电脑问与答(三)

天津河西区丁向东问:电脑的内部存储器有什么特征?兼容机内部存储器分为几种? 答:电脑的内部存储器是用集成电路制成的。内部存储器简称内存,分为只读存储器(ROM) 和随机存储器(RAM)两大类,二者在电脑中统一编址。只读存储器(ROM)占据高端地址,它通常固定在主机板上,不需另购。目前市售的主机板通常都没有焊上随机存储器(RAM),购买主机板后还需要在内存条接口上插入焊有随机存储器的内存条。     

磁心存储器自动检测机

磁心存储器自动检测机(JCJ)是由中国科学院计算所、沈阳计算所、江西抚州无线电三厂为磁心存储器联合研制的一台自动测试机。它在计算机控制下,可以自动寻找被测存储器(MUT)的工作域,确定它的最佳工作点,并对失效存储器进行故障诊断。 JCJ(见图1)可以在磁心存储器的生产、     

MCM7001型N-沟道MOS随机存储器——为微型信息处理机存储器设计提供新的可能性

1.MCM7001超高速MOS随机存储器 a.主要特点 MCM7001是1024字×1位(容量1K单元)的随机存储器(RAM),图1给出MCM 存储器所要求的主要功耗仅当芯选信号(CS)为高电平时才需要。在这一点上即使大的存储器系统中,其功耗也不会比被选的几个存储器大,实际上所选的存储器数量总和字长相适应的。因此,在大的存储器系统中就不存7001的逻辑图。其最大取数时间只有55毫微秒,它比同样规摸的其它MOS或双极型存储器(包括ECL双极型存储器)都快。与其它类型存储器相比,MOS器件的低功耗以及高速度成为其突出优点。表1给出三种不同类型1K单元存储器每位的功耗,取数时间及其乘积(速度-功耗积)。     

1A处理机的存储器系统

1A处理机存储器系统包括有呼叫/程序存储器,文件存储器和使用磁带的辅助数据系统。呼叫/程序存储器是65536个字,每个字26位的存储器系统,它使用两线、电流重合法、铁氧体磁心矩阵作为存储体,它能以1.4微秒读写周期时间工作。由于文件存储(FS)有磁盘文件存储器,使得1A 处理机成为高性能大容量的存储系统。每个FS 控制器能控制一到四个盘文件,使得最大的存储量为2.56×10~6字。两个FS 组成总合容量为5.12×10~6字的双工文件存储器。辅助数据系统(ADS)可在1A 处理机呼叫或程序存储存储器和磁带之间作为有效的传输数据的设备。磁带用于输入通用的程序,工作数据和故障定位信息,并用于输出拟定计算,通信量和误差分析数据。ADS 硬件包含有数据单元选择器(DUS)和磁带体制读数系统(TF)。     

4096个数的铁氧体磁心存储器

本文所述的磁心存储器是矩阵式的操作存储器,在 M-2计算机中用它来代替示波管操作存储器和磁鼓辅助存储器。磁心存储器的容量为4096个数,每个数有36位二进位,而其中有两位在 M-2计算机中作为备用。(示波管存储器和磁鼓存储器的容量都是512个数,每个数有34位二进位数。)存储器的,访问周期约为30微秒;其中一部份是与机器其他一些操作的时间相重合的。(示波管存储数的访问周期为37.5～50微秒,磁鼓的工作更慢。)磁心存储器用了526个电子管,此外,电源用了108个电子管。此数还没有包括存储器不用主机而单独进行检查的设备所用的电子管数;示波管存储器和磁鼓存储器需用644个电子管,此外,电源需用约150个电子管。     

惠瑞捷HSM3G高速存储器测试方案为未来三代内存提供低廉测试成本

<正>近日,惠瑞捷(Verigy)公司(纳斯达克代码:VRGY)宣布推出全新的HSM3G高速存储器测试解决方案,进一步拓展了面向DDR3世代主流存储器IC和更高级存储器件测试能力的V93000 HSM平台。V93000 HSM3G独     

超大容量存储器K9F2G08U0M及其在管道通径仪中的应用

新型超大容量Flash存储器K9F2G08U0M的基本组织结构,给出了存储器与C8051F020单片机外部存储器接口(EMIF)的硬件连接方式以及存储器的主要操作流程和部分C语言代码。     

三星用铁存信息

三星电子首次成功开发4Mb 铁介质随机存储器(FRAM),该产品结合了动态随机存取存储器(DRAM)、静态随机存取存储器(SRAM)和快闪存储器的技术优势,并首次应用1T/1C 及 COB 技术,使该产品较同类产品的体积减少一半。FRAM 一直是业界公认的半导体存储器领域性能最好的器件,它便于设计,可应用于传统上采用 DRAM 的数据存储应用领域,同时具有 SRAM 的     

FPGA块存储器的多位翻转容错设计

在高可靠性航空航天、航空电子设备和军用应用中,辐射引发的多比特翻转(MBU)成为FPGA存储器的一个主要的可靠性问题;传统的单比特错误纠正(SEC)和双比特错误检测(DED)无法对FPGA存储器发生的MBU故障提供防护,引发存储器的存储故障;为了减少MBU造成的影响,设计了RM(2,5)编码防护系统对FPGA块存储器进行容错防护,实现了单个码字小于4位的翻转错误的纠正;对RM编码系统进行了三模冗余设计,解决了RM码不具备抗辐射的缺陷;设计的RM(2,5)编译码模块在Xilinx Virtex-5 FPGA中实现,编码模块频率以225.284 MHz运行,占用LUT资源1.33％;通过理论分析和硬件实验表明,该错误检测与纠正(EDAC)系统能够纠正4位以下的翻转,提高FPGA存储器的可靠性.     

64K MOS动态随机存储器

MOS随机存储器(RAM)通常用来做数据处理系统的主存储器。人们不断地改进它,增加存储器的位密度,缩短读出时间以及降低功耗。目前16K MOS RAM已有商品。由于尺寸和功耗方面的限制,制造64K MOS随机存储器(RAM)还存在一些困难。本文提出了一     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。