当前位置：文档库 › 专业英语第四章

专业英语第四章

Chapter 4 The Evolution of Management Thought

[本章学时]：2学时

[本章内容概要]：4.1 Classical management perspective

4.2 Behavioral Management Perspective

4.3 Quantitative Management Perspective

[本章教学目的与要求]： describe the background of managerial theory; know something about of Taylor; define scientific management and administrative management; discuss the open system and closed system; master the contingency approach.

[本章重点与难点]：the definition of scientific management, contingency approach; background of management theory.

4.1 Classical management perspective

1 Precursors of Management Theory

The practice of management can be traced back thousands of years, such as pyramids in Egypt, the Great Wall in China, and floating warship assembly lines in Venice.

Adam Smith—“The Wealth of Nations” advocated the division of

labor to increase the productivity of workers.

Industrial Revolution—large organizations were created in need of

management and machine power was substituted for human labor.

2 The definition

(1) Scientific Management

Scientific management concerned with improving the performance of individual workers and grew out of the industrial revaluation’s labor shortage at the beginning of the twentieth century.

(2) Administration Management

Administrative management theory focuses on managing the total organization.

3 Fredrick Winslow Taylor

Fredrick Winslow Taylor who published principle of scientific management in 1911,and was considered the father of scientific management, who replaced old rule-of-thumb methods of how to do work with scientifically-based work methods.

4 Important views

How do today’s managers use scientific management? They use time

and motion studies to increase productivity. Hire the best qualified

employees, and design incentive systems based on output.

Administrative management theory focus on managing the whole

organization rather than individuals.

4.2 Behavioral Management Perspective

1 what is behavioral management

Behavioral management theory emphasized individual attitudes and behaviors, group processes, and recognized the importance of behavioral processes in the workplace. It was stimulated by a number of writers and theoretical movement.

2 Organizational behaviors

Organizational behavior is the study of the actions of people at work, and people are most important asset of an organization. It is a contemporary field,

which draws on psychology, sociology, anthropology, economics, and medicine, focus on behavioral perspectives on management.

4.3 Quantitative Management Perspective

1 Quantitative Management

Quantitative management, also called operations research or management science, focus on improving managerial decision making by applying statistics, optimization models, information models, and computer stimulations.

2 Operations Management

Operation management is the practical application of management science to efficiently manage the production and distribution of products and services.

3 Systems Perspective

A system is an interrelated and interdependent set of elements functioning as a whole.

There are two basic types of systems

Open systems are organizations that dynamically interacts with their

external environment by taking in inputs and transforming them into

outputs that are distributed into their environment.

Closed system are organizations that are not influenced by and do

not interact their environment (all system input and output in

internal).

4 Synergy and Entropy

(1) Synergy is the notion that the whole system (subsystem working together

as one system) is more productive and efficient than the sum of its parts.

(2) Entropy is a normal process in which an organizational system declines due to failing to adjust to change in its environment.

5 The Contingency Perspective

The contingency perspective, sometimes called the situational approach, is the appropriate managerial behavior for managing an organization which depends on the current situation in the organization.

It suggests that each organization be unique, organizations be individually different, face different situations (contingency variables), and require different ways of managing. There is no one universally applicable set of management principles by which to manage organizations.

本章小结

Scientific management concerned with improving the performance of individual workers and grew out of the industrial revaluation’s labor shortage at the beginning of the twentieth century.

Administrative management theory focuses on managing the total organization.

Operation management is the practical application of management science to efficiently manage the production and distribution of products and services.

Systems Approach called a system is an interrelated and interdependent set of elements functioning as a whole.

The contingency perspective, sometimes called the situational approach, is the appropriate

managerial behavior for managing an organization which depends on the current situation in the organization.

复习思考题

a. Can you set examples of early examples of management?

b. What’s the historical background of management theories?

c. What are the open system and closed system?

d. What is the situational approach?

