计算机英语 计 算 机 英 语 刘艺 王春生 主编 Computer English 前 言 英语作为计算机及 IT 业的行业性语言,有着其他语言所不能替代的功能。无论是学习最 新的计算机技术,还是使用最新的计算机软硬件产品,都离不开对计算机英语的熟练掌握。 正是为了适应这种要求,不少有实力、有远见的院校纷纷开设了计算机英语课。有些院校甚 至不仅把它作为计算机专业的必修课,还将其作为一门实用的选修课推广到其他专业。 本书是按照最新《大学英语教学大纲》对专业英语的要求,为开设计算机英语课程而编 写的面向 21 世纪的教材。在满足计算机专业英语教学的同时,我们并没有过分沉溺于晦涩 抽象的理论和专业术语之中,而是更多地关注计算机素养、计算机应用以及 IT 对社会和生活 的深刻影响。所以,在选材的过程中,除了计算机基础知识、软硬件结构体系、软件工程和 网络通信等专业文章外,还精心挑选了电子商务、因特网、计算机安全、IT 业精英论点等方 面的精彩内容。同时在所有选材上着重体现一个“新”字,例如:Linux、Java、Web 编程、 ATM、黑客防范等。 在版式上,我们采用了旁注生词、脚注难点的同步对照注释方法,使读者不必前后查找 就可以在当前页获得学习指导,解决阅读困难。另外,书后还附有生词表和缩略语表,而且 所有生词与缩略语均注明在书中首次出现的课次与具体文章。它们既可作为全书的索引,方 便读者进行相关内容的查阅复习,也可作为一本实用的英汉计算机小词典,在日常学习和生 活中备用。同时,我们还为大部分文章精心选配了插图和示意图,以增加文章内容的直观性 与趣味性,使读者能更好地理解原文和提高学习兴趣。 本书在出版过程中得到机械工业出版社华章公司的鼎力支持,同时洪蕾、王珊珊、蒋丹 丹等也为本书的编撰和顺利出版付出了心血,在此一并表示感谢! 尽管本书在编写过程中,在资料的查核、术语的汉译以及文字的规范等方面都做了大量 工作,但由于计算机领域的发展日新月异,许多新术语尚无确定的规范译法,加上编者水平 有限,书中难免有不尽如人意之处,还恳请广大读者不吝赐教。 编者 2000 年 12 月 19 日于南京 E-mail: [email protected] 计算机英语 使 用 说 明 1、本教材根据其内容分为四大部分,共 15 课。每一课包括三篇文章。课文 A 为精读材 料,课文 B 和课文 C 为泛读材料。三篇课文均围绕同一主题。课文 A 一般为该主题的概述, 课文 B 和课文 C 多就该主题的某一具体方面或具体例子展开讨论。 2、课文 A 长度一般为 1400~1800 词,要求能正确理解和熟练掌握其内容。课文 B 和课 文 C 长度一般为 1200~1600 词,要求能掌握中心大意,抓住主要事实。 3、课文 A 配有四项练习,即“课文理解填空”、 “词组中英文互译”、 “完形填空”和“段 落翻译”;课文 B 和课文 C 配有两项练习,即“课文理解填空”和“词组中英文互译”。各项 练习均与课文内容和计算机专业紧密结合,旨在巩固和拓展学生所学内容。 4、国家教育部于 1999 年新颁布的《大学英语教学大纲》 (修订本)规定: “学生在完成 基础阶段的学习任务,达到四级或六级后,都必须修读专业英语。”这就意味着学生在学习 专业英语之前必须达到大学英语四级水平,但不一定达到六级。因此,本教材的生词选注以 四级为起点,参照标准为 2000 年 7 月出版的《大学英语教学大纲》(修订本)配套词汇表。 所注生词计有两类:一类是通用词,即大纲词汇表未列入 1~4 级的词汇;另一类为计算机 及相关专业词汇,是大纲词汇表未列入 1~4 级,或未注明有关词义的词汇。生词均用黑体 在课文中标出,并在课文对应段落旁边进行注释,以便于阅读和记忆。相同生词原则上只在 首次出现之处进行注释,但书后附有生词表以备查检。 5、计算机英语的特点之一是大量缩略语的使用。本教材对其采取两种处理方式:一是 在首次出现处进行脚注;二是对大家十分熟知或其意思在文中不言自明的缩略语未加脚注。 但是,无论那种情况,所有缩略语均收入书后的缩略语表,以备查阅和方便记忆。另外,在 计算机英语中,缩略语所代表的词组或术语在大小写上有比较随意和不一致的现象。本教材 原则上尊重原文所采用的形式。 6、完成本教材的学习后应达到的要求,可参照《大学英语教学大纲》 (修订本)有关专 业英语的规定。 7、计算机专业英语课及其本教材的使用,本科生可安排在第五至第七学期,研究生可 安排在第一学年。对于教学时数比较充裕的院校,可全书使用;对教学时数比较少的院校, 重点可放在前三部分,而将第四部分作为课外阅读,也可按照自身的需求进行取舍。 编者 2000 年 12 月 19 日 Computer English 目 录 PART ONE Computer Basics Unit 1 My Computer 3 Section A Computer Overview 3 Section B Computing on the Go 13 Section C Tips for Computer Beginners 19 Computer Architecture 21 Section A Computer Hardware 21 Section B The Universal Serial Bus 28 Section C DVD 34 Operating System 39 Section A Operating System 39 Section B What Is Linux? 48 Section C Performance in Windows 2000 52 Computer Language and Programming 56 Section A Programming Language 56 Section B Visual C++ and MFC Basics 64 Section C The Java Language 71 Unit 2 Unit 3 Unit 4 1 PART TWO Software Engineering Unit 5 Software Development 81 Section A Computer Program 81 Section B Why Choose Visual Basic as a Web Programming Tool? 91 Section C Using PowerBuilder to Build Cross-Platform Applications 96 79 Distributed Systems 102 Section A Distributed Systems 102 Section B What Does “Client-Server” Really Mean? (Part I) 112 Section C What Does “Client-Server” Really Mean? (Part II) 120 Unit 6 计算机英语 Database 125 Section A Enter the World of Relational Databases 125 Section B Database Objects of SQL Server 134 Section C Delphi Database Architecture 139 Unit 7 PART THREE Network and Communication Unit 8 Telecommunications and Information Superhighway 149 Section A Telecommunications and Computer 149 Section B Internet and Information Superhighway 157 Section C ATM and Its Advantages 164 Computer Networks 172 Section A Computer Networks 172 Section B Switched LAN Network Designs 180 Section C How Are Networks Used? 189 Network Infrastructure 195 Section A Network Topologies 195 Section B TCP/IP: the Basics 205 Section C Network-Level Protocols 212 Internet 218 Section A How Does the Internet Work? 218 Section B What’s E-Mail? 226 Section C Videoconferencing 229 Unit 9 Unit 10 Unit 11 147 PART FOUR IT and Our Life Unit 12 IT and Computer Application 239 Section A Information Revolution 239 Section B Geographic Information System 248 Section C Agent Technology 255 e-Business 260 Section A Electronic Commerce 260 Section B The Evolution of e-Business 268 Section C Setting Goals for Your Online Business 274 Unit 13 237 Computer English Computer Security 279 Section A Computer Security 279 Section B Computer Virus 288 Section C Through a Hacker’s Eyes 294 Remarks by IT Giants 300 Section A Remarks by Bill Gates 300 Section B Louis V. Gerstner Jr: IT and the Reformation of Chinese Unit 14 Unit 15 Section C State-Owned Enterprises 307 Andrew S. Grove: Only the Paranoid Survive 313 Appendix I Glossary 318 Appendix II Abbreviations 347 计算机英语 Part One Computer Basics 1 2 Computer English 第一部分 计算机基础 第一单元 我的电脑 第二单元 计算机硬件结构 第三单元 操作系统 第四单元 计算机语言与编程 ● 课文 A:计算机概览 ● 课文 B:可穿带的计算机 ● 课文 C:计算机初学者技巧 ● 课文 A:计算机硬件 ● 课文 B:通用串行总线 ● 课文 C:DVD ● 课文 A:操作系统 ● 课文 B:什么是 Linux? ● 课文 C:Windows 2000 的性能 ● 课文 A:编程语言 ● 课文 B:Visual C++ 和 MFC 基础 ● 课文 C:Java 语言 计算机英语 3 Unit 1: My Computer (我的电脑) Section A Computer Overview I. INTRODUCTION numerical / nju:5merikEl / a. 数字的;数值的 manipulate / mE5nipjUleit / v. 操作;处理 transaction / trAn5zAkFEn / n. 交易;业务 1 A computer is an electronic device that can receive a set of instructions, or program, and then carry out this program by performing calculations on numerical data or by manipulating other forms of information. The modern world of high technology could not have come about1 except for the development of the computer. Different types and sizes of computers find uses throughout society in the storage and handling of data, from secret governmental files to banking transactions to private household accounts. Computers have opened up a new era in manufacturing come about:发生,产生。 4 Computer English automation / 7C:tE5meiFEn / n. 自动化 enhance / in5hB:ns / v. 增强 conjecture / kEn5dVektFE / n. 推测,猜想 database / 5deitEbeis / n. 数据库 privacy / 5praivEsi / n. 隐私;秘密 precursor / 7pri:5kE:sE / n. 先驱 digit / 5didVit / n. 数字 loom / lu:m / n. 织机 perforated / 5pE:fEreitid / a. 穿孔的 conceive / kEn5si:v / v.(构)想出 punched card 穿孔卡片 electrical contact 电触点 compile / kEm5pail / v. 汇编;编译 census / 5sensEs / n. 人口普查 analytical / 7AnE5litikEl / a. 分析的 Analytical Engine 分析机,解析机 1 2 3 4 5 6 through the techniques of automation, and they have enhanced modern communication systems. They are essential tools in almost every field of research and applied technology, from constructing models of the universe to producing tomorrow’s weather reports, and their use has in itself opened up new areas of conjecture. Database services and computer networks make available a great variety of information sources.1 The same advanced techniques also make possible invasions of personal and business privacy. Computer crime has become one of the many risks that are part of the price of modern technology. II. HISTORY The first adding machine, a precursor of the digital computer, was devised in 1642 by the French scientist, mathematician, and philosopher Blaise Pascal2 This device employed a series of ten-toothed wheels, each tooth representing a digit from 0 to 9. The wheels were connected so that numbers could be added to each other by advancing the wheels by a correct number of teeth. In the 1670s the German philosopher and mathematician Gottfried Wilhelm Leibniz3 improved on this machine by devising one that could also multiply. The French inventor Joseph-Marie Jacquard 4 , in designing an automatic loom, used thin, perforated wooden boards to control the weaving of complicated designs. During the 1880s the American statistician Herman Hollerith5 conceived the idea of using perforated cards, similar to Jacquard’s boards, for processing data. Employing a system that passed punched cards over electrical contacts, he was able to compile statistical information for the 1890 United States census. A. The Analytical Engine Also in the 19th century, the British mathematician and inventor Charles Babbage6 worked out the principles of the modern digital computer. Database services and computer networks make available a great variety of information sources.:数据库服务和 计算机网络使各种各样的信息源可供使用。这句话由于宾语(a great variety of information sources)较长, 而将宾语的补语(available)放到了宾语的前面。文中下一句话也属同样情况。 Blaise Pascal:布莱斯·帕斯卡(1623~1662),法国数学家、物理学家、哲学家,概率论创立者之一。 Gottfried Wilhelm Leibniz:戈特弗里德·威廉·莱布尼兹(1646~1716),德国自然科学家、哲学家,微 积分、数理逻辑的先驱,提出了二进制。 Joseph-Marie Jacquard:约瑟夫―玛丽·雅卡尔(1752~1834),法国著名的织机工匠,纹板提花机的主 要改革家。 Herman Hollerith:赫尔曼·何勒里斯(1860~1929),美国发明家和统计学家。 Charles Babbage:查尔斯·巴比奇(1792~1871),英国数学家和发明家。 计算机英语 Difference Engine 差分机 input stream 输入(信息)流 analog(ue) / 5AnElCg / a.模拟的 shaft / FB:ft / n. 轴 approximation / E7prCksi5meiFEn / n. 近似(值) computing / kEm5pju:tiN / n. 计算(技术) torpedo / tC:5pi:dEu / n. 鱼雷 submarine / 7sQbmE5ri:n / n. 潜艇 bombsight / 5bCmsait / n. 轰炸瞄准器 incorporate / in5kC:pEreit / v. 包含 vacuum tube 真空管 crack / krAk / v. 破译 encipher / in5saifE / v. 把…译成密码 prototype / 5prEutEtaip / n. 原型;样品 1 2 3 4 5 6 7 5 He conceived a number of machines, such as the Difference Engine, that were designed to handle complicated mathematical problems. Many historians consider Babbage and his associate, the mathematician Augusta Ada Byron1, the true pioneers of the modern digital computer. One of Babbage’s designs, the Analytical Engine, had many features of a modern computer. It had an input stream in the form of a deck of punched cards, a “store” for saving data, a “mill” for arithmetic operations, and a printer that made a permanent record.2 Babbage failed to put this idea into practice, though it may well have been technically possible at that date. B. Early Computers Analogue computers began to be built in the late 19th century. Early models calculated by means of rotating shafts and gears. Numerical approximations of equations too difficult to solve in any other way were evaluated with such machines. Lord Kelvin 3 built a mechanical tide predictor that was a specialized analogue computer. During World Wars I and II, mechanical and, later, electrical analogue computing systems were used as torpedo course predictors in submarines and as bombsight controllers in aircraft. Another system was designed to predict spring floods in the Mississippi River4 basin. C. Electronic Computers During World War II, a team of scientists and mathematicians, working at Bletchley Park, north of London, created one of the first all-electronic digital computers: Colossus5. By December 1943, Colossus, which incorporated 1,500 vacuum tubes, was operational. It was used by the team headed by Alan Turing6, in the largely successful attempt to crack German radio messages enciphered in the Enigma code7. Independently of this, in the United States, a prototype electronic Augusta Ada Byron:奥古斯塔·埃达·拜伦(1815~1852),英国数学家,诗人拜伦之女。 It had an input stream in the form of a deck of punched cards, a “store” for saving data, a “mill” for arithmetic operations, and a printer that made a permanent record.:其输入流形式为一叠穿孔卡片、一个储存数据的“仓 库”、一个进行算术运算的“工厂”,以及产生永久记录的打印机。 William Thomson Kelvin:威廉·汤姆森·开尔文(1824~1907),英国物理学家,发展了热力学理论,创 立了热力学绝对温标(即开尔文温标)。 Mississippi River:密西西比河,发源于美国中北部的湖沼区,南注墨西哥湾,系美国主要河流。 Colossus:该词读作 / kE5lCsEs/ ,有“巨像”、“巨人”、“巨物”等意。 Alan Turing:艾伦·图灵(1912~1954),英国数学家和逻辑学家。 Enigma code:恩尼格码,德军在第二次世界大战期间采用的一种密码。 6 Computer English overshadow / 7EuvE5FAdEu / v. 使相形见绌 integrator / 5intigreitE / n. 积分器 patent / 5peitEnt / n. 专利(权) overturn machine had been built as early as 1939, by John Atanasoff1 and Clifford Berry 2 at Iowa State College3 . This prototype and later research were completed quietly and later overshadowed by the development of the Electronic Numerical Integrator And Computer (ENIAC 4 ) in 1945. ENIAC was granted a patent, which was overturned decades later, in 1973, when the machine was revealed to have incorporated principles first used in the Atanasoff-Berry Computer. / 7EuvE5tE:n / v. 推翻;废除 Hungarian / hQN5geEriEn / a. 匈牙利的 memory / 5memEri / n. 存储器,内存 paper-tape reader 纸带阅读器 execution / 7eksi5kjuFEn / n. 执行,运行 1 2 3 4 5 6 Figure 1A-1: ENIAC was one of the first fully electronic digital computers. ENIAC (See Figure 1A-1) contained 18,000 vacuum tubes and had a speed of several hundred multiplications per minute, but originally its program was wired into the processor5 and had to be manually altered. Later machines were built with program storage, based on the ideas of the Hungarian-American mathematician John von Neumann6. The instructions, like the data, were stored within a “memory”, freeing the computer from the speed limitations of the paper-tape reader during execution and John Atanasoff:约翰·阿塔纳索夫(1903~1995),美国物理学家。 Clifford Berry:克利福德·贝里(1918~1963),美国物理学家。 Iowa State College:(美国)艾奥瓦州立学院。 ENIAC:电子数字积分计算机,ENIAC 计算机(Electronic Numerical Integrator And Computer 的首字母缩略)。 its program was wired into the processor:程序通过导线传送到处理器内。 John von Neumann:约翰·冯·诺伊曼(1903~1957),美籍匈牙利数学家,对量子物理、数学逻辑和高 速计算机的发展均有贡献。 计算机英语 transistor / trAn5sistE / n. 晶体管 advent / 5Advent / n. 出现,到来 versatile / 5vE:sEtail / a. 多用途的, 通用的 logical element 逻辑元件 fabricate / 5fAbrikeit / v. 制作 silicon / 5silikEn / n. 硅 substrate / 5sQbstreit / n. 衬底,基底 microprocessor / 7maikrEu5prEusesE / n. 微处理器 microchip / 5maikrEutFip / n. 微芯片 etch / etF / v. 蚀刻 7 permitting problems to be solved without rewiring the computer. The use of the transistor in computers in the late 1950s marked the advent of smaller, faster, and more versatile logical elements than were possible with vacuum-tube machines. Because transistors use much less power and have a much longer life, this development alone was responsible for the improved machines called second-generation computers. Components became smaller, as did inter-component spacings, and the system became much less expensive to build. D. Integrated Circuits Late in the 1960s the integrated circuit, or IC, was introduced, making it possible for many transistors to be fabricated on one silicon substrate, with interconnecting wires plated in place1. The IC resulted in a further reduction in price, size, and failure rate. The microprocessor became a reality in the mid-1970s with the introduction of the large-scale integrated (LSI) circuit and, later, the very large-scale integrated (VLSI) circuit (microchip), with many thousands of interconnected transistors etched into a single silicon substrate. Figure 1A-2: An integrated circuit To return, then, to the switching capabilities of a modern computer: computers in the 1970s were generally able to handle eight switches at a time. That is, they could deal with eight binary digits, or bits, of data, at 1 making it possible for many transistors to be fabricated on one silicon substrate, with interconnecting wires plated in place:从而有可能将许多晶体管制作在一块硅衬底上,晶体管之间以覆镀固定的导线相连接。 8 Computer English binary / 5bainEri / a. 二进制的 bit / bit / n. 位,比特 byte / bait / n. 字节 datum / 5deitEm / ([复]data) n. 数据 graphics / 5grAfiks / n. 图形,图形显示 decimal / 5desimEl / a. 十进制的 switch / 5switF / n. 交换(设备) instruction set 指令集 ongoing / 5Cn7gEuiN / a. 正在进行的 conceptually / kEn5septjuEli / ad. 概念上 microcomputer / 5maikrEukEm5pju:tE/ n. 微型计算机 desktop / 5desktCp / a. 桌面的;台式的 laptop / 5lAptCp / n. 膝上型计算机, 便携式计算机 briefcase / 5bri:fkeis / n. 公文包 palmtop / 5pB:mtCp / n. 掌上型计算机 workstation / 5wE:k7steiFEn / n. 工作站 minicomputer / 7minikEm5pju:tE / n. 小型计算机 mainframe / 5meinfreim / n. 主机,大型机 supercomputer / 5sju:pEkEmpju:tE / n. 超级计算机,巨 型计算机 bus / bQs / n. 总线 every cycle. A group of eight bits is called a byte, each byte containing 256 possible patterns of ONs and OFFs (or 1s and 0s). Each pattern is the equivalent of an instruction, a part of an instruction, or a particular type of datum, such as a number or a character or a graphics symbol. The pattern 11010010, for example, might be binary data—in this case, the decimal number 210—or it might be an instruction telling the computer to compare data stored in its switches to data stored in a certain memory-chip location. The development of processors that can handle 16, 32, and 64 bits of data at a time has increased the speed of computers. The complete collection of recognizable patterns—the total list of operations—of which a computer is capable is called its instruction set. Both factors—the number of bits that can be handled at one time, and the size of instruction sets—continue to increase with the ongoing development of modern digital computers. III. HARDWARE Modern digital computers are all conceptually similar, regardless of size. Nevertheless, they can be divided into several categories on the basis of cost and performance: the personal computer or microcomputer, a relatively low-cost machine, usually of desktop size (though “laptops” are small enough to fit in a briefcase, and “palmtops” can fit into a pocket); the workstation, a microcomputer with enhanced graphics and communications capabilities that make it especially useful for office work; the minicomputer, generally too expensive for personal use, with capabilities suited to a business, school, or laboratory; and the mainframe computer, a large, expensive machine with the capability of serving the needs of major business enterprises, government departments, scientific research establishments, or the like (the largest and fastest of these are called supercomputers). A digital computer is not a single machine: rather, it is a system composed of five distinct elements: (1) a central processing unit; (2) input devices; (3) memory storage devices; (4) output devices; and (5) a communications network, called a bus, which links all the elements of the system and connects the system to the external world. IV. PROGRAMMING A program is a sequence of instructions that tells the hardware of a computer what operations to perform on data. Programs can be built into 计算机英语 dedicated / 5dedikeitid / n. 专用的 embed / im5bed / v. 把…嵌入 circuitry / 5sE:kitri / n. 电路 9 the hardware itself, or they may exist independently in a form known as software. In some specialized, or “dedicated”, computers the operating instructions are embedded in their circuitry; common examples are the microcomputers found in calculators, wristwatches, car engines, and microwave ovens. A general-purpose computer, on the other hand, although it contains some built-in programs (in ROM) or instructions (in the processor chip), depends on external programs to perform useful tasks. Once a computer has been programmed, it can do only as much or as little as the software controlling it at any given moment enables it to do. Software in widespread use includes a wide range of applications programs—instructions to the computer on how to perform various tasks. V. FUTURE DEVELOPMENTS microminiaturization / 5maikrEu7minitFErai5zeiFEn / n. 微小型化,超小 型化 superconductivity / 5sju:pE7kCndQk5tivEti / n. 超导(电)性 artificial intelligence 人工智能 neural / 5njuErEl / a. 神经的 neural network 神经(元)网络 mimic / 5mimik / v. 模仿 networking / 5net7wE:kiN / n. 联网,建网 One continuing trend in computer development is microminiaturization, the effort to compress more circuit elements into smaller and smaller chip space. Researchers are also trying to speed up circuitry functions through the use of superconductivity, the phenomenon of decreased electrical resistance observed in certain materials at very low temperatures. The “fifth-generation” computer effort to develop computers that can solve complex problems in ways that might eventually merit the description “creative”1 is another trend in computer development, the ideal goal being true artificial intelligence. One path actively being explored is parallel-processing computing, which uses many chips to perform several different tasks at the same time. One important parallel-processing approach is the neural network, which mimics the architecture of the nervous system. Another ongoing trend is the increase in computer networking, which now employs the worldwide data communications system of satellite and cable links to connect computers globally. There is also a great deal of research into the possibility of “optical” computers—hardware that processes not pulses of electricity but much faster pulses of light. ———————————————— Exercises 1 I. Fill in the blanks with the information given in the text: 1. According to many historians, the true pioneers of the modern merit the description “creative”:与“创造性的”这一形容名副其实。 10 Computer English digital computer are ________ and ________. 2. A digital computer is generally made up of five distinct elements: a central processing unit, ________ devices, memory storage devices, ________ devices and a bus. 3. The microprocessor is a central processing unit on a single chip. It was made possible in the mid-1970s with the introduction of the LSI circuit and the ________ circuit. 4. According to the text, modern digital computers can be divided into four major categories on the basis of cost and performance. They are microcomputers, ________, minicomputers, and ________. 5. The first electronic computers, such as Colossus and ENIAC created in Britain and the United States respectively, used ________ tubes, which later gave place to ________. 6. A program is a sequence of ________ that can be executed by a computer. It can either be built into the hardware or exist independently in the form of ________. 7. The smallest unit of information handled by a computer is bit, which is the abbreviation of binary ________. A group of ________ bits makes up a(n) ________, which is short for binary term. 8. One of the trends in computer development is ________, the effort to compress more circuit elements into smaller and smaller ________ space. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. artificial intelligence paper-tape reader optical computer neural network instruction set parallel processing difference engine versatile logical element silicon substrate 11. 12. 13. 14. 15. 16. 17. 18. 19. 数据的存储与处理 超大规模集成电路 中央处理器 个人计算机 模拟计算机 数字计算机 通用计算机 处理器芯片 操作指令 11 计算机英语 10. vacuum tube 20. 输入设备 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: microcomputer advent chip minicomputer computing mode appear combine digital circuit speed categorization base significance transistor integration We can define a computer as a device that accepts input, processes data, stores data, and produces output. According to the ________ of processing, computers are either analog or ________. They can also be classified as mainframes, ________, workstations, or microcomputers. All else (for example, the age of the machine) being equal, this ________ provides some indication of the computer’s ________, size, cost, and abilities. Ever since the ________ of computers, there have been constant changes. First-generation computers of historic ________, such as UNIVAC (通用自动计算机), introduced in the early 1950s, were ________ on vacuum tubes. Second-generation computers, ________ in the early 1960s, were those in which ________ replaced vacuum tubes. In third-generation computers, dating from the 1960s, integrated ________ replaced transistors. In fourth-generation computers such as ________, which first appeared in the mid-1970s, large-scale ________ enabled thousands of circuits to be incorporated on one ________. Fifth-generation computers are expected to ________ very-large-scale integration with sophisticated approaches to ________, including artificial intelligence and true distributed processing. IV. Translate the following passage from English into Chinese: A computer system includes a computer, peripheral(外围的)devices, and software. The electric, electronic, and mechanical devices used for processing data are referred to as hardware. In addition to the computer itself, the term “hardware” refers to components called peripheral devices that expand the computer’s input, output, and storage capabilities. Computer hardware in and of itself does not provide a particularly useful mind tool. To be useful, a computer requires a set of instructions, called software or a computer program, which tells the computer how to perform a 12 Computer English particular task. Computers become even more effective when connected to other computers in a network so users can share information. 计算机英语 13 Section B Computing on the Go Wearable computers are the next wave of portable 1 computing—and they go way beyond laptops. cutting-edge / 5kQtiNedV / a. 尖端的,先进的 techie / 5teki / n. (尤指计算机方 面的)技术人员; 计算机迷 interface / 5intEfeis / n. 界面;接口 innovative / 5inE7veitiv / a. 革新的,新颖的; 富有革新精神的 wearable / 5weErEbl / n. 佩带式计算机 1 Imagine watching a movie projected through your eyeglasses onto a virtual screen that seems to float in your field of vision. Or imagine working on an automobile, an airplane, or an underwater mission and reading an instruction manual, communicating with co-workers, or inputting data via computer—all without lifting a finger from the task at hand. The realities are closer than most may suspect as cutting-edge wearable computers for industrial and consumer use are already being designed. For techies fluent in user interface, hardware, and software design, it means lots of job opportunity. Here’s a quick list of a few innovative wearables coming to market. The Ultimate in Eyewear Wearable computers are the next wave of portable computing—and they go way beyond laptops.:佩带式计算机 是便携式计算机的下一个浪潮——而且在此方面远远超过膝上型计算机。在该句中,way 是副词,意为“远 远地”、“大大地”等,系口语用法。 14 vendor / 5vendE / n. 卖主;厂商 clip / klip / v.(用夹子、回形针 等)夹住,扣住 cell phone 蜂窝电话,移动电 话,手机 temple / 5templ / n. 太阳穴,鬓角 illusion / i5lu:VEn / n. 错觉,幻觉 disclose / dis5klEuz / v. 透露;揭露 beta / 5bi:tE / n. 希腊语的第二 个字母(B,β); 测试版 beta testing β测试 endoscopic / 7endE5skCpik / a. 内窥镜的;(用) 内窥镜检查的 surgeon / 5sE:dVEn / n. 外科医生 probe / prEub / v. 探查,探测 vein / vein / n. 静脉;血管 accessory / Ek5sesEri / n. 附件,配件 1 2 3 4 5 Computer English While wearable computer devices aren’t generally available to consumers today, more and more industries are beginning to take advantage of the wearable computer—and more vendors are entering the market, designing smaller, comfortable, integrated devices. MicroOptical Corp.1, based in Westwood2, Mass.3, has designed two basic models of an eyeglass display—one that clips onto the side of the user’s glasses, and one integrated directly into the eyewear. Though the user still needs a CPU—a laptop, a wearable computer, or even a DVD player or cell phone—the monitor or screen is actually projected through the user’s eyeglasses. Greg Jenkins, sales manager at MicroOptical, says the LCD 4 is positioned near the user’s temple. A projected image passes through the lenses of regular eyeglasses, bounces off a mirror, and displays the illusion of a full-size monitor floating in front of the user’s face. The display weighs less than an ounce, so it’s much more comfortable than some of the earlier head-mounted displays. Jenkins says he can’t disclose which companies are currently using the product, as it is still in beta testing. But the display can incorporate night vision capabilities for the military, and is used in electronics sectors to aid in working on circuit boards, for example. And in medicine, the eyeglass display is aiding the work of endoscopic surgeons, enabling them to probe the veins of patients without having to look up at a screen to view their work. Jenkins says his company is also paying close attention to the cell phone and WAP5 industry. Eventually the technology will put video in your cell phone LCD, but right now the displays on cell phones—especially the newer, smaller designs—aren’t large enough to handle the images. That’s where integrated eyeglass displays can play a part, says Jenkins. MicroOptical hopes to sell its display as an accessory for other products, such as cell phones, DVD players, and wearable CPUs. Corp.:公司(corporation 的缩略)。 Westwood:韦斯特伍德,美国马萨诸塞州一地名。 Mass.:(美国)马萨诸塞州,又名麻省(Massachusetts 的缩略)。 LCD:液晶显示(器)(liquid crystal display 的首字母缩略)。 WAP:无线应用协议(Wireless Application Protocol 的首字母缩略),这里指使用该协议的产品。 15 计算机英语 snorkeler / 5snC:kElE / n. 使用水下呼吸管 潜游者 grand / grAnd / n. [常单复同]<美 俚>一千美元 miniature / 5minitFE / a. 小型的,微小的 housing / 5hauziN / n. 外壳,外罩 specs / speks / n. [复]<口>规格 differential / 7difE5renFEl / a. 差分的;微分的 sensor / 5sensE / n. 传感器 coral / 5kCrEl / n. 珊瑚 reef / ri:f / n. 礁 salvage / 5sAlvidV / n. 海上救助 maritime / 5mAritaim / a. 海的;海上的 archeologist / 7B:ki5ClEdVist / n. 考古学家 navigate / 5neivigeit / v. 航 行 ( 于 ); (为…)领航;指引 refinery / ri5fainEri / n. 提炼厂 The WetPC1 It’s not for the average diver or snorkeler—unless you’ve got about 20 grand to spend. An underwater wearable computer called the WetPC includes a miniature personal computer and a five-button GUI2 that mounts in a waterproof housing on the diver’s air tank. A cable connects it all to a waterproof virtual display attached to the diver’s mask. The five-key Kord pad3 can be used in either hand by pressing single or multiple keys. Currently, the SeaPC4—a version of the WetPC—is being sold to the Royal Australian Navy5 and some research organizations, says Dr. Peter Moran, director of WetPC, in Australia. “Apart from having all the normal specs of a desktop machine, they incorporate differential GPS6, depth and temperature sensors, a digital compass, and digital video,” says Moran. “One of the units we are building at the present time will be used for mapping and monitoring coral reefs.” The WetPC can help salvage-divers, maritime archeologists, and police divers find objects, record or look up information, or simply monitor their location at all times. Scientists could use the unit for mapping and monitoring coral reefs. Navy divers could use the WetPC to search for mines and other unexploded devices. The WetPC has applications in education, recreation, and tourism as well. Divers can use the WetPC to navigate reefs and create a digital guided tour for underwater tourists. Golden Eye It won’t make you James Bond7, but if you work in a manufacturing plant or oil refinery, it could make your job a lot easier. Honeywell contracted 1 2 3 4 5 6 7 Logic, a product development firm in WetPC:湿 PC,一种可在水下使用的计算机。参见题图。 GUI:图形用户界面(graphical user interface 的首字母缩略)。 five-key Kord pad:五键考德机,一种计算机移动输入设备。参见题图。 SeaPC:海 PC,一种可在海中使用的计算机。参见题图。 Royal Australian Navy:(皇家)澳大利亚海军。 GPS:全球卫星定位系统(Global Positioning System 的首字母缩略)。 James Bond:詹姆斯·邦德,英国作家 Ian Fleming(1908~1964)所著系列间谍小说中的主人公,代号 007。 16 thin-client computer 瘦客户机 radio frequency 射频;无线电频率 intranet / intrE5net / n. 企 业 内 部 ( 互 联)网,内联网 compact / kEm5pAkt / a. 小巧的;紧密的 mouse / maus / n. 鼠标 click / klik / v. 鼠标点击 strive / straiv / v. 努力,奋斗 functionality / 7fQNkFE5nAlEti / n. 功能性 user-friendly / 5ju:zE5frendli / a. 用户友好的,使 用方便的 specification / 7spesifi5keiFEn / n. [常作~s]规格, 规范;明确说明 unobtrusive / 7QnEb5tru:siv / a. 不唐突的;考虑 周到的 elusive / i5lu:siv / a. 难以捉摸的;令 人困惑的 Computer English Minneapolis1, to develop Golden Eye, a wearable, thin-client computer linked to a server via radio frequency LAN 2 . Designed to boost the efficiency of plant operations—particularly oil refineries—Golden Eye allows operators to access information and process data via the company’s intranet. Golden Eye has two compact, lightweight components—a hand-held I/O device and an RF4 transmitter worn on a belt. Its smooth lines, simple design, and bright yellow color make it look almost like a toy. 3 “We make a lot of wearable devices at Logic, and this is probably one of the coolest ones we picked out,” says Troy Kopischke, vice president of engineering. “I think the user interface is quite unique. You look into a very small device and it optically blows up5 the image to be like a 21-inch monitor about a foot away. And there’s an integrated mouse that allows you to point and click.” The Challenges of Wearable Computing The creation of wearable computers is not without challenge—primarily, how to produce an affordable product. Most units aren’t priced for the average consumer. On the development side, designers and engineers continually strive to increase the functionality and comfort of wearable computers. “One of the big challenges for us is to continue to make them user-friendly—to maintain usability as the functionality goes up and the size goes down,” says Danny Cunagin, president of Logic. He says the next generation of Golden Eye will be a one-piece, integrated unit. And while most wearable computers use standard desktop computer 6 specifications—Pentium processors, Windows operating systems—creating a user interface that is easy, unobtrusive, and comfortable to use and wear remains a little elusive. Opportunities in the Field 1 2 3 4 5 6 Minneapolis:明尼阿波利斯,美国明尼苏达州东南部城市。 LAN:局域网(local area network 的首字母缩略) 。 I/O:输入∕输出(input/output 的首字母缩略)。 RF:射频;无线电频率(radio frequency 的首字母缩略)。 blow up:<口> 放大。 Pentium:Intel 公司生产的 CPU 芯片,中文译名为“奔腾”。 17 计算机英语 ergonomics / 7E:gE5nCmiks / n. [用作单或复]人 机工程学,人类工 程学,工效学 Moran, of WetPC, says opportunities in the field of underwater computing will increase considerably over the next few years. “Already we are starting to see increased interest for our products without having to advertise them,” he says. “Given the rather unique nature of the underwater environment, professionals will need rather specialized skills. I can see that there will be a need for a variety of hardware and software engineers who have skills in mobile interface design, ergonomics design, and integration of underwater technologies, to name a few.” “There’s definitely a need for people who understand the new form,” says Adam Robinson, director of Alliance Programs at Xybernaut, another wearable computer manufacturer based in Fairfax1, Va.2 “You really need innovative designs to take it to the next level.” ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The wearable computer device designed by MicroOptical is a kind of eyeglass ________ which can create the illusion of a full-size monitor floating in your field of vision. 2. The WetPC is a(n) ________ wearable computer. Among its components are a miniature personal computer and a five-button ________. 3. An operator can use Golden Eye to access information and process data via his company’s ________. 4. On the development side, one of the big challenges of wearable computing is how to increase the ________ and comfort of wearable computers. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 1 2 circuit board beta testing thin-client computer Fairfax:费尔法克斯,美国弗吉尼亚州一地名。 Va.:(美国)弗吉尼亚州(Virginia 的缩略) 。 6. 7. 8. 奔腾处理器 虚拟屏幕 台式计算机规格 18 Computer English 4. 5. cell phone digital video 9. 10. 射频 可佩带式计算机 计算机英语 19 Section C Tips for Computer Beginners tip / tip / n. 指点;技巧 boot / bu:t / v. & n.(亦作 boot up)引导,启动 registry / 5redVistri / n. 注册表 tweak / twi:k / v. 微调,调理 tinker / 5tiNkE / v. 修补,摆弄 socket / 5sCkit / n. 插座;插槽 driver / 5draivE / n. 驱动器,驱动程序 surf / 5sE:f / v. 浏览,(在…上) 冲浪 swap / 5swCp / n. & v. 交换 desktop / 5desktCp / n. 桌面;台式(计 算)机 megabyte / 5megEbait / n. 兆字节 drive / draiv / n. 驱动器 1 2 3 4 1. Shut Windows properly using the Shut Down option from the Start Menu. If you just turn off your computer, you can damage files on your computer and could eventually end up with a computer that doesn’t want to do much, including boot up. 2. Uninstall your programs with the Add/Remove Programs option in Windows Control Panel. Simply deleting them can leave a big mess behind. 3. Read and learn more about the Windows Registry before you attempt to tweak or tinker with it. The Registry does not take kindly to1 clumsy editing. 4. Two general rules for a misbehaving piece of hardware: 1) if it has a power plug, make certain this plug is plugged into a wall socket that you know works; and 2) try deleting the driver for the hardware and see if Windows is able to redetect (and operate properly) the hardware in question when it reboots. 5. Many hardware problems may be temporary, caused by a lock-up of resources or too few resources available because you have been opening and closing a lot of programs, including many pages of Web2 surfing. You may find that shutting down your computer and rebooting corrects these. 6. Don’t go below 100MB3 of free hard disk space. This is often the amount Windows needs for a swap file (where it treats hard disk space as a form of memory to help move pages in and out of your desktop). If you’re running low, try uninstalling programs you do not use, and cleaning up any TMP4 files you may have on your system (megabytes of space can be lost to these). It may be time to add or replace an older, smaller, and slower hard drive. 7. Visit the hardware manufacturer’s Web site to find any technical Web site 网站,站点 take kindly to:对…有好感。 Web:万维网,WWW 网(全称为 World Wide Web 或 World-Wide Web,常缩略为 WWW、w3、W3 和 Web)。 update / Qp5deit / MB:兆字节(megabyte 的首字母缩略)。 TMP:暂(时)存(储)器(temporary memory 的缩略) 。 v. 更新;修改 forum / 5fC:rEm / n. 论坛 newsgroup / 5nju:zgru:p / 20 Computer English papers or frequently asked questions (FAQs) relating to the product you want to install or add, or have a problem operating. 8. Keep your hardware drivers updated as necessary. 9. If your system is very slow to start, check the Start Menu to see what programs may be loading at startup. If there are many programs loading, remove some to try to speed up your startup. 10. Still need help? Visit the Hardware Forum’s newsgroups, where experts and novices trade tips. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. If a computer is very slow to start, it may be caused by many programs ________ at startup. 2. As a general rule, you should keep at least ________ of free hard disk space. 3. When you want to delete a program, you should use the ________ option in Windows ________. 4. The right way to shut Windows is to use the ________ option from the ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. Windows Registry swap file TMP file power plug 5. 6. 7. 8. 可用磁盘空间 控制面板 开始菜单 添加∕删除程序选项 计算机英语 21 Unit 2: Computer Architecture (计算机体系结构) Section A Computer Hardware INTRODUCTION computational / 7kCmpju:5teiFEnEl / a. 计算(机)的 Computer hardware is the equipment involved in the function of a computer and consists of the components that can be physically handled. The function of these components is typically divided into three main categories: input, output, and storage. Components in these categories connect to microprocessors, specifically, the computer’s central processing unit (CPU), the electronic circuitry that provides the computational ability and control of the computer, via wires or circuitry called a bus. Software, on the other hand, is the set of instructions a computer uses to manipulate data, such as a word-processing program or a video game. These programs are usually stored and transferred via the computer’s 22 retrieve / ri5tri:v / v. 