as turbo coding/decoding to further improve the density and reliability of both magnetic and optical recording systems.     

一种有效保护数据的文件系统

提出了一种可有效保护被误删除数据的新的文件系统PSFS,以一个伪循环队列为核心,充分利用了磁盘和u盘等存储设备越来越大的容量,保证在存储介质有空余空间时不覆盖被删除的文件。在此重点描述了所提文件系统的结构,通过举例分析了其工作原理及恢复数据的方法。该方法表明所提文件系统的数据恢复速度比现有其他数据恢复技术要快,且数据恢复的准确率也大大提高。     

The rewritable MiniDisc system

The MiniDisc system was designed with the obvious objective of replacing the conventional Compact Cassette tape recorder system. The MiniDisc format defines two types of optical discs. One is a recordable magneto-optical disc for user recording and another is a conventional read-only disc for music-software publishing. Audio data compression is used to achieve 74 min of playing time on a 64-mm disc. By means of a built-in buffer memory called Shock Resistant Memory, MiniDisc can be used for outdoor portable application with great ease. Furthermore, MiniDisc was evolved to MD Data system and with a data capacity of 140 Mbytes and a very compact size, the MD Data system is expected to become one of the standards for removable data storage systems     

中国电视台视频记录存储设备的发展历史和前瞻

追述中国电视台60年来视频记录存储设备发展的历史,从只是依靠电影胶片记录存储电视信号,发展到当今的标清和高清录像机、蓝光盘、高清记录存储卡、数据流磁带机、以多通道和网络化的硬盘阵列为主的视频服务器系统等等,存储媒介也从胶片和磁带,向多媒体记录方式的文件化、高清化、网络化转变.从现代科技的视角阐述了对电视台未来视频记录存储设备发展策略的思考.     

An SSD‐Based Storage System for an Interactive Media Server Using Video Frame Grouping

For real‐time interactive multimedia operations, such as video uploading, video play, fast‐forward, and fast‐rewind, solid state disk (SSD)‐based storage systems for video streaming servers are becoming more important. Random access rates in storage systems increase significantly with the number of users; it is thus difficult to simultaneously serve many users with HDD‐based storage systems, which have low random access performance. Because there is no mechanical operation in NAND flash‐based SSDs, they outperform HDDs in terms of flexible random access operation. In addition, due to the multichannel architecture of SSDs, they perform similarly to HDDs in terms of sequential access. In this paper, we propose a new SSD‐based storage system for interactive media servers. Based on the proposed method, it is possible to maximize the channel utilization of the SSD's multichannel architecture. Accordingly, we can improve the performance of SSD‐based storage systems for interactive media operations.     

大数据时代的光存储技术

概述了光存储技术的发展历史和现状，分析了在大数据时代光盘的作用和存在的意义。面对传统光盘容量低、速度慢等问题，介绍了能够妥善解决此问题的光盘库技术。最后介绍了可替代传统光盘的全息光存储技术。其中，同轴全息光存储既可与传统光盘相兼容，又可作为大数据高密度高速率长期保存的解决方案。     

基于FAT32文件系统的数据恢复技术

针对用户在FAT32文件系统下由于误操作,造成硬盘上数据被误删除等数据丢失的情况,提出如何恢复数据的方法。通过对FAT32文件系统的结构,文件的存储特点等方面的介绍,重点分析了FAT32文件系统下数据恢复的原理,并在此基础上对数据恢复的具体方法和过程进行了阐述。