计算机专业英语第3章在线测试

A B C D The data, when they are not encrypted, are called A B C D A virus is a A B C D Many viruses go resident in the memory like a ( ). A B C D Now, about ( ) different viruses account for all the viruses that actually spread in t A B C D

C、attack phase D、creaｔe phase 2、( ) maybe a certain cause that some viruses infect upon. A、a day B、a time C、an external event on your PC D、a counter within the virus 3、Many viruses do harmful things such as ( ). A、deleting files B、simulating typos C、slowing your PC down D、changing random data on your disk 4、If a virus simply reproduce and have no cause for an attack phase, but it will still ( ) without your permission. A、stealing storage B、pilfer CPU cycles C、del＿ete files D、play music 5、Some viruses, with no attack phase, often damage the programs or disks they infect bec ause they ( ). A、have bugs in them B、contain poor quality code C、steal storage D、show messages on your screen 第三题、判断题（每题1分，5道题共5分）

计算机专业英语第四章译文

第四单元课文A：计算机程序一、引言计算机程序是指导计算机执行某个功能或功能组合的一套指令。要使指令得到执行，计算机必须执行程序，也就是说，计算机要读取程序，然后按准确的顺序实施程序中编码的步骤，直至程序结束。一个程序可多次执行，而且每次用户输给计算机的选项和数据不同，就有可能得到不同的结果。程序可分为两大类：应用程序和操作系统。应用程序直接为用户执行某项功能，如字处理或玩游戏。操作系统管理计算机和与之相连的各种资源和设备，如随机访问存储器、硬盘驱动器、监视器、键盘、打印机和调制解调器，以便使其他程序可以使用它们。操作系统的例子包括：DOS、Windows 95、OS/2和UNIX。二、程序开发软件设计者通过特殊的应用程序来开发新程序，这些应用程序常被称作实用程序或开发程序。程序员使用称作文本编辑器的另一种程序，来以称作编程语言的特殊标记编写新程序。使用文本编辑器，程序员创建一个文本文件，这个文本文件是一个有序指令表，也称为程序源文件。构成程序源文件的单个指令被称为源代码。在这个时候，一种特殊的应用程序将源代码翻译成机器语言或目标代码——操作系统将认作真程序并能够执行的一种格式。将源代码翻译成目标代码的应用程序有3种：编译器、解释器和汇编程序。这3种应用程序在不同类型的编程语言上执行不同的操作，但是它们都起到将编程语言翻译成机器语言的相同目的。编译器将使用FORTRAN、C和Pascal等高级编程语言编写的文本文件一次性从源代码翻译成目标代码。这不同于BASIC等解释执行的语言所采取的方式，在解释执行的语言中程序是随着每条指令的执行而逐个语句地翻译成目标代码的。解释执行的语言的优点是，它们可以立即开始执行程序，而不需要等到所有的源代码都得到编译。对程序的更改也可以相当快地作出，而无需等到重新编译整个程序。解释执行的语言的缺点是，它们执行起来慢，因为每次运行程序，都必须对整个程序一次一条指令地翻译。另一方面，编译执行的语言只编译一次，因此计算机执行起来要比解释执行的语言快得多。由于这个原因，编译执行的语言更常使用，而且在专业和科学领域几乎总是得到采用。另一种翻译器是汇编程序，它被用于以汇编语言编写的程序或程序组成部分。汇编语言也是一种编程语言，但它比其他类型的高级语言更接近于机器语言。在汇编语言中，一条语句通常可以翻译成机器语言的一条指令。今天，汇编语言很少用来编写整个程序，而是最经常地采用于程序员需要直接控制计算机某个方面功能的场合。程序经常被编写作一套较小的程序段，每段代表整个应用程序的某个方面。各段独立编译之后，一种被称为连接程序的程序将所有编译好的程序段组合成一个可以执行的完整程

自动化专业英语常用词汇

自动化专业英语常用词汇 acceleration transducer 加速度传感器 accumulated error 累积误差 AC-DC-AC frequency converter交-直-交变频器 AC (alternating current) electric drive 交流电子传动 active attitude stabilization 主动姿态稳定 adjoint operator 伴随算子 admissible error 容许误差 amplifying element 放大环节 analog-digital conversion 模数转换 operational amplifiers运算放大器 aperiodic decomposition 非周期分解 approximate reasoning 近似推理 a priori estimate 先验估计 articulated robot 关节型机器人 asymptotic stability 渐进稳定性 attained pose drift 实际位姿漂移 attitude acquisition 姿态捕获 AOCS (attitude and orbit control system) 姿态轨道控制系统attitude angular velocity 姿态角速度 attitude disturbance 姿态扰动 automatic manual station 自动-手动操作器 automaton 自动机 base coordinate system 基座坐标系 bellows pressure gauge 波纹管压力表 gauge测量仪器

