从Doremi到SeaChange--南京电视台硬盘播出系统应用谈

本从硬盘播出系统的应用出发，介绍了南京电视台先后使用的两代硬盘播出系统的构成和技术特点，总结了我们对硬盘播出系统的应用体会。     

互动点播频道的计算机管理

论述作为互动点播频道基础的计算机网络的配置和管理,对互动频道节目播出网络中的计算机硬盘、网卡以及节目的自动播出以及与微软SQL SERVER数据库的编程连接与控制做了详细的描述.     

RAID系统的设计与实现

容错盘阵列通过采用多盘并发操作和冗余技术，可显著改善Ｉ／Ｏ系统的数据传输率和可靠性。在本文中，我们描述了一个高性能ＲＡＩＤ系统的设计与实现。该ＲＡＩＤ系统基于标准接口（ＥＩＳＡ，总线和ＳＣＳＩ总线）和高效纠错码（Ｒｅｅｄ－Ｓｏｌｏｍｏｎ码），具有高性能、高可靠性和通用性强的特点。本文重点是所设计的ＲＡＩＤ控制器的逻辑结构、设计方法、以及ＲＡＩＤ系统的软件构成、性能评价。最后我们提出了进一步改进设计的努力方向。     

Performance Comparison of Mirrored Disk Scheduling Methods with a Shared Non-Volatile Cache

Mirrored disks or RAID1 is a popular disk array paradigm, which in addition to fault-tolerance, doubles the data access bandwidth. This is important in view of rapidly increasing disk capacities and the slow improvement in disk access time. Caching of dirty data blocks in a non-volatile storage (NVS) cache allows the destaging of dirty blocks to be deferrable, so as to improve the response time of read requests by giving them a higher priority than write requests. Destaging of dirty blocks in batches to take advantage of disk geometry entails in lowered disk utilization due to writes and improved performance for reads. Polyzois et al. [12] propose a scheduling policy for mirrored disks equipped with an NVS cache, so that one disk processes read requests, while the other disk is processing a write batch according to the CSCAN policy. We propose an improved scheduling policy as follows: (i) eliminating the forced idleness caused by the batch processing paradigm for write requests, i.e., allowing write requests to be processed individually; (ii) using SATF or even an exhaustive search, to reduce destaging time compared to CSCAN; (iii) introducing a threshold for the number of read requests, which when exceeded defers the destaging of dirty blocks. We compare these two scheduling policies with each other and also against prioritizing the processing of reads versus writes: (i) the head-of-the-line (HOL) priority queueing discipline, (ii) SATF with conditional priorities. It follows from simulation results that the new method outperforms Polyzois' method, which is even outperformed by the HOL priority policy. SATF with conditional priorities slightly outperforms the proposed method from the viewpoint of its throughput and response time, but is susceptible to more variability in response time. Recommended by: Ahmed Elmagarmid     

虚拟存储技术的研究及其应用

详细介绍了虚拟存储技术的概念及特点,并对基于服务器端的虚拟存储、存储子系统端的虚拟存储、网络设备端实施虚拟存储以及它们在网络系统中的应用进行了分析和总结。     

一种用于图像检索的新型空间关系特征

为了提高对二维图像中空间关系的描述能力,提出了一种新的空间关系量化特征IBS-SC（Interaction Bisector Surface-Shape Context）。以IBS为基础,采用形状上下文描述子SC对IBS与空间关系中的主体区域之间的分布进行描述,将区域与区域之间的交互分布转换为一个点直方图的集合,再使用SC对这些点直方图进行二次统计,得到最终归一化的空间关系特征IBS-SC。为了验证IBS-SC特征的性能,实现了一个图像检索的原型系统,通过对检索结果的对比分析与评价,证明了IBS-SC特征对于空间关系具有良好的表征能力。     

逆码：一种可容3错的低密度MDS横式阵列码方法

磁盘阵列存储可采用阵列码技术提高系统的容错能力。随着对阵列存储系统的深入认识,阵列码的更新效率也逐步成为一项重要的性能指标。针对当前可容3错横式阵列码更新效率低的问题,提出了一种具有低密度特性的横式阵列码构造方法,称为逆码。不同于传统阵列码是利用特殊几何方法确定编码过程,逆码是从生成矩阵角度出发,通过构造编码分布矩阵确定编码过程。首先,基于域GF(2^w)给出了一种具有超正规性质但只有3行元素的矩阵结构,称为逆结构矩阵;然后,利用w×w大小的比特方阵表示域GF(2^w)中元素;最后,通过提出的优化算法得到具有低密度性质的编码分布矩阵,进而确定逆码的编码过程。理论分析表明：逆码满足最大距离可分性质,可取得最优的存储效率;与STAR码、RTP码等容3错的阵列码相比,逆码的参数取值范围将不受素数的限制,参数设置更加连续。实验分析表明：相比于同样从生成矩阵确定编码过程的CRS码,逆码的稀疏度、更新效率以及编译码效率均有明显优势;相比于STAR码、RTP码,逆码的更新效率平均可提高20 %;为了提高逆码的译码效率,文中也尝试了不同的异或序列技术。     

Rabb et: Using Layout-Aware Backup for RAID Reconstruction

Once a disk of storage system is failed, RAID mechanism will reconstruct to keep the reliability. The reconstruction leads to a sharp deterioration in I/O performance of RAID, and the storage system cannot pro-vide high performance service for the applications. The Multi-TB disk capacity and high load of the application make the reconstruction last for a very long time. This paper proposes Rabbet, a method accelerating RAID re-construction using data of backup. Rabbet includes a new RAID reconstruction frame, a RAID layout-aware map-ping mechanism for backup, and a reconstruction algo-rithm. The result of experiments shows that, comparing to the classic DOR methods Rabbet shortens the RAID5 reconstruction process to 13.9%–42.8% and decreases the average response time for applications during reconstruc-tion by 3.2%–14.6%. Rabbet also improves the reliability of storage systems.     

浅析服务器结构体系及技术

本文从服务器的性能、可靠性、可管理性、存储方式及吞吐能力等方面出发,分析了与之相关的一些技术。针对服务器结构体系的发展,尤其是新一代总线结构、共享内存和集群等技术的提出及应用,作了必要的探讨。     

存储区域网中磁盘阵列光纤通道接口的设计与实现

光纤通道具有高带宽、低延迟、适宜远距离传输等特点,已用于构造高性能、高可用性的存储区域网,而光纤通道磁盘阵列是构成存储区域网的基本存储单元之一。本文介绍了一种光纤通道磁盘阵列FC-RAID3000的设计与实现,为海量数据快速,高可靠存储提供了一种可行的解 决方案。