检索 firmware / 5fE:mweE / n. [总称]固件 light pen 光笔 stylus / 5stailEs / ([复]-luses 或 -li / -lai / )n. 输入笔, 光笔 clip / klip / n. 夹子,夹具 pointer / 5pCintE / n. 指针(光标) cursor / 5kE:sE / n. 光标 joystick / 5dVCistik / n. 控制杆,操纵杆, 游戏杆 lever / 5li:vE / n.(杠)杆;控制杆 graphic(al) / 5grAfik(El) / a. 图形的 trackball / 5trAkbC:l / n. 跟踪球,轨迹球 touch-sensitive / 5tQtF7sensitiv / a. 触敏的 scanner / 5skAnE / n. 扫描仪 flatbed scanner 平板扫描仪 photocopier / 7fEutEu5kCpiE / n. 复印机 hand-held scanner 手持式扫描仪 module / 5mCdju:l / n. 模块 Computer English hardware to and from the CPU. Software also governs how the hardware is utilized; for example, how information is retrieved from a storage device. The interaction between the input and output hardware is controlled by software called the Basic Input Output System (BIOS) software. Although microprocessors are still technically considered to be hardware, portions of their function are also associated with computer software. Since microprocessors have both hardware and software aspects they are therefore often referred to as firmware. INPUT HARDWARE Input hardware consists of external devices—that is, components outside of the computer’s CPU—that provide information and instructions to the computer. A light pen is a stylus with a light sensitive tip that is used to draw directly on a computer’s video screen or to select information on the screen by pressing a clip in the light pen or by pressing the light pen against the surface of the screen. The pen contains light sensors that identify which portion of the screen it is passed over. A mouse is a pointing device designed to be gripped by one hand. It has a detection device (usually a ball) on the bottom that enables the user to control the motion of an on-screen pointer, or cursor, by moving the mouse on a flat surface. As the device moves across the surface, the cursor moves across the screen. To select items or choose commands on the screen, the user presses a button on the mouse. A joystick is a pointing device composed of a lever that moves in multiple directions to navigate a cursor or other graphical object on a computer screen. A keyboard is a typewriter-like device that allows the user to type in text and commands to the computer. Some keyboards have special function keys or integrated pointing devices, such as a trackball or touch-sensitive regions that let the user’s finger motions move an on-screen cursor. An optical scanner uses light-sensing equipment to convert images such as a picture or text into electronic signals that can be manipulated by a computer. For example, a photograph can be scanned into a computer and then included in a text document created on that computer. The two most common scanner types are the flatbed scanner, which is similar to an office photocopier, and the hand-held scanner, which is passed manually across the image to be processed. A microphone is a device for converting sound into signals that can then be stored, manipulated, and played back by the computer. A voice recognition module is a device that converts spoken 计算机英语 23 words into information that the computer can recognize and process. modem / 5mEudem / n. 调制解调器 modulator / 5mCdjuleitE / n. 调制器 demodulator / di:5mCdjuleitE / n. 解调器 video display 视频显示(器) cathode / 5kAWEud / n. 阴极 cathode ray tube 阴极射线管 liquid crystal display 液晶显示(器) phosphorescent / 7fCsfE5resEnt / a. 发磷光的 laptop / 5lAptCp / a. 膝上型的,便携 式的 matrix / 5meitriks / ([复] -trices / -trisi:z / 或 -trixes) n.(矩)阵 drum / drQm / n. 磁鼓 toner / 5tEunE / n. 色粉,墨粉 fuse / fju:z / v. 熔化;熔合;熔 接;熔凝 inkjet / 5iNkdVet / a. 喷墨的 droplet / 5drCplit / n. 小滴 retrieval / ri5tri:vEl / n. 检索 floppy / 5flCpi / a.(松)软的 magneto-optical / mAg7ni:tEu5CptikEl / a. 磁光的 floppy disk n. 软(磁)盘 A modem, which stands for modulator-demodulator, is a device that connects a computer to a telephone line and allows information to be transmitted to or received from another computer. Each computer that sends or receives information must be connected to a modem. The information sent from one computer is converted by the modem into an audio signal, which is then transmitted by telephone lines to the receiving modem, which converts the signal into information that the receiving computer can understand. OUTPUT HARDWARE Output hardware consists of external devices that transfer information from the computer’s CPU to the computer user. A video display, or screen, converts information generated by the computer into visual information. Displays commonly take one of two forms: a video screen with a cathode ray tube (CRT) or a video screen with a liquid crystal display (LCD). A CRT-based screen, or monitor, looks similar to a television set. Information from the CPU is displayed using a beam of electrons that scans a phosphorescent surface that emits light and creates images. An LCD-based screen displays visual information on a flatter and smaller screen than a CRT-based video monitor. LCDs are frequently used in laptop computers. Printers take text and image from a computer and print them on paper. Dot-matrix printers use tiny wires to impact upon an inked ribbon to form characters. Laser printers employ beams of light to draw images on a drum that then picks up fine black particles called toner. The toner is fused to a page to produce an image. Inkjet printers fire droplets of ink onto a page to form characters and pictures. STORAGE HARDWARE Storage hardware provides permanent storage of information and programs for retrieval by the computer. The two main types of storage devices are disk drives and memory. There are several types of disk drives: hard, floppy, magneto-optical, and compact. Hard disk drives store information in magnetic particles embedded in a disk. Usually a permanent part of the computer, hard disk drives can store large amounts of information and retrieve that information very quickly. Floppy disk drives also store information in magnetic particles embedded in removable disks that may be floppy or rigid. Floppy disks store less information than a hard 24 pit / pit / n. 凹区,凹槽 erase / i5reiz / v. 擦除,清除 overwrite / 7EuvE5rait / v. 改写,重写 random / 5rAndEm / a. 随机的 volatile / 5vClEtail / a. 易失的 volatile memory 易失性存储器 nonvolatile memory 非易失性存储器 computation / 7kCmpju:5teiFEn / n. 计算 interact / 7intEr5Akt / v. 互相作用;互相 影响 address bus 地址总线 data bus 数据总线 1 2 Computer English disk drive and retrieve the information at a much slower rate. Magneto-optical disc1 drives store information on removable discs that are sensitive to both laser light and magnetic fields. They can typically store as much information as hard disks but have slightly slower retrieval speeds. Compact disc drives (CD-ROM) store information on pits burned into the surface of a disc of reflective material. 2 The information stored on CD-ROMs cannot be erased or overwritten with new information. They can store about as much information as a hard drive but have a slower rate of information retrieval. Memory refers to the computer chips that store information for quick retrieval by the CPU. Random access memory (RAM) is used to store the information and instructions that operate the computer’s programs. Typically, programs are transferred from storage on a disk drive to RAM. RAM is also known as volatile memory because the information within the computer chips is lost when power to the computer is turned off. Read-only memory (ROM) contains critical information and software that must be permanently available for computer operation, such as the operating system that directs the computer’s actions from start up to shut down. ROM is called nonvolatile memory because the memory chips do not lose their information when power to the computer is turned off. Some devices serve more than one purpose. For example, floppy disks may also be used as input devices if they contain information to be used and processed by the computer user. In addition, they can be used as output devices if the user wants to store the results of computations on them. HARDWARE CONNECTIONS To function, hardware requires physical connections that allow components to communicate and interact. A bus provides a common interconnected system composed of a group of wires or circuitry that coordinates and moves information between the internal parts of a computer. A computer bus consists of two channels: one that the CPU uses to locate data, called the address bus, and another to send the data to that address, called the data bus. A bus is characterized by two features: how much disc:disc 本来是英国英语的拼法,其对应的美国拼法为 disk。但是,在计算机英语中,现在标准的做法 被认为是将 disc 用于表示光盘的场合,而把 disk 用于所有其他的场合。因此,本文在同一段落中出现了 disc 和 disk 两种拼写形式。另外,optical disc 与 compact disc 都指光盘。 Compact disc drives (CD-ROM) store information on pits burned into the surface of a disc of reflective material.: 由反射材料制成的光盘,其表面烧蚀出凹陷区。光驱(CD-ROM)就是将信息储存于此。 计算机英语 25 information it can manipulate at one time, called the bus width, and how quickly it can transfer these data. serial / 5siEriEl / a. 串行的;连续的 block / blCk / n.(字、信息、程序、 数据等的)块;分 程序 simultaneously / 7simEl5teiniEsli / ad. 同时(发生)地 A serial connection is a wire or set of wires used to transfer information from the CPU to an external device such as a mouse, keyboard, modem, scanner, and some types of printers. This type of connection transfers only one piece of data at a time, and is therefore slow. The advantage to using a serial connection is that it provides effective connections over long distances. A parallel connection uses multiple sets of wires to transfer blocks of information simultaneously. Most scanners and printers use this type of connection. A parallel connection is much faster than a serial connection, but it is limited to distances of less than 3 m (10 ft) between the CPU and the external device. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The function of computer hardware is typically divided into three main categories. They are ________, ________ and ________. 2. The software that controls the interaction between the input and output hardware is called BIOS, which stands for ________. 3. The two most common types of scanners are ________ and ________. 4. Video displays commonly take one of two forms. They are CRT-based screens and ________ screens. 5. In the text, the author mentions three of the most commonly used types of printer. They are ________, laser printers and ________. 6. According to the text, the two main types of storage devices are ________ and ________. 7. It can be said that having a steady power source is important for a computer because RAM is ________ memory. 8. A(n) ________ connection transfers only one piece of data at a time while a(n) ________ connection transfers blocks of information at the 26 Computer English same time. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. information retrieval voice recognition module touch-sensitive region address bus flatbed scanner dot-matrix printer parallel connection cathode ray tube video game audio signal 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 操作系统 液晶显示(器) 喷墨打印机 数据总线 串行连接 易失性存储器 激光打印机 磁盘驱动器 基本输入输出系统 视频显示器 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: commercial laser access reflect light represent store equivalent disc floppy erase information optical retrieve flat surface CD-ROM stands for compact disc read-only memory. Unlike ________ and hard disks, which use magnetic charges to represent 1s and 0s, ________ discs use reflected light. On a CD-ROM disc, 1s and 0s are represented by ________ areas and bumpy (高低不平的) areas (called “pits”) on its bottom ________. The CD-ROM disc is read by a(n) ________ that projects a tiny beam of ________ on these areas. The amount of ________ light determines whether the area ________ a 1 or a 0. Like a(n) ________ CD found in music stores, a CD-ROM is a “read-only” ________. Read-only means it cannot be written on or ________ by the user. Thus, you as a user have ________ only to the data imprinted (压印) by the publisher. A single CD-ROM disc can ________ 650 megabytes of data. That is ________ to 451 floppy disks. With that much ________ on a single disc, 计算机英语 27 the time to ________ or access the information is very important. An important characteristic of CD-ROM drives is their access rate. IV. Translate the following passage from English into Chinese: A modem is a device that converts between analog and digital signals. Digital signals, which are used by computers, are made up of separate units, usually represented by a series of 1’s and 0’s. Analog signals vary continuously; an example of an analog signal is a sound wave. Modems are often used to enable computers to communicate with each other across telephone lines. A modem converts the digital signals of the sending computer to analog signals that can be transmitted through telephone lines. When the signal reaches its destination, another modem reconstructs the original digital signal, which is processed by the receiving computer. If both modems can transmit data to each other simultaneously, the modems are operating in full duplex (双工的) mode; if only one modem can transmit at a time, the modems are operating in half duplex mode. 28 Computer English Section B The Universal Serial Bus peripheral / pE5rifErEl / n. 外围设备 slot / slCt / n.(插)槽 fraught / frC:t / a. [一般作表语]充 满的,伴随着的 (with) jumper / 5dVQmpE / n. 跳线,跨接线 prone / prEun / a. 有…倾向的,易 于…的 Plug ’n Play 即插即用 (=Plug and Play) The PCI 1 bus is fine for attaching high-speed peripherals to a computer, but it is far too expensive to have a PCI interface for each low-speed I/O device such as a keyboard or mouse. Historically, each standard I/O device was connected to the computer in a special way, with some free ISA2 and PCI slots for adding new devices. Unfortunately, this scheme has been fraught with problems from the beginning. For example, each new I/O device often comes with its own ISA or PCI card. The user is often responsible for setting switches and jumpers on the card and making sure the settings do not conflict with other cards. Then the user must open up the case, carefully insert the card, close the case, and reboot the computer. For many users, this process is difficult and error prone. In addition, the number of ISA and PCI slots is very limited (two or three typically). Plug ’n Play cards eliminate the jumper settings, but the user still has to open the computer to insert the card and bus slots are still limited. To deal with this problem, in the mid 1990s, representatives from seven companies (Compaq3, DEC4, IBM5, Intel6, Microsoft7, NEC8, and Northern Telecom9) got together to design a better way to attach low-speed I/O devices to a computer. Since then, hundreds of other companies have joined them. The resulting standard is called USB10 and it is being widely implemented in personal computers. Some of the goals of the companies that originally conceived of11 the 1 PCI:外部设备互连(总线) ,外围元件互连(Peripheral Component Interconnect 的首字母缩略) 。 ISA:工业标准结构(Industry Standard Architecture 的首字母缩略)。 3 Compaq: (美国)康柏公司,世界著名的电脑生产厂家。 4 DEC:(美国)数字设备公司(Digital Equipment Corporation 的首字母缩略)。 5 IBM:(美国)国际商用机器公司(International Business Machines 的首字母缩略)。 6 Intel:(美国)英特尔公司,世界最大的 CPU 制造厂家。 7 Microsoft:(美国)微软公司,世界最大的软件生产商。 8 NEC:日本电气公司,世界五大电脑制造商之一(Nippon Electric Company 的首字母缩略) 。 9 Northern Telecom:(加拿大)北方电信公司。 10 USB:通用串行总线(Universal Serial Bus 的首字母缩略)。 11 conceive of:构想出,设想。 2 计算机英语 29 USB and started the project were as follows: 1. Users must not have to set switches or jumpers on boards or devices. 2. Users must not have to open the case to install new I/O devices. 3. There should be only one kind of cable, good for connecting all devices. 4. I/O devices should get their power from the cable. 5. Up to 127 devices should be attachable to a single computer. 6. The system should support real-time devices (e.g., sound, telephone). 7. Devices should be installable while the computer is running. 8. No reboot should be needed after installing a new device. 9. The new bus and its I/O devices should be inexpensive to manufacture. still camera 静物照相机 snapshot / 5snApFCt / n. 快照;快相 snapshot scanner 快照扫描仪 hub / hQb / n.(轮)毂; (网络) 集线器 root hub 根集线器 topology / tE5pClEdVi / n. 拓扑(结构) voltage transition 电压翻转 query / 5kwiEri / v. & n. 查询 download / 7daun5lEud / v. & n. 下载 configuration / kEn 7figju5reiFEn / n. 配置 register / 5redVistE / n. 寄存器 1 USB meets all these goals. It is designed for low-speed devices such as keyboards, mice, still cameras, snapshot scanners, digital telephones, and so on. The total USB bandwidth is 1.5 MB/sec1, which is enough for a substantial number of these devices. This low limit was chosen to keep the cost down. A USB system consists of a root hub that plugs into the main bus (see Figure 2B-1). This hub has sockets for cables that can connect to I/O devices or to expansion hubs, to provide more sockets, so the topology of a USB system is a tree with its root at the root hub, inside the computer. The cables have different connectors on the hub end and on the device end, to prevent people from accidentally connecting two hub sockets together. The cable consists of four wires: two for data, one for power (+5 volts), and one for ground. The signaling system transmits a 0 as a voltage transition and a 1 as the absence of a voltage transition, so long runs of 0s generate a regular pulse stream. When a new I/O device is plugged in, the root hub detects this event and interrupts the operating system. The operating system then queries the device to find out what it is and how much USB bandwidth it needs. If the operating system decides that there is enough bandwidth for the device, it assigns the new device a unique address (1 – 127) and downloads this address and other information to configuration registers inside the device. MB/sec:兆字节/秒(megabyte/second 的缩略)。 30 on-the-fly / 5CnTE5flai / ad. 自由地;随意地 uninitialized / 7Qni5niFElaizd / a. 未初始化的 accommodate Computer English In this way, new devices can be added on-the-fly, without any user configuration required and without having to install new ISA or PCI cards. Uninitialized cards start out with address 0, so they can be addressed. To make the cabling simpler, many USB devices contain built-in hubs to accept additional USB devices. For example, a monitor might have two hub sockets to accommodate the left and right speakers. / E5kCmEdeit / v. 容纳;使适应 pipe / paip / n. 管道(符) frame / freim / n. 帧;单幅画面 synchronize / 5siNkrEnaiz / v.(使)同步 packet / 5pAkit / n. 包,数据包,信 息包 1 2 Figure 2B-1: The architecture of a typical Pentium II system The thicker buses have more bandwidth than the thinner ones. Logically, the USB system can be viewed as a set of bit pipes from the root hub to the I/O devices. Each device can split its bit pipe up into at most 16 sub-pipes for different types of data (e.g., audio and video). Within each pipe or sub-pipe, data flows from the root hub to the device or the other way1. There is no traffic between two I/O devices. Precisely every 1.00 ± 0.05 msec2, the root hub broadcasts a new frame to keep all the devices synchronized in time. A frame is associated with a bit pipe, and consists of packets, the first of which is from the root hub to the device. Subsequent packets in the frame may also be in this direction, or they may be back from the device to the root hub. A sequence of four frames is shown in Figure 2B-2. In Figure 2B-2 there is no work to the other way:通常作 the other way about (或 around),意为“相反地”、“倒过来”、“以相反方式”等。 msec:毫秒(millisecond 的缩略)。 计算机英语 poll / pEul / n. & v. 轮询,探询 31 be done in frames 0 and 2, so all that is needed is one SOF1 (Start of Frame) packet. This packet is always broadcast to all devices. Frame 1 is a poll, for example, a request to a scanner to return the bits it has found on the image it is scanning. Frame 3 consists of delivering data to some device, for example to a printer. Figure 2B-2: The USB root hub sounds out frames every 1.00 msec. isochronous / ai5sCkrEnEs / a. 同步的,等时的 configure / kEn5figE / v. 配置 loudspeaker / 5laud5spi:kE / n. 扬声器,喇叭 pending / 5pendiN / a. 未决的;在进行 中的;行将发生的 token / 5tEukEn / n. 权标,令牌 handshake / 5hAndFeik / n. 握手(信号) field / fi:ld / n. 字段,域, 信息组 1 USB supports four kinds of frames: control, isochronous, bulk, and interrupt. Control frames are used to configure devices, give them commands, and inquire about their status. Isochronous frames are for real-time devices such as microphones, loudspeakers, and telephones that need to send or accept data at precise time intervals. They have a highly-predictable delay but provide no retransmissions in the event of errors. Bulk frames are for large transfers to or from devices with no real-time requirements such as printers. Finally, interrupt frames are needed because USB does not support interrupts. For example, instead of having the keyboard cause an interrupt whenever a key is struck, the operating system can poll it every 50 msec to collect any pending keystrokes. A frame consists of one or more packets, possibly some in each direction. Four kinds of packets exist: token, data, handshake, and special. Token packets are from the root to a device and are for system control. The SOF, IN, and OUT packets in Figure 2B-2 are token packets. The SOF (Start of Frame) packet is the first one in each frame and marks the beginning of the frame. If there is no work to do, the SOF packet is the only one in the frame. The IN token packet is a poll, asking the device to return certain data. Fields in the IN packet tell which bit pipe is being polled so the device knows which data to return (if it has multiple streams). The OUT token packet announces that data for the device will follow. A fourth type SOF:帧首(Start Of Frame 的首字母缩略)。 32 setup / 5setQp / n. 设置;安装; 建立 synchronization / 7siNkrEnai5zeiFEn / n. 同步 payload / 5peilEud / n. 有效载荷 redundancy / ri5dQndEnsi / n. 冗余 stall / stC:l / v. 拖延,推迟 Computer English of token packet, SETUP (not shown in the figure), is used for configuration. Besides the token packet, three other kinds exist. These are DATA (used to transmit up to 64 bytes of information either way), handshake, and special packets. The format of a data packet is shown in Figure 2B-2. It consists of an 8-bit synchronization field, an 8-bit packet type (PID1), the payload, and a 16-bit CRC2 (Cyclic Redundancy Code) to detect errors. Three kinds of handshake packets are defined: ACK3 (the previous data packet was correctly received), NAK4 (a CRC error was detected), and STALL (please wait—I am busy right now). Now let us look at Figure 2B-2 again. Every 1.00 msec a frame must be sent from the root hub, even if there is no work. Frames 0 and 2 consist of just an SOF packet, indicating that there was no work. Frame 1 is a poll, so it starts out with SOF and IN packets from the computer to the I/O device, followed by a DATA packet from the device to the computer. The ACK packet tells the device that the data were received correctly. In case of an error, a NAK would be sent back to the device and the packet would be retransmitted for bulk data (but not for isochronous data). Frame 3 is similar in structure to frame 1, except that now the flow of data is from the computer to the device. ———————————————— Exercises I. 1. mice. Fill in the blanks with the information given in the text: USB is designed for ________ devices such as keyboards or 2. The ________ of a USB system is a tree with its root at the root ________, inside the computer. 3. According to the text, USB supports four kinds of frames. They are ________ frames, isochronous frames, ________ frames, and interrupt frames. 1 2 3 4 PID:包类型标识(Packet Identification 的缩略)。 CRC:循环冗余代码(Cyclic Redundancy Code 的首字母缩略)。 ACK:确认,应答(acknowledgement 的缩略)。 NAK:否定确认,否定应答(negative acknowledgement 的缩略)。 33 计算机英语 4. A frame consists of one or more packets, which fall into four categories: ________, data, ________, and special. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. ISA slot configuration register still camera token packet expansion hub 6. 7. 8. 9. 10. 通用串行总线 根集线器 输入输出设备 控制帧 外部设备互连 34 Computer English Section C DVD blockbuster / 5blCk7bQstE / n. 重磅炸弹;了不 起的人(或事物) multimedia / 7mQlti5mi:diE / a. 多媒体的 acronym/ 5AkrEnim/ n. 首字母缩拼词 polycarbonate / 7pCli5kB:bEnit / n. 聚碳酸酯 1 2 3 The basic CD/CD-ROM format has been around since 1980.1 The technology has improved since then, so higher-capacity optical disks are now economically feasible and there is great demand for them. Hollywood2 would dearly love to replace analog video tapes by digital disks, since disks have a higher quality, are cheaper to manufacture, last longer, take up less shelf space in video stores, and do not have to be rewound. The consumer electronics companies are looking for a new blockbuster product, and many computer companies want to add multimedia features to their software. This combination of technology and demand by three immensely rich and powerful industries has led to DVD, originally an acronym for Digital Video Disk, but now officially Digital Versatile Disk. DVDs use the same general design as CDs, with 120-mm injection-molded polycarbonate disks containing pits and lands3 that are illuminated by a laser diode and The basic CD/CD-ROM format has been around since 1980.:CD/CD-ROM 的基本格式自 1980 年就存在了。 句中的 around 为形容词,意思相当于 in existence(存在着的)。 Hollywood:好莱坞,美国加利福尼亚州西南部港市洛杉矶的一部分,在北郊,是美国的电影业中心。 120-mm injection-molded polycarbonate disks containing pits and lands:包含凹凸区的 120 毫米注模聚碳酸酯 计算机英语 land / lAnd / n. 凸区,槽脊 illuminate / i5lu:mineit / v. 照明;照射 diode / 5daiEud / n. 二极管 photodetector / 7fEutEudi5tektE / n. 光电探测器 micron / 5maikrCn / n. 微米 versus / 5vE:sEs / prep. 对;与…相比 spiral / 5spaiErEl / n. 螺旋(形) sevenfold / 5sevEnfEuld / ad. 七倍地 conversion / kEn5vE:FEn / n. 转换;转变 optic / 5Cptik / n. 光学仪器 resolution / rezE5lu:FEn / n. 分辨率;清晰度 dual / 5dju:El / a. 双的;双重的 35 read by a photodetector. What is new is the use of: 1. Smaller pits (0.4 microns versus 0.8 microns for CDs). 2. A tighter spiral (0.74 microns between tracks versus 1.6 microns for CDs). 3. A red laser (at 0.65 microns versus 0.78 microns for CDs). Together, these improvements raise the capacity sevenfold, to 4.7 GB1. A 1x DVD drive operates at 1.4 MB/sec (versus 150 KB/sec2 for CDs). Unfortunately, the switch to the red lasers used in supermarkets means that DVD players will require a second laser or fancy conversion optics to be able to read existing CDs and CD-ROMs, something not all of them may provide. Also, reading CD-Rs3 and CD-RWs4 on a DVD drive may not be possible. Is 4.7 GB enough? Maybe. Using MPEG-2 5 compression (standardized in IS6 13346), a 4.7 GB DVD disk can hold 133 minutes of full-screen, full-motion video at high resolution (720 × 480), as well as soundtracks in up to eight languages and subtitles in 32 more. About 92 percent of all the movies Hollywood has ever made are under 133 minutes. Nevertheless, some applications such as multimedia games or reference works may need more, and Hollywood would like to put multiple movies on the same disk, so four formats have been defined: 1. 2. 3. 4. Single-sided, single-layer (4.7 GB). Single-sided, dual-layer (8.5 GB). Double-sided, single-layer (9.4 GB). Double-sided, dual-layer (17 GB). Why so many formats? In a word: politics. Philips7 and Sony8 wanted single-sided, dual-layer disks for the high capacity version, but Toshiba9 and Time Warner10 wanted double-sided, single-layer disks. Philips and 盘片。 GB:吉字节,千兆字节(gigabyte 的缩略) 。 2 KB/sec:千字节∕秒(kilobyte/second 的缩略)。 3 CD-R:可刻录光盘(compact disc-recordable 的首字母缩略)。 4 CD-RW:可擦写光盘(compact disc-rewritable 的首字母缩略)。 5 MPEG:运动图像专家组(Moving Pictures Experts Group 的首字母缩略) 。 6 IS:国际标准(International Standard 的首字母缩略)。 7 Philips:(荷兰)飞利浦公司。 8 Sony:(日本)索尼公司。 9 Toshiba:(日本)东芝公司。 10 Time Warner:(美国)时代华纳公司。 1 36 Computer English Sony did not think people would be willing to turn the disks over, and Time Warner did not believe putting two layers on one side could be made to work. The compromise: all combinations, but the market will determine which ones survive. layering / 5leiEriN / n. 分层 The dual layering technology has a reflective layer at the bottom, topped with a semireflective layer. Depending on where the laser is focused, it bounces off one layer or the other. The lower layer needs slightly larger pits and lands to be read reliably, so its capacity is slightly smaller than the upper layer’s. Double-sided disks are made by taking two 0.6-mm single-sided disks and gluing them together back to back. To make the thicknesses of all versions the same, a single-sided disk consists of a 0.6-mm disk bonded to a blank substrate (or perhaps in the future, one consisting of 133 minutes of advertising, in the hope that people will be curious as to what is down there). The structure of the double-sided, dual-layer disk is illustrated in Figure 2C-1. consortium Figure 2C-1: A double-sided, dual-layer DVD disk / kEn5sC:tjEm / ([复]-tia / -tjE / 或 -tiums)n. 联营企 业; (国际)财团, 联盟 telecommunication / 5telikE7mju:ni5keiFEn / n. 电信 skip / skip / v. 略过,跳过 crop / krCp / v. 裁切,裁剪 1 DVD was devised by a consortium of 10 consumer electronics companies, seven of them Japanese, in close cooperation with the major Hollywood studios (some of which are owned by the Japanese electronics companies in the consortium). The computer and telecommunications industries were not invited to the picnic, and the resulting focus was on using DVD for movie rental and sales shows. For example, standard features include real-time skipping of dirty scenes, six-channel sound, and support for Pan-and-Scan1. The latter feature allows the DVD player to dynamically decide how to crop the left and right edges off movies (whose width:height ratio is 3:2) to fit on current television sets (whose aspect ratio is 4:3). Pan-and-Scan:画面的放大和扫描。 aspect ratio (电视、电影图像 的)高宽比,纵横比 incompatibility / 5inkEm7pAtE5bilEti / n. 不可兼容性 计算机英语 37 Another item the computer industry probably would not have thought of is an intentional incompatibility between disks intended for the United States and disks intended for Europe and yet other standards for other continents. Hollywood demanded this “feature” because new films are always released first in the United States and then shipped to Europe when the videos come out in the United States. The idea was to make sure European video stores could not buy videos in the U.S. too early, thereby reducing new movies’ European theater sales. If Hollywood had been running the computer industry, we would have had 3.5-inch floppy disks in the United States and 9-cm floppy disks in Europe. If DVD is a big success, DVD-R1 (recordable) and DVD-rewritable will be mass produced within a short time. The success of DVD is not guaranteed, however, since the cable companies2 have quite a different plan for delivering movies—video on demand3 over the cable—and the battle has barely begun. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The advantages of digital disks over analog video tapes are that they have a(n) ________ quality, are ________ to manufacture, last longer, take up less ________ in video stores, and do not have to be rewound. 2. According to the text, four formats have been defined for DVD: single-sided, ________; single-sided, dual-layer; ________, single-layer; and double-sided, dual-layer. The reason for so many formats is ________. 3. A single-sided disk consists of a 0.6-mm disk bonded to a blank ________ in order to make the thicknesses of all versions the same. 4. As stated in the text, there is an intentional ________ between disks intended for different continents. II. 1 2 3 Translate the following terms or phrases from English into DVD-R:可刻录 DVD 光盘(digital versatile disk-recordable 的首字母缩略) 。 cable companies:此处指有线电视公司。 on demand:一经要求,承索。 38 Computer English Chinese and vice versa: 1. 2. 3. 4. video tape aspect ratio CD-RW laser diode 5. 6. 7. 8. 反射层 光盘 高分辨率 软盘 计算机英语 39 Unit 3: Operating System (操作系统) Section A Operating System I. INTRODUCTION compact disc 光盘 An operating system (OS), in computer science, is the basic software that controls a computer. It has three major functions: it coordinates and manipulates computer hardware, such as computer memory, printers, disks, keyboard, mouse, and monitor; it organizes files on a variety of storage 40 Computer English media, such as floppy disk, hard drive, compact disc, and tape; and it manages hardware errors and the loss of data. II. HOW AN OS WORKS spreadsheet / 5spredFi:t / n.电子数据表,电子 表格 interpreter / in5tE:pritE / n. 解释程序, 解释器 orient / 5C:rient / v. 给…定向;使适 应;使面向 icon / 5aikCn / n. 图标,图符 multitasking / 5mQlti7tB:skiN / n. 多任务处理,同 时执行多项任务 time-slice / 5taimslais / n. 时间片 whereby / weE5bai / ad. 靠那个;借以 allot / E5lCt / n. 分配;分派 context switching 上下文转换 bookkeeping / 5buk7ki:piN / n. 簿记,登录账目 scheduler / 5Fedju:ElE; 5skedVu:ElEr / n. 调度程序,计划 任务程序 minimize / 5minimaiz / v. 使减少到 最低限度 perceptible Operating systems control different computer processes, such as running a spreadsheet program or accessing information from the computer’s memory. One important process is the interpretation of commands that allow the user to communicate with the computer. Some command interpreters are text-oriented, requiring commands to be typed in. Other command interpreters are graphically oriented and let the user communicate by pointing and clicking on an icon, an on-screen picture that represents a specific command. Beginners generally find graphically oriented interpreters easier to use, but many experienced computer users prefer text-oriented command interpreters because they are more powerful. Operating systems are either single-tasking or multitasking. The more primitive single-tasking operating systems can run only one process at a time. For instance, when the computer is printing a document, it cannot start another process or respond to new commands until the printing is completed. All modern operating systems are multitasking and can run several processes simultaneously. In most computers there is only one central processing unit (CPU), (the computational and control unit of the computer), so a multitasking OS creates the illusion of several processes running simultaneously on the CPU. The most common mechanism used to create this illusion is time-slice multitasking, whereby each process is run individually for a fixed period of time. If the process is not completed within the allotted time, it is suspended and another process is run. This exchanging of processes is called context switching. The OS performs the “bookkeeping” that preserves the state of a suspended process. It also has a mechanism, called a scheduler, that determines which process will be run next. The scheduler runs short processes quickly to minimize perceptible delay. The processes appear to run simultaneously because the user’s sense of time is much slower than the processing speed of the computer. / pE5septEbl / a. 可感知的; 可察觉的 virtual memory 虚拟内存 main memory 主存(储器) Operating systems can use virtual memory to run processes that require more main memory than is actually available. With this technique, space on the hard drive is used to mimic the extra memory needed. Accessing the hard drive is more time-consuming than accessing main 计算机英语 41 memory, however, so performance of the computer slows. III. CURRENT OPERATING SYSTEMS The operating systems commonly found on personal computers are UNIX, Macintosh1 OS, MS-DOS, OS/2, and Windows. ■ UNIX release / ri5li:s / n. 版本;发布 -specific / spi5sifik / comb. form 表示“限 定的”,“特有的” compatible / kEm5pAtEbl / a. 兼容的 clone / klEun / n. 克隆;克隆机, 兼容机 1 UNIX, in computer science, is a multiuser, multitasking operating system originally developed by Ken Thompson2 and Dennis Ritchie3 at AT&T4 Bell Laboratories5 in 1969 for use on minicomputers. UNIX exists in various forms and implementations; among these are versions developed at the University of California at Berkeley6 (known as BSD7 releases) and versions released by AT&T, the most recent being AT&T System V. UNIX is considered a powerful operating system which, because it is written in the C language, is more portable—less machine-specific—than other operating systems. UNIX is available in several related forms, including AIX, a version of UNIX adapted by IBM (to run on RISC8-based workstations), A/UX (a graphical version for the Apple 9 Macintosh), and Mach (a rewritten but essentially UNIX-compatible operating system for the NeXT computer). Its popularity is due in large part to the growth of the interconnected computer network known as the Internet, the software for which initially was designed for computers that ran UNIX. Variations of UNIX include SunOS (distributed by SUN Microsystems Inc.10), Xenix (distributed by Microsoft Corporation), and Linux 11 . UNIX and its clones support multitasking and multiple users. Its file system provides a simple means of Macintosh:麦金托什个人计算机,由 Apple 计算机公司于 1984 年 1 月推出的个人计算机系列。相对于 PC 机,俗称苹果机(电脑) 。 2 Ken Thompson:肯·汤普森(1943~),美国计算机科学家,与丹尼斯·里奇一起开发了 UNIX 操作系统。 3 Dennis Ritchie:丹尼斯·里奇(1941~),美国计算机科学家,开发了 C 语言,并与肯·汤普森一起开发 了 UNIX 操作系统。 4 AT&T:美国电话电报公司(American Telephone and Telegraph 的缩略)。 5 Bell Laboratories:贝尔实验室。 6 University of California at Berkeley:加利福尼亚大学伯克利分校。 7 BSD:伯克利软件发行中心(Berkeley Software Distribution 的首字母缩略)。 8 RISC:精简指令集计算机(reduced instruction set computing 的首字母缩略)。 9 Apple:(美国)苹果计算机公司。 10 SUN Microsystems Inc.:(美国)太阳微系统公司,主要生产 SUN 系列工作站和网络产品,是 JAVA 语言 的创始者。SUN 系 Stanford University Network 的首字母缩略。 11 Linux:Linux 操作系统,自 UNIX 发展而来,由芬兰人 Linus Torvalds 于 1991 年编写成功,随后采用开放 源代码方式在 Internet 上由全球编程人员共同开发,取得极大成功。 42 intuitive / in5tju:itiv / a. 直觉的;凭直觉 获知的 Computer English organizing disk files and lets users protect their files from other users. The commands in UNIX are not intuitive, however, and mastering the system is difficult. ■ MS-DOS oversee / 7EuvE5si: / v. 