物流专业英语课后习题答案

Exercises 1 Part I I Vocabulary exercises 1. B 2. C 3. D 4.B 5. D 6. B 7. A 8. C 9. C 10. B II Fill in the blanks with words or phrases from the list below: 1.“Logistics” is a term, which originates from both the army and French. According to the French, the Baron of Jomini, who of Swiss origin who had served in Napoleon?s army before joining the Russians and who later founded the Military Academy of St. Petersburg, first used the term in the early 19th century. So in a military sense, the term …logistics? encompasses transport organization, army replenishments and material maintenance. 2.Logistics deals with satisfying the customer. This implies that management must first understand what those requirements are before a logistics strategy can be developed and implemented to meet them. As will be discussed in more detail later, customer service is the most important output of an organization?s logistics system. This focus on customer satisfaction will be emphasized through the text just as it should be in the firm. Part II I Vocabulary exercises 1. B 2. D 3. A 4.C 5. D 6.D 7.A 8.A 9.C 10. A II Fill in the blanks with words or phrases from the list below: 1.Transportation refers to the physical movement of goods from a point of origin to a point of consumption and can involve raw materials being brought into the production process and/or finished goods being shipped out to the customer. 2.Since these inputs can have a direct impact on both the cost and quality of the final product/service offered to the consumer, this activity is vital to the overall success of the logistics effort. In addition, the move away from local sourcing in favor of global buying has complicated this entire process dramatically in recent years. Part III

济南大学计算机专业英语第一章答案

Homework of Chapter One 1. Chapter 1 Multiple Choice Select the best answer for each question below. When you are finished, check your answers by clicking the 'Check Answers' button at the bottom of the page. 1. People, procedures, software, hardware, and data are the five parts of a(n) competency system computer system information system software system 2. Procedures are typically documented in manuals written by computer specialists end users Microsoft service providers 3. Which of the following is an example of connectivity data hard disk

Internet power cord 4. Windows 7 is an example of a(n) application software browser operating system shareware 5. The most powerful type of computer. mainframe computers microcomputers minicomputers supercomputers 6. The system component that controls and manipulates data in order to produce information is called the keyboard microprocessor monitor mouse

计算机专业英语教程(第四版)习题答案解析

计算机专业英语（第四版）课后习题答案 Unit 1 [Ex 1] 1. F 2. T 3. T 4. F 5. T 6. T 7. T 8. T 9. T 10. F [Ex 2] 1. input, storage, processing, and output 2. power; speed; memory 3. central processing unit 4. internal; primary; memory 5. keyboard; central processing unit; main memory; monitor [Ex 3] A. 1. F 2. D 3. G 4. C 5. B 6. A 7. E 8. H B. 1. user 2. monitor 3. data 4. keyboard 5. data processing 6. information 7. computer 8. memory [Ex 4] 1. input device 2. screen, screen 3. manipulates 4. instructions 5. retrieve 6. code 7. hard copy 8. Function [Ex. 5] 新处理器开始IT技术的新时代 New Processors Open New Era of IT Technologies Last week, Intel introduced to the public in Russia and other CIS countries a family of processors Intel Xeon E5-2600. They are more powerful and reliable and, importantly, are very economical in terms of energy consumption. Their presence opens a new era in the field of IT technologies and means that the cloud technology is getting closer. These processors are primarily designed for servers, data centers (DPC) and supercomputers. The emergence of this class of devices is not accidental. According to the regional director of Intel in Russia and other CIS states Dmitri Konash who spoke at the event, the market of IT-technology is developing so rapidly that, according to forecasts, by 2015 there will be 15 billion devices connected to the Internet, and over 3 billion of active users. 上周，英特尔公司向俄罗斯和其它独联体国家的公众推出了英特尔Xeon E5-2600系列处理器，它们更加强大可靠，尤其是在能量消耗方面更加经济实惠。它们的问世意味着IT技术领域开始了一个新时代，标志着云技术距离我们越来越近。这些处理器主要是为服务器、数字处理中心和超级计算机设计的。这种处理器的出现并非偶然。根据英特尔公司俄罗斯和其他独联体地区负责人Dmitri Konash就此事发表的看法，IT技术市场的发展速度极快，根据预测，到2015年与英特网连接的设施将有150亿，用户超过30亿。 [Ex 6] 1. T 2. T 3. F 4. F 5. T 6. F 7. T 8. F Unit 2 [Ex 1] 1. T 2. F 3. T 4. F 5. T 6. T 7. T 8. F [Ex 2] 1. sizes, shapes, processing capabilities

