基于BMC的服务器可信启动方法研究

可信计算技术以硬件安全为基础,通过信任链、远程证明等技术能够有效实现本地和远程计算系统的安全,在系统安全启动、度量证明等方面得到了广泛应用.当前,终端设备的安全启动技术已经比较成熟,但是对服务器可信启动技术的研究仍然较少.针对服务器BIOS固件、操作系统内核镜像可能被篡改,服务器启动过程中由于信任链过长而导致信任丢失、...     

自定义镜像为下载提速

FlashGet的镜像功能可以从不同的服务器上下载同一个文件,并可根据服务器的响应速度自动选择较快的服务器。但是镜像功能默认使用的镜像服务器地址都是由安装目录的"mirrors.lst"文件控制,其中的镜像服务器地址都是固定的,限制了使用。在1.8版本中,FlashGet允许自行添加新的镜像服务器地址,只要按一定的格式编辑安装目录中的"mymirror.lst"文件即可。     

高性能光盘镜像服务器的研究与实现

随着网络上光盘资源的增长，光盘镜像服务器成为光盘网络接享的重要技术。针对传统光盘镜像服务器的缺点，文章实现了一个新的基于iSCSI协议思想的高性能光盘镜像服务器，详细介绍了这种光盘镜像服务器的设计方案，并进行了相应的试验测试和性能分析。     

Linux下高效可靠的应用同步升级技术

为了能够向用户提供既可靠又高效的系统及软件更新方法,我们设计了以镜像源管理服务器为主的软件更新方案。本文详细介绍了镜像源管理服务器技术的设计方案,并对技术方案进行了理论分析,对技术方案的验证方法和验证结论做了详细的分析和说明。镜像源管理服务器技术在实现中,相较于当前Linux通用的镜像源更新方案,能够避免单一镜像源更新不够及时的问题、源服务器网络负载过高问题,为用户提供稳定且快速的资源下载。     

三方面顾安全

北京市公安局出入境管理处的办公自动化网络建于1998年,在局域网络中的服务器主要包括:数据库服务器,内部 Web 服务器,外部 Web 服务器及 E-mail 服务器、财务软件服务器等,其中数据库服务器为 Compaq公司生产的 Alpha Server4100,安装 Compaq Unix 操作系统,Oracle 数据库,完成全部涉外系统数据的存储。信息中心在系统建设初期曾采取了许多防范措施,例如,利用数据库服务器 Alpha Server 4000的软件镜像技术,实现硬盘的镜像,保护数据。但是,这种技术存在着很多的局限性,包括:服务器可扩充磁盘数量有限,镜像技术使系统消耗一半数量的磁盘用于备份。镜像技术不能将操作系统备份,这样一旦系统故障,将导致业务终断,必须耗费一定的时延恢复系统。镜像技术     

光盘镜像服务器的Cache技术研究与实现

本文提出了一种基于光盘镜像服务器系统的两级Cache结构，即在客户端建立一个小的Cache，通过预取机制增大一次请求的规模；同时，在服务器端设计一个大的Cache，加快数据请求的响应速度。实验证明，两级Cache结构大大提高了光盘镜像服务器系统的数据传输率。     

光盘共享设备如何选之应用篇

清华同方徐学雷博士: 用户选择光盘镜像服务器时主要应从容量、速度和价格三方面考虑。光盘镜像服务器的容量主要取决于内置的硬盘数量和大小。有些厂家的光盘镜像服务器在厂岀时已经预置了一定容量的硬盘,如果用户需要扩容,可将光盘镜像服务器上的可插拔硬盘盒抽岀,自行安裝硬盘进行扩容。     

虚拟镜像光盘网络服务器的设计与实现

提出并实现了一种具有较高性能价格比的、基于PC的虚拟镜像光盘网络服务器方案。该虚拟光盘网络服务器具有如下优点：支持多种格式盘片的镜像读取；支持多种网络协议；虚拟光盘镜像服务器在功能上完全独立于网络上的主服务器；价格低廉，无须特殊硬件等。初步实验验证了该方案的可行性。由于该方案具有很好的应用前景，正准备将其推向市场。     