监视;检查; 管理 command line 命令行 MS-DOS is the acronym for Microsoft Disk Operating System. In computer science, MS-DOS—like other operating systems—oversees such operations as disk input and output, video support, keyboard control, and many internal functions related to program execution and file maintenance. MS-DOS is a single-tasking, single-user operating system with a command-line interface. ■ OS/2 data set 数据集 graphical user interface 图形用户界面 presentation manager 表示管理程序 pull-down / 5puldaun / a. 下拉(式)的 collaboration / kE7lAbE5reiFEn / n. 合作,协作 OS/2, or Operating System 2, is an operating system developed for the personal computer in the mid-1980s by International Business Machines Corporation (IBM) and Microsoft Corporation. At the time OS/2 was introduced in late 1987, the most common personal computers were IBM-compatible computers running the Microsoft Disk Operating System (MS-DOS) and computers manufactured by Apple Computer Corporation running Apple’s system for the Macintosh (Mac OS). The Macintosh operating system included multitasking, a feature that enabled computers to run several applications simultaneously. In a computer network, multitasking allows several users on different computers to have simultaneous access to the same application or data set. OS/2 was the first operating system designed for IBM-compatible personal computers that allowed multitasking. The first version of OS/2, version 1.0, was text-oriented and lacked a graphical user interface (GUI) that would allow users to enter commands with a point-and-click input device, such as a computer mouse. A year later IBM and Microsoft released OS/2 version 1.1, which included a GUI called the Presentation Manager. The Presentation Manager interface contained icons, pictures or words on the screen that users could click on with a mouse to enter instructions. OS/2 version 1.1 also allowed users to have multiple windows open (windows are portions of the screen that each contain a different document or program) and included pull-down lists of commands that the user could choose by clicking on them with their mouse. IBM and Microsoft ended their collaboration on OS/2 in 1991 after Microsoft released its Windows software, a multitasking environment that 计算机英语 43 ran on MS-DOS. In 1992 IBM released version 2.0 of OS/2, which ran Microsoft Windows programs and could perform multitasking of DOS operations. It also contained an object-oriented programming environment that allowed software designers to create programs using high-level, object-oriented programming languages. array / E5rei / n. 一系列,大量 upgrade / Qp5greid / v. 使升级;改善 Subsequent versions of OS/2 offered enhanced performance and multimedia capabilities, and in 1994 IBM announced that more than 5 million copies of OS/2 had been sold since its introduction. The same year, IBM introduced a new version of OS/2 called OS/2 Warp that featured improved performance, more multimedia capabilities, an array of integrated applications, and easy access to the Internet. IBM has continued to upgrade and extend OS/2 Warp. ■ Windows Windows, in computer science, is a personal computer operating system sold by Microsoft Corporation that allows users to enter commands with a point-and-click device, such as a mouse, instead of a keyboard. The Windows operating system provides users with a graphical user interface (GUI), which allows them to manipulate small pictures, called icons, on the computer screen to issue commands. Windows is the most widely used operating system in the world. It is an extension of and replacement for Microsoft’s Disk Operating System (MS-DOS). click-on / 5klikCn / a.(鼠标)点击 (式)的 overlap / 7EuvE5lAp / v. 重叠,层叠 The Windows GUI is designed to be a natural, or intuitive, work environment for the user. With Windows, the user can move a cursor around on the computer screen with a mouse. By pointing the cursor at icons and clicking buttons on the mouse, the user can issue commands to the computer to perform an action, such as starting a program, accessing a data file, or copying a data file. Other commands can be reached through pull-down or click-on menu items. The computer displays the active area in which the user is working as a window on the computer screen. The currently active window may overlap with other previously active windows that remain open on the screen. This type of GUI is said to include WIMP1 features: windows, icons, menus, and pointing device (such as a mouse). Computer scientists at the Xerox Corporation’s2 Palo Alto Research 1 2 WIMP:窗口-图标-菜单-指点设备(windows-icons-menus-pointing device 的首字母缩略)。 Xerox Corporation:施乐公司。 44 innovation / 7inE5veiFEn / n. 革新,创新 tiled / taild / a. 平铺(式)的 high-end / 5hai5end / a. 高端的,尖端的 network / 5netwE:k / v. 联网 sleek / sli:k / a. 光滑的;线条明 快的,造型优美的 window / 5windEu / v. 把…分隔成多个 窗口 Computer English Center (PARC1) invented the GUI concept in the early 1970s, but this innovation was not an immediate commercial success. In 1983 Apple Computer featured a GUI in its Lisa computer. This GUI was updated and improved in its Macintosh computer, introduced in 1984. Microsoft began its development of a GUI in 1983 as an extension of its MS-DOS operating system. Microsoft’s Windows version 1.0 first appeared in 1985. In this version, the windows were tiled, or presented next to each other rather than overlapping. Windows version 2.0, introduced in 1987, was designed to resemble IBM’s OS/2 Presentation Manager, another GUI operating system. Windows version 2.0 included the overlapping window feature. The more powerful version 3.0 of Windows, introduced in 1990, and subsequent versions 3.1 and 3.11 rapidly made Windows the market leader in operating systems for personal computers, in part because it was prepackaged on new personal computers. It also became the favored platform for software development. In 1993 Microsoft introduced Windows NT (New Technology). The Windows NT operating system offers 32-bit multitasking, which gives a computer the ability to run several programs simultaneously, or in parallel, at high speed. This operating system competes with IBM’s OS/2 as a platform for the intensive, high-end, networked computing environments found in many businesses. In 1995 Microsoft released a new version of Windows for personal computers called Windows 95. Windows 95 has a sleeker and simpler GUI than previous versions. It offers 32-bit processing, efficient multitasking, network connections, and Internet access. Few computer users run MS-DOS or OS/2 directly. They prefer versions of UNIX or windowing systems with graphical interfaces, such as Windows 98 or the Macintosh OS, which make computer technology more accessible. However, graphical systems generally have the disadvantage of requiring more hardware—such as faster CPUs, more memory, and higher-quality monitors—than command-oriented operating systems. IV. FUTURE TECHNOLOGIES Operating systems continue to evolve. A recently developed type of OS called a distributed operating system is designed for a connected, but 1 PARC:(施乐公司)帕洛阿尔托研究中心(Palo Alto Research Center 的首字母缩略)。 计算机英语 45 independent, collection of computers that share resources such as hard drives. In a distributed OS, a process can run on any computer in the network (presumably a computer that is idle) to increase that process’s performance. All basic OS functions—such as maintaining file systems, ensuring reasonable behavior, and recovering data in the event of a partial failure—become more complex in distributed systems. Research is also being conducted that would replace the keyboard with a means of using voice or handwriting for input. Currently these types of input are imprecise because people pronounce and write words very differently, making it difficult for a computer to recognize the same input from different users. However, advances in this field have led to systems that can recognize a small number of words spoken by a variety of people. In addition, software has been developed that can be taught to recognize an individual’s handwriting. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. An operating system is the basic ________ that controls a computer. 2. If you want to run more than one process at a time, you must use an operating system with ________ capability. 3. Operating systems can use ________ memory to run processes that require more main memory than is actually available. 4. OS/2 is an operating system developed jointly by ________ and Microsoft Corporation for the personal computer. 5. ________, whose popularity is due in large part to the growth of the Internet, is a(n) ________, multitasking operating system. 6. The most widely used operating system in the world is ________, which provides users with a(n) ________ user interface. 7. MS-DOS, the acronym for Microsoft Disk Operating System, is a single-tasking, single-user operating system with a(n) ________ interface. 8. A(n) ________ OS is designed for a connected, but independent, collection of computers that share resources. 46 Computer English II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. data set pointing device graphical user interface time-slice multitasking object-oriented programming click on an icon context switching distributed system pull-down lists of commands simultaneous access 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 命令行界面 多任务化环境 电子制表程序 主存 存储介质 磁盘文件 命令解释器 网络连接 磁盘操作系统 拷贝数据文件 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: program storage document internal interface classify efficiently security system unauthorized function password user control detect input Operating systems for micro, mini, and mainframe computers perform many services. These services can be ________ either as “external” or “internal.” The operating system provides external services that help ________ start programs, manage stored data, and maintain ________. You, as the computer user, control these external ________. Using a command-line (命 令行), menu-driven, or GUI user ________, an operating system provides you with a way to select the ________ you would like to use. The operating system also helps you find, rename, and delete ________ and other data stored on disk or tape. On many, but not all computer ________, the operating system helps you maintain security by checking your user ID (用 户标识) and ________, as well as protecting your data from ________ access and revisions (修改). The operating system provides ________ services “behind the scenes” to ensure that the computer system functions ________. These internal 计算机英语 47 services are not generally under your ________, but instead are controlled by the operating system itself. The operating system controls ________ and output, allocates (分配) system resources, manages the ________ space for programs and data, and ________ equipment failure without any direction from you. IV. Translate the following passage from English into Chinese: Multitasking, in computer science, is a mode of operation offered by an operating system in which a computer works on more than one task at a time. There are several types of multitasking. Context switching is a very simple type of multitasking in which two or more applications are loaded at the same time but only the foreground (前台的) application is given processing time; to activate (激活) a background (后台的) task, the user must bring the window or screen containing that application to the front. In cooperative (合作的) multitasking, background tasks are given processing time during idle times in the foreground task (such as when the application waits for a keystroke), and only if the application allows it. In time-slice multitasking each task is given the microprocessor’s attention for a fraction of a second. To maintain order, tasks are either assigned priority levels or processed in sequential (顺序的) order. Because the user’s sense of time is much slower than the processing speed of the computer, time-slice multitasking operations seem to be simultaneous. 48 Computer English Section B What Is Linux? scratch / skrAtF / n. 起跑线;零分 compliance Linux is a free UNIX clone written from scratch1 by Linus Torvalds2 and a team of programmers over the Internet. Linux aims towards POSIX3 compliance (a set of standards that show what a UNIX should be). / kEm5plaiEns / n. 遵从;顺从 library / 5laibrEri / n. 程序库,库 port / pC:t / n. 端口,通信口 fledged / fledVd / a. 羽毛已长成的; 成熟的 conform / kEm5fC:m / v. 遵照;符合(to, with) uninitiated / 7Qni5niFieitid / a. 缺乏某种特定知 识和经验的 utility / ju:5tilEti / n. 实用程序 installer / in5stC:lE / n. 安装程序 1 2 3 4 5 6 7 8 9 It contains all of the features that you would expect in not only a UNIX, but any operating system. Some of the features included are true multitasking, virtual memory, the world’s fastest TCP/IP4 drivers, shared libraries, and of course multi-user capabilities (this means hundreds of people can use one computer at the same time, either over a network, the Internet, or on laptops/computers or terminals connected to the serial ports of that computer). Linux runs fully in protected mode (unlike Windows) and supports fully fledged 32-bit and 64-bit multitasking. Linux also has a completely free X Windows 5 implementation conforming to the X/Open6 standard. Most existing X Based7 programs will run under Linux without any modification. X Windows for the uninitiated8 is a GUI, similar to Microsoft Windows but is feature packed (and is rather large, consuming around 15-20MB). 9 Most Linux distributions come completely pre-configured to a factory configuration, and distributions such as RedHat Linux also have graphical based configuration utilities and installers (not unlike Windows’ Control Panel). from scratch:从零开始,白手起家。 Linus Torvalds:莱纳斯·托瓦尔兹(1969~),芬兰人,Linux 操作系统的创始人。 POSIX:可移植的 UNIX 操作系统(Portable Operating System Interface for UNIX 的首字母或尾字母缩略)。 TCP/IP:TCP/IP 协议,传输控制协议∕网际协议(Transmission Control Protocol/Internet Protocol 的首字母 缩略)。 X Windows:由美国麻省理工学院技术人员开发的在 UNIX 工作站上使用的图形窗口,支持客户机/服务器 模式。不同于微软的 Windows。简称 X。 X/Open:支持 UNIX 开放标准的厂商联盟,也称 X/Open group。他们提供的系统通用于任何 UNIX 模块。 X Based:基于 X Windows 的。 the uninitiated:属定冠词加形容词表示一类人或事物的结构,指“缺乏某种特定知识和经验的人”。 X Windows for the uninitiated is a GUI, similar to Microsoft Windows but is feature packed (and is rather large, consuming around 15-20MB).:为缺乏经验者开发的 X Windows 是一种图形用户界面,类似于微软的 Windows,但其特性封装(而且比较庞大,耗费大约 15-20 兆空间)。 计算机英语 emulator / 5emjuleitE / n. 仿真器; 仿真程序 buffer / 5bQfE / v. 缓冲,缓存 collaborate / kE5lAbEreit / v. 合作,协作 packet radio 无线电包通信,无 线电分组通信 protocol / 5prEutEkCl / n. 协议 token ring 权标环,令牌环 1 49 In addition, programs intended for SCO Unix 4.2 and SVR4 will run on most Linux systems unaltered (this is due to the assistance of a driver called IBCS), for example Corel Draw!1 for SCO and the Dataflex database system. The Linux DOS emulator, DOSEMU, will run packets of MS-DOS applications, including some that require VGA 2 or SVGA 3 graphics capabilities. Windows programs can also be run inside of X-Windows with the help of an emulator called WINE. Usually, Windows programs can run up to 10 times faster than on a native system4, due to Linux’s buffering capabilities. As usually expected from most Unices5 , Linux includes advanced networking capabilities. Since the people developing Linux collaborated and used the Internet for their development efforts, networking support came early in Linux’s development stage. Networking support in Linux is superior to most other operating systems. Linux supports connection to the Internet or any other network using TCP/IP or IPX6 via Ethernet7, fast Ethernet8, ATM9, modem, packet radio (X.2510 protocol), ISDN11, token ring, or PLIP 12 (modified printer cable to another computer). As an Internet/WWW server, Linux is a very good choice, often out performing Windows NT, Novell13 and most UNIX systems on the same hardware (even multiprocessor boxes). Linux has been chosen by hundreds of thousands of ISPs14, by many university computer labs, and surprisingly by many businesses—by all people that need reliable server and network performance in many different situations. Corel Draw!: (加拿大)Corel 公司发行的一套绘图程序。 VGA:视频图形阵列(Video Graphics Array 的首字母缩略)。 3 SVGA:超级视频图形阵列(Super Video Graphics Array 的首字母缩略)。 4 a native system:原属系统,这里指 Windows 系统。 5 Unices:Unix 的复数形式。 6 IPX:网间报文交换,互联网络包交换(Internetwork Packet Exchange 的首字母缩略)。 7 Ethernet:以太网(标准)。 8 fast Ethernet:快速以太网,支持 100Mbps 容量的以太网。 9 ATM:异步传输模式(Asynchronous Transfer Mode 的首字母缩略) 。 10 X.25:一种专用网络,使用包交换协议,绕过有噪音的电话线路传输数据。该协议依赖于具有包转送节点 的包罗万象的广域网,这些节点可以参与将 X.25 数据包传递到指定的地址。 11 ISDN:综合业务数字网,俗称一线通(Integrated Services Digital Network 的首字母缩略)。 12 PLIP:并行线路接口协议(Parallel Line Interface Protocol 的首字母缩略)。 13 Novell:Novell 网络操作系统平台。美国著名的网络产品开发商 Novell 公司的产品。 14 ISP:因特网服务提供者(Internet service provider 的首字母缩略)。 2 50 Computer English Linux supports all of the most common Internet protocols, including FTP , POP2, SNMP3, and many more. Linux can operate as a client or as a server for all of the above and has already been widely used and tested in the above roles. 1 local area network 局域网 seamless / 5si:mlis / a. 无缝的 swap space 交换空间 blinding / 5blain diN / a. 眩目的,使人眼 花缭乱的 source code 源(代)码 kernel / 5kE:nEl / n.(果核或果壳内 的)仁;核心 Linux also fits easily and tightly into your local area network, no matter what combination of systems you might be running. Full and seamless support for Macintosh, DOS, Windows, Windows NT, Windows 95, Novell, OS/2, all using their own native protocols—Linux can do all of this in just 16MB of memory or even less (with swap space). Typically, you can have all the above running in 8MB with 16MB swap (a total of 24MB RAM). Linux is developing at a blindingly fast speed, and ports exist to PowerPC4, Macintosh, and so on. If Linus Torvalds ever does decide to abandon the project, since we have the full source code available, he can just assign somebody else to take his place. The Linux kernel development will still continue no matter what happens to Linus. Somebody else will just continue with it. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Linux is a free ______ clone developed by Linus Torvalds and a team of programmers over the Internet. 2. Since it was developed through cooperative efforts over the Internet, ________ support in Linux is superior to most other operating systems. 3. The features contained in Linux include true ________, virtual memory, the world’s fastest TCP/IP ________, shared libraries, and multi-user capabilities. 4. 1 2 3 4 According to the text, Linux can operate as a(n) ________ or as a FTP:文件传输协议(File Transfer Protocol 的首字母缩略)。 POP:邮局协议(Post Office Protocol 的首字母缩略)。 SNMP:简单网络管理协议(Simple Network Management Protocol 的首字母缩略)。 PowerPC:PowerPC 微处理器,一种由 Motorola 公司和 IBM 公司于 1992 年开发的微处理器体系结构,Apple 公司也参与了部分开发工作。 51 计算机英语 server for all of the most common Internet ________, including FTP, POP, SNMP, and so on. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. serial port configuration utility ISDN token ring fast Ethernet 6. 7. 8. 9. 10. 虚拟内存 源代码 交换空间 邮局协议 超级视频图形阵列 52 Computer English Section C Performance in Windows 2000 INTRODUCTION deploy / di5plCi / v. 部署;配置 benchmark / 5bentFmB:k / n. 基准(尺度) ;基 准程序;基准测试 scenario / si5nB:riEu / n. 方案;设想 1 2 Whether deploying the Microsoft Windows 2000 operating system on the desktop or in the most demanding Web server environment, you can expect significant performance advantages over previous releases. In addition to providing the highest levels of reliability, providing a comprehensive set of features to Internet-enable your business1, lowering TCO 2 through enhanced management, and adding support for new hardware devices, Windows 2000 also delivers better performance. Using a wide range of benchmarks, this paper will provide you with information on the performance improvements of Windows 2000 in different deployment scenarios. to Internet-enable your business:使你的商务网络化。 TCO:总拥有成本(total cost of ownership 的首字母缩略)。 计算机英语 53 CLIENT PERFORMANCE Plug and Play 即插即用 binary / 5bainEri / n. 二进制 optimize / 5Cptimaiz / v. 使优化, 使最佳化 registry access 注册表存取 gigabit / 5dVigEbit / n. 吉位,千兆比特 throughput / Wru:5put / n. 吞吐量,吞吐率 adapter / E5dAptE / n. 适配器 checksum / 5tFeksQm / n. 检查和,校验和, 检验和 offload / 5CflEud / v. 卸载 In addition to the many new desktop features that have been added to Windows 2000 Professional such as Plug and Play, power management, single worldwide binary for all languages, IntelliMirrorTM1 management technologies, and many others, the performance on the desktop is significantly faster than Windows 95 & 98 and comparable to Windows NT Workstation 4.0. By optimizing fundamental system services such as memory management, registry access, and disk I/O, Windows 2000 is able to deliver the added benefit of new features while delivering the performance that customers expect. NETWORKING PERFORMANCE Windows 2000 is gigabit ready. This means that Windows 2000 is capable of sustaining the highest levels of network throughput using gigabit adapters. For example, using network adapters designed to utilize the advanced TCP/IP features in Windows 2000 such as TCP/IP checksum offloading and large send support, Windows 2000 can deliver up to 25% better network throughput than Windows NT Server 4.0 and sustain close to 4 gigabits per second (Gbps) of data throughput. With the improved networking efficiency provided by Windows 2000, customers will benefit from higher capacity Web servers, file servers, and application servers. WEB SERVER PERFORMANCE scalability / 7skeilE5bilEti / n. 可缩放性 1 2 3 4 The performance of Web sites running Windows NT Server 4.0 can immediately be improved by upgrading to Windows 2000. Advances have been made in Windows 2000 that significantly improve Active Server Pages (ASP 2 ) performance and SMP 3 scalability. In addition, ASP applications running in out-of-process mode perform significantly better on Windows 2000. For example, an ASP application running in out-of-process mode on Windows 2000 is as fast as the same ASP application running in the Web server process on Windows NT Server 4.0. Furthermore, the raw performance of serving static Web pages has increased significantly according to publicly available SPECWeb4 96 results. IntelliMirrorTM:智能镜像技术,Windows 2000 中的专利技术。TM 是 trademark 的缩写,表示 IntelliMirror 为注册商标。 ASP:活动服务器网页(Active Server Pages 的首字母缩略)。 SMP:对称多(任务)处理(symmetric multiprocessing 的首字母缩略)。 SPECWeb:一种 Web 性能的基准测试程序。 54 Computer English FILE & PRINT SERVER PERFORMANCE cache / kAF / n. 高速缓冲存储器 redirector / 7ri:di5rektE / n. 呼叫转移器,重 定向器 scalable / 5skeilEbl / a. 可缩放的,可扩 缩的,可升级的 partition / pB:5tiFEn / n. & v. 分区,分割, 划分 degrade / di5greid / v. 降低;退化 rendering / 5rendEriN / n. 渲染(计算机图 形处理术语,专指 诸如 3D 等图形效 果处理运算) physical memory 物理内存 profound / prE5faund / a. 深邃的;深刻的 By improving many aspects of the file server components such as increasing the virtual size of the file cache from 496MB to 960MB, optimizing the SMB1 redirector on Windows 2000, and optimizing the Windows NT File System (NTFS2), Windows 2000 provides customers with a better performing and scalable file server solution. Using the NetBench 3 benchmark, Windows 2000 Server with Windows 2000 Professional-based clients provides up to 20% better performance than Windows NT Server 4.0 with Windows NT Workstation 4.0-based clients. In some cases, especially where the file shares are stored on a single partition, Windows 2000 provides up to 2-times better file server performance than Windows NT Server 4.0. As a print server, Windows 2000 is capable of processing up to 3-times more pages per second when compared to Windows NT Server 4.0. Moreover, print performance doesn’t degrade on Windows 2000 Server as additional printers are added. Furthermore, Windows 2000 can perform the rendering in 1/3 of the time it took on Windows NT Server 4.0 and requires 1/3 of the CPU resources. APPLICATION SERVER PERFORMANCE Windows 2000 Server is a better platform for running business applications. Better SMP scalability, improved networking performance, and support for more physical memory have a profound impact on the performance of Windows 2000 in an application server environment. Advances to what is now known as COM+ 4 (formerly COM 5 and Microsoft Transaction Server 6 ) also provide better performance to customers running COM-based applications. In addition, transaction-processing capabilities of COM+ can be used as a transaction monitor when running to improve performance of database applications. ———————————————— Exercises 1 2 3 4 5 6 SMB:服务器消息块(Server Message Block 的首字母缩略)。 NTFS:NT 文件系统,一种专为 Windows NT 设计的高级文件系统(NT File System 的缩略)。 NetBench:一种标准网络性能的基准测试程序。 COM+:扩展组件对象模型。 COM:组件对象模型(Component Object Model 的首字母缩略)。 Microsoft Transaction Server:微软事务服务器软件,常用于分布式系统的事务处理。 55 计算机英语 I. Fill in the blanks with the information given in the text: 1. Windows 2000 has significant performance advantages over previous ________. 2. By upgrading to ________, the performance of Web sites running Windows NT Server 4.0 can immediately be improved. 3. Using network adapters designed to utilize its advanced TCP/IP features, Windows 2000 can sustain close to ________ of data throughput. 4. Improvements made in ________ scalability, ________ performance, and support for physical ________ greatly enhance the performance of Windows 2000 in an application server environment. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. network throughput registry access scalable file server static Web page 5. 6. 7. 8. 物理内存 即插即用 网络适配器 对称多任务处理 56 Computer English Unit 4: Computer Language and Programming (计算机语言与编程) Section A Programming Language I. INTRODUCTION syntax / 5sintAks / n. 句法 ambiguous / Am5bigjuEs / a. 含糊不清的, 模棱两可的 punctuation / 7pQNktju5eiFEn / n. 标点符号 sophistication / sE7fisti5keiFEn / n. 复杂性;尖端性 versatility / 7vE:sE5tilEti / n. 多用途;通用性 address / E5dres / v. 对付,处理 portable / 5pC:tEbEl / a. 可移植的; 便携的 1 2 3 Programming languages, in computer science, are the artificial languages used to write a sequence of instructions (a computer program) that can be run by a computer. Similar to natural languages, such as English, programming languages have a vocabulary, grammar, and syntax. However, natural languages are not suited for programming computers because they are ambiguous, meaning that their vocabulary and grammatical structure may be interpreted in multiple ways. The languages used to program computers must have simple logical structures, and the rules for their grammar, spelling, and punctuation must be precise. Programming languages vary greatly in their sophistication and in their degree of versatility. Some programming languages are written to address a particular kind of computing problem or for use on a particular model of computer system. For instance, programming languages such as FORTRAN1 and COBOL2 were written to solve certain general types of programming problems—FORTRAN for scientific applications, and COBOL for business applications. Although these languages were designed to address specific categories of computer problems, they are highly portable, meaning that they may be used to program many types of computers. Other languages, such as machine languages, are designed to be used by one specific model of computer system, or even by one specific computer in certain research applications. The most commonly used programming languages are highly portable and can be used to effectively solve diverse types of computing problems. Languages like C, PASCAL3, FORTRAN:FORTRAN 语言,公式翻译程序语言(Formula Translation 的缩合)。 COBOL:COBOL 语言,面向商业的通用语言(Common Business-Oriented Language 的首字母缩略)。 PASCAL:PASCAL 语言。 计算机英语 57 and BASIC fall into this category. II. LANGUAGE TYPES assembly language 汇编语言 intermediate language 中间语言,中级语言 linguistic / liN5gwistik / a. 语言(学)的 Programming languages can be classified as either low-level languages or high-level languages. Low-level programming languages, or machine languages, are the most basic type of programming languages and can be understood directly by a computer. Machine languages differ depending on the manufacturer and model of computer. High-level languages are programming languages that must first be translated into a machine language before they can be understood and processed by a computer. Examples of high-level languages are C, C++, PASCAL, and FORTRAN. Assembly languages are intermediate languages that are very close to machine languages and do not have the level of linguistic sophistication exhibited by other high-level languages, but must still be translated into machine language. A. Machine Languages storage register 存储寄存器 statement / 5steitmEnt / n. 语句 In machine languages, instructions are written as sequences of 1s and 0s, called bits, that a computer can understand directly. An instruction in machine language generally tells the computer four things: (1) where to find one or two numbers or simple pieces of data in the main computer memory (Random Access Memory, or RAM), (2) a simple operation to perform, such as adding the two numbers together, (3) where in the main memory to put the result of this simple operation, and (4) where to find the next instruction to perform. While all executable programs are eventually read by the computer in machine language, they are not all programmed in machine language. It is extremely difficult to program directly in machine language because the instructions are sequences of 1s and 0s. A typical instruction in a machine language might read 10010 1100 1011 and mean add the contents of storage register A to the contents of storage register B. B. High-Level Languages High-level languages are relatively sophisticated sets of statements utilizing words and syntax from human language. They are more similar to normal human languages than assembly or machine languages and are therefore easier to use for writing complicated programs. These programming languages allow larger and more complicated programs to be developed faster. However, high-level languages must be translated into machine language by another program called a compiler before a computer 58 compiler / kEm5pailE / n. 编译程序, 编译器 Computer English can understand them. For this reason, programs written in a high-level language may take longer to execute and use up more memory than programs written in an assembly language. C. Assembly Languages Computer programmers use assembly languages to make machine-language programs easier to write. In an assembly language, each statement corresponds roughly to one machine language instruction. An assembly language statement is composed with the aid of easy to remember commands. The command to add the contents of the storage register A to the contents of storage register B might be written ADD B, A in a typical assembly language statement. Assembly languages share certain features with machine languages. For instance, it is possible to manipulate specific bits in both assembly and machine languages. Programmers use assembly languages when it is important to minimize the time it takes to run a program, because the translation from assembly language to machine language is relatively simple. Assembly languages are also used when some part of the computer has to be controlled directly, such as individual dots on a monitor or the flow of individual characters to a printer. III. CLASSIFICATION OF HIGH-LEVEL LANGUAGES essence / 5esEns / n. 本质,实质 procedural language 过程语言 1 High-level languages are commonly classified as procedure-oriented, functional, object-oriented, or logic languages. The most common high-level languages today are procedure-oriented languages. In these languages, one or more related blocks of statements that perform some complete function are grouped together into a program module, or procedure, and given a name such as “procedure A.” If the same sequence of operations is needed elsewhere in the program, a simple statement can be used to refer back to the procedure. In essence1, a procedure is just a mini-program. A large program can be constructed by grouping together procedures that perform different tasks. Procedural languages allow programs to be shorter and easier for the computer to read, but they require the programmer to design each procedure to be general enough to be used in different situations. Functional languages treat procedures like mathematical functions functional language and allow them to be processed like any other data in a program. This 函数式语言 allows a much higher and more rigorous level of program construction. rigorous / 5rigErEs / a. 严密的;严格的 in essence:本质上,实质上。 计算机英语 59 Functional languages also allow variables—symbols for data that can be specified and changed by the user as the program is running—to be given values only once. This simplifies programming by reducing the need to be concerned with the exact order of statement execution, since a variable does not have to be redeclared, or restated, each time it is used in a program statement. Many of the ideas from functional languages have become key parts of many modern procedural languages. Object-oriented languages are outgrowths of functional languages. In object-oriented languages, the code used to write the program and the data processed by the program are grouped together into units called objects. Objects are further grouped into classes, which define the attributes objects must have. A simple example of a class is the class Book. Objects within this class might be Novel and Short Story. Objects also have certain functions associated with them, called methods. The computer accesses an object through the use of one of the object’s methods. The method performs some action to the data in the object and returns this value to the computer. Classes of objects can also be further grouped into hierarchies, in which objects of one class can inherit methods from another class. The structure provided in object-oriented languages makes them very useful for complicated programming tasks. Logic languages use logic as their mathematical base. A logic program consists of sets of facts and if-then rules, which specify how one set of facts may be deduced from others, for example: If the statement X is true, then the statement Y is false. In the execution of such a program, an input statement can be logically deduced from other statements in the program. Many artificial intelligence programs are written in such languages. IV. LANGUAGE STRUCTURE AND COMPONENTS Programming languages use specific types of statements, or instructions, to provide functional structure to the program. A statement in a program is a basic sentence that expresses a simple idea—its purpose is to give the computer a basic instruction. Statements define the types of data allowed, how data are to be manipulated, and the ways that procedures and functions work. Programmers use statements to manipulate common components of programming languages, such as variables and macros (mini-programs within a program). macro / 5mAkrEu / n. 宏,宏指令 60 data declaration 数据声明 array / E5rei / n. 数组,阵列 expression / ik5spreFEn / n. 表达式 assignment statement 赋值语句 conditional statement 条件语句 function statement 函数语句 parameter / pE5rAmitE / n. 参数,参量 Computer English Statements known as data declarations give names and properties to elements of a program called variables. Variables can be assigned different values within the program. The properties variables can have are called types, and they include such things as what possible values might be saved in the variables, how much numerical accuracy is to be used in the values, and how one variable may represent a collection of simpler values in an organized fashion, such as a table or array. In many programming languages, a key data type is a pointer. Variables that are pointers do not themselves have values; instead, they have information that the computer can use to locate some other variable—that is, they point to another variable. An expression is a piece of a statement that describes a series of computations to be performed on some of the program’s variables, such as X+Y/Z, in which the variables are X, Y, and Z and the computations are addition and division. An assignment statement assigns a variable a value derived from some expression, while conditional statements specify expressions to be tested and then used to select which other statements should be executed next. Procedure and function statements define certain blocks of code as procedures or functions that can then be returned to later in the program. These statements also define the kinds of variables and parameters the programmer can choose and the type of value that the code will return when an expression accesses the procedure or function. Many programming languages also permit minitranslation programs called macros. Macros translate segments of code that have been written in a language structure defined by the programmer into statements that the programming language understands. V. HISTORY Programming languages date back almost to the invention of the digital computer in the 1940s. The first assembly languages emerged in the late 1950s with the introduction of commercial computers. The first procedural languages were developed in the late 1950s to early 1960s: FORTRAN, created by John Backus1, and then COBOL, created by Grace Hopper 2 . The first functional language was LISP 3 , written by John 1 2 3 John Backus:约翰·巴克斯(1924~),美国计算机科学家。 Grace Hopper:格雷斯·霍珀(1906~1992),美国应用数学家,计算机程序语言的开拓者。 LISP:LISP 语言,表处理语言(List Processing 的缩合)。 计算机英语 61 McCarthy1 in the late 1950s. Although heavily updated, all three languages are still widely used today. merge / mE:dV / v. 合并;结合 relational language 关系语言, 相关语言 In the late 1960s, the first object-oriented languages, such as SIMULA2, emerged. Logic languages became well known in the mid 1970s with the introduction of PROLOG3, a language used to program artificial intelligence software. During the 1970s, procedural languages continued to develop with ALGOL4, BASIC, PASCAL, C, and Ada5. SMALLTALK6 was a highly influential object-oriented language that led to the merging of object-oriented and procedural languages in C++ and more recently in JAVA 7 . Although pure logic languages have declined in popularity, variations have become vitally important in the form of relational languages for modern databases, such as SQL8. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. A programming language is any ________ language that can be used to write a sequence of ________ that can ultimately be processed and executed by a computer. 2. We can classify programming languages under two types: ________ languages and ________ languages. 3. A machine language is a(n) ________ language in binary code that the computer can understand and execute directly. 4. High-level languages must first be translated into a(n) ________ language before they can be understood and processed by a computer. 5. High-level languages are commonly classified as procedure-oriented, ________, object-oriented, or ________ languages. 6. 1 2 3 4 5 6 7 8 In an assembly language, each ________ corresponds roughly to John McCarthy:约翰·麦卡锡(1927~),美国计算机科学家。 SIMULA:SIMULA 语言,仿真语言,模拟语言(Simulation Language 的缩合)。 PROLOG:PROLOG 语言,逻辑程序设计语言(Programming in Logic 的缩合)。 ALGOL:ALGOL 语言,算法语言(Algorithmic Language 的缩合) 。 Ada:Ada 语言。 SMALLTALK:SMALLTALK 语言,IBM 开发的面向对象的编程环境(语言)。 JAVA:Java 语言,一种新型的计算机语言,可以跨平台运行。 SQL:结构化查询语言(structured query language)。 62 Computer English one machine language instruction. 7. In procedure-oriented languages, one or more related blocks of statements that perform some complete function are grouped together into a program ________, or procedure. 8. The history of programming languages can be traced back almost to the invention of the ________ computer in the 1940s. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. storage register function statement program statement object-oriented language assembly language intermediate language relational language artificial language data declaration SQL 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 可执行程序 程序模块 条件语句 赋值语句 逻辑语言 机器语言 过程语言 程序设计语言 运行计算机程序 计算机程序设计员 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: reuse high-level program programming translate computer processing combine step machine inconvenient programmer memory execution separate powerful A programming language is a language used to write instructions for the computer. It lets the programmer express data ________ in a symbolic manner without regard to machine-specific details. The difficulty of writing programs in the ________ language of 0s and 1s led first to the development of assembly language, which allows ________ to use mnemonics (助记符) for instructions and symbols for variables. Such programs are then ________ by a program known as an assembler into the binary encoding used by the ________. Other pieces of 计算机英语 63 system software known as linking loaders (连接装入程序) ________ pieces of assembled code and load them into the machine’s main ________ unit, where they are then ready for execution. The concept of linking ________ pieces of code was important, since it allowed “libraries” of ________ to be built up to carry out common tasks—a first ________ toward the increasingly emphasized notion of software ________. Assembly language was found to be sufficiently ________ that higher-level languages (closer to natural languages) were invented in the 1950s for easier, faster ________; along with them came the need for compilers, programs that translate ________ language programs into machine code. As programming languages became more ________ and abstract, building efficient compilers that create high-quality code in terms of ________ speed and storage consumption became an interesting computer science problem in itself. IV. Translate the following passage from English into Chinese: One especially powerful feature of OOP (object-oriented programming) languages is a property which is known as inheritance. Inheritance allows an object to take on the characteristics and functions of other objects to which it is functionally connected. Programmers connect objects by grouping them together in different classes and by grouping the classes into hierarchies. These classes and hierarchies allow programmers to define the characteristics and functions of objects without needing to repeat source code, the coded instructions in a program. Thus, using OOP languages can greatly reduce the time it takes for a programmer to write an application, and also reduce the size of the program. OOP languages are flexible and adaptable, so programs or parts of programs can be used for more than one task. Programs written with OOP languages are generally shorter in length and contain fewer bugs (缺陷), or mistakes, than those written with non-OOP languages. 64 Computer English Section B Visual C++ and MFC Basics basic / 5beisik / n. [常作~s]基本原 理;基本因素 class hierarchy 类层次 encapsulate / in5kApsEleit / v. 封装 editor / 5editE / n. 编辑器, 编辑程序 1 2 Visual C++ is much more than a compiler. It is a complete application development environment that, when used as intended, lets you fully exploit the object-oriented nature of C++ to create professional Windows applications. To take advantage of these features, you need to understand the C++ programming language. You must then understand the Microsoft Foundation Class (MFC1) hierarchy. This class hierarchy encapsulates the user interface portion of the Windows API2, supplies other useful classes, and makes it significantly easier to create Windows applications in an object-oriented way. Let’s say you want to create a Windows application. You might, for example, need to create a specialized text or drawing editor, or a program MFC:微软基础类(Microsoft Foundation Class 的首字母缩略)。 API:应用程序接口(Application Program Interface 的首字母缩略)。 计算机英语 visualize / 5vizjuElaiz / v. 使可视化,使可 见;使直观化 control / kEn5trEul / n. 控件,控制器 scroll / skrEul / v. & n. 滚动 scroll bar 滚动条 code / kEud / v. 编码,编程序 customize / 5kQstEmaiz / v. 定制,使用户化 dialog box 对话框 pull-down menu 下拉(式)菜单 specific / spi5sifik / n. [~s]详情,细节 65 that finds files on a large network, or an application that lets a user visualize the interrelationships in a big data set. Where do you begin? A good starting place is the design of the user interface. First, decide what the user should be able to do with the program, and then pick a set of user interface objects accordingly. The Windows user interface has a number of standard controls, such as buttons, menus, scroll bars, and lists, that are already familiar to Windows users. With this in mind, you can choose a set of controls and decide how they should be arranged on screen. You might start with a rough sketch of the interface if the program is small, or go through a complete user interface specification and design cycle if the program is large. The next step is to implement the code. When creating a program for any Windows platform, the programmer has two choices: C or C++. With C, the programmer codes at the level of the Windows Application Program Interface (API). This interface consists of a collection of hundreds of C functions described in the Window’s API reference books. When you use MFC, you write code that creates the necessary user interface controls and customizes their appearance. You also write code that responds when the user manipulates these controls. For example, if the user clicks a button, you want to have code in place that responds appropriately. It is this sort of event-handling code that will form the bulk of any application. Once the application responds correctly to all of the available controls, it is finished. All window-based GUIs contain the same basic elements and all operate in the same way. On screen the user sees a group of windows, each of which contains controls, icons, objects, and so on that are manipulated with the mouse or the keyboard. The interface objects seen by the user are the same from system to system: push buttons, scroll bars, icons, dialog boxes, pull-down menus, etc. These interface objects all work the same way, although some have minor differences in their “look and feel.” For example, scroll bars look slightly different as you move from Windows to the Mac, but they all do the same thing. From a programmer’s standpoint, the systems are all similar in concept, although they differ radically in their specifics. To create a GUI program, the programmer first puts all the needed user interface controls into a window. For example, if the programmer is trying to create a simple 66 Fahrenheit / 5fArEnhait / a. 华氏(温度计)的 Celsius / 5selsiEs / a.(温度)摄氏的 Computer English program such as a Fahrenheit to Celsius converter, then the programmer selects user interface objects appropriate to the task and displays them on screen. In this example, the programmer might let the user enter a temperature in an editable text area, display the converted temperature in another un-editable text area, and let the user exit the program by clicking on a push button labeled “Quit.” This structure is shown in Figure 4B-1. Figure 4B-1: Elements of a typical application showing the selection of user interface controls in a Fahrenheit to Celsius conversion program highlight / 5hailait / v. 突出显示,强光 显示 child window 子窗口 function call 函数调用 event-driven / i5vent7drivEn / a. 事件驱动的 As the user manipulates the application’s controls, the program must respond appropriately. For example, if the user clicks the Quit button, the button must update the screen appropriately, highlighting itself as necessary. Then the program must respond by quitting. Normally the button manages its appearance itself, and the program in some way receives a message from the button that says, “The Quit button was pressed. Do something about it.” The program responds by exiting. Windows follows this same general pattern. In a typical application you will create a main window and place inside it different user interface controls. These controls are often referred to as child windows—each control is like a smaller and more specialized sub-window inside the main application window. As the application programmer, you manipulate the controls by sending them messages via function calls, and they respond to user actions by sending messages back to your code. If you have never done any “event-driven” programming, then all of 计算机英语 67 this may seem foreign to you. However, the event-driven style of programming is easy to understand when compared to a normal command-driven user interface. prompt / prCmpt / v. & n. 提示(符) explanatory In a command-driven user interface, the system interacts with the user in three steps. First, the system prompts the user for a command. The prompt could be something explanatory such as: / ik5splAnEtEri / a. 解释的,说明的 obtuse / Eb5tju:s / a. 不 被 明 显 感 知 的; (感觉)迟钝的 parse / pB:z / v.(从语法上)分析 modifier / 5mCdifaiE / n. 限定语符; 修改量 interface / 5intEfeis / v.(使)联系; (使) 接合 loop / lu:p / n. & v. 循环(体) click / klik / n.(鼠标的)点击 abstraction / Ab5strAkFEn / n. 抽象;提取 1 Please enter the next command> Or it could be something more obtuse: % The user is expected to know all the commands in the system and to type whichever one is needed. Second, the user types a command at the prompt and the system reads it. Third, the system parses the command and any modifiers following the command. The parsing step allows the system to call appropriate code to “execute” the command. Once command execution is complete, the program issues a new command prompt and the cycle repeats. Users of DOS or UNIX are familiar with this process. An event-driven user interface works somewhat differently. The exact details depend on the system and the level at which you are interfacing with it, but the basic concepts are similar. In an event-driven interface, the application paints several (or many) user interface objects such as buttons, text areas, and menus onto the screen. Now the application waits—typically in a piece of code called an event loop—for the user to do something. The user can do anything to any of the objects on screen using either the mouse or the keyboard. The user might click one of the buttons, for example. The mouse click is called an event. Event-driven systems define events for user actions such as mouse clicks and keystrokes, as well as for system activities such as screen updating.1 At the lowest level of abstraction, you have to respond to each event in a fair amount of detail. This is the case when you are writing normal C code directly to the API. In such a scenario, you receive the mouse-click event in some sort of structure. Code in your event loop looks at different fields in the structure, determines which user interface object was affected, Event-driven systems define events for user actions such as mouse clicks and keystrokes, as well as for system activities such as screen updating.:事件驱动系统为鼠标点击和按键等用户行为,以及屏幕更新等系统活动 定义事件。 68 Computer English perhaps highlights the object in some way to give the user visual feedback, and then performs the appropriate action for that object and event. When there are many objects on the screen, the application becomes very large. It can take quite a bit of code simply to figure out which object was clicked and what to do about it. handler / 5hAndlE / n. 处理程序 Fortunately, you can work at a much higher level of abstraction. In MFC, almost all these low-level implementation details are handled for you. If you want to place a user interface object on the screen, you create it with two lines of code. If the user clicks on a button, the button does everything needed to update its appearance on the screen and then calls a pre-arranged function in your program. This function contains the code that implements the appropriate action for the button. MFC handles all the details for you: you create the button and tell it about a specific handler function, and it calls your function when the user presses it. The labor involved in creating MFC applications is almost completely devoted to the creation of the handler functions. One of the best ways to begin understanding the structure and style of a typical MFC program is to enter, compile, and run a small example. Listing 4B-1 contains a simple “Hello World” program. The goal is to use the Visual C++ environment to create, compile, and execute this simple program. Listing 4B-1: hello.cpp—a simple “Hello World” program in MFC //hello.cpp #include <afxwin.h> // Declare the application class class CHelloApp : public CWinApp { public: virtual BOOL InitInstance(); }; // Create an instance of the application class CHelloApp HelloApp; // Declare the main window class class CHelloWindow : public CFrameWnd { CStatic* cs; 计算机英语 69 public: CHelloWindow(); }; // The InitInstance function is called each // time the application first executes. BOOL CHelloApp::InitInstance() { m_pMainWnd = new CHelloWindow(); m_pMainWnd->ShowWindow(m_nCmdShow); m_pMainWnd->UpdateWindow(); return TRUE; } // The constructor for the window class CHelloWindow::CHelloWindow() { // Create the window itself Create(NULL, "Hello World!", WS_OVERLAPPEDWINDOW, CRect(0,0,200,200)); // Create a static label cs = new CStatic(); cs->Create("hello world", WS_CHILD|WS_VISIBLE|SS_CENTER, CRect(50,80,150,150), this); } initialization / i7niFElai5zeiFEn / n. 初始化,赋初值 straightforward / 7streit5fC:wEd / a. 简单的;直截了 当的 custom / 5kQstEm / a. 定制的 This small program does three things. First, it creates an “application object.” Every MFC program you write will have a single application object that handles the initialization details of MFC and Windows. Next, the application creates a single window on the screen to act as the main application window. Finally, inside that window the application creates a single static text label containing the words “Hello World.” The steps necessary to enter and compile this program are straightforward. If you have not yet installed Visual C++ on your machine, do so now. You will have the option of creating standard and custom installations. ———————————————— 70 Computer English Exercises I. Fill in the blanks with the information given in the text: 1. When used as intended, Visual C++ lets you make full use of the ________ nature of C++ to create professional Windows applications. 2. According to the text, a good starting place to create a Windows application is the design of the ________. 3. A(n) ________ is an action, such as a keystroke or mouse click, to which a program might respond. 4. In a typical Windows application, you should create a main window and place inside it different user interface ________, which are often referred to as child windows. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. function call event-driven programming click on a push button application window class hierarchy 6. 7. 8. 9. 10. 子窗口 应用程序开发环境 下拉菜单 对话框 滚动条 计算机英语 71 Section C The Java Language superfluous / sju:5pE:fluEs / a. 多余的;过剩的 instantaneous / 7instEn5teinjEs / n. 瞬间的,即刻的 overhead / 5EuvEhed / n. 开销;经常(或 管理、间接)费用 The Java language is a remarkable example of programming language evolution. Java builds on the familiar and useful features of C++ while removing its complex, dangerous, and superfluous elements. The result is a language that is safer, simpler, and easier to use. The following sections describe Java in contrast to C++. Java Is Familiar and Simple If you have ever programmed in C++, you will find Java’s appeal to be instantaneous. Since Java’s syntax mirrors that of C++, you will be able to write Java programs within minutes. Your first programs will come quickly and easily, with very little programming overhead. 72 clutter / 5klQtE / n. 凌乱,杂乱;杂 乱的东西 cryptic / 5kriptik / a. 隐含的;意义含 糊的 header / 5hedE / n. 页眉;标头 preprocessor / pri:5prEusesE / n. 预处理程序,预 处理器 arcane / B:5kein / a. 神秘的,晦涩难 解的;秘密的 delve / delv / v. 搜索,翻查 reference / 5refErEns / v. 引用;参照 software package 软件包 directory / di5rektEri / n. 目录 revolve / ri5vClv / v. 旋转;围绕 encapsulation / in7kApsE5leiFEn / n. 封装 polymorphism / 7pCli5mC:fizEm / n. 多态性,多形性 clarity / 5klArEti / n. 清晰,明晰 1 2 3 4 Computer English You will have the feeling that you have eliminated a lot of clutter from your programs—and you will have. All the cryptic header files and preprocessor statements of C and C++ are gone. All the arcane #define1 statements and typedefs2 have been taken away. You will no longer have to delve through several levels of header files to correctly reference API calls. And no one will have to suffer to figure out how to use your software. Java programs simply import the software packages they need. These packages may be in another directory, on another drive, or on a machine on the other side of the Internet. The Java compiler and interpreter figure out what objects are referenced and supply the necessary linkage. Java Is Object-Oriented If you think C++ is an object-oriented programming language, you are in for a big surprise3. After using Java to write a few programs, you’ll get a better feeling for what object-oriented software is all about. I know I did. Java deals with classes and objects, pure and simple4. They aren’t just more data structures that are available to the programmer—they are the basis for the entire programming language. In C++, you can declare a class, but you don’t have to. You can declare a structure or a union instead. You can declare a whole bunch of loosely associated variables and use them with C-style functions. In Java, classes and objects are at the center of the language. Everything else revolves around them. You can’t declare functions and procedures. They don’t exist. You can’t use structures, unions, or typedefs. They’re gone, too. You either use classes and objects or you don’t use Java. It’s that simple. Java provides all the luxuries of object-oriented programming: class hierarchy, inheritance, encapsulation, and polymorphism—in a context that is truly useful and efficient. The main reason for developing object-oriented software, besides clarity and simplicity, is the desperate hope that somehow the objects you develop will be reused. Java not only encourages software reuse, it demands it. To write any sort of Java program, no matter how simple, you must build #define:C 语言中的特定字符,只有编程上的含义。 typedef:C 语言中的特定字符,只有编程上的含义。 you are in for a big surprise:你一定会大吃一惊。句中的 be in for 为固定搭配,意为“肯定会经历”、“注 定要遭受”。 pure and simple:纯粹的,不折不扣的。 计算机英语 73 on the classes and methods of the Java API. Once you have begun developing software in Java, you have two choices: tailor / 5teilE / v. 针 对 特 定 目 的 (或对象)作修改, 使适应(特定需要) ● Build on the classes you have developed, thereby reusing them. ● Rewrite your software from scratch, copying and tailoring useful parts of existing software. With Java, the temptation to start from scratch is no longer appealing. Java’s object-oriented structure forces you to develop more useful, more tailorable, and much simpler software the first time around. Java Is Safer and More Reliable Java is safer to use than C++ because it keeps you from doing the things that you do badly, while making it easier to do the things that you do well. explicitly / ik5splisitli / ad. 明确地;直言地 assembly code 汇编码 dinosaur / 5dainEsC: / n. 恐龙; (尤指废弃 过时的)庞然大物 runtime / 5rQntaim / n. 运行时刻 syntactic / sin5tAktik / a.(按照)句法的 semantically / si5mAntikEli / ad. 在语义上 mom / mCm / n. <主美口> 妈妈 linker / 5liNkE / n. 连接程序,链接 程序 Java won’t automatically convert data types. You have to explicitly convert from one class to another. C++, under the most undesirable conditions, will automatically convert one type to another. It has all the flexibility of assembly code. Java doesn’t assume that you know what you are doing. It makes sure that you do. C++ pointers don’t exist in Java. You can no longer access objects indirectly or by chance. You don’t need to. You declare objects and reference those objects directly. Complex pointer arithmetic is avoided. If you need an indexed set of objects, you can use an array of objects. The concept of “the address of an object” is eliminated from the programming model, and another assembly language dinosaur is laid to rest. As a result, it becomes much easier to do things correctly in Java. Java’s reliability extends beyond the language level to the compiler and the runtime system. Compile-time checks identify many programming errors that go undetected in other programming languages. These checks go beyond syntactic checking to ensure that statements are semantically correct. Runtime checks are also more extensive and effective. Remember your teacher or mom telling you to “Check your work twice to make sure it’s right”? The Java linker understands class types and performs compiler-level type checking, adding redundancy to reliability. It also 74 bound / baund / n. [常作~s] 边界; 界限,界线 bounds checking 边界检查 hacker / 5hAkE / n. 黑客 flaw / flC: / n. 缺点,瑕疵 spoof / spu:f / v. 哄骗,欺骗 browse / brauz / v. 浏览 unauthorized / 7Qn5C:WEraizd / a. 未经授权的 vulnerable / 5vQlnErEbl / a. 脆弱的;易受攻 击的 constrain / kEn5strein / v. 限制,约束 offense / E5fens / n. 冒犯;攻击 browser / 5brauzE / n. 浏览器 applet / 5AplEt / n. 小应用程序 Trojan / 5trEudVEn / (horse) n. 特 洛 伊 木马程序(或病毒) malicious / mE5liFEs / a. 恶意的 bytecode / 5baitkEud / n. 字节码 theorem / 5WiErEm / n. 定理 prover / pru:vE / n. 证明程序 theorem prover 定理证明程序, 定理证明器 segregate / 5segrigeit / v. 隔离;分开 trustworthy / 5trQst7wE:Ti / a. 值得信任的;可 信的;可靠的 Computer English performs bounds checking and eliminates indirect object access, even under error conditions. Java Is Secure If you gave a skilled hacker a program written in C or C++ and told him to find any security flaws, there are half a dozen things that he would immediately look for: gaining access to the operating system, causing an unexpected return of control, overwriting critical memory areas, acquiring the ability to spoof or modify other programs, browsing for security information, and gaining unauthorized access to the file system. Why is C or C++ more vulnerable than Java? When a programmer develops software, he or she usually focuses on how to get the software to work correctly and efficiently. C and C++ do not constrain the programmer from meeting these goals and provide a number of flexible features that enable the programmer to meet his end. The hacker is also able to take advantage of these features and use them in ways that weren’t originally intended, causing the undesirable consequences identified in the previous paragraph. In short, C and C++ provide a great offense, but no defense. Java, on the other hand, is defensive by nature. Every time a Java-enabled browser downloads a compiled Java class, such as an applet, it runs the risk of running Trojan horse code. Because of this ever-present threat, it subjects the code to a series of checks that ensure that it is correct and secure. The Java runtime system is designed to enforce a security policy that prevents execution of malicious code. It does this by remembering how objects are stored in memory and enforcing correct and secure access to those objects according to its security rules. It performs bytecode verification by passing compiled classes through a simple theorem prover that either proves that the code is secure or prevents the code from being loaded and executed. The class is Java’s basic execution unit and security is implemented at the class level. The Java runtime system also segregates software according to its origin. Classes from the local system are processed separately from those of other systems. This prevents remote systems from replacing local system software with code that is less trustworthy. 计算机英语 multithreaded / 5mQlti7Wredid / a. 多线程的 multithreading / 5mQlti7WrediN / n. 多线程操作 thread / Wred / n. 线程,线索 duke / dju:k / n. 公爵 seemingly / 5si:miNli / ad. 表面上;看来 convoluted / 5kCnvElu:tid / a. 盘绕的;盘错的, 错综复杂的 gaggle / 5gAgl / n.(紊乱而有联系 的)一堆 intertwine / 7intE5twain / v.(使)缠结, (使) 缠绕在一起 concurrently / kEn5kQrEntli / ad. 同时发生地,并 发地,并行地 75 Java-enabled browsers, such as HotJava1, allow the user to control the accesses that Java software may make of the local system. When a Java applet needs permission to access local resources, such as files, a security dialog box is presented to the user, requesting explicit user permission. This “Mother may I?” approach ensures that the user always has the final say in the security of his system. Java Is Multithreaded Java, like Ada, and unlike other languages, provides built-in language support for multithreading. Multithreading allows more than one thread of execution to take place within a single program. This allows your program to do many things at once: make the Duke dance, play his favorite tune, and interact with the user, seemingly all at the same time. Multithreading is an important asset because it allows the programmer to write programs as independent threads, rather than as a convoluted gaggle of intertwined activities. Multithreading also allows Java to use idle CPU time to perform necessary garbage collection and general system maintenance, enabling these functions to be performed with less impact on program performance. Writing multithreaded programs is like dating several people concurrently. Everything works fine until the threads start to interact with each other in unexpected ways. Java provides the support necessary to make multithreading work safely and correctly. Java supports multithreading by providing synchronization capabilities that ensure that threads share information and execution time in a way that is thread safe. Java Is Interpreted and Portable compiled code 编译执行的代码 interpreted code 解释执行的代码 field / fi:ld / v. 派…上场;实施; 产生 native code 本机代码 1 While it is true that compiled code will almost always run more quickly than interpreted code, it is also true that interpreted code can usually be developed and fielded more inexpensively, more quickly, and in a more flexible manner. It is also usually much more portable. Java, in order to be a truly platform-independent programming language, must be interpreted. It does not run as fast as compiled native code, but it doesn’t run much slower, either. For the cases where execution in native machine code is absolutely essential, work is underway to translate Java bytecode into machine code as it is loaded. HotJava:由美国 SUN 公司开发的、支持 Java 开发环境的 Internet 浏览器。 76 outweigh / aut5wei / v. 在价值(或重要 性、影响等)方面 超过 Computer English The advantages of being interpreted outweigh any performance impacts. Because Java is interpreted, it is much more portable. If an operating system can run the Java interpreter and support the Java API, then it can faithfully run all Java programs. Interpreted programs are much more easily kept up-to-date. You don’t have to recompile them for every change. In Java, recompilation is automatic. The interpreter detects the fact that a program’s bytecode file is out-of-date with respect to its source code file and recompiles it as it is loaded. Because of Java’s interpreted nature, linking is also more powerful and flexible. Java’s runtime system supports dynamic linking between local class files and those that are downloaded from across the Internet. This feature provides the basis for Web programming. Java Is the Programming Language of the Web de facto / di:5fAktEu / a. <拉>实际的,事 实上的 offshoot / 5CfFu:t / n. 支族,旁系;衍 生事物 broker / 5brEukE / n. 代理者; 代理程序 Java has become the de facto programming language of the Web. It is being licensed by nearly every major software company. It has some offshoots and potential competition, such as JavaScript1 and VBScript2, but it remains the first Web programming language and the most powerful language for developing platform-independent software. Java is also evolving beyond the Web and becoming a key component in distributed application development. Some releases of Sun’s products emphasize Java’s importance to distributed object-based software development. Several other vendors have introduced products that enable Java to be integrated into the Common Object Request Broker Architecture (CORBA3), which is the framework for distributed object communication. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Java is an object-oriented programming language, for which classes and ________ are the basis. 1 2 3 JavaScript:Java 脚本语言。 VBScript:Visual Basic 脚本语言。 CORBA:公用对象请求代理程序体系结构(Common Object Request Broker Architecture 的首字母缩略)。 77 计算机英语 2. Java is designed to be ________, which makes it a useful language for programming Web applications, since users access the Web from many types of computers. 3. Java provides built-in language support for ________. That is, it allows more than one thread of execution to take place within a single program. 4. The Java ________ system is designed to enforce a security policy that prevents execution of malicious code. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. native code header file multithreaded program Java-enabled browser 5. 6. 7. 8. 机器码 汇编码 特洛伊木马程序 软件包 78 Computer English 计算机英语 Part Two Software Engineering 79 80 Computer English 第二部分 软件工程 第五单元 软件开发 第六单元 分布式系统 第七单元 数据库 ● 课文 A:计算机程序 ● 课文 B:为什么选择 Visual Basic 作 为 Web 编程工具? ● 课文 C:使用 PowerBuilder 构建跨平 台应用程序 ● 课文 A:分布式系统 ● 课文 B:“客户机-服务器”的真正含 义是什么?(第一部分) ● 课文 C:“客户机-服务器”的真正含 义是什么?(第二部分) ● 课文 A:进入关系型数据库的世界 ● 课文 B:SQL Server 的数据库对象 ● 课文 C:Delphi 数据库体系结构 计算机英语 81 Unit 5: Software Development (软件开发) Section A Computer Program I. INTRODUCTION encode / en5kEud / v. 把…编码;把… 译成电码(或密码) A computer program is a set of instructions that directs a computer to perform some processing function or combination of functions. For the instructions to be carried out, a computer must execute a program, that is, the computer reads the program, and then follows the steps encoded in the program in a precise order until completion. A program can be executed many different times, with each execution yielding a potentially different result depending upon the options and data that the user gives the computer. 82 Computer English Programs fall into two major classes: application programs and operating systems. An application program is one that carries out some function directly for a user, such as word processing or game playing. An operating system is a program that manages the computer and the various resources and devices connected to it, such as RAM (random access memory), hard drives, monitors, keyboards, printers, and modems, so that they may be used by other programs. Examples of operating systems are DOS, Windows 95, OS/2, and UNIX. II. PROGRAM DEVELOPMENT utility program 实用程序, 工具程序 text editor 文本编辑器, 文本编辑程序 notation / nEu5teiFEn / n.(系统成套的)记 号;标记法 source file 源文件 object code 目标(代)码 assembler / E5semblE / n. 汇编程序 interpreted language 解释执行的语言 compiled language 编译执行的语言 Software designers create new programs by using special applications programs, often called utility programs or development programs. A programmer uses another type of program called a text editor to write the new program in a special notation called a programming language. With the text editor, the programmer creates a text file, which is an ordered list of instructions, also called the program source file. The individual instructions that make up the program source file are called source code. At this point, a special applications program translates the source code into machine language, or object code—a format that the operating system will recognize as a proper program and be able to execute. Three types of applications programs translate from source code to object code: compilers, interpreters, and assemblers. The three operate differently and on different types of programming languages, but they serve the same purpose of translating from a programming language into machine language. A compiler translates text files written in a high-level programming language—such as FORTRAN, C, or Pascal—from the source code to the object code all at once. This differs from the approach taken by interpreted languages such as BASIC, in which a program is translated into object code statement by statement as each instruction is executed. The advantage to interpreted languages is that they can begin executing the program immediately instead of having to wait for all of the source code to be compiled. Changes can also be made to the program fairly quickly without having to wait for it to be compiled again. The disadvantage of interpreted languages is that they are slow to execute, since the entire program must be translated one instruction at a time, each time the program is run. On the other hand, compiled languages are compiled only once and thus can be executed by the computer much more quickly than interpreted languages. 计算机英语 83 For this reason, compiled languages are more common and are almost always used in professional and scientific applications. translator / trAns5leitE / n. 翻译程序, 翻译器 Another type of translator is the assembler, which is used for programs or parts of programs written in assembly language. Assembly language is another programming language, but it is much more similar to machine language than other types of high-level languages. In assembly language, a single statement can usually be translated into a single instruction of machine language. Today, assembly language is rarely used to write an entire program, but is instead most often used when the programmer needs to directly control some aspect of the computer’s function. Programs are often written as a set of smaller pieces, with each piece representing some aspect of the overall application program. After each piece has been compiled separately, a program called a linker combines all of the translated pieces into a single executable program. debugger / di:5bQgE / n. 调试程序,调试 器,排错程序 bug / bQg / n.(程序)错误,缺 陷,故障 debug / di:5bQg / v. 调试,排除(程 序)中的错误 source program 源程序 interpreter program 解释程序 Programs seldom work correctly the first time, so a program called a debugger is often used to help find problems called bugs. Debugging programs usually detect an event in the executing program and point the programmer back to the origin of the event in the program code. Recent programming systems, such as Java, use a combination of approaches to create and execute programs. A compiler takes a Java source program and translates it into an intermediate form. Such intermediate programs are then transferred over the Internet into computers where an interpreter program then executes the intermediate form as an application program. III. PROGRAM ELEMENTS Most programs are built from just a few kinds of steps that are repeated many times in different contexts and in different combinations throughout the program. The most common step performs some computation, and then proceeds to the next step in the program, in the order specified by the programmer. repetitive / ri5petEtiv / a. 重复的 Programs often need to repeat a short series of steps many times, for instance in looking through a list of game scores and finding the highest score. Such repetitive sequences of code are called loops. One of the capabilities that make computers so useful is their ability to 84 Computer English make conditional decisions and perform different instructions based on the values of data being processed. If-then-else statements implement this function by testing some piece of data and then selecting one of two sequences of instructions on the basis of the result. One of the instructions in these alternatives may be a goto statement that directs the computer to select its next instruction from a different part of the program. For example, a program might compare two numbers and branch to a different part of the program depending on the result of the comparison: If x is greater than y then goto instruction #10 else continue subroutine / 5sQbru:7ti:n / n. 子例程,子(例 行)程序 routine / ru:5ti:n / n. 例(行)程(序) ; 程序 library routine 库程序 device driver 设备驱动程序 realign / 7ri:E5lain / v. 重新调整 cartridge / 5kB:tridV / n. 