物流专业英语

CHAPTER1 1. The 4 types of economic utility（四种经济效用形式） (1) possession utility(2) form utility(3) place utility(4) time utility 2. The increased importance of logistics（物流日益增长的重要性） (1)a reduction in economic regulation（经济规制的放松）(2)changes in consumer behavior（顾客行为的改变） (3)technological advanced（技术进步）(4)the growing power of retailers （零售商权力的不断增大） (5)globalization of trade(贸易全球化) 3. Business logistics（企业物流） (1)inbound logistics（内向物流）(2)materials management（物料管理） (3)physical distribution（实物配送） 4. Logistical relationships within firm（公司内部的物流关系） (1)finance（财务）(2)marketing（营销）(3)production（价格决策） 5.4ps of marketing（营销4P） (1)place(地点)(2)price（价格）(3)product（产品）(4)promotion（促销）6. Marketing channels（营销渠道） (1)ownership channel（所有权渠道）(2)negotiations channel（协商渠道） (3)financing channel（财务渠道） (4)promotions channel（促销渠道）(5)logistics channel（物流渠道） (6)facilitators or channel intermediaries（渠道促进者和渠道中介） 7. Sorting function 4 steps（分类功能有四个步骤） (1)sorting out（分类）(2)accumulating（积聚）(3)allocating（分配）(4)assorting（再次分类） 8. Activities in the logistical channel（物流渠道中的活动） (1)customer service(顾客服务)(2)demand forecasting（需求预测） (3)facility location decision（设施选址决策） (4)industrial packaging（工业包装）(5)inventory management（库存管理） (6)materials handling（物料搬运） (7)order management（订单管理）(8)parts and service support（零配件和服务支持）(9)production scheduling（生产作业计划） (10)procurement（采购）(11)returned products（退货）(12)salvage and scrap disposal（残料和废料处理） (13)transportation management（运输管理）(14)warehousing management（仓储管理） CHAPTER 2 1. SCOR process（供应链运作参考流程） (1)plan（计划）(2)source（采购）(3)make（制造）(4)deliver（交货）(5)return （退货） 2. GSCF process（全球供应链论坛流程） (1)customer relationship management（顾客关系管理）(2)customer service management（顾客服务管理） (3)demand management（需求管理）(4)order fulfillment（订单履行） (5)manufacturing flow management（制造流程管理）

自动化专业英语全文翻译

《自动化专业英语教程》-王宏文主编-全文翻译 PART 1Electrical and Electronic Engineering Basics UNIT 1A Electrical Networks ————————————3 B Three-phase Circuits UNIT 2A The Operational Amplifier ———————————5 B Transistors UNIT 3A Logical Variables and Flip-flop ——————————8 B Binary Number System UNIT 4A Power Semiconductor Devices ——————————11 B Power Electronic Converters UNIT 5A Types of DC Motors —————————————15 B Closed-loop Control of D C Drivers UNIT 6A AC Machines ———————————————19 B Induction Motor Drive UNIT 7A Electric Power System ————————————22 B Power System Automation PART 2Control Theory UNIT 1A The World of Control ————————————27 B The Transfer Function and the Laplace Transformation —————29 UNIT 2A Stability and the Time Response —————————30 B Steady State—————————————————31 UNIT 3A The Root Locus —————————————32 B The Frequency Response Methods: Nyquist Diagrams —————33 UNIT 4A The Frequency Response Methods: Bode Piots —————34 B Nonlinear Control System 37 UNIT 5 A Introduction to Modern Control Theory 38 B State Equations 40 UNIT 6 A Controllability, Observability, and Stability B Optimum Control Systems UNIT 7 A Conventional and Intelligent Control B Artificial Neural Network PART 3 Computer Control Technology UNIT 1 A Computer Structure and Function 42 B Fundamentals of Computer and Networks 43 UNIT 2 A Interfaces to External Signals and Devices 44 B The Applications of Computers 46 UNIT 3 A PLC Overview B PACs for Industrial Control, the Future of Control