丸子在线

问:现在很多网站都说自己有镜像站点.请问何为镜像? 　　答:镜像在网络中主要是对于网站来说的,与主网站的内容相同的其它位置的网站就叫做镜像网站.比如,我有一个主网站放在A服务器,同时我也把此网站内容复制到另一个B服务器,但两者的网址与域名不同,那么B服务器里的网站就叫做A服务器的主网站的镜像.……     

NOVELL网文件服务器的快速复制方法

MethodofRapidlyDuplicatingNovellFileServerLiLupunNOVELL网络以其安全性好、硬件投资少、易于管理维护等特点，在全世界拥有极高的占有率。目前，我国多数院校将其作为公用机房管理的首选系统。我们知道，安装NOVELL文件服务器、安装应用软件、建立用户帐号等工作至少要花费系统管理员数小时的工作。由此看来，有必要找到一种快速安装文件服务器的方法。一些国内计算机杂志曾介绍使用文件服务器卷镜像的方法来复制文件服务器。这种方法虽简单可行，但仍存在一定的局限性：其一：镜像磁盘与被镜像磁盘的卷大小必须相等；其二：镜…     

High aspect ratio micro tool manufacturing for polymer replication using μEDM of silicon, selective etching and electroforming

Mass fabrication of polymer micro components with high aspect ratio micro-structures requires high performance micro tools allowing the use of low cost replication processes such as micro injection moulding. In this regard an innovative process chain, based on a combination of micro electrical discharge machining (μEDM) of a silicon substrate, electroforming and selective etching was used for the manufacturing of a micro tool. The micro tool was employed for polymer replication by means of the injection moulding process.     

基于单向散列链的定点布设无线传感器网络密钥分配方案

针对有重部署需求的定点布设无线传感器网络,提出基于单向散列链、支持身份认证的密钥分配方案。方案采用密钥链分段激活方式,可以有效抵制节点俘获攻击造成的安全威胁,安全性能好;支持节点重部署,从而可以保障有良好的网络覆盖率。     

Microfluidic chip designs process optimization and dimensional quality control

The challenge of fabricating geometries with critical dimensions ranging from few microns down to 10 nm with high production rate is delaying the development of nanotechnology based products. Diverse research works have shown the capability of technologies such as UV lithography, nano imprint lithography and e-beam lithography to produce micro and nano features. However, their application for tooling purposes is relatively new and the potential to produce nanometer features with high volume and low cost is enormous. Considering possible implementation in a mass production environment the precision of measuring results and the accuracy of measurement relocation are very relevant. In this paper, the capability of producing with high volume Lab-on-chip devices through injection molding is evaluated. Preparation of master geometries was made in a Si wafer using e-beam lithography and reactive ion etching. Subsequent nickel electroplating was employed to replicate the obtained geometries on the tool, which was used to mold on transparent polymer substrates the functional structures. To assess the critical factors affecting the replication quality throughout the different steps of the proposed process chain, test geometries were designed and produced on the side of the functional features. The so-called “Finger Print” of the lithography and molding processes was qualitatively and quantitatively evaluated through scanning electron microscopy and atomic force microscopy respectively. The entire process chain is therefore characterized and the degree of replication among the different replication steps quantified with precise measurements using a high accuracy relocation technique on the produced key test geometries. Influence of injection molding process parameters, feature dimensions and orientation relative to the polymer flow direction have been assessed in respect of the replication fidelity of the produced micro/sub-μm channels. Finally the paper addresses product compliance with specifications, focusing on tolerances of vertical dimensions using a metrological approach: sub-μm features on silicon, nickel stampers and injection molded substrates are measured. Results of measurement uncertainty calculation, quantitative replication fidelity assessment, and dimensional tolerances at the nanometer scale verification are reported.     