盒,匣 ink cartridge 墨盒 Programs often use a specific sequence of steps more than once. Such a sequence of steps can be grouped together into a subroutine, which can then be called, or accessed, as needed in different parts of the main program. Each time a subroutine is called, the computer remembers where it was in the program when the call was made, so that it can return there upon completion of the subroutine. Preceding each call, a program can specify that different data be used by the subroutine, allowing a very general piece of code to be written once and used in multiple ways. Most programs use several varieties of subroutines. The most common of these are functions, procedures, library routines, system routines, and device drivers. Functions are short subroutines that compute some value, such as computations of angles, which the computer cannot compute with a single basic instruction. Procedures perform a more complex function, such as sorting a set of names. Library routines are subroutines that are written for use by many different programs. System routines are similar to library routines but are actually found in the operating system. They provide some service for the application programs, such as printing a line of text. Device drivers are system routines that are added to an operating system to allow the computer to communicate with a new device, such as a scanner, modem, or printer. Device drivers often have features that can be executed directly as applications programs. This allows the user to directly control the device, which is useful if, for instance, a color printer needs to be realigned to attain the best printing quality after changing an ink cartridge. 计算机英语 85 IV. PROGRAM FUNCTION free memory 自由内存, 闲置内存 default / di5fC:lt / n. 默认,缺省, 系统设定值 reformat / 7ri:5fC:mAt / v. 重新定义格式; 重新格式化 system call 系统调用 Modern computers usually store programs on some form of magnetic storage media that can be accessed randomly by the computer, such as the hard drive disk permanently located in the computer, or a portable floppy disk. Additional information on such disks, called directories, indicates the names of the various programs on the disk, when they were written to the disk, and where the program begins on the disk media. When a user directs the computer to execute a particular application program, the operating system looks through these directories, locates the program, and reads a copy into RAM. The operating system then directs the CPU (central processing unit) to start executing the instructions at the beginning of the program. Instructions at the beginning of the program prepare the computer to process information by locating free memory locations in RAM to hold working data, retrieving copies of the standard options and defaults the user has indicated from a disk, and drawing initial displays on the monitor. The application program requests a copy of any information the user enters by making a call to a system routine. The operating system converts any data so entered into a standard internal form. The application then uses this information to decide what to do next—for example, perform some desired processing function such as reformatting a page of text, or obtain some additional information from another file on a disk. In either case, calls to other system routines are used to actually carry out the display of the results or the accessing of the file from the disk. When the application reaches completion or is prompted to quit, it makes further system calls to make sure that all data that needs to be saved has been written back to disk. It then makes a final system call to the operating system indicating that it is finished. The operating system then frees up the RAM and any devices that the application was using and awaits a command from the user to start another program. V. HISTORY player piano 自动钢琴 People have been storing sequences of instructions in the form of a program for several centuries. Music boxes of the 18th century and player pianos of the late 19th and early 20th centuries played musical programs stored as series of metal pins, or holes in paper, with each line (of pins or holes) representing when a note was to be played, and the pin or hole indicating what note was to be played at that time. More elaborate control 86 automate / 5C:tEmeit / v.(使)自动化 tapestry / 5tApistri / n. 花毯;挂毯 deck / dek / n. 叠;卡片叠, 卡片组 counterpart / 5kauntEpB:t / n. 对应的物(或人) Computer English of physical devices became common in the early 1800s with French inventor Joseph Marie Jacquard’s invention of the punch-card controlled weaving loom. In the process of weaving a particular pattern, various parts of the loom had to be mechanically positioned. To automate this process, Jacquard used a single paper card to represent each positioning of the loom, with holes in the card to indicate which loom actions should be done. An entire tapestry could be encoded onto a deck of such cards, with the same deck yielding the same tapestry design each time it was used. Programs of over 24,000 cards were developed and used. The world’s first programmable machine was designed—although never fully built—by the English mathematician and inventor, Charles Babbage. This machine, called the Analytical Engine, used punch cards similar to those used in the Jacquard loom to select the specific arithmetic operation to apply at each step. Inserting a different set of cards changed the computations the machine performed. This machine had counterparts for almost everything found in modern computers, although it was mechanical rather than electrical. Construction of the Analytical Engine was never completed because the technology required to build it did not exist at the time. The first card deck programs for the Analytical Engine were developed by British mathematician Augusta Ada Byron, daughter of the poet Lord Byron1. For this reason she is recognized as the world’s first programmer. The modern concept of an internally stored computer program was first proposed by Hungarian-American mathematician John von Neumann in 1945. Von Neumann’s idea was to use the computer’s memory to store the program as well as the data. In this way, programs can be viewed as data and can be processed like data by other programs. This idea greatly simplifies the role of program storage and execution in computers. VI. THE FUTURE The field of computer science has grown rapidly since the 1950s due to the increase in their use. Computer programs have undergone many changes during this time in response to user need and advances in technology. Newer ideas in computing such as parallel computing, distributed computing, and artificial intelligence, have radically altered the traditional concepts that once determined program form and function. 1 Lord Byron:拜伦勋爵(1788~1824),英国诗人,全名 George Gordon Byron。 计算机英语 87 Computer scientists working in the field of parallel computing, in which multiple CPUs cooperate on the same problem at the same time, have introduced a number of new program models. In parallel computing parts of a problem are worked on simultaneously by different processors, and this speeds up the solution of the problem. Many challenges face scientists and engineers who design programs for parallel processing computers, because of the extreme complexity of the systems and the difficulty involved in making them operate as effectively as possible. Another type of parallel computing called distributed computing uses CPUs from many interconnected computers to solve problems. Often the computers used to process information in a distributed computing application are connected over the Internet. Internet applications are becoming a particularly useful form of distributed computing, especially with programming languages such as Java. In such applications, a user logs on1 to a Web site and downloads a Java program onto their computer. When the Java program is run, it communicates with other programs at its home Web site, and may also communicate with other programs running on different computers or Web sites. inference engine 推理机 Research into artificial intelligence (AI) has led to several other new styles of programming. Logic programs, for example, do not consist of individual instructions for the computer to follow blindly, but instead consist of sets of rules: if x happens then do y. A special program called an inference engine uses these rules to “reason” its way to a conclusion when presented with a new problem. Applications of logic programs include automatic monitoring of complex systems, and proving mathematical theorems. A radically different approach to computing in which there is no program in the conventional sense is called a neural network. A neural network is a group of highly interconnected simple processing elements, designed to mimic the brain. Instead of having a program direct the information processing in the way that a traditional computer does, a neural network processes information depending upon the way that its processing elements are connected. Programming a neural network is accomplished by presenting it with known patterns of input and output data and adjusting the relative importance of the interconnections between the processing elements until the desired pattern matching is accomplished. Neural networks are 1 log on:登录。 88 simulate / 5simjuleit / v. 模拟;模仿 Computer English usually simulated on traditional computers, but unlike traditional computer programs, neural networks are able to learn from their experience. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Computer programs fall into two major classes: ________ programs and ________ systems. 2. There are three types of application programs to translate source code into object code. They are compilers, interpreters, and ________. 3. A(n) ________ translates all the source code of a program written in a high-level language into object code prior to the execution of the program. 4. In the case of a(n) ________, a program is translated into executable form and executed one statement at a time rather than being translated completely before execution. 5. A(n) ________ is a program that is often used to help find problems in other programs. 6. A(n) ________ is a sequence of code in a program executed repeatedly, either for a fixed number of times or until a certain condition is met. 7. When you install a new device in a computer, you have to add the correct ________ to the operating system to allow the computer to communicate with the device. 8. The modern concept of an internally stored computer program was first proposed by ________ in 1945. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. inference engine system call compiled language parallel computing 11. 12. 13. 14. 解释执行的语言 设备驱动程序 源程序 调试程序 89 计算机英语 5. 6. 7. 8. 9. 10. pattern matching free memory interpreter program library routine intermediate program source file 15. 16. 17. 18. 19. 20. 目标代码 应用程序 实用程序 逻辑程序 墨盒 程序的存储与执行 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: similar produce program translation computer engineer instruction manufacturer directly assembler machine language compiler low-level different version A compiler, in computer science, is a computer program that translates source code into object code. Software ________ write source code using high-level programming ________ that people can understand. Computers cannot ________ execute source code, but need a(n) ________ to translate these instructions into a(n) ________ language called machine code. Compilers collect and reorganize (compile) all the ________ in a given set of source code to ________ object code. Object code is often the same as or ________ to a computer’s machine code. If the object code is the same as the ________ language, the computer can run the ________ immediately after the compiler produces its ________. If the object code is not in machine language, other programs—such as ________, binders (联 编程序), linkers, and loaders (装入程序)—finish the translation. Most computer languages use different ________ of compilers for different types of ________ or operating systems, so one language may have ________ compilers for personal computers (PC) and Apple Macintosh computers. Many different ________ often produce versions of the same programming language, so compilers for a language may vary between manufacturers. IV. Translate the following passage from English into Chinese: In software, a bug is an error in coding or logic that causes a program 90 Computer English to malfunction or to produce incorrect results. Minor bugs—for example, a cursor that does not behave as expected—can be inconvenient or frustrating, but not damaging to information. More severe bugs can cause a program to “hang” (stop responding to commands) and might leave the user with no alternative but to restart the program, losing any previous work that has not been saved. In either case, the programmer must find and correct the error by the process known as debugging. Because of the potential risk to important data, commercial application programs are tested and debugged as completely as possible before release. Minor bugs found after the program becomes available are corrected in the next update; more severe bugs can sometimes be fixed with special software, called patches, that circumvents (规避) the problem or otherwise alleviates (减轻) its effects. 计算机英语 91 Section B Why Choose Visual Basic1 as a Web Programming Tool? Welcome to Web programming with Visual Basic. As you can probably tell by the title, the topic here is the integration of Visual Basic and the World Wide Web. hype / haip / n. 天花乱坠的广告 宣传;大肆宣传 deem / di:m / v. 认为;相信 Why the World Wide Web? You may ask, “Besides all the hype, what good is the Web?” The answer is simple: the Web allows for the distribution of information over a wide area, to a wide audience at a low cost (compared to a WAN2). This network of networks enables users from across the world to access data on any computer whose administrator has deemed that the data should be made public using the Web. This opens up a lot of possibilities for both providing and gathering 1 2 Visual Basic:可视化 Basic 语言,微软公司出品的可视化 Basic 语言开发环境。 repository area network 的首字母缩略)。 /WAN:广域网(wide ri5pCzitEri / n. 仓库,储存库 92 Computer English information. Couple the Web with the other features of the Internet (e-mail, network news, file repositories), and it’s easy to see all the potential applications of the Web. Here are a few ideas to get your mind going. First, it can provide a Web-based order entry form. This gives a remote salesman using a Web browser on a notebook computer the ability to place orders minutes after a deal is made. Another potential application is to provide a Visual Basic search engine that scans Web-based databases of résumés for keywords. Finally, it enables you to provide a custom Web browser to your customers. The browser allows access only to your Web site and even provides the ability to personalize the information on your Web server to match the customer. The applications are as wide open as the Web itself, and I’m sure that as more people jump on the Web bandwagon1, more and more applications will spring up. Why Choose Visual Basic as a Web Programming Tool? An important question at the start of any software design project is the choice of a language or languages to use. When you think about designing applications that use Web-based information, the question still applies: “Why should I use Visual Basic?” Visual Basic makes sense for the following reasons: ● Database Connectivity—By using ODBC 2 or RDO 3 , you can easily wrap database accessibility into a Visual Basic Web application. The question is no longer what can be done via the current set of Web tools but what can be done using Visual Basic. ● Up-to-date custom controls—The market for third party custom controls in Visual Basic is huge. At least 10 different companies currently make OCXs4 or VBXs5 for Internet programming. This is reassuring because a change in an Internet specification used somewhere in your application doesn’t mandate a change in the application’s code. Instead, it means upgrading a custom control 1 2 3 4 5 jump on the Web bandwagon:赶浪潮上网。jump on the bandwagon 是习语,意为“赶浪头”。 ODBC:开放式数据库连接(open database connectivity 的首字母缩略)。 RDO:远程数据对象(Remote Data Object 的首字母缩略)。 OCX:OLE 定制控件(OLE custom control 的缩略)。 VBX:可视化 Basic 定制控件(Visual Basic custom control 的缩略)。 计算机英语 93 and then performing the much easier task of verifying that the control works as intended with the application. plus / plQs / n. 好处,有利因素 relay / ri:5lei / v. 接力传送;传递 textbox / 5tekstbCks / n. 文本框 combobox / 5kCmbEubCks / n. 组合框 flux / flQks / n.(不断的)变动 hyperlink / 5haipEliNk / n. 超链接 stock quote 股票行情 gateway / 5geitwei / n. 网关 1 2 3 ● OLE 1 —The ability to control and to access data from other applications is a big plus to application development. Not only can a Visual Basic application control several OLE-enabled Web browsers, but you can also relay information from the Web to an OLE-enabled application. ● The Windows user interface—The usability of a Windows application far exceeds the current set of HTML2 tags that allow for textboxes, comboboxes, and buttons. Combining Visual Basic and the Web The merging of Visual Basic and the ability to access real-time, distributed information using the Internet produces an interesting and very powerful tool.3 In the constant flux of the Internet, Visual Basic becomes a very practical choice for Web application development thanks to Visual Basic’s rapid application development aspect. Visual Basic can be used to create both client-side and server-side Web applications. A Web browser such as Microsoft’s Internet Explorer is one example of a client-side application. It is used to “surf” the Web—browsing the Web pages at a Web site and moving to other pages or to a completely different Web site by using the hyperlinks provided on most Web pages. Another example of a client-side application is an application that retrieves stock quotes from a quote provider’s Web sites and provides the quotes to the user in some fashion. This application is not a Web browser but does access Web-based information. Server-side applications run alongside a Web server, such as Microsoft’s Internet Information Server. The server-side application is executed under the direction of the Web server, typically in response to a request made by a client-side application such as a Web browser. Server-side applications typically serve as gateways between a user’s Web browser and information stored on the Web server that is not typically OLE:对象链接和嵌入(object linking and embedding 的首字母缩略)。 HTML:超级文本标签语言(Hypertext Markup Language 的首字母缩略)。 The merging of Visual Basic and the ability to access real-time, distributed information using the Internet produces an interesting and very powerful tool.:Visual Basic 和使用 Internet 访问实时分布信息的能力融为一 体,产生了一种有趣而强大的工具。 94 Computer English accessible using a Web browser. Such information can include database tables, information-providing machines attached to the server, and even OLE-enabled applications to which the server has access. Past, Present, and Future predominantly / pri5dCminEntli / ad. 占主导地位地; 主要地 outright / aut5rait / ad. 完全地,彻底地 Windows socket Windows 套接字 接口 reside / 5rizaid / v. 居住;存在 atop / E5tCp / prep. 在…顶上 abstract / Ab5strAkt / v. 把…抽象出来; 提出,抽出 messy / 5mesi / a. 凌乱的,杂乱的 In the beginning, the Web was predominantly used by, maintained by, and programmed under the UNIX platform. The reasons for this are simple. First, UNIX was designed from the ground up1 to allow computers to easily communicate with one another. Second, UNIX has always been available for a wide variety of hardware platforms. Additionally, the TCP/IP protocol on which the Web is based was initially designed with the UNIX operating system in mind. For these reasons, integrating the Web with Visual Basic was very impractical, if not outright impossible. Then recently, with the standardized Windows socket (or Winsock for short) interface, things got a lot easier. The Winsock interface is a layer that resides between the Windows operating system and the TCP/IP protocol. By making API calls to the Winsock interface, the Windows programmer can avoid the complexities of the TCP/IP protocol and instead concentrate on developing services and tools that run over TCP/IP networks. Built atop the Winsock interface is a large group of tools that abstract the messy details of TCP/IP and the Internet protocols. With these tools, Web programming became a very practical solution to most distributed information programming tasks. Many custom controls and other tools exist that the Visual Basic programmer can use to further remove the application code from the complexities of the TCP/IP protocol. What will the future hold? One thing that I can guarantee about the future is change. The Internet is still a very cutting-edge and young technology. This means that your work as an Internet programmer will be a “work in progress” for a long time to come. Unlike COBOL programming, Web programming will be a skill that requires frequent reading and training to keep up-to-date. ———————————————— Exercises 1 from the ground up:完全地,彻底地。 95 计算机英语 I. Fill in the blanks with the information given in the text: 1. Visual Basic can be used to create both ________ and ________ Web applications. 2. At first the Web was mainly used by, maintained by, and programmed under the ________ platform. 3. A Visual Basic Web application can incorporate ________ accessibility through the use of ODBC or RDO. 4. The Winsock interface is a layer that resides between the Windows ________ and the TCP/IP protocol. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. Windows socket Winsock interface file repository client-side application HTML tag 6. 7. 8. 9. 10. 万维网浏览器 硬件平台 定制控件 对象链接和嵌入 广域网 96 Computer English Section C Using PowerBuilder1 to Build Cross-Platform Applications comply / kEm5plai / v. 遵从,顺从 (with) subtle / 5sQtl / a. 微妙的;细微的 tempt / tempt / v. 引诱,诱惑 font / fCnt / n. 字体 Before you can create an application, you need to identify which platforms the users and developers will have access to. The difficulty in writing a cross-platform application is designing it so that it takes advantage of the different platforms and complies with the standard behavior of the common applications for that environment. Because your interface should comply with the standards for each environment, you will have to keep these in mind as you build the application. A very simple example is that in Windows, most applications have an Exit menu item under the File menu option. For a Macintosh, there is a Quit menu option under File. These subtle differences must be considered because they will be immediately obvious (and possibly confusing) to the end user. Because each environment has its own special behavior and coding techniques, you might be tempted to create several different applications and deploy a different version of the same application to each platform. This would defeat the purpose of PowerBuilder’s cross-platform capability. The following sections discuss how to control the fonts used and how to code one application so that it can dynamically incorporate the functionality required for each platform. 1. The Environment Object populate / 5pCpjuleit / v. 充填;置入 argument / 5B:gjumEnt / n. 变元,自变量 1 2 Coding a multiplatform application depends on a PowerBuilder structure that gives you the ability to get information about the platform on which your application is running. The Environment object has variables defined for it. Once an Environment object has been declared, you need to populate the structure with values. This is done using the GetEnvironment() 2 function. GetEnvironment() takes the name of your newly declared Environment object as an argument. The function returns PowerBuilder:由 Powersoft 公司出品的可视化软件开发工具,与 Visual Basic 和 Delphi 齐名,尤其擅长数 据库应用程序的快速开发。Powersoft 公司现已合并到 Sybase 公司。 GetEnvironment():PowerBuilder 专用函数。 计算机英语 integer / 5intidVE / n. 整数 script / skript / n. 脚本, 过程(文件) instance variable 实例变量 97 an integer, 1 for success and -1 for failure. Once the function has been successfully called, you will want to evaluate the Environment object’s attributes to determine what processing you want to occur. The next three sections deal with some common situations you might encounter when working in a multiplatform environment. Each section details a script that can be incorporated into a custom class user object for use with all your applications. In these examples, the user object example is implemented with an environment instance variable declared; it is called i_Environment1. 2. The Dynamic Library Search Path Because one of the complexities of application development on multiple platforms is creating objects that take full advantage of the environment’s functionality and appearance, it is often necessary to create different copies of the same object. As shown in the API user object example, you can use inheritance to assist in building your objects. Unfortunately, this is not always possible. After you have developed your platform-specific objects, you most likely will maintain that platform’s objects in their own library file (in other words, one PBL2 per platform). Each library file would be specified in the library search path for your application (for example, common.pbl, windows.pbl, mac.pbl, unix.pbl). PowerBuilder uses the order in the search path to find objects requested by your application. If an object is located in the PBL listed last in the search path, PowerBuilder looks through all the other PBLs before looking in the last one. If you are using platform-specific objects that have the same name as other objects, you will always use the object first found in the library list. Therefore, you would never use any of your platform-specific objects. This is also fine if you do not use objects in the last PBL very often. If you often do need the objects in the last PBL, your performance will be affected because all library files must be searched first. This would be true for the example if you needed objects from the Mac or UNIX PBLs. Therefore, performance would be fine for those people requiring objects from windows.pbl, but users on different platforms would notice a slight performance degradation. 1 2 i_Environment:PowerBuilder 专用函数。 PBL:PowerBuilder 库(PowerBuilder library 的首字母缩略)。 98 alleviate / E5li:vieit / v. 减轻,缓解 executable / 5eksikju:tEbl / n. 可执行文件 hard-code / 5hB:dkEud / v. 硬编码 instantiate / in5stAnFieit / v. 例示,实例化 generic / dVi5nerik / a. 通用的;一般的; 类属的 INI file 初始化文件 ( initialization file 的缩略) ancestor menu 祖辈菜单(面向对 象编程术语,指所 有的菜单都要继承 该菜单的属性、方 法、事件等特征) 1 2 3 4 Computer English Most likely you would create a dynamic library (either PBD1 or DLL2) for each PBL, and PowerBuilder would maintain the library search path for the dynamic libraries, which would affect the runtime environment as well as development. To alleviate this problem, you could deploy several different executables, each with a different search path defined. This would not be particularly efficient. A different approach would be to dynamically modify the library search path for your application using the function SetLibraryList()3. To implement this functionality, you could hard-code the dynamic library list into your application, but that would result in a new executable being created if you changed the library list. A better approach would be to create a function in a custom class user object that is instantiated in your application object. The best method of maintaining this list would be to place it in a table in your database and then, based on the user’s environment, read the table and assign the appropriate library order to the application. The idea is that only the table needs to be changed; the code can remain generic. You could also do this by reading in information from an INI file. 3. Menu Modification One subtle difference between Windows and the Macintosh is that the word for the menu item to leave the application is Exit in Windows and Quit on the Mac. You need to consider the difference in interface design; the code in Listing 5C-1 gives you a base function to work from. The function, wf_SetExitText() 4 , accepts an argument of type m_ancestor, which is the ancestor menu for all menus in your application. Listing 5C-1: Public window function wf_SetExitText() //Arguments: menu_id m_ancestor //Returns: none Environment l_environ GetEnvironment (l_environ) // Change menu "Exit" to "Quit" if on Mac if l_environ.OSType = Windows! then PBD:PowerBuilder 动态链接库(PowerBuilder DLL 的首字母缩略)。 DLL:动态链接库(dynamic-link library 的首字母缩略)。 SetLibraryList():PowerBuilder 专用函数。 wf_SetExitText():PowerBuilder 专用函数。 计算机英语 99 menu_id.m_file.m_exit.text = "E&xit" elseif l_environ.OSType = Macintosh! then menu_id.m_file.m_exit.text = "Quit" end if The code that calls this function should be placed in the window Open event and look something like this: wf_SetExitText(this.menuid) This assumes that the menu associated with the window has been inherited from m_ancestor. 4. Internationalization Hebrew / 5hi:bru: / n. 希伯来语 ship / Fip / v. 推出(产品) character set 字符集 Korean / kE5riEn / n. 朝鲜语 surpass / sE5pB:s / v. 超过;优于 character code 字符代码 code set 代码集 1 2 3 4 In complying with the continually growing need to create an application that can service multiple countries, Powersoft has extended the functionality of PowerBuilder 6.0. These changes include additional support for applications in Arabic and Hebrew, Double Byte Character Set (DBCS1), and a Unicode2 version of PowerBuilder. PowerBuilder will now ship a version using the Double Byte Character Set (DBCS) for Chinese application development. The DBCS supports the Chinese character set, setting it apart from the ANSI3 version of PowerBuilder. The DBCS will also be extended to include Japanese and Korean. In addition to the DBCS and ANSI versions of PowerBuilder, PowerBuilder 6.0 will be available in a Unicode version (under NT 4.x only). Unicode is being embraced because it surpasses the limitation of ASCII 4 to encode only information using the Latin alphabet. Unicode introduces a new character code that gives the ability to encode all characters used for written languages across the world. This is done by using a 16-bit code set versus ASCII, which uses a 7-bit code set. Unicode can, therefore, create codes for 65,000 characters as opposed to 128 characters like ASCII. Each character in the Unicode version is assigned a unique 16-bit character that makes the processing for software much easier DBCS:双字节字符集(Double Byte Character Set 的首字母缩略),该字符集主要用于中文、日文、韩文等 东方国家的文字。 Unicode:Unicode 编码标准,统一代码。 ANSI:美国国家标准协会(American National Standards Institute 的首字母缩略)。 ASCII:ASCII 码,美国国家信息交换标准代码(American Standard Code for Information Interchange 的首字 母缩略)。 100 Computer English to encode. compliant / kEm5plaiEnt / a. 遵从的,顺从的 extension / ik5stenFEn / n. 扩展名 migrate / mai5greit / v. 移居;迁徙; 移植 toolkit / 5tu:lkit / n.(软件)工具箱 Applications that are created using the Unicode version of PowerBuilder need to be deployed using the Unicode deployment DLLs on an operating system that is Unicode compliant. The PowerBuilder library files will be saved with the extension .pul for PowerBuilder Unicode Library. PowerBuilder applications can be migrated from ANSI to Unicode and back. In addition, the PowerScript1 language also supports two new functions, ToAnsi() and ToUnicode(), to aid in the conversion of characters. To aid in the process of translating an application from one language to another, Powersoft plans to release a Translation Toolkit that assists you in translating phrases in your application to the necessary languages. Once the translation has been completed using the Toolkit, the application only needs to be compiled and deployed to the appropriate platforms. 5. Summary front-end / 5frQnt5end / a. & n. 前端(的) suite / swi:t / n.(软件的)套件; (同类物的)系 列,套 The need for a front-end development that crosses multiple platforms has been answered by PowerBuilder. With support for the Microsoft suite, the Macintosh, and UNIX, PowerBuilder gives developers the ability to use the same product to develop applications that can be run on and take advantage of each platform. With the incorporation of the Environment object, PowerBuilder allows you to modify your application at runtime to access each platform-specific object. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. PowerBuilder enjoys ________ capability. It offers developers the ability to create applications that can be run on and take advantage of each platform. 2. The word for the menu item to leave an application in Windows is ________ whereas it is ________ for the Macintosh. 3. 1 ________ introduces a new character code that gives the ability PowerScript:PowerBuilder 使用的是一种脚本语言,称为 PowerScript。 101 计算机英语 to encode all characters used for written languages across the world. 4. With the incorporation of the ________ object, PowerBuilder makes it possible to modify an application at runtime to access each platform-specific object. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. search path dynamic library code set ancestor menu 5. 6. 7. 8. 最终用户 菜单项 跨平台应用程序 字符集 102 Computer English Unit 6: Distributed Systems (分布式系统) Section A Distributed Systems INTRODUCTION node / nEud / n. 节点 negligible / 5neglidVEbl / a. 可略而不计的 transient / 5trAnziEnt / a. 短暂的;临时的 segmentation / 7segmen5teiFEn / n. (分)段,分割 The field of distributed computing has witnessed an explosive expansion during the last decade. As the use of distributed computing systems for large-scale computations is growing, so is the need to increase their reliability. Nevertheless, the probability of failure of an individual processing node in multimode distributed systems is not negligible. Hence, it is necessary to develop mechanisms that prevent the waste of computations performed on distributed processing nodes if one of the nodes fails, either due to a hardware transient fault (bus error or segmentation fault) or a permanent fault (power failure or communication network 计算机英语 103 malfunction). homogeneous / 7hCmEu5dVi:niEs / a. 同种类的;同性 质的;同构的 heterogeneous / 7hetErEu5dVi:niEs / a. 各种各样的;混 杂的;异构的 infrastructure Advances in communications technology and methods of work introduced at diverse workplace environments naturally led to a greater distribution of information processing. Initially, most distributed systems were homogeneous, but now many distributed environments are heterogeneous. Therefore, the distributed systems design must focus on heterogeneous environments, treating homogeneous systems as special cases in a heterogeneous world. Key issues in distributed systems design include where specific functionality should be located within the information infrastructure. / 5infrE7strQktFE / n. 基础结构 WHAT ARE DISTRIBUTED SYSTEMS? A distributed system is a collection of independent computers which appear to the users of the system as a single computer. Nearly all large software systems are by necessity 1 distributed. For example, enterprise-wide business systems must support multiple users running common applications across different sites. encompass / in5kQmpEs / v. 包含,包括 underlying / 7QndE5laiiN / a. 基本的,根本的 pervasive / pE5veisiv / a. 遍布的;普遍的 coexist / 7kEuig5zist / v. 共存;同时存在 A distributed system encompasses a variety of applications, their underlying support software, the hardware they run on, and the communication links connecting the distributed hardware. The largest and best-known distributed system is the set of computers, software, and services comprising the World Wide Web, which is so pervasive that it coexists with and connects to most other existing distributed systems. The most common distributed systems are networked client/server systems. Distributed systems share the general properties described below. 1. Resource Sharing collaborative / kE5lAbEreitiv / a. 合作的,协作的 The most common reason for connecting a set of computers into a distributed system is to allow them to share physical and computational resources (printers, files, databases, mail services, stock quotes, and collaborative applications, for example). Distributed system components that support resource sharing play a similar role as, and are increasingly indistinguishable from, operating systems. 2. Multiple Nodes Software for the distributed system executes on nodes, or multiple 1 by necessity:无法避免地,势必,必定。 104 peer / piE / n. 同位体,同级设 备,对等层 Computer English independent computers (not merely multiple processors on the same computer, which is the realm of parallel computing). These nodes can range among personal computers, high-performance workstations, file servers, mainframes, and supercomputers. Each can take the role of a client, which requests services by others; a server, which provides computation or resource access to others; or a peer, which does both. A distributed system may be as small as two nodes, provided software connectivity is present. This arrangement is represented in Figure 6A-1. Request Client Server Reply Peer Peer Figure 6A-1: A small distributed system concurrency 3. Concurrency / kEn5kQrEnsi / n. 同时发生,并发, 并行性 termination / 7tE:mi5neiFEn / n. 结束,终止 heterogeneity / 7hetErEudVi5ni:Eti / n. 各种各样;非均 匀性;多相性 bridge / bridV / n. 网桥,桥接器 Each of the nodes in a distributed system functions both independently and concurrently with all of the others. More than one process (executing program) per node and more than one thread (concurrently executing task) per process can act as components in a system. Most components are reactive, continuously responding to commands from users and messages from other components. Like operating systems, distributed systems are designed to avoid termination and so should always remain at least partially available. 4. Heterogeneity The nodes participating in a system can consist of diverse computing and communication hardware. The software comprising the system can include diverse programming languages and development tools. Some heterogeneity issues can be addressed with common message formats and low-level protocols that are readily implemented across different platforms (e.g., PCs, servers, and mainframes). Others may require construction of bridges that translate one set of formats and protocols to another. More thorough system integration can be attained by requiring that all nodes 计算机英语 105 support a common virtual machine that processes platform-independent program instructions. The systems that use the Java programming language follow this approach. 