计算机专业英语

Chapter1 Competencies After you have read this chapter, you should be able to: 1. Explain the five parts of an information system: people, procedures, software, hardware, and data. 2. Distinguish between system software and application software. 3. Discuss the three kinds of system software programs. 4. Distinguish between basic and specialized application software. 5. Identify the four types of computers and the four types of microcomputers. 6. Describe the different types of computer hardware including the system unit, input, output, storage, and communication devices. 7. Define data and describe document, worksheet, database, and presentation files. 8. Explain computer connectivity, the wireless revolution, and the Internet. 第一章能力当你阅读本章，你应该能够： 1。解释了信息系统的五个部分：人，程序，软件，硬件和数据。

计算机专业英语教程(第四版)习题答案

计算机专业英语教程(第四版)习题答案
计算机专业英语（第四版）课后习题答案 Unit 1 [Ex 1] Fb5E2RGbCAP [Ex 2] 1. input, storage, processing, and output 2. power; speed; 1. F 2. T 3. T 4. F 5. T 6. T 7. T 8. T 9. T 10.
memoryp1EanqFDPw 3. central processing unit memoryDXDiTa9E3d 5. keyboard; [Ex 3] B. A. central processing unit; 1. F 2. D 2. monitor 3. G 4. C 5. B main memory; 6. A 7. E monitorRTCrpUDGiT 8. H5PCzVD7HxA 4. internal; primary;
1. user
3. data
4. keyboard
5. data processingjLBHrnAILg
6. information [Ex 4] instructions
7. computer
8. memory 3. manipulates 4.
1. input device 2. screen, screen 5. retrievexHAQX74J0X 8. Function
6. code 7. hard copy
[Ex. 5] 新处理器开始 IT 技术的新时代 New Processors Open New Era of IT Technologies Last week, Intel introduced to the public in Russia and other CIS countries a family of processors Intel Xeon E5-2600. They are more powerful and reliable and, importantly, are very economical in terms of energy consumption. Their
1 / 30

自动化专业英语单词

Abound v.大量存在Accelerate v.加速Access v.存取，接近Accommodate v.容纳，使适应 Acoustic adj.听觉的Acousticsensor声传感器，声敏原件 Acronym n.首字母缩写词 Active adj.主动的，有源的 Active network 有源网络 Actuator n.执行器 Ad hoc 尤其，特定地Address n.寻址Addressgenerators地址发生器 Adjoint n.，adj.伴随（的），共轭（的） Admissible adj.可采纳的，允许的 Advent n.出现Aerodynamic adj.空气动力学的Aerodynamic n.空气动力学，气体力学Aesthetically adv.美术地，美学地Aforementioned adj.上述的，前面提到的Agility n.灵活，便捷 Ai 人工智能 Air gap 气隙 Aircraft n.飞行器 Airgap=air gap 气隙 Air-to-close（AC）adj.气关的 Air-to-open（AO）adj.气开的 Albeit conj.虽然Algebraic equation 代数方程Alignment n.组合 All-electricrange全电动行驶里程 Alleviate v.减轻，缓和 Allowance for finish 加工余量 Alloy n.合金 Alnico n.铝镍钴合金，铝镍钴永磁合金 Aloft adv.高高地 Alphanumeric adj.字母数字混合的 Alternative n.可供选择的办法 Altitude n.海拔 Aluminum n.铝 Amortisseur n.阻尼器 Amplifier n.放大器 Amplify v.放大 Amplitude n.振幅 Answeringmachine电话答录机 Anthropomorphically adv. 拟人的 Anti-aliasfilter抗混叠滤波器 Antilockbrakingsystem 防抱死系统 APICS=AmericanProduct ionandInventoryControl Society美国生产与库存管理学会 Apparatus n.一套仪器，装置 Application n.应用（程序） Approach n.途径，方法；研究 Aptness n.恰当 Arbitrary adj.任意的 Arbitrary adj.任意的 Architecture n.架构 Architecture n.体系结构 Archive v.存档 Argument n.辐角，相位 Arithmetic-logic unit 算术逻辑部件 Armature n.电枢，衔铁，加固 Arrival angle 入射角 Arrival point 汇合点 Artificial intelligence 人工智能 Artillery shell 炮弹 ASIC=ApplicationSpecific IntegratedCircuit特定用途集成电路 Assembly n.装置，构件 Assemblyline装配生产线 Assumption n.假设 Asymmetric adj.不对称的 Asymptote n.渐近线 Asymptotically stable 渐近稳定 Asynchronous adj.异步的 At rest 处于平衡状态 At the most 至多 Attached adj.附加的 Attain v.达到，实现 Attenuate v.减弱 Attenuation n.衰减 Attitude n.姿态 Attribute n.品质，特征 Audio adj.音频的 Auto-isolation n.自动隔离 Automatictellermachine 自动柜员机 Autonomous adj.自治的 Autonomous adj.自治的，自激的 Auto-restoration n.自动恢复供电 Auto-sectionalizing n.自动分段 Auxiliary material 辅助材料 Axon n.轴突 Backlash n.齿隙游移 Bandwidth n.带宽 Bar code scanner 条码扫描仪 Baud n.波特 Become adept in 熟练 Bench mark 基准点 Bias n.偏压 Bi-directional adj.双向的 Binary adj.二进制的 Binary-coded adj.二进制编码的 Biomass n.生物质 Biopsy n.活体检查 Bipolar adj.双向的 Bjt 双极结型晶体管 Blackout n.（大区域的）停电 Bldm 无刷直流电动机 Block diagram algebra 方块图计算（代数） Boiler n.汽锅，锅炉 Boolean algebra 布尔代数 Boost chopper 升压式变压器 Bound v.限制 Bracket v.加括号 Break frequency 转折频率 Breakaway point 分离点 Breakdown n.击穿，雪崩 Breakover n.导通 Brush n.电刷 Buck chopper 降压式变压器 Building blocks 积木 Buildingautomation楼宇自动化 Bulky adj.庞大的，笨重