Diversity and fault avoidance for dependable replication systems

In the hot-standby replication system, the system cannot process its tasks anymore when all replicated nodes have failed. Thus, the remaining living nodes should be well-protected against failure when parts of replicated nodes have failed. Design faults and system-specific weaknesses may cause chain reactions of common faults on identical replicated nodes in replication systems. These can be alleviated by replicating diverse hardware and software. Going one-step forward, failures on the remaining nodes can be suppressed by predicting and preventing the same fault when it has occurred on a replicated node. In this paper, we propose a fault avoidance scheme which increases system dependability by avoiding common faults on remaining nodes when parts of nodes fail, and analyze the system dependability.     

RACMan: Replication-aware cache management for manycore CMPs with private LLCs

The last level cache (LLC) in private configurations offer lower latency and isolation but extinguishes the possibility of sharing underutilized cache resources. Cooperative Caching (CC) provides capacity sharing by spilling a line evicted from one cache to another. However, CC proposals did not pay enough attention to the natural problem of private LLC, replication. The static policies either indulging the replicated blocks (replicas) in or excluding them out of LLC invariably are deficient for the complex cache capacity situations in manycore environment. In this paper, we present replication-aware cache management (RACMan) to optimize replication for private configurations. RACMan relies on a novel coarse-grained low-overheard mechanism PBFP that monitors and predicts the replica reusability to dynamically adjust LLC insertion policies giving replicas different positions of LRU chain and chances of survival in LLC according to the prediction. Experiment results show our proposal is competent to optimize replication by performing better than two baseline systems in the respects of L2 Hit Rate, Network Traffics, IPC, and Dynamic Energy. RACMan fulfils the requirements of manycore CMPs with private LLC for increasing system performance, area efficiency, and scalability.     

基于NTC热敏电阻器的实时PCR仪数据采集器设计

实时聚合酶链反应(PCR)是一种通过热循环与荧光信号检测方法实现特定DNA片段的快速复制与定量检测的技术.PCR反应过程中,热循环温度控制精度决定了PCR反应效率,从而直接影响定量检测的精度.根据非稳态传热原理,热量从基座传递到试液需要一定的时间,为了检测这一延迟时间对温控的影响,基于NTC热敏电阻器,采用USB总线和...     

基于MMTD的复制策略研究及算法设计

主动复制和被动复制各有优缺点。分析主动复制和被动复制的过程,得出两者在响应进程的副本数目、处理时间上存在对立性。引入处理模糊信息的中介数学系统,将主动复制和被动复制视为一对反对对立面。提出副本协调时间、副本更新时间和副本恢复时间的概念。在此基础上应用中介真值程度的数值化度量MMTD(Measure of Medium Truth Degree)设计出了一种新的复制算法,新算法结合了主动复制和被动复制的优点,更具有实用性和有效性。     

基于超市模型的文件复制策略*

为了有效地对文件复制进行管理,在资源网格中引入了超市模型,提出了基于超市模型的文件复制管理策略,利用超市模型与叠层复制相结合的方法来复制文件的副本,使文件复制过程中既有推力也有拉力,提高了整体系统效率。     

基于半被动复制技术的业务连续性模型

个基于制节点能成为组通信中的主动复制技术和被动复制技术在实现能容错和容灾的分布式系统时,都具有很大的局限性。本文提出了一半被动复制技术的业务连续性模型,半被动复制技术吸取了上面两种复制技术各自的优点,在被动复制的基础上,每个复都可以作为主节点向外提供服务,这种实现不仅保证了各个复制节点上数据的一致性,也避免了被动复制技术中主节点可瓶颈的问题。此外,两阶段提交代理的引入使该模型具有更高的通用性。     

分布式数据库系统中数据一致性维护方法

讨论了在分布式数据系统中，对于各个数据库副本维护数据一致性的问题，介绍了Oracle8i数据库系统中数据复制的基本概念，基本原理，复制配置以及数据复制的基本配置和实现方法。