5. Multiple Protocols invocation / 7invE5keiFEn / n. 启用,调用 procedure call 过程调用 confine / 5kCnfain / n. [常作~s] 界限, 范围 sequential / si5kwenFEl / a. 顺序的 asynchronous / ei5siNkrEnEs / a. 不同时的;异步 的,非同步的 recipient / ri5sipiEnt / n. 接受者;收件人 messaging / 5mesidViN / n. 通信,消息接发 synchronous / 5siNkrEnEs / a. 同时的;同步的 multicast protocol 多址通信协议 Most distributed message passing differs significantly from the kinds of invocations (such as procedure calls) used within the confines of sequential programs. The most basic form of distributed communication is asynchronous. Similar to letters mailed in a postal system, senders issue messages without relying on receipt of or reply by their recipients. Such basic distributed messages usually take much longer to reach recipients than do local invocations. They sometimes reach recipients in a different order than they were sent and they may fail to reach them at all. To avoid this, more sophisticated protocols must be constructed. These may include: ● Procedural messaging, in which senders wait for full replies ● Semi-synchronous messaging, in which senders wait for an acknowledgment of message receipt before proceeding ● Transactional protocols, in which all messages in a given session or transaction are processed in an all-or-none fashion1 ● Callback protocols, in which receivers later issue different messages back to their senders ● Time-out protocols, in which senders only wait for replies for a certain period before proceeding ● Multicast protocols, in which senders simultaneously issue messages to a group of other nodes These and other protocols are often extended and specialized to enhance reliability, security, and efficiency. fault tolerance n. 容错 outright / 5autrait / a. 完全的,彻底的 contention / kEn5tenFEn / n. 争用;争夺 software overhead 软件开销 1 6. Fault Tolerance A program running on a single computer is, at best, only as reliable as that computer. Most distributed systems, on the other hand, need to remain at least partially available and functional even if some of their nodes, applications, or communication links fail or misbehave. In addition to outright failures, applications may suffer from unacceptably low quality of service due to bandwidth shortages, network contention, software Transactional protocols, in which all messages in a given session or transaction are processed in an all-or-none fashion:事务处理协议,即在一个给定的活动时间或事务内,所有消息要么被全部处理,要么全部不被处 理。 106 Computer English overhead, or other system limitations, so fault-tolerance requirements present some of the most central, yet difficult challenges in the construction of distributed systems. authorized / 5C:WEraizd / a. 经授权的 intrinsically / in5trinsikEli / ad. 固 有 地 ; 本 质 上;内在地 encryption / in5kripFEn / n. 加密 authentication / C:7Wenti5keiFEn / n. 验证,认证 trustworthiness / 5trQst7wE:Tinis / n. 值得信任;可信; 可靠 certificate / sE5tifikEt / n. 证(明)书 component code 组件编码 mediate / 5mi:dieit / v. 调解;传递 routing / 5ru:tiN / n. 路由选择 algorithm / 5AlgEri TEm / n. 算法 routing algorithm 路由算法 7. Security Only authorized users may access sensitive data or perform critical operations. Security in distributed systems is intrinsically a multilevel issue, ranging from the basic safety guarantees provided by the hardware and operating systems residing on each node; to message encryption and authentication protocols; to mechanisms supporting issues concerning privacy, appropriateness of content, and individual responsibility. Techniques for addressing trustworthiness include using digital certificates and preventing component code performing potentially dangerous operations such as modifying disk files. 8. Message Passing Software on separate computers communicates via structured message-passing disciplines built upon a number of networking protocols (for example, TCP/IP). These, in turn, may run on any of a number of connection technologies (for example, Ethernet and modems). The nodes in most distributed systems are completely connected—any node may send a message to any other node. Delivery is mediated by underlying routing algorithms and related networking support. Messages include commands, requests for services, event notifications, multimedia data, file contents, and even entire programs. It should be noted that most multiprocessors communicate via shared memory rather than message passing and therefore are not distributed. 9. Openness commence / kE5mens / v. 开始 extensibility / ik7stensE5bilEti / n.可扩展性, 可扩充性 minimal / 5minimEl / a. 最小的;最低限 度的 Most sequential programs are considered closed because their configurations never change after execution commences. Most distributed systems are, to some degree, open, because nodes, components, and applications can be added or changed while the system is running. This provides the extensibility necessary to accommodate expansion, and the ability to evolve and cope with the changing world in which a system resides. Openness requires that each component obey a certain minimal set of 计算机英语 interoperability / 5intEr7CpErE5bilEti / n. 互操作性, 互用性 hypertext / 5haipEtekst / n. 超文本 underlie / QndE5lai / v. 构成…的基础; 支持 domain / dE5mein / n. 领域,域 107 policies, conventions, and protocols to ensure interoperability among updated or added components. Historically, the most successful open systems have been those with the most minimal requirements. For example, the simplicity of the Hypertext Transfer Protocol (HTTP1) was a major factor in the success of the World Wide Web. Standards organizations such as International Standards Organization (ISO) and American National Standards Institute (ANSI), along with industrial consortia such as the Object Management Group (OMG 2 ), establish the basic format and protocol standards underlying many interoperability guarantees. Individual distributed systems additionally rely on context-specific or domain-dependent policies and mechanisms.3 10. Isolation autonomous / C:5tCnEmEs / a. 自治的;独立存 在的 corporate / 5kC:pErEt / a. 公司的;社团的 firewall / 5faiEwC:l / n. 防火墙 persistence / pE5sistEns / n. 持续性,持久性 persistent / pE5sistEnt / a. 持续的,持久的 outlast / 7aut5lB:st / v. 比…持久 decentralize / 7di:5sentrElaiz / v. 分散 autonomous agent 自主主体 aggregate / 5AgrigEt / a. 聚集的 1 2 3 Each component is logically or physically autonomous, and it communicates with others only via structured message protocols. In addition, groups of components may be segregated for purposes of functionality, performance, or security. For example, while the connectivity of a corporate distributed system might extend to the entire Internet, its essential functionality could be segregated (often by a firewall) to an intranet operating only within the firewall. It would communicate then with other parts of the system via a restricted secure protocol. 11. Persistence At least some data and programs are maintained on persistent media that outlast the execution of a given application. Persistence may be arranged at the level of file systems, database systems, or programming language runtime support mechanisms. 12. Decentralized Control No single computer is necessarily responsible for configuration, management, or policy control for the system as a whole. Distributed systems are instead domains joined by protocol of autonomous agents that agree on enough common policies to provide an aggregate functionality. Some aspects of decentralization are desirable, such as fault-tolerance provisions. Others are essential because centralized control cannot HTTP:超文本传输协议(Hypertext Transfer Protocol 的首字母缩略)。 OMG:对象管理组(Object Management Group 的首字母缩略)。 Individual distributed systems additionally rely on context-specific or domain-dependent policies and mechanisms.:单个分布式系统还依赖于和上下文细节或域相关的策略和机制。 108 administer / Ed5ministE / v. 掌管;实施 Computer English accommodate the number of nodes and connections supported by contemporary systems. The tools for administering system-wide policies, however, may be restricted to particular users. ADVANTAGES AND DISADVANTAGES 1. Advantages of Distributed Systems inherent / in5hiErEnt / a. 内在的;固有的 incremental / 7inkri5mentEl / a. 增量的;递增的 Distributed systems have many inherent advantages, especially over centralized systems. Some applications are inherently distributed as well. In general, distributed systems: ● Yield higher performance ● Provide higher reliability ● Allow incremental growth. Distributed computing offers higher rates of return over individual CPUs: ● It is both feasible and easy to construct systems of a large number of CPUs connected by a high-speed network. ● It answers a need to share data scattered over these CPUs. ● It provides a way to share expensive peripherals. ● It allows one user to run a program on many different machines. 2. Disadvantages of Distributed Systems In spite of their many advantages, distributed systems do create a few disadvantages. Some of these are: reliance / ri5laiEns / n. 依靠,依赖 ● ● ● ● ● The need for new operating systems to support them A reliance on network communications The need for enhanced security Offer no nice classification of operating systems Use loosely and tightly coupled systems CONCLUSIONS maximize / 5mAksimaiz / v. 使增加(或扩大) 到最大限度 cost effectiveness 成本效益 We want to fully utilize a heterogeneous computing environment where different types of processing resources and interconnection technologies are used effectively and efficiently. Using distributed resources provides the potential of maximizing performance and cost effectiveness for a wide range of scientific and distributed applications. Distributed computing environments comprising networked heterogeneous workstations are becoming the standard configuration in both engineering and scientific environments. However, the lack of a 109 计算机英语 unify / 5ju:nifai / v. 使成一体;统一 unifying parallel computing model (a parallel equivalent of a von Neumann model) means that the current parallel applications are nonportable. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Now many distributed systems are ________ whereas most of them were initially homogeneous. 2. The most common reason for connecting a set of computers into a distributed system is to allow them to share physical and computational ________. 3. Networked ________ systems are the most common type of distributed system. 4. The most basic form of distributed communication is ________. 5. In ________ protocols, senders simultaneously issue messages to a group of other nodes. 6. Some of the heterogeneity issues in a system may be dealt with through the construction of ________ that translate one set of formats and protocols to another. 7. Distributed systems usually need to remain at least partially available and functional even if some of their nodes, applications, or communication links fail or misbehave, so they should possess ________ ability. 8. One of the general properties shared by distributed systems is ________, which allows nodes, components, and applications to be added or changed while the systems are running. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. procedure call structured message protocol restricted secure protocol networking protocol 11. 12. 13. 14. 顺序程序 多址通信协议 路由算法 开放式系统 110 Computer English 5. 6. 7. 8. 9. 10. processing node homogeneous system cost effectiveness message encryption message format component code 15. 16. 17. 18. 19. 20. 异构型环境 分布式处理 资源共享 结构化信息传送 通信链路 开发工具 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: administration programmable time-sharing application efficiently processing mainframe component architecture client power range terminal split server network The client/server architecture is a proven approach to building flexible, scalable environments. It is an arrangement used on local area ________ that makes use of “distributed intelligence” to treat both the ________ and the individual workstations as intelligent, ________ devices, thus exploiting the full computing power of each. This is done by ________ the processing of an application between two distinct ________: a “front-end” client and a “back-end” server. The ________ component, itself a complete, stand-alone (独立的) personal computer (versus the “dumb” ________ found in older architectures such as the time-sharing used on a mainframe) offers the user its full ________ of power and features for running ________. The server component, which can be another personal computer, minicomputer, or a(n) ________, enhances the client component by providing the traditional strengths offered by minicomputers and mainframes in a(n) ________ environment: data management, information sharing between clients, and sophisticated network ________ and security features. The advantage of the client/server architecture over older ________ is that the client and server machines work together to accomplish the ________ of the application being used. Not only does this increase the processing ________ available, but it also uses that power more ________. The client portion of the application is typically optimized for user interaction, whereas the server portion provides the centralized, multi-user functionality. 计算机英语 IV. 111 Translate the following passage from English into Chinese: Distributed processing is a form of information processing in which work is performed by separate computers that are linked through a communications network. Distributed processing is usually categorized ( 将 … 分 类 ) as either plain distributed processing or true distributed processing. Plain distributed processing shares the workload among computers that can communicate with one another. True distributed processing has separate computers perform different tasks in such a way that their combined work can contribute to a larger goal, such as the transfer of funds from one bank to another. This latter type of processing requires a highly structured environment that allows hardware and software to communicate, share resources, and exchange information freely. At the highest (and most visible) levels, such distributed processing can also require data-transfer mechanisms that are relatively invisible to users but that enable different programmes to use and share one another’s data. 112 Computer English Section B What Does “Client-Server” Really Mean? (Part I) 1. Introduction dizzying / 5diziiN / a. 使 人 头 晕 目 眩 的;使人困惑的 terminology / 7tE:mi5nClEgVi / n. [总称]术语 buzzword / 5bQzwE:d / n. 玄妙的术语;时 髦词语 connotation / 7kCnE5teiFEn / n. 内涵意义,隐含 意义;内涵 denote / di5nEut / v. 表示;意思是 entity / 5entiti / n. 实体 As computer professionals, we all must cope with a never-ending stream of new technology. Along with the introduction of each new technology comes a dizzying array of matching terminology. We use (or abuse) the many technical terms to the point that they begin to take on the quality of a “buzzword”, that is, a word or phrase frequently heard but seldom understood. “Client-server” is one term that has fulfilled its potential for becoming an industry buzzword. This is unfortunate; the term “client-server” has a lot of relevance to today’s networks. Part of the difficulty with understanding the term is that it takes on different meanings or connotations, depending upon who is doing the defining. In a very general sense, the term client-server really denotes a type of relationship between entities. The entities we will discuss, of course, are software applications running on networked computer systems. There are many such types of possible relationships (such as a hierarchy) between multiple entities, but we will only examine two here: “peer-to-peer” and “client-server”. Let’s take a short look at one of those relationships, “peer-to-peer”, that will help us when we look more closely at a client-server relationship. 2. Examining a “Peer-to-Peer” Relationship standing / 5stAndiN / n. 级别;地位 cost-effective / 5kCsti5fektiv / a. 有成本效益的; 合算的 allocate / 5AlEkeit / v. 分配;分派 In a peer-to-peer relationship, all entities have equal standing with one another, and all are equally capable of running the same set of services. In many ways, this relationship is the easiest type to recognize, configure, and manage. This does not mean that it is necessarily the most efficient or cost-effective way of allocating computer resources. In peer-to-peer configuration, all of the individual systems are configured (more or less) alike. They have relatively equal amounts of resources (e.g., disk, memory, and CPU power), and all resources are 计算机英语 113 equally shared among the various systems in the group. Each machine is completely capable of performing any task that a particular user may desire, without the involvement of, or reliance on, another system’s resources. Figure 6B-1: Hardware resources in a peer-to-peer computer relationship depict / di5pikt / v. 描绘;描写 thermal / 5WE:mEl / a. 热的;热量的 optimum / 5CptimEm / a. 最适的,最佳的 Figure 6B-1 depicts a network of computer systems configured in a peer-to-peer manner. Every computer has the same hardware resources—disk, RAM, and CPU—as well as the same software configuration in terms of operating system and applications. Because the machines are all similarly configured, a user who is running a word-processing application uses far less of the local resources than a user that might be doing a thermal analysis of a circuit board. In the first case, there are very probably underutilized resources, such as RAM, CPU cycles, or hardware graphics acceleration. In the second case, the local resources are more likely to be fully utilized, possibly even overutilized. Underutilization of resources is common in a peer-to-peer network where there are multiple applications types being used. The underutilization of resources on some systems, along with full or overutilization on others can mean that some users are not able to get their tasks completed in the optimum amount of time, while others may have no difficulties. Here is an example of how misallocation of resources in a networked environment can actually cost money. 3. The Client-Server Relationship 114 Computer English In a client-server relationship, there are at least two types of logical entities involved: the client entity and the server entity. It is important to note at this point that the term client-server may be applied either to hardware (computer system) or to software (applications) running on the hardware. This is one potential point of confusion, as the hardware may be configured differently to run the client software or the server software, but does not necessarily have to be. In the case of software entities, it is possible that both client and server may exist on the same computer system or be split across multiple systems in the network. How the actual tasks that an application performs are split between the client and the server entities will vary, usually determined by the application’s designer. Figure 6B-2: Hardware resources in a client-server computer relationship well-defined / 5weldi5faind / a. 明确的;界线分 明的 Unlike the peer-to-peer environment, the client-server relationship is not one of equal capability between client and server entities. The server entity “possesses” and manages a well-defined set of resources on behalf of its client or clients. The client-server model may also be characterized as a “request-response” interaction. To use the resource, the clients must make requests to the server entity. The server responds to, services, or “serves” its client’s requests for the resource that it manages. Since the client-server relationship is a logical one, nothing prevents both the client and the server 计算机英语 115 components of an application from running on the same underlying hardware. reapportion / 7ri:E5pC:FEn / v. 重新分派;重新 按比例分配 Figure 6B-2 shows an environment that has resources unequally distributed between client and server machines. You can think of the system resources as being water in a set of buckets associated with each system; in this example there are buckets for RAM, CPU cycles, and disk storage. Resources are moved from the client system’s buckets and reapportioned to the resource bucket belonging to a server or group of servers in the network. In this type of environment, there are usually N clients to each server, with the server providing all of the services associated with its resource to multiple clients. The client-server relationship may be thought of as a many-to-one relationship. The number of clients that a server can handle depends on several factors, including the type of resource being managed, the number of total simultaneous requests, and the request frequency from each client. One of the defining characteristics of today’s client-server applications is the presence of a network connection between the client and the server, so another important performance factor is the type of connection between the client and the server and its relative “health”. Obviously a poor network connection can influence clients and servers communicating across the network. Figure 6B-3: Client-server application components 116 Computer English 4. Client-Server Application Configurations and Components Within the term client-server, there are many possible application configurations. The configuration of a client-server architecture is determined by where the associated application is broken into separate components. At the most basic level, the application may be split into several different components: the graphical user interface (presentation logic), application logic, and data management logic. monolithic / 7mCnE5liWik / a. 单块的,单片的 hybrid / 5haibrid / a. 杂种的;混合的 whim / wim / n. 突 然 产 生 的 念 头;异想天开的念 头,怪念头 transition / trAn5siVEn / n. 过渡;转变 It is possible to insert distribution services between any, all, or none of the three basic components. In the latter case, you end up with the familiar “monolithic” application configuration, running on a single system. With distribution services inserted, the result is a client-server application. This is diagrammed in Figure 6B-3. Sometimes identifying a client-server relationship is difficult because the system being studied is a hybrid design. Under these circumstances, there may be multiple levels of client-server relationships, or a single level where one client may in turn be a server to other clients. There are some commonly encountered client-server configurations which involve more complicated physical distributions of the application components and some more complicated interactions between those components. Some examples are shown in Figure 6B-4. Combinations involving other relationship models are possible, based on the whims of the application designers. For these reasons, and others, there may not be a clean distinction in hybrid system designs or systems that are in transition between the client-server model and other configurations. We will try to stick to the clearly identifiable cases, and you should avoid designing such complicated relationships if at all possible. 5. Client-Server Distribution Services conceptual / kEn5septjuEl / a. 概念的 literally / 5litErEli / ad. 确实地,不加夸 张地;逐字地 1 While describing the client-server application architecture, we did not venture beyond the conceptual description of the application being split into components and “glued” together with “distribution services”. Examining the available distribution services in an environment is an important aspect of both good design and analysis. If the necessary services are not available or reliable, client-server applications may quite literally fall apart1. fall apart:崩溃;破裂;破碎。 计算机英语 117 Figure 6B-4: Examples of client-server physical distribution models load balancing 负载平衡 schematic / ski5mAtik / a. 图表的;图解的; 纲要的 compute / kEm5pju:t / v. & n. 计算 The term “distribution services” is a very general label. The services used to allow distribution of client-server application components include: remote procedure call facilities (RPC 1 ), directory services, system management services, performance measurement services, load balancing, and a whole host of other potential components. These services may be distributed across multiple systems or reside on a single server. When designing an environment, it is easier to separate the services as if they were running on their own computer systems, only collapsing the relationships between services and the physical server system when the final hardware configuration is determined. Our schematic view of the client-server world, then, is the client logic communicating with servers providing data access, transaction processing, and compute power. Interaction between the client and the rest of the environment takes place through some form of communication facility. A set of infrastructure services provides the glue to hold the application architecture together. A transaction processing function or database server may, in some 1 RPC:远程过程调用(remote procedure call 的首字母缩略)。 118 differentiate / 7difE5renFieit / v. 区分,区别 Computer English cases, differentiate a “commercial” client-server application from a “technical” client-server application. The transaction facility may be viewed as providing the business logic necessary to properly direct client behavior, according to a predefined set of rules used to model data flow in a business. In most technical applications, this particular service is usually absent or may be viewed as part of the data service. The infrastructure services are common functionality needed by all client-server applications and their users for proper operation. Time synchronization between computers systems, software licensing, electronic mail, directory services, user authentication and access (security), software distribution, and especially environmental management are all examples of services needed by almost every application in the client-server environment. Determining what these common services are and ensuring their availability is an important part of the design or assessment of a client-server environment. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. In a(n) ________ relationship, all entities have equal standing with one another, and all are equally capable of running the same set of services. 2. The number of clients that a server can handle depends on such factors as the type of resource being managed, the number of total ________ requests, and the request ________ from each client. 3. Among the services used to allow distribution of client-server application components are remote ________ call facilities, directory services, system ________ services, performance measurement services, and ________ balancing. 4. The term “client-server” may be applied either to hardware or to ________ running on the hardware. II. Translate the following terms or phrases from English into Chinese and vice versa: 119 计算机英语 1. 2. 3. 4. 5. logical entity client-server architecture CPU cycle graphics acceleration software licensing 6. 7. 8. 9. 10. 字处理应用程序 负载平衡 远程过程调用 硬件配置 对等网络 120 Computer English Section C What Does “Client-Server” Really Mean? (Part II) 6. How Do I Recognize a Client-Server Relationship? permutation / 7pE:mju5teiFEn / n. 排列;置换;改 变 purport / pE:5pC:t / v. 声称;自称 For those of us that are used to other relationship models, the client-server model and its many permutations may seem strange at first. The natural tendency is to configure everything in peer-to-peer mode, which is easier to grasp conceptually. This is also the way that environments tend to evolve, starting with one machine, adding another, and another, and so on. We may ask, “Just how do I recognize a client-server environment when I see one?” This can be easier than it first seems. When confronted by something that purports to use a client-server model, start by asking the following questions: ● What is the resource that is being managed? ● Who is doing the resource management? ● Who is using the resource? With the answers to these questions in hand, try drawing a picture that represents the relationships among the entities being examined. You should see: ● A clear logical or physical division between the manager and the users of the resource (the server and the clients) ● Usually, one server to multiple clients ● A clear division of “intelligence” or “responsibility” with regard to managing the resource, with the client being the least capable of the two entities For simplicity, we have only considered a single client to single server relationship up to this point. Figure 6C-1 shows a slightly more complicated situation. The X-windows system, used by Unix and other operating systems to provide remote graphical display capabilities, is a good example of a client-server relationship that takes a little analysis to understand. Users that 计算机英语 121 are new to the X-windows system frequently ask, “Aren’t the programs that are using the X-windows display actually the servers, since they are acting on behalf of the user?” Figure 6C-1: Where is the client and where is the server? vice versa At first glance, it appears that the client and the server entities are reversed. After identifying the resources being managed, the picture makes a little more sense. It is the user’s graphics display and input devices that are being managed by the X-windows server on behalf of the X-windows clients that are using them. So, with regard to the X-windows services, the programs are indeed clients to the X-windows server and not vice versa. / 7vaisi5vE:sE / ad. 反之亦然 resourceful / ri5sC:sful / a. 善 于 随 机 应 变 的;足智多谋的; 资源丰富的 administrator / Ed5ministreitE / n.(系统)管理员 Note also that the X-windows server itself makes use of the X-windows font server. So, as shown in Figure 6C-1, there are multiple client-server relationships at work. The X-windows clients are using resources “served” by the X-windows server, and the X-windows server is using resources that are “served” by the X-windows font server. There is another important point to be made here. Because of the flexibility inherent in the example, a resourceful system administrator is free to move the components to the physical system in the network that best suits the needs. The X-windows font server and the X-windows client are free to run on any physical machine, but the X-windows server is tied to the physical resource, the graphics display, that it is managing. 7. What Is Important About the Client-Server Model? 122 conceptual model 概念模型 insulate / 5insjuleit / v. 使绝缘;隔离 scaling / 5skeiliN / n. 缩放 optimal / 5CptimEl / a. 最适的,最佳的 (= optimum) warrant / 5wCrEnt / v. 证 明 … 是 正 当 ( 或 有 理 ); 授 权 给;保证 Computer English So far, we have talked about what the client-server model is, shown conceptual models of the supporting environment, and discussed how to identify some client-server characteristics in a system. But why is the client-server model important? Why does a large portion of the industry focus on this particular way of designing applications? There are several very good reasons to consider client-server design in your computer environment: ● The per seat cost of a computerized solution may be lower with the client-server model. ● Specialized hardware may be used to provide resource-intensive services, improving client performance. ● General-purpose hardware may be specifically tuned to perform the specialized service, improving client performance. ● Measuring (and therefore managing) the usage of a service may be easier if it is localized to specific places in the environment. ● The clients may be insulated from changes in the server environment. ● The client-server model provides better scaling than other usage models. Remember that in a peer-to-peer relationship every system is equally capable of providing a particular service. For optimal performance, this implies that all systems should be configured with the same hardware and software resources. This can lead to overconfiguration of resources in areas like Random Access Memory (RAM), disk space, CPU power, I/O capability, and system expandability. Due to the overconfiguration, each system may cost more than it should, especially if the local resources are underutilized. By designing the environment so that the clients use services provided by suitably configured servers, the server resources may be better utilized and the clients need not be so heavily configured. Whenever a server must provide access to a specialized resource, there are two common ways to approach the situation: choose a specialized machine type, if the need warrants it, or choose a general-purpose machine that is capable of providing the service if properly tuned. The specialized computer usually provides a unique service, or provides it in a way that no other machine can, often at an extra cost. A general-purpose computer can be moved from place to place and retuned to meet the new service needs. Providing the proper level of performance to clients of a particular 计算机英语 123 service and measuring the level of that performance can be a challenge. This is especially true if the resources are scattered all over the network as in the peer-to-peer model. With the client-server model, if you know that a particular machine provides only one type of service to its clients, it is far easier to measure the total resource utilization and, therefore, the machine’s ability to provide the service. If more access to the resource being served is required, then the machine may be upgraded or, if possible, additional servers added. implicit / im5plisit / a. 不言明的;含蓄 的;无疑问的 Under the client-server model, it is possible to insulate a client from implicit knowledge of where the requested service is located in the network. This is desirable for a number of reasons, but the most important is: if a client cares only that the service is provided, not where it is provided, then the client can be insulated from changes in the service environment. For example, in a client-server environment designed with this rule in mind, if a system manager noticed that additional capacity was necessary for a given service, he would only need to plug another server into the network to provide the additional capacity. Furthermore, if the need for additional capacity was a temporary situation, when the extra capacity was no longer needed the server could be removed without impacting clients of the service. 8. Client-Server Model Summary disparity / dis5pArEti / n. 不同,差异 In summary, the term “client-server” defines a specific type of relationship between two, or possibly more, logical entities. These entities are usually software in nature and may co-exist on the same computer system hardware or be separated by a network connection. The server-to-client ratio is one to many, as opposed to one-to-one as in a peer-to-peer relationship. There usually is a disparity in capability between the client and server entity, with the client requesting use of a resource from the server, which manages the desired resource. Client-server applications consist of individual components with distribution services inserted between them. Common client-server application components are the presentation logic, the application logic, and the data management logic. While this model is useful in the initial understanding of client-server principles, real-life applications tend to be more complicated and require more analysis to understand the roles that each component plays in the whole. 124 Computer English There are multiple “styles” of client-server applications. The style of client-server application depends on where the application designers inserted distribution services into the application logic. There are advantages and disadvantages to each of the commonly encountered client-server application styles. Finally, there is a basic choice to be made between using general-purpose and special-purpose computer systems to run server software. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. In a client-server relationship, there is a clear logical or ________ division between the manager (server) and the users (clients) of the resource. 2. For optimal performance, all the systems in a peer-to-peer relationship should be configured with the same hardware and software resources. This can lead to ________ of resources. 3. In a client-server relationship, the clients may be insulated from the ________ in the server environment. 4. Common client-server application components are the ________ logic, the ________ logic, and the ________ logic. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. font server data management logic disk space conceptual model 5. 6. 7. 8. 客户∕服务器模型 图形显示 通用硬件 系统可扩展性 计算机英语 125 Unit 7: Database (数据库) Section A Enter the World of Relational Databases 1. What Is a Relational Database? focal / 5fEukEl / a. 焦点的 1 In today’s business world, information technology is in its full bloom1. Processing data and pumping out information has become the focal point of the modern-day computing environment. Data can be stored in various ways, depending on how it will be used later on. This data store is called a database. The rawest form of data storage is a file where data is stored without any attributes, characteristics, or links. It requires a lot of programming effort to process this type of data, so the relational data model evolved. The relational data model represents data and relationships among the data elements. This model is based on real-world scenarios, which in full bloom:盛开着花;正在充分发展。 