计算机专业英语名词翻译

第一章（计算机系统概论） digital computer 数字计算机 decimal digits 十进制数字 binary 二进制 bit 位 ASCII 美国国家信息交换标准代码 computer system 计算机系统 hardware system 硬件系统 software system 软件系统 I/O devices 输入输出设备 central processing unit(CPU) 中央处理器memory 存储器 application software 应用软件 video game 计算机游戏 system software 系统软件 register 寄存器 floating point data浮点数据 Boolean布尔值 character data字符数据 EBCDIC扩充的二十一进制交换代码 punched cards穿孔卡片 magnetic tape磁带 main memory主存 vacuum tubes电子管 magnetic drum磁鼓 transistors晶体管 solid-state devices固体器件 magnetic cores磁芯 integrated circuit（IC）集成电路 silicon chip硅芯片 multiprogramming多道程序设计 timessharing分时分时技术 minicomputers小型计算机 mainframe大型计算机 large-scaleintegrated(LSI)大规模集成 very-large-scale integrated(VLSI)超大规模集成word processing文字处理 eletronic spreedsheets电子表格 database management programs数据库管理程序desktop publishing桌面印刷personalcomputer(PC)个人计算机microcomputer微型计算机 storage capacities存储容量 stand-alone computer独立计算机 local area network(LAN)局域网 peripheral devices外部设备 assembly line流水线 supercomputer巨型计算机第二章（计算机系统结构） memmory subsystem存储子系统 I/O subsystem输入输出子系统 bus总线 system bus系统总线 chip 芯片 address bus地址总线 instructions指令 memory location存储单元 data bus数据总线 control bus控制总线 local bus 局部总线 microprocessor微处理器 register set寄存器组 arithmetic logic unit(ALU)运算器 clock cycle时钟周期 control unit控制器 computer architecture计算机体系结构introduction format指令格式 addressing modes寻址方式 introduction set指令集 internal memory内存 main memory主存 Random Access Memory(RAM)随机存取存储器Read Only Memory (ROM)只读存储器secondary storage副主存储器 vitual memory虚拟存储器 Dynamic RAM(DRAM)动态存储器 refresh circuitry刷新电路 Static RAM(SRAM)静态RAM cache memory高速缓冲存储器 masked ROM掩膜ROM PROM可编程RAM EPROM可擦写PROM ultraviolet light紫外线 EEPROM or EEPROM电擦写PROM basic input/output system(BIOS)基本输入输出系统flash EEPROM 快闪存储器

计算机专业英语课文翻译部分(第四版)