126 Computer English consist of basic objects known as entities and how these entities are connected with each other, which constitutes the relationships. A representation of this concept is known as an ERD1 (entity relationship diagram). Let’s take a simple example of a database for a bookstore. Book titles and authors are two entities in it (among many others). The relationship between authors and books is that many authors can write one book and one author can have several books. This type of relationship is called a “any-to-many” relationship. Any two entities (e.g., “A” and “B”) can have one of the following types of relationships: ● One-to-one “A” is associated with only one value of “B” and vice versa. ● One-to-many “A” can be associated with many values of “B,” however “B” is associated with only one value of “A.” ● Many-to-one “A” is associated with only one value of “B” whereas “B” can be associated with many values of “A.” ● Many-to-many “A” is associated with one or many values of “B” and vice versa. modeling / 5mCdEliN / n. 建模,模型化 facilitate / fE5siliteit / v. 使变得(更)容 易;促进 To identify all the entities and their relationships is the first step of relational data modeling. This is also known as “logical database design.” Once the logical design is complete, it requires creating some kind of physical objects (known as “tables”) to store this information. We would need a system that would facilitate storing entities with their attributes and relationships. This system should also provide the capability of retrieving the desired information about the entities. 2. Introduction to a Database Management System (DBMS) A database management system is a computer-based system to record interrelated data, and it provides interfaces to access the data. A database system is designed to handle a large amount of data and is both convenient and efficient to use. 2.1 Purpose of a DBMS The overall purpose of a database system is to maintain information in 1 ERD:实体关系图(entity relationship diagram 的首字母缩略)。 计算机英语 127 such a way that: duplication / 7dju:pli5keiFEn / n. 重复;复制 inconsistency / 7inkEn5sistEnsi / n. 不一致 integrity / in5tegrEti / n. 完整(性) constraint / kEn5streint / n. 约束;限制 ● Data redundancy is reduced Data duplication is minimized as much as possible, which is an efficient storage strategy that eliminates data inconsistencies. If the same data item is stored at two different places in the database and is changed at only one place, that can lead to data inconsistency. To avoid such situations, the data is stored in such a way that the duplication is minimal. ● Data integrity is maintained Data stored in a database should be accurate. The data inaccuracy can be due to inconsistencies (as discussed previously) or due to not following some valid constraints—e.g., 30th day of February is an inaccurate data value. Thus the data values stored in the database must satisfy certain constraints to make the data accurate. ● Data access is easy Data access is one of the key features of any database system. The data is useless unless it can be processed to generate information, hence a DBMS provides good tools and interfaces to access the data. ● Data is secured A DBMS can support multiple users and not every user should be able to access all the data. DBMS provides methods to restrict user access in order to enforce security. concurrent / kEn5kQrEnt / a. 同时发生的,并 发的,并行的 anomaly / E5nCmEli / n. 异常(现象); 不按常规 ● Concurrent access anomalies can be handled This point also arises from the fact that multiple users can use a database at the same time. If two people decide to change the same data item with different values, then there is a possibility of ending up with inaccurate data. A DBMS provides functionality to handle such situations. ● Data sharing is possible A DBMS lets one data store be shared among different applications. 2.2 Typical DBMS Structure A database system is divided into several modules to achieve the overall functionality. It works very closely with the operating system to get 128 query language 查询语言 host / hEust / n. 主机 host language 主机语言 embedded / im5bedid / a. 嵌入(式)的, 内嵌的 programmatically Computer English the basic services—e.g., disk I/O. Data is stored on the disk either on top of the file system or on the raw disk itself. DBMS provides a query language to access data. Thus a “query” is a query language statement that is sent by the user to access data. The query is processed by the system and brings the results back to the user. The most common query language is SQL (Structured Query Language), developed by IBM, and the American National Standard Institute (ANSI) has developed standards for SQL. SQL is the direct way to access data. Another way to access data is through programs. These programs, known as “application programs,” are written in a host language and have embedded Data Modification Language (DML 1 ) calls to interact with DBMS. A DML is a language through which a user can access or manipulate data programmatically. SQL is also commonly known as a DML, but it cannot be directly used from an application program. The main components of a DBMS are: / 7prEugrE5mAtikEli / ad. 用编程方法 storage engine 存储引擎 metadata ● Storage engine Manages the allocation of space on disk storage. It also maintains the user data and metadata (database of all the user databases). / 7metE5deitE / ● Database manager This is the interface between low-level data stored in the database and the application program and queries. n. 元数据 database manager 数据库管理器 query optimization 查询优化 precompiler / 7pri:kEm5pailE / n. 预编译程序 1 ● Query processor Translates statements in a query language into low-level instructions to pass to a database manager. It also generates a strategy for the most efficient query execution. This strategy is called the “query execution plan,” and the process of generation of the plan is known as “query optimization.” ● Language precompiler This is the precompiler for the host language provided by DBMS. It converts the DML statements embedded in the application program into normal procedure calls. The precompiler interacts with the query processor in order to process embedded SQL code. (See Figure 7A-1) DML:数据修改语言(Data Modification Language 的首字母缩略)。 129 计算机英语 Application Query Language Precompiler Query Database Manager Data File Manager Figure 7A-1: DBMS architecture 3. Different Computing Models Until now we have focused only on the DBMS functionality. Now let’s take a step back and look at a broader picture, which is the complete computing module. The complete database application can be divided into three major categories: report / ri5pC:t / n. 报表 ● Data presentation How data is presented to the end user—e.g., report formatting, etc. ● Business logic How data is processed according to the application rules and requirements. ● Data storage Storing and securing the user data. In a mainframe environment all of the three functions are performed at a centralized server, and the user can see results on a terminal or through a printed report. This model has advantages such as maintainability of application code (all components reside at a central location), but it requires maintaining high-cost computers. To minimize the operational cost of these expensive computers, the idea of distributed computing evolved. 3.1 Client/Server Computing 130 analogous / E5nAlEgEs / a. 相似的; 可比拟的 validity / vE5lidEti / n. 有效性 bottleneck / 5bCtlnek / n. 瓶颈,障碍 chunk / tFQNk / n.(大)块;程序块; 组块 tiered / tiEd / a. 分层的,层叠的 Computer English In client/server computing, processing is distributed between two machines—the client machine and the server machine. A client machine is analogous to a terminal in a mainframe environment, and the server is still the centralized host. In this environment, client machines take care of the data presentation and most of the business logic implementation. The server machine is responsible for data storage and some of the business logic. Since the processing is now distributed, server machines do not need to be as big as the mainframe computers. Instead, resources can be added to client machines, which is more cost-effective. Now the question is how this processing is distributed. The client issues a command to the server, which gets processed at the server and the results are sent back to the client machine. This sounds quite like the mainframe environment, but the difference is the pre- and post-processing of the command. Before the command is sent to the server, some processing takes place at the client machine. The client does data validity checks and creates a very simple request for the server. After the server has processed the command, formatting for data presentation is also done at the client machine. Hence the client also does data processing to reduce load from the server. A well-designed client/server application uses an optimum balance of client and server machine resources. Multiple users connect to a server machine over the network, hence the network becomes a crucial part of the client/server computing environment. A fast and stable network environment is needed to run any client/server application efficiently. Applications should be designed properly so that network bottlenecks are not created. Clients should always bring back only as much data as required, and possibly in smaller chunks at a time. Client/server computing has its disadvantages too. In a large user environment, maintainability and scalability become the limiting factors. It is a major effort to update every client machine with the changing versions of application. Processing power is limited to the smallest client machine. All the client machines need to be upgraded if the client part of the application needs extra resources. Tiered architecture was evolved to resolve the issues with the client/server computing environment. 3.2 Multitiered Computing In a multitiered environment, an application goes through at least three layers of processing. The client is very thin and does not require much processing power, since it contains only a data presentation layer. 131 计算机英语 tier / tiE / n.(一)层 tiering / 5tiEriN / n. 层叠 Business-logic-related software is installed on a separate server(s), which is accessible to all the client machines. The third layer is the DBMS, which takes care of data storage. The functionality of each tier (commonly known as a component) can be written in any language and maintained independently. The idea behind tiering is dividing a complex task into smaller ones and then implementing it. This technique facilitates code reusability and provides better manageability and greater scalability. Figure 7A-2 shows a three-tier processing system. It also shows examples of the tools that can be used to implement each tier. Visual Basic, Delphi, C++ Microsoft Transaction Server, Jaguar CTS Microsoft SQL Server, Oracle Data Business Presentation Logic Figure 7A-2: Three-tier processing model —————————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The rawest form of ________ is a file where data is stored without any attributes, characteristics, or links. 2. In relational data modeling, the first step is to identify all the ________ and their relationships. 3. A(n) ________ is a computer-based system which records interrelated data, and provides interfaces to access the data. 4. Data ________ occurs if the same data item is stored at two different places in the database and is changed at only one place. 5. The most common query language is ________. 132 Computer English 6. The main components of a DBMS are the ________, the database manager, the ________, and the language precompiler. 7. The language precompiler serves to convert the DML statements embedded in the application program into normal ________. 8. The complete database application can be divided into three major categories: ________, business logic, and ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. language precompiler business logic implementation query processor data modeling storage engine tiered architecture database manager data presentation layer logical database design entity relationship diagram 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 查询语言 主机语言 数据修改语言 数据冗余 关系数据库 关系数据模型 数据库管理系统 数据元素 数据存取 查询优化 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: equipment available data identification important communicate database on-line keyboard graphics appear field centre screen link modem A database is any collection of data organized for storage in a computer memory and designed for easy access by authorized users. The ________ may be in the form of text, numbers, or encoded ________. Since their first, experimental appearance in the 1950s, databases have become so ________ in industrial societies that they can be found in almost every ________ of information. In the 1960s, some databases became commercially ________, but their use was funnelled (传送) through a few so-called research ________ 计算机英语 133 that collected information inquiries and handled them in batches (一批). ________ databases—that is, databases available to anyone who could ________ up to them by computer—first ________ in the 1970s. For the home user, the ________ required includes a computer terminal, a telephone, and a(n) ________, which enables the terminal and the ________ (usually some type of search-service system) to ________. The user simply dials the number of the service, provides a password code for ________ and billing (记账), and types in questions to a chosen database on the terminal’s ________. The data received may either be displayed on a terminal ________ or printed out. IV. Translate the following passage from English into Chinese: Structured Query Language (SQL), in computer science, is a database sublanguage used in querying, updating, and managing relational databases. Derived from an IBM research project that created Structured English Query Language (SEQUEL) in the 1970s, SQL is an accepted standard in database products. Although it is not a programming language in the same sense as C or Pascal, SQL can either be used in formulating (系统地阐述) interactive (交 互 式的 ) queries or be embedded in an application as instructions for handling data. The SQL standard also contains components for defining, altering, controlling, and securing data. SQL is designed for both technical and non-technical users. 134 Computer English Section B Database Objects of SQL Server Database objects can be anything from tables to small pieces of code that can be used to perform application functions in the database. Tables A table is simply a database object made up of columns and rows that can be used to store data. A database can contain as many as two billion tables with as many as 1,024 columns per table. The only limiting factor to the number of rows in the database is the amount of disk space that you have to allocate to that database. The maximum row length in an SQL Server table is 8,060 bytes long. Each column in the table will contain data only of a specific datatype. SQL Server supports two different types of tables—permanent and temporary. Permanent tables are created in the database and remain there until 计算机英语 135 they are dropped. Normally, these tables are used to store permanent data, such as anything that is created by your users. These tables are created in the database that you specify. prefix / 5pri:fiks / n. 前缀 view / vju: / n. 视图 The other type of table is temporary tables. These tables are usually created by the user application for temporary storage space. Two types of temporary table exist. The first is local temporary tables. These tables are created by one user and accessible only by that user. The other type of temporary table is a global temporary table. These tables are created by one user and then accessible by any user who is on the system. A local temporary table is dropped as soon as the user who created it logs out1 of the system. A global temporary table is dropped as soon as the user who created the table logs out of the system, and any other users who have been referencing it log out. Temporary tables are created in the tempdb2 database. They are created with a prefix of # for local temporary tables and # # for global temporary tables. Views Views are intrinsically related to tables in that they are essentially virtual tables. Views are used to represent data from one table or more than one in an alternative way. Views are created only in the database that you are currently using. There are many reasons for using views, including: customization / kQstEmai5zeiFEn / n. 定制,用户化 ● ● ● ● ● ● Focusing on Specific Data Query Simplification Data Customization Security Exporting Data Simplifying Access to Partitioned Data It is important for you to realize that there is no data at all stored in the view itself. The view is only a simpler way to access the data that is contained in other tables in the database. Indexes An index is a special type of database object that is associated with a table directly. An index is used to speed up access to the data in that table and can enforce some data integrity issues, such as uniqueness of rows in 1 2 log out:退出登录,脱机。 tempdb:SQL Server 专用的临时数据库。 136 key / ki: / n. 键值;关键字 pinpoint / 5pinpCint / v. 精确地确定…的 位置 Computer English that table. Indexes contain keys that are made up of at least one column in the table. The keys allow SQL Server to pinpoint rows in the table quickly without needing to scan the entire table for the requested rows. If you create a table that contains no indexes on it, SQL Server will store the data in that table in no particular order. The two types of indexes that can be created on tables in SQL Server are as follows: clustered / 5klQstEd / a. 成簇的 ● Clustered ● Nonclustered When you are working with indexes, it is important to remember that the columns which are frequently searched on, such as an employee’s ID1 number or last name, should be indexed. This will speed the process of getting at the data. Datatypes numeric / nju:5merik / a. 数字的;数值的 A datatype is a definition for the type of data that you are going to be placing in a table or variable. Datatypes are used for several purposes. First, they tell SQL Server what type of data to expect, thereby allowing space allocation to be optimized for that specific datatype. Secondly, they allow the developer to determine what type of data needs to be collected—for example, numeric data or character data—and force the user to input that type of data. Any attempt to input data not of that type results in an error. Lastly, they ensure consistency across all the rows in the table. Many different datatypes are available in SQL Server. If these datatypes are not enough for you, though, you can also create your own based on the original ones provided to you by SQL Server. Constraints null / nQl / a. 空的 n. 空值 1 Constraints are a way to ensure that data in your databases is in the form that you expect it to be. Constraints can be used to define rules on the format of data, ensure uniqueness in a table, ensure that data is actually entered into a column, and ensure that columns maintain integrity between tables. Five types of constraints can be used in SQL Server: ● NOT NULL ● CHECK ID:身份证明(identification 的缩略)。 计算机英语 primary key 主键 foreign key 外键 137 ● UNIQUE ● PRIMARY KEY ● FOREIGN KEY Constraints are very powerful tools if you use them correctly. Stored Procedures Stored procedures are groupings of SQL statements that have been compiled together into a single execution plan. These can be used to return data to the user and to achieve a consistent implementation of logic across applications. You can do a lot of things with stored procedures. The many advantages of using stored procedures include the following: ● SQL statements and logic that are used to perform similar tasks can be designed, coded, and tested at one place. Then, when applications need that functionality, all they have to do is to execute the stored procedure. ● Stored procedures can increase performance on the server by eliminating large amounts of network traffic required to execute large SQL scripts. Instead, all the client needs to do is to execute the single stored procedure. ● Stored procedures can keep your users from having to know everything about the underlying table structure. All they need to know is that they have to execute a particular stored procedure to attain a specific result. trigger / 5trigE / n. 触发器 Triggers Last but not least1, you need to learn about triggers. Triggers are similar to stored procedures in that they are groupings of SQL statements. The major difference is how triggers are executed. Triggers are executed when a row is inserted, updated, or deleted from a table, depending on how the triggers were created. Triggers are a powerful way to enforce business rules when data is modified. A single table can have up to three different triggers on it. You can have a trigger that fires when an UPDATE occurs, one that fires when an INSERT occurs, and one that fires when a DELETE occurs. Triggers can be a way that the SQL Server automates business processes. For example, when an author has sold enough books to cover the 1 last but not least:最后但并非最不重要的(一点)。 138 royalty / 5rCiElti / n.(著作的)版税 caution / 5kC:FEn / n. 小心,谨慎 Computer English advance that the publishing company paid, a trigger could be used to automatically begin calculating the royalty payments. Triggers fire after the record has been successfully modified in the table. If the modification fails because of a syntax error or constraint violation, the trigger is not fired. You need to be aware of one point of caution when dealing with triggers. Although triggers can be very powerful, they can also be very damaging to the performance of your server. Be very careful that you do not try to put too much functionality into your triggers because it will slow down response and can really frustrate your users. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. In relational databases, a table consists of ________ and ________ that can be used to store data. 2. SQL Server supports two different types of tables. They are ________ and ________ tables. 3. ________ and ________ indexes are the two types of indexes that can be created on tables in SQL Server. 4. There are five types of constraints that can be used in SQL Server. They are NOT NULL, ________, UNIQUE, ________, and FOREIGN KEY. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. global temporary table partitioned data virtual table permanent table log out of a system 6. 7. 8. 9. 10. 主键 外键 数据库对象 簇索引 本地临时表 计算机英语 139 Section C Delphi1 Database Architecture dataset / 5deitEset / n. 数据集 Database applications are built from user interface elements, components that manage the database or databases, and components that represent the data contained by the tables in those databases (datasets). How you organize these pieces is the architecture of your database application. Figure 7C-1: Object Repository of Delphi By isolating database access components in data modules, you can develop forms in your database applications that provide a consistent user interface. By storing links to well-designed forms and data modules in the Object Repository as illustrated in Figure 7C-1, you and other developers can build on existing foundations rather than starting over2 from scratch for each new project. Sharing forms and modules also makes it possible for you 1 2 Delphi:美国 Borland 公司出品的面向对象软件开发工具,具有强大的数据库应用程序开发功能。 start over:重新开始 140 corporate / 5kC:pErEt / a. 共同的;一致的 Computer English to develop corporate standards for database access and application interfaces. Many aspects of the architecture of your database application depend on the type of database you are using, the number of users who will be sharing the database information, and the type of information you are working with. local database 本地数据库 site license 站点许可证 When writing applications that use information that is not shared among several users, you may want to use a local database in a single-tiered application. This approach can have the advantage of speed (because data is stored locally), and does not require the purchase of a separate database server and expensive site licenses. However, it is limited in how much data the tables can hold and the number of users your application can support. Writing a two-tiered application provides more multi-user support and lets you use large remote databases that can store far more information. When the database information includes complicated relationships between several tables, or when the number of clients grows, you may want to use a multi-tiered application. Multi-tiered applications include middle tiers that centralize the logic which governs your database interactions so that there is centralized control over data relationships. This allows different client applications to use the same data while ensuring that the data logic is consistent. They also allow for smaller client applications because much of the processing is off-loaded onto middle tiers. These smaller client applications are easier to install, configure, and maintain because they do not include the database connectivity software. Multi-tiered applications can also improve performance by spreading the data-processing tasks over several systems. Planning for Scalability involved / in5vClvd / a. 复杂(难懂)的 scale / skeil / v. 缩放 1 The development process can get more involved and expensive as the number of tiers increases. Because of this, you may wish to start developing your application as a single-tiered application. As the amount of data, the number of users, and the number of different applications accessing the data grow, you may later need to scale up1 to a multi-tiered architecture. By planning for scalability, you can protect your development investment when writing a single- or two-tiered application so that the code can be reused as scale up:按比例增加,相应增加。 计算机英语 141 your application grows. data-aware / 5deitEE7weE / a. 数据敏感的,数 据感知的 The VCL1 data-aware components make it easy to write scalable applications by abstracting the behavior of the database and the data stored by the database. Whether you are writing a single-tiered, two-tiered, or multi-tiered application, you can isolate your user interface from the data access layer as illustrated in Figure 7C-2. Figure 7C-2: You can isolate your user interface from the data access layer. flat file 平面文件 1 2 3 4 A form represents the user interface, and contains data controls and other user interface elements. The data controls in the user interface connect to datasets which represent information from the tables in the database. A data source links the data controls to these datasets. By isolating the data source and datasets in a data module, the form can remain unchanged as you scale your application up. Only the datasets must change. Note some user interface elements require special attention when you are planning for scalability. For example, different databases enforce security in different ways. When you are using Delphi’s data access components (whether they use the BDE2, ADO3, or InterBase Express4 ) it is easy to scale from one-tiered to two-tiered. Only a few properties on the dataset must change to direct the dataset to connect to an SQL server rather than a local database. A flat-file database application is easily scaled to the client in a multi-tiered application because both architectures use the same client dataset component. In fact, you can write an application that acts as both a flat-file application and a multi-tiered client. If you plan to scale your application up VCL:(Delphi 的)可视化组件库(Visual Component Library 的首字母缩略)。 BDE:Borland 数据库引擎(Borland Database Engine 的首字母缩略)。 ADO:ActiveX 数据对象(ActiveX Data Object 的首字母缩略)。 InterBase Express:Delphi 提供的一种快速开发 InterBase 数据库应用程序的技术。InterBase 数据库也是 Borland 公司的产品。 142 artifice / 5B:tifis / n. 巧妙办法 Computer English to a three-tiered architecture eventually, you can write your one- or two-tiered application with that goal in mind. In addition to isolating the user interface, isolate all logic that will eventually reside on the middle tier so that it is easy to replace at a later time. You can even connect your user interface elements to client datasets (used in multi-tiered applications), and connect them to local versions of the InterBase-, BDE- or ADO-enabled datasets in a separate data module that will eventually move to the middle tier. If you do not want to introduce this artifice of an extra dataset layer in your one- and two-tiered applications, it is still easy to scale up to a three-tiered application at a later date. Figure 7C-3: Single-tiered database applications Single-Tiered Database Applications In single-tiered database applications, the application and the database share a single file system. They use local databases or files that store database information in a flat-file format. A single application comprises the user interface and incorporates the data access mechanism (either the BDE or a system for loading and saving flat-file database information). The type of dataset component used to represent database tables depends on whether the data is stored in a local database (such as Paradox1, dBASE2, Access3, or FoxPro4) or in a flat file. Figure 7C-3 illustrates these two possibilities. Two-Tiered Database Applications 1 2 3 4 Paradox:Paradox 数据库管理系统。 dBASE:dBASE 数据库管理系统。 Access:微软公司出品的一种关系型数据库系统。 FoxPro:微软公司出品的一种关系型数据库系统。 计算机英语 143 In two-tiered database applications, a client application provides a user interface to data, and interacts directly with a remote database server. Figure 7C-4 illustrates this relationship. Figure 7C-4: Two-tiered database applications In this model, all applications are database clients. A client requests information from and sends information to a database server. A server can process requests from many clients simultaneously, coordinating access to and updating of data. Multi-Tiered Database Applications In multi-tiered database applications, an application is partitioned into pieces that reside on different machines. A client application provides a user interface to data. It passes all data requests and updates through an application server (also called a “remote data broker”). The application server, in turn, communicates directly with a remote database server or some other custom dataset. Usually, in this model, the client application, the application server, and the remote database server are on separate machines. Figure 7C-5 illustrates these relationships for different types of multi-tiered applications. 144 Computer English Figure 7C-5: Multi-tiered database applications You can use Delphi to create both client applications and application servers. The client application uses standard data-aware controls connected through a data source to one or more client dataset components in order to display data for viewing and editing. Each client dataset communicates with an application server through an IappServer1 interface that is implemented by the application server’s remote data module. The client application can use a variety of protocols (TCP/IP, HTTP, DCOM2, MTS3, or CORBA) to establish this communication. The protocol depends on the type of connection component used in the client application and the type of remote data module used in the server application. The application server contains provider components that mediate the communication between client 1 2 3 IAppServer:Delphi 专用术语,IAppServer 是客户端数据集用于和应用服务器通信的接口。 DCOM:分布式组件对象模型(Distributed Component Object Model 的首字母缩略)。 MTS:微软事务服务器(Microsoft Transaction Server 的首字母缩略)。 145 计算机英语 datasets on the client application and the datasets on the application server. All data is passed between the client application and the provider components through the IAppServer interface. Usually, several client applications communicate with a single application server in the multi-tiered model. The application server provides a gateway to your databases for all your client applications, and it lets you provide enterprise-wide database tasks in a central location, accessible to all your clients. —————————————————— Exercises I. Fill in the blanks with the information given in the text: 1. In single-tiered database applications, the application and the database share a single ________ system. 2. In two-tiered database applications, a client application provides a(n) ________ to data, and interacts directly with a remote database server. 3. In multi-tiered database applications, usually several client applications communicate with a single application ________, which in turn communicates directly with a remote database server. 4. It is easy to write scalable applications through the use of ________ data-aware components. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. data module object repository local database client dataset 5. 6. 7. 8. 远程数据库服务器 平面文件 数据源 分布式组件对象模型 146 Computer English 计算机英语 Part Three Network and Communication 147 148 Computer English 第三部分 网络与通信 第八单元 电信与信息高速公路 第九单元 计算机网络 第十单元 网络基础结构 第十一单元 因特网 ● 课文 A:电信与计算机 ● 课文 B:因特网与信息高速公路 ● 课文 C:ATM 及其优势 ● 课文 A:计算机网络 ● 课文 B:交换局域网的网络设计 ● 课文 C:网络是如何使用的? ● 课文 A:网络拓扑结构 ● 课文 B:TCP/IP 基础 ● 课文 C:网络级协议 ● 课文 A:因特网是如何工作的? ● 课文 B:什么是电子邮件? ● 课文 C:视频会议 计算机英语 149 Unit 8: Telecommunications and Information Superhighway (电信与信息高速公路) Section A Telecommunications and Computer Telecommunications allows people around the world to contact one another, to access information instantly, and to communicate from remote areas. Telecommunications usually involves a sender of information and one or more recipients linked by a technology, such as a telephone system, that transmits information from one place to another. Telecommunications devices convert different types of information, such as sound and video, into electronic signals. The signals can then be transmitted by means of media such as telephone wires or radio waves. When a signal reaches its destination, the device on the receiving end converts the electronic signal back into an understandable message, such as sound over a telephone, moving images on a television, or words and pictures on a computer screen. 150 Computer English Telecommunications enables people to send and receive personal messages across town, between countries, and to and from outer space. It also provides the key medium for news, data, information and entertainment. facsimile / fAk5simili / n. 传真 programming / 5prEugrAmiN / n. 节目的播送; 编程 decode / 7di:5kEud / v. 译(码),解(码) telegraph / 5teligrB:f / n. 电报(机) modulate / 5mCdjuleit / v. 调制 impulse / 5impQls / n. 脉冲 decipher / di5saifE / v. 破译,译解 Telecommunications messages can be sent in a variety of ways and by a wide range of devices. The messages can be sent from one sender to a single receiver (point-to-point) or from one sender to many receivers (point-to-multipoint). Personal communications, such as a telephone conversation between two people or a facsimile (fax) message, usually involve point-to-point transmission. Point-to-multipoint telecommunications, often called broadcasts, provide the basis for commercial radio and television programming. Telecommunications begin with messages that are converted into electronic signals. The signals are then sent over a medium to a receiver, where they are decoded back into a form that the person receiving the message can understand. There are a variety of ways to create and decode signals, and many different ways to transmit signals. Devices such as the telegraph and telephone relay messages by creating modulated electrical impulses, or impulses that change in a systematic way. These impulses are then sent by wires, radio waves, or other media to a receiver that decodes the modulation. The telegraph, the earliest method of delivering telecommunications, works by converting the contacts (connections between two conductors that permit a flow of current) between a telegraph key and a metal conductor into electrical impulses. These impulses are sent along a wire to a receiver, which converts the impulses into short and long bursts of sound or into dots and dashes on a simple printing device. Specific sequences of dots and dashes represent letters of the alphabet. In the early days of the telegraph, these sequences were decoded by telegraph operators. In this way, telegraph operators could transmit and receive letters that spelled words. Later versions of the telegraph could decipher letters and numbers automatically. Telegraphs have been largely replaced by other forms of telecommunications, such as fax machines and electronic mail (e-mail), but they are still used in some parts of the world to send messages. Telegraphs, telephones, radio, and television all work by modifying electronic signals, making the signals imitate, or reproduce, the original message. This form of transmission is known as analog transmission. Computers and other types of electronic equipment, however, transmit 计算机英语 pitch / pitF / n. 音高 demodulate / di:5mCdjuleit / v. 解调 fiber-optic / 5faibEr5Cptik / a. 光纤的 microwave / 5maikrEweiv / a. & n. 微波(的) categorize / 5kAtigEraiz / v. 将…分类 cordless telephone 无绳电话 cellular / 5seljulE / a. 蜂窝状的, 多孔的 radio telephone 无线电话 walkie-talkie / 5wC:ki5tC:ki / n. 步话机 pager / 5peidVE / n. 