1.2 总线互连总线是连接两个或多个设备的通信通路。总线的关键特征是，它是一条共享传输介质。多个设备连接到总线上，任一个设备发出的信号可以为其他所有连接到总线上的设备所接收。如果两个设备同时传送，它们的信号将会重叠，引起混淆。因此，一次只能有一个设备成功地（利用总线）发送数据。典型的情况是，总线由多条通信通路或线路组成，每条线(路)能够传送代表二进制1和0的信号。一段时间里，一条线能传送一串二进制数字。总线的几条线放在一起能同时并行传送二进制数字。例如, 一个8位的数据能在8条总线线上传送。计算机系统包含有多种不同的总线，它们在计算机系统层次结构的各个层次提供部件之间的通路。连接主要计算机部件(处理机, 存储器, I/O)的总线称为系统总线。系统总线通常由50~100条分立的(导)线组成。每条线被赋予一个特定的含义或功能。虽然有许多不同的总线设计，但任何总线上的线都可以分成三个功能组：数据线、地址线和控制线。此外可能还有为连接的模块提供电源的电源线。数据线提供系统模块间传送数据的路径，这些线组合在一起称为数据总线。典型的数据总线包含8、16或32根线，线的数量称为数据总线的宽度。因为每条线每次传送1位，所以线的数目决定了每次能同时传送多少位。数据总线的宽度是决定系统总体性能的关键因素。地址线用于指定数据总线上数据的来源和去向。例如，如果处理机希望从存储器中读一个字的数据，它将所需要字的地址放在地址线上。显然，地址总线的宽度决定了系统最大可能的存储器容量。控制线用来控制对数据线和地址线的访问和使用。由于数据线和地址线被所有部件共享，因此必须用一种方法来控制它们的使用。控制信号在系统模块之间传送命令和定时信息。定时信息指定了数据和地址信息的有效性，命令信号指定了要执行的操作。大多数计算机系统使用多总线，这些总线通常设计成层次结构。图1.3显示了一个典型的高性能体系结构。一条局部总线把处理机连接到高速缓存控制器，而高速缓存控制器又连接到支持主存储器的系统总线上。高速缓存控制器集成到连接高速总线的桥中。这一总线支持连接到：高速LAN、视频和图形工作站控制器，以及包括SCSI 和FireWire的局部外设总线的接口控制器。低速设备仍然由分开的扩充总线支持，用一个接口来缓冲该扩充总线和高速总线之间的通信流量。 PCI 外部设备互连是流行的高带宽的、独立于处理机的总线，它能够作为中间层或外围设备总线。当前的标准允许在66MHz频率下使用多达64根数据线，其原始传输速率为528MB/s, 或4.224Gbps。PCI被设计成支持各种各样基于微处理机的配置，包括单处理机和多处理机的系统。因此，它提供了一组通用的功能。PCI使用同步时序以及集中式仲裁方案。在多处理机系统中，一个或多个PCI配置可通过桥接器连接到处理机的系统总线上。系统总线只支持处理机/高速缓存单元、主存储器以及PCI桥接器。使用桥接器使得PCI独立于处理机速度，又提供快速接收和传送数据的能力。 2.1 光存储介质：高密度存储器 2.1.1 光盘光盘技术最终可能使磁盘和磁带存储淘汰。用这种技术，磁存储器所用的读/写头被两束激光代替。一束激光通过在光盘上刻制微小的凹点，对记录表面进行写；而另一束激光用来从光敏感的记录表面读取数据。由于光束容易被偏转到光盘上所需要的位置，所以不需要存取臂。对用户而言，光盘正成为最有吸引力的选择。它们(光盘)对环境变化不太敏感，并且它们以每兆字节比磁盘低得多的存储器价格提供更多的直接存取存储器。光盘技术仍在出现，并且还需要稳定；然而，目前有三种主要类型的光盘。它们是CD-ROM、WORM盘和磁光盘。 CD-ROM 1980年引入的，非常成功的CD，或紧密盘是设计来提高音乐的录音重放质量的光盘。为了制作一张CD，把音乐的模拟声音转换成等价的数字声音，并且存储在一张4.72英寸的光盘上。在每张光盘上可以用数字格式（用20亿数字位）记录74分钟的音乐。因为它的巨大存储容量，计算机工业的企业家们立刻认