寻呼机 1 151 digital information. Digital technologies convert a message into electronic form first by measuring different qualities of the message, such as the pitch and volume of a voice, many times. These measurements are then encoded into multiple series of binary numbers, or 1s and 0s. Finally, digital technologies create and send electrical impulses that correspond to the series of 1s and 0s. Digital information can be transmitted faster and more clearly than analog signals, because the electrical impulses only need to correspond to two digits and not to the full range of qualities that compose the original message, such as the pitch and volume of a human voice. While digital transmissions can be sent over wires, cables or radio waves, they must be decoded by a digital receiver. New digital telephones and televisions are being developed to make telecommunications more efficient. Most personal computers communicate with each other and with larger networks, such as the Internet, by using the ordinary telephone network. Since the telephone network functions by converting sound into electronic signals, the computer must first convert its digital data into sound. Computers do this with a device called a modem, which is short for modulator/demodulator. A modem converts the stream of 1s and 0s from a computer into an analog signal that can then be transmitted over the telephone network, as a speaker’s voice would. The modem of the receiving computer demodulates the analog sound signal back into a digital form that the computer can understand. Telecommunications systems deliver messages using a number of different transmission media, including copper wires, fiber-optic cables, communication satellites, and microwave radio. One way to categorize telecommunications media is to consider whether or not the media uses wires. Wire-based (or wireline) telecommunications provide the initial link between most telephones and the telephone network, and are a reliable means for transmitting messages. Telecommunications without wires, commonly referred to as wireless communications, use technologies such as cordless telephones, cellular radio telephones, walkie-talkies, citizens band (CB1) radios, pagers, and satellites. Wireless communications offer increased mobility and flexibility. Individual people, businesses, and governments use many different types of telecommunications systems. Some systems, like the telephone system, use a network of cables, wires, and switching stations for CB:民用波段,民用电台频带(citizens band 或 Citizens’ Band 的首字母缩略)。 152 Computer English point-to-point communication. Other systems, such as radio and television, broadcast signals through space, which can be received by anyone who has a device to receive them. Some systems make use of several types of media to complete a transmission. For example, a telephone call may travel by means of copper wire, fiber-optic cable, and radio waves as the call is sent from sender to receiver. All telecommunications systems are constantly evolving as telecommunications technology improves. conditioning / kEn5diFEniN / n. 调节,调整 addressee / 7Adre5si: / n. 收信人;收件人 credit card 信用卡 bill / bil / v. 给 … 开 账 单 ; 把…登帐 1 Computer telecommunications, with the ability to send and receive audio, video, text, software, and multimedia, is one of the fastest-growing segments of the telecommunications market. Computer telecommunications takes advantage of existing telephone connections to transmit digital data. This type of transmission is frequently done over the Internet, a decentralized network of personal, business, government, educational computers, and sources of information. Some computers connect directly to the digital portion of the telephone network using the Integrated Services Digital Network (ISDN), but this requires the installation of special devices and telephone line conditioning. An improved modem system for regular phone lines, called Digital Subscriber Line (DSL1), is being developed to increase modem speed tremendously. Electronic mail, or e-mail, is a key attraction of the Internet and a common form of computer telecommunications. E-mail is a text-based message delivery system that allows information such as typed messages and multimedia to be sent to individual computer users. Local e-mail messages (within a building or a company) typically reach addressees by traveling through wire-based internal networks. E-mail that must travel across town or across a country to reach the final destination usually travels through the telephone network. Other computer telecommunications technologies that businesses frequently use include automated banking terminals and devices for credit card transactions that bill charges directly to a customer’s bank account. Personal computers have pushed the limits of the telephone system as more and more complex computer messages are being sent over telephone lines, and at rapidly increasing speeds. This need for speed has encouraged the development of digital transmission technology. Innovations in fiber-optic technology will hopefully keep up with the growing use of personal computers for telecommunications. The next generation of DSL:数字用户线路(Digital Subscriber Line 的首字母缩略)。 cellular telephone 蜂窝电话,移动电 话,手机 converge / kEn5vE:dV / v. 收敛,会聚 convergence / kEn5vE:dVEns / n. 收敛,会聚; (数 码技术与模拟技术 的)结合 blur / blE: / v. 使模糊不清 trigger / 5trigE / v. 触发,引起 interactive / 7intEr5Aktiv / a. 交互(式)的 actualization / 7AktFuElai5zeiFEn / n. 实现 upcoming / 5Qp7kQmiN / a. 即将来到的 计算机英语 153 cellular telephones, pagers, and televisions will also benefit from the speed and clarity of digital telecommunications. Telecommunications and information technologies are merging and converging. This means that many of the devices that we associate with only one function may evolve into more versatile equipment. This convergence is already happening in various fields. Some telephones and pagers are able to store not only phone numbers but also names and personal information about callers. Advanced phones with keyboards and small screens are now in development that can access the Internet and send and receive e-mail. Personal computers can now access information and video entertainment and are in effect becoming a combined television set and computer terminal. Television sets, which we currently associate with broadcast and cable-delivered video programming, are able to gain access to the Internet through add-on appliances. Future modifications and technology innovations may blur the distinctions between appliances even more. Convergence of telecommunications technologies will also trigger a change in the content available and the composition of the content provider. Both television and personal computers will be incorporating new multimedia, interactive, and digital features. For example, an entertainment program might have on-screen pointers to World Wide Web pages containing more information about the actors. In the near term1, before the actualization of a fully digital telecommunications world, devices like modems will still be necessary to provide an essential link between the old analog world and the upcoming digital one. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The earliest method of delivering telecommunications is the ________. 2. In the case of the telegraph, specific sequences of ________ and ________ represent letters of the alphabet. 3. 1 in the near term:在近期。 Copper wires, fiber-optic cables, communication satellites, and 154 Computer English microwave radio are all examples of the transmission ________ used by telecommunications systems to deliver messages. 4. Some telecommunications systems, like the telephone system, usually involve ________ communication, that is, from one sender to a single receiver. 5. In ________ transmission, telecommunications devices work by modifying electronic signals, making the signals imitate, or reproduce, the original message. 6. With ________ technology, the electrical impulses only need to correspond to two digits instead of the full range of qualities that compose the original message. 7. E-mail is a(n) ________ message delivery system that allows information such as typed messages and multimedia to be sent to individual computer users. 8. A(n) ________ is a device that converts between analog and digital signals, making it possible for a computer to transmit information over a standard telephone line. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. microwave radio digital television DSL analog transmission on-screen pointer computer terminal radio telephone cellular telephone decentralized network wire-based internal network 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 光缆 传真机 无线通信 点对点通信 调制电脉冲 通信卫星 电报电键 传输媒体 无绳电话 金属导体 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: configure printer apply derive 155 计算机英语 concept phone regard communication computer telecommunications block fax send difference destination system Data communications is the process of transmitting and receiving data in an orderly way so the data that arrives at its ________ is an accurate duplication of the data that was ________. When data travels a short distance, such as when you send data from your computer to your ________, it is referred to as local communications. When data travels a long distance, the ________ is referred to as telecommunications; the prefix “tele” is ________ from a Greek word that means “far” or “far off.” The ________ between a short distance and a long distance is somewhat arbitrary (武断的). For example, if your ________ sends data to a printer in the next room, it is ________ as local communications; if you ________ the person in the next room, you are transmitting data over a(n) ________ device. However, the same basic communications concepts ________ to both local communications and telecommunications. Basic data communications concepts are the building ________ for understanding how data travels on a communications ________. These concepts come in handy (派得上用处) when you install, ________, or upgrade a local area network. In addition, these ________ help you set up modems, ________ machines, and cellular data transfers. IV. Translate the following passage from English into Chinese: Information superhighway, a term used primarily in public policy and politics, refers to the availability and use of advanced information services through a variety of high-capacity transport facilities. The word superhighway was intended to convey images of a core national infrastructure providing abundant information at high speeds to the general public. It was made popular by former United States Vice-President Albert Gore to highlight the importance of such an infrastructure. The concept of information superhighway remains abstract, and has been superseded (替代) somewhat by the terms National or Global Information Infrastructure which are less focused on the notion of a single, publicly owned means of information transport. In practice, the Internet has been the chief contemporary example for all these terms. However, many different segments of the telecommunications industry point to services, such as 156 Computer English interactive television, promoting an information superhighway. 计算机英语 157 Section B Internet and Information Superhighway backbone / 5bAkbEun / n. 骨干;基础; 骨干网 exotic / ig5zCtik / a. 奇异的 state of the art 最新水平,发展水平 implementer / 5implimentE / n. 实现者;实现程序 packet switching 包交换 collision detection 冲突检测 hierarchical / 7haiE5rB:kikEl / a. 分级的,分层的, 层次的 Networks have become a fundamental, if not the most important, part of today’s information systems. They form the backbone for information sharing in enterprises, and in governmental and scientific groups. That information can take several forms. It can be notes and documents, data to be processed by another computer, files sent to colleagues, and even more exotic forms of data. Most of these networks were installed in the late 60s and 70s, when network design was the “state of the art” topic of computer research and sophisticated implementers. It resulted in multiple networking models such as packet-switching technology, collision-detection local area networks, hierarchical enterprise networks, and many other excellent technologies. From the early 70s on, another aspect of networking became important: protocol layering, which allows applications to communicate with each other. A complete range of architectural models were proposed and 158 Computer English implemented by various research teams and computer manufacturers. know-how / 5nEuhau / n. 技术;实际知识 parity / 5pArEti / n. 奇偶性;校验 parity function 奇偶校验功能 wide area network 广域网 down side 不利的一面,缺点 internetworking / 7intE5netwE:kiN / n. 互联网(技术) layer / 5leiE / v. 使分层 internetwork / 7intE5netwE:k / n. 互联网 protocol suite 协议组,协议族 virtualize / 5vE:tFuElaiz / v. 使虚拟化 The result of all this great know-how is that today any group of users can find a physical network and an architectural model suitable for their specific needs. This ranges from cheap asynchronous lines with no other error recovery than a bit-per-bit parity function, through full-function wide area networks (public or private) with reliable protocols such as public packet-switching networks or private SNA1 networks, to high-speed but limited-distance local area networks. The down side of this exploding information sharing is the rather painful situation when one group of users wants to extend its information system to another group of users who happen to have a different network technology and different network protocols. As a result, even if they could agree on a type of network technology to physically interconnect the two locations, their applications (such as mailing systems) still would not be able to communicate with each other because of the different protocols. This situation was recognized rather early (beginning of the 70s) by a group of researchers in the U.S. who came up with a new principle: internetworking. Other official organizations became involved in this area of interconnecting networks, such as ISO. All were trying to define a set of protocols, layered in a well-defined suite, so that applications would be able to talk to other applications, regardless of the underlying network technology and the operating systems where those applications run. Internetworks Those original designers, funded by the Defense Advanced Research Projects Agency (DARPA2), of the ARPANET3 protocol suite introduced fundamental concepts such as layering and virtualizing in the world of networking, well before ISO even took an interest in networking. The official organization of those researchers was the ARPANET Network Working Group, which had its last general meeting in October 1971. DARPA continued its research for an internetworking protocol suite, from the early NCP (Network Control Program) host-to-host protocol to the TCP/IP protocol suite, which took its current form around 1978. At that time, DARPA was well known for its pioneering of packet-switching over 1 2 3 SNA:系统网络体系结构(system network architecture 的首字母缩略)。 DARPA:国防部高级研究计划局(Defense Advanced Research Projects Agency 的首字母缩略) 。 ARPANET:ARPA 网,阿帕网(Advanced Research Projects Agency net 的缩合)。 计算机英语 159 radio networks and satellite channels. The first real implementations of the Internet were found around 1980 when DARPA started converting the machines of its research network (ARPANET) to use the new TCP/IP protocols. In 1983, the transition was completed and DARPA demanded that all computers willing to connect to its ARPANET use TCP/IP. DARPA also contracted Bolt, Beranek, and Newman to develop an implementation of the TCP/IP protocols for Berkeley UNIX on the VAX1 and funded the University of California at Berkeley2 to distribute that code free of charge with their UNIX operating system. The first release of the Berkeley Software Distribution to include the TCP/IP protocol set was made available in 1983 (4.2BSD). From that point on, TCP/IP spread rapidly among universities and research centers and has become the standard communications subsystem for all UNIX connectivity. The second release (4.3BSD) was distributed in 1986, with updates in 1988 and 1990. 4.4BSD was released in 1993. Due to funding constraints, 4.4BSD was the last release of the BSD by the Computer Systems Research Group of the University of California at Berkeley. As TCP/IP internetworking spread rapidly, new wide area networks were created in the U.S. and connected to ARPANET. In turn, other networks in the rest of the world, not necessarily based on the TCP/IP protocols, were added to the set of interconnected networks. The result is what is described as the Internet. Some examples of the different networks that have played key roles in this development are described in the next sections. The Internet internet / 5intEnet / n. 互联网,互连网 contraction / kEn5trAkFEn / n. 缩约词;缩约形 式;缩约 What exactly is the Internet? First, the word internet 3 (also internetwork) is simply a contraction of the phrase interconnected network. However, when written with a capital “I” the Internet refers to a worldwide set of interconnected networks, so the Internet is an internet, but the reverse does not apply. The Internet is sometimes called the connected Internet. The Internet consists of the following groups of networks: ● Backbones: large networks that exist primarily to interconnect 1 2 3 VAX:虚(拟)地址扩充系统(virtual address extension 的首字母缩略)。 University of California at Berkeley:加利福尼亚大学伯克利分校。 internet:常译作“互联网(络)”,系 internetwork 简写形式,指的是一组通过网关联结在一起的可能互不 相同的计算机网络。注意 internet 与 Internet 的不同,后者常译作“因特网” 、 “国际互联网”和“网际网” 。 160 subscriber / sEb5skraibE / n. 用户;订户 Computer English other networks. Currently the backbones are NSFNET1 in the US, EBONE2 in Europe, and large commercial backbones. ● Regional networks connecting, for example, universities and colleges. ● Commercial networks providing access to the backbones to subscribers, and networks owned by commercial organizations for internal use that also have connections to the Internet. ● Local networks, such as campus-wide university networks. In many cases, particularly for commercial, military and government networks, traffic between these networks and the rest of the Internet is restricted. Information Superhighway One recent and important initiative was the creation of the U.S. Advisory Council on the National Information Infrastructure (NIIAC 3 ) headed by U.S. Vice President Al Gore4 (who has been credited with coining the phrase “information superhighway”). The Advisory Council, which was made up of representatives from many areas of industry, government, entertainment and education, met for a period of two years from 1994-6. At the end of their term, they concluded their work with the publishing of two major reports: kickstart / 5kik7stB:t / n. & v.(用)脚踏起 动器(启动) ● Kickstart Initiative: Connecting America’s Communities to the Information Superhighway ● A Nation of Opportunity: Realizing the Promise of the Information Superhighway Among the findings in these reports is the goal that every person in the U.S. should have access to the Internet by the year 2005, with all schools and libraries being connected by the year 2000. regulatory / 5regjulEtEri / a. 管理的;调整的 1 2 3 4 Although the reports do not specify direct government funding for expansion of the Internet, preferring “commercial and competitive initiatives” to be the driving force, it does give a responsibility to all levels of government to ensure fair access and remove regulatory obstacles. Both NSFNET:(美国)国家科学基金会网络(National Science Foundation Network 的缩合)。 EBONE:欧洲骨干网(European Backbone 的缩合)。 NIIAC:(美国)国家信息基础设施顾问委员会(Advisory Council on the National Information Infrastructure 的首字母缩略) 。 Al Gore:艾尔·戈尔(1948~),美国前副总统,1992 年当选,1996 年再次当选。 计算机英语 161 reports may be found at: http://www.benton.org/contents.html From a more international perspective, the Group of Seven (G71 ) ministers met in Brussels2 in February 1995 to discuss the emerging Global Information Infrastructure (GII3). The conference was attended by science, technology and economic ministers of Canada, the United Kingdom, France, Japan, Germany, Italy and the United States, and focused on technological, cultural and economic issues regarding the development of an international infrastructure. substantive / 5sQbstEntiv / a. 根本性的, 本质的 affirmation Both the NIIAC and the GII described above were important initiatives which increased acceptance, and encouraged further growth, of the Internet. Another substantive government affirmation for the Internet came, in 1996, in the form of the Next Generation Internet initiative. This was launched by the Clinton4 administration with the goals of: / 7AfE5meiFEn / n. 肯定 ● Connecting universities and national labs with networks that are 100-1000 times faster than today’s (as of5 October 1996) Internet. ● Promote experimentation with the next generation of networking technologies. ● Demonstrate new applications that meet important national goals and missions. The initiative included funding of $100 million for 1998. Future of the Internet bandwidth / 5bAndwidW / n. 带宽 1 2 3 4 5 6 Trying to predict the future of the Internet is not an easy task. Few would have imagined even say6, three years ago, the extent to which the Internet has now become a part of everyday life in business, homes and schools. There are a number of things, however, about which we can be fairly certain. Bandwidth requirement will continue to increase at massive rates; not only is the number of Internet users growing rapidly, but the applications G7:西方七(大工业)国(Group of Seven 的缩略)。 Brussels:布鲁塞尔,比利时首都。 GII:全球信息基础设施(Global Information Infrastructure 的首字母缩略)。 Bill Clinton:比尔·克林顿(1946~),美国前总统,1992 年当选,1996 年再次当选。 as of:到…时为止,直至。 say:此处作副词,意思为“比方说”,“例如”。 162 multiplexing / 5mQltipleksiN / n. 多路复用,多路 传输 fiber / 5faibE / n. 光纤 video-on-demand / 7vidiEuCndi5mB:nd / n. 视频点播 Computer English being used are becoming more advanced and therefore need more bandwidth. This is the reason why the number of core (backbone) service providers has grown from four in 1995 to around 48 today (whereas the number of Internet connection providers has grown only moderately). However, new technologies such as Dense Wave Division Multiplexing (DWDM1) will help to get the most bandwidth from currently installed fiber. Today it is possible to hear radio stations from almost any part of the globe via the Internet. Today this is at around AM quality. Soon FM-quality radio and video-on-demand will be driving the bandwidth requirement.2 Many businesses have already completed an experimental period of Internet access and are moving towards using the Internet for serious business use both intra- and inter-company. in-house / 5in5haus / a. 存在(或起源) 于机构内部的;内 部的;自用的 deregulate / di:5regjuleit / v. 撤销对…的管制 规定,解除对…的 控制 This has been made possible by the rapid advances in TCP/IP security technologies made in only the last one to two years. In the not too distant future, the availability of private, secure high bandwidth networking from Internet providers may well make many companies question the feasibility of their current in-house wide area networks. Today we already have Voice over IP3 technology. As this technology matures we are almost certain to see a sharing of bandwidth between voice and data across the Internet. This raises some interesting questions for phone companies. The cost to a user of an Internet connection between New York and Japan is the same as a connection within New York—not so a phone connection. This, and the fact that the Internet is deregulated, will raise many interesting questions in the years to come. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Protocol ________ makes it possible for applications to communicate with each other regardless of the underlying network 1 2 3 DWDM:密集波分多路技术(Dense Wave Division Multiplexing 的首字母缩略)。 Today this is at around AM quality. Soon FM-quality radio and video-on-demand will be driving the bandwidth requirement.:目前这(广播)还停留在调幅音质的水平,但不久调频音质的广播和视频点播将驱动对带宽 的需求。 Voice over IP:一种利用 IP 协议传输语音的技术。 163 计算机英语 technology and the operating systems where those applications run. 2. The term “internet” is the shortened form of the phrase ________ network. 3. The phrase “information superhighway” is said to have been created by former U.S. Vice President ________. 4. According to the text, with the number of Internet users growing rapidly and the applications becoming more advanced, the need for more ________ will continue to increase. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. error recovery parity function video on demand collision detection protocol layering 6. 7. 8. 9. 10. 体系结构模型 包交换 企业网 协议组 商用骨干网 164 Computer English Section C ATM and Its Advantages What Is ATM? cell / sel / n. 单元;单元格 multiplex / 5mQltipleks / v. & n. 多路复用, 多路传输 The Asynchronous Transfer Mode (ATM) is a packet switching and multiplexing technique. Even though the word “asynchronous” appears in its description, it is not in any way an asynchronous transmission procedure. Because of the way it has been designed, it is particularly suitable for high-bandwidth and low-delay applications. With ATM, information is sent out in fixed-size packets or cells, each containing in its header a VCI1 that provides a means for creating multiple logical channels and multiplexing them as needed. Because the cells have a fixed size, they may contain unused bits. ATM is actually a very simple protocol: it merely transfers data from 1 VCI:虚拟通道标识符(virtual channel identifier 的首字母缩略)。 计算机英语 interoperate / 7intEr5CpEreit / v. 互操作,互用 165 one point to another, and does not, by itself, provide any error recovery. However, ATM has been designed to interoperate with other, existing protocols. In fact, it can accommodate almost any upper-layer protocols that support end-to-end error recovery. Figure 8C-1: The ATM protocol layers protocol stack 协议(堆)栈 trailer / 5treilE / n. 尾部(信息) octet / Ck5tet / n. 八位位组, 八位元 fill / fil / n. 填充 1 The complete ATM protocol stack is shown in Figure 8C-1. The higher-layer protocols shown in the topmost box are application-specific. For example, they could be the standard file transfer protocol at the application layer with transmission control protocol (TCP) at the transport layer and Internet protocol (IP) at the network layer. Or, they could be simply the network-layer protocol for call and connection controls with a suitable application layer on top. As the name implies, the ATM adaptation layer (AAL1) “adapts” the upper-layer packets to the ATM layer below. While the details might vary from one service to another (e.g., connectionless data services, connection-oriented data services, constant-bit-rate data services, variable-bit-rate data services, etc.), this adaptation is achieved by adding a header, a trailer, and some fill octets to the upper-layer packets and segmenting them into fixed-size ATM cells. Below this layer is the so-called ATM layer. This layer can be thought of as a link-layer protocol. However, in some respects, it is different from other AAL:异步传输模式适配层(ATM adaptation layer 的首字母缩略)。 166 preamble / pri:5Ambl / n. 前同步码,前同 步信号 sync / siNk / a. <口>同步的 (=synchronous) sync bit 同步位 padding / 5pAdiN / n. 填充 Computer English link-layer protocols. For example, with the high-level data link control (HDLC 1) or Q.921 link access procedures on the D channel (LAPD2 ) protocol, the length of a frame varies—it may vary from 2 octets to 256 octets. With the IEEE3 802.3 protocol, the length of a packet, excluding the preamble and sync bits, may be anywhere from 64 octets to 1518 octets. In ATM, cell length is fixed at 53 octets. Also, unlike the link-layer protocols, ATM does not provide for acknowledgment procedures at the receiver. Errors can be detected in a cell, but not corrected. It is assumed that the transmission medium is highly reliable. Blocks of user data of variable lengths from upper layers are passed to the ATM Adaptation Layer (AAL), which adds headers, trailers, padding octets, and/or cyclic redundancy check (CRC4) bits according to some rules that depend upon the service type. Each resulting data block is segmented into smaller blocks, which are then encapsulated into 53-octet cells in the ATM layer. It is these ATM cells that are transmitted to the destination. Many different media-dependent, physical-layer interfaces can be used for ATM. Advantages of ATM frame relay 帧中继 router / 5ru:tE / n. 路由器 route / 5ru:t / v.(按特定路线) 发送 hop / hCp / n. 跳跃;转发; 信程 map / mAp / v. 映射,使变换 identifier / ai5dentifaiE / n. 标识符 explicit / ik5splisit / a. 明确的;详述的 1 2 3 4 There are many advantages of an ATM network. Some of them are listed below: ■ Label switching The ATM protocol, like the frame relay protocol, is ideally suited for label switching. It works in the following way: in a traditional packet-switched network, when a packet arrives at a router, it examines its layer 3 header and routes the packet to the next hop along an appropriate route based upon the destination address. Since the network layer address generally contains much more information than would be required in making the routing decision, the layer 3 routing process is relatively complex. In label switching, the layer 3 address is mapped to a shorter identifier, which is called a label. It is important to emphasize here that a label is not an explicit address of an end-point. When the packet is routed to the next hop, the label is sent along with it as part of the header so that the HDLC:高级数据链路控制规程(high-level data link control 的首字母缩略)。 LAPD:D 信道连接访问程序(link access procedures on the D channel)。 IEEE:(美国)电气和电子工程师协会(Institute of Electrical and Electronics Engineers 的首字母缩略)。 CRC:循环冗余码校验(cyclic redundancy check 的首字母缩略)。 计算机英语 167 router at the next hop can use it to derive subsequent routing information (see Figure 8C-2). In ATM, labels are formed with the 24-bit virtual path identifier (VPI1) and virtual channel identifier (VCI) fields. Figure 8C-2: Label switching in an ATM network Router R1 gets a packet with Label L1 in its header. It uses L1 to route the packet to R2, replacing L1 with Label L2. mesh / meF / n. 网格;网孔;网 状结构 cut-through / 5kQtWru: / a. 穿越式的,直通 的 obviate / 5Cbvieit / v. 排除;避免 latency / 5leitEnsi / n. 潜伏时间,等待 时间 span / spAn / v. 横跨,跨越 1 2 Label switching offers a number of advantages. First, since packets can now be routed using a label as an index into the switch memory to determine the next hop, and since labels are shorter than IP addresses, it is easier to build a label-switching router. Second, if IP packets are to be routed between any two end-points in an ATM network in the traditional way, either virtual circuits must be connected in a full mesh configuration among ATM switches, or cut-through switched virtual channels (SVCs2) must be established using an appropriate protocol. Label switching obviates the need for such mesh connections and reduces the number of peer routers that need to communicate with each other. Consequently, a label-switching network is cheaper and faster. Third, label switching in an ATM environment is similar in many respects to label switching in other protocols. It may, therefore, be possible to use common methods for packet forwarding and even network management. ■ Low latency An important feature of the ATM protocol is its low latency and seamless capacity to span local area networks (LANs) and wide area networks (WANs). ATM’s low latency results from the fact that all packets in the ATM layer have a fixed length. To see this, consider Figure 8C-3 (a), which shows a server with three inputs. Assume that all packets have a fixed size, d. The packets on any input link may arrive randomly with respect to the other input lines. If the server scans the inputs every d VPI:虚拟路径标识符(virtual path identifier 的首字母缩略)。 SVC:交换式虚拟通道(switched virtual channel 的首字母缩略)。 168 scheduling / 5Fedju:EliN; 5skedVu:EliN / n. 调度;安排 a priori / 7eiprai5C:rai / ad. < 拉> 用演绎方 法,经推理 microsecond Computer English seconds, which is the length of a packet, then the average service delay for any packet on any input is d/2 seconds. Perfect scheduling is possible here because the packet size is known a priori. For example, if the data rate on each input line is 25 Mb/s1, then for 53-octet ATM cells, the service period is 16.96 microseconds, and the average delay is 8.48 microseconds. / 5maikrEu7sekEnd / n. 微秒,10-6 秒 Figure 8C-3: Illustration of service delays in a packet-switched network (a) Fixed-size packets, as in ATM (b) Variable-size packets, as in Ethernets Next, consider the case where the size of a packet varies from some minimum value, say L, to a maximum value, M. This is shown in Figure 8C-3 (b) and is applicable to Ethernet. In this case, the server must scan the inputs frequently enough to match the length of the shortest packets; otherwise, these packets will be subjected to long delays. For example, if the packet size varies from 2 octets to 100 octets, the server should scan the 1 Mb/s:兆位∕秒(megabit/second 的缩略)。 计算机英语 169 inputs every 640 ns1, which may be an excessive burden on the CPU. If the service period is increased to 16.96 microseconds, the average delay is about 13 times the size of the shortest packet. If all packets are fixed-length, scheduling of network resources is much easier. ■ High-speed and high-bandwidth metropolitan / 7metrE5pClitEn / a. 大城市的,大都 会的 integrated network 综合网络 bursty / 5bE:sti / a. 猝发的,突发的 1 2 3 4 5 6 7 Because of its low latency, ATM is particularly suitable for applications that require high-speed transport and high bandwidths. For example, one can use ATM in a network backbone that interconnects traditional LANs such as Ethernets and token ring LANs. Currently, there are many high-speed LANs such as gigabit Ethernets and metropolitan area networks (MANs2) covering tens of kilometers in diameter using such protocols as fiber-distributed data interface (FDDI3) and distributed queue dual bus (DQDB 4 ). ATM could very well form the basis of the new generation of high-speed LANs and MANs. Furthermore, ATM is equally suitable for applications that do not require high speed or high capacity. For example, currently, vendors are offering ATM switches at 25.6, 44.736, 51.84, 155, and 622 Mb/s bandwidths with various cabling types—two- or four-wire category 3 unshielded twisted pair (UTP 5 ), multi-mode and single-mode fibers, and so on6. ■ Integrated network Normally, a packet protocol is only suitable for bursty, variable-bit-rate services, and would not be able to transport information that is sensitive to delays. For example, the public-switched telephone network (PSTN7) can only transport circuit-switched information. An X.25 or frame relay network can handle only packet-switched data. The ATM protocol has been designed such that it can carry not only bursty, variable-bit-rate services, but also delay-sensitive information such as voice and video that would normally be carried by circuit-switched networks. In fact, over the last few years, a rich set of procedures and protocols that enable ATM to support many different services have been developed by the ns:纳秒,毫微秒,10_9 秒(nanosecond 的缩略)。 MAN:市域网,城域网(metropolitan area network 的首字母缩略)。 FDDI:光纤分布式数据接口(fiber-distributed data interface 的首字母缩略)。 DQDB:分布式队列双总线(distributed queue dual bus 的首字母缩略) 。 UTP:非屏蔽双绞线(unshielded twisted pair 的首字母缩略)。 two- or four-wire category 3 unshielded twisted pair, multi-mode and single-mode fibers, and so on:2 或 4 芯三 类非屏蔽双绞线、多模和单模光纤等等。 PSTN:公用交换电话网(public-switched telephone network 的首字母缩略)。 170 premise / 5premis / n. [~s]房屋(及其 附属建筑、基地等) broadband / 5brC:dbAnd / Computer English ATM Forum 1 —connection-oriented as well as connectionless, constant-bit-rate as well as variable, and they provide different qualities of service according to the application and customer needs. Thus, with ATM, it is possible to provide all different services with a single, integrated network. a. 宽带的 pay-per-view / 5peipE5vju: / n. 付费节目服务, 有偿点播服务 high-definition / 5haidefi5niFEn / a. 高清晰度的 set-top box 机顶盒,顶置盒 demultiplex / 7di:5mQltipleks / v. 分路,把…分成 多路 upstream / 5Qp5stri:m / a. 向上流的 interwork / intE5wE:k / v. & n. 配合工作, 互工作 legacy / 5legEsi / a. 旧版本的, 老化的 imaging / 5imidViN / n. 成像(技术) augment / C:g5ment / v. 扩大;增加 innate / 7i5neit / a. 固有的;天生的 provision / prEu5viVEn / v. 供应,提供 inverse / 5invE:s / a. 反的,逆的 originate / E5ridVEneit / v. 发源;产生; 创始 1 ■ Integrated access from customer premises ATM provides a means for achieving integrated access to broadband services from public or private networks. Services such as compact disc (CD)-quality music, pay-per-view movie channels, high-definition TV, high-speed Internet data downloading, etc. can all be combined with traditional, circuit-switched voice and low-speed data services and then presented over a single ATM pipe to the customer premises, where a set-top box would demultiplex these services. The user could even request special services from a network provider using an upstream control channel. ■ Interworking with existing protocols and legacy LANs There are many instances where new applications would almost certainly require the bandwidth and speed of an ATM network. One such example involves collaboration among different research organizations with high-resolution, high-bandwidth imaging data. The ATM network, if installed, would still be able to interwork with traditional data networking protocols and legacy LANs such as Ethernet, token ring, and FDDI. Thus, the existing network infrastructure needs to be augmented only when or where necessary, leading to a graceful but less expensive evolution to the new technology. ■ Bandwidth-on-demand Bandwidth-on-demand is another innate benefit of ATM. In private networks, higher bandwidths can be requested by users. However, generally, they must be provisioned through network managers, and cannot be assigned dynamically at connection setup time. With some private networks that are equipped with inverse multiplexing capability at both ends, it may be possible to request and obtain increased bandwidth dynamically. Even then, the range is rather limited. With ATM, users may request a desired bandwidth when originating a call, and the network would attempt to dynamically allocate the requested bandwidth only if the customer had ATM Forum:ATM 论坛。 171 计算机英语 subscribe / sEb5skraib / v. 订购;订阅 congestion / kEn5dVestFEn / n. 拥挤;拥塞 reserve / ri5zE:v / a. 保留的;后备的 subscribed to this feature at subscription time. Furthermore, for ATM networks, there are traffic and congestion control mechanisms in place which, in the event of congestion, allow the network to maintain the quality of service for each customer with minimum degradation. Thus, initially, one could install a network with only a minimum amount of reserve capacity, and add to the network only when the demand for bandwidth has grown to a point where it is no longer possible to provide each customer with the subscribed quality of service. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. ATM, which stands for Asynchronous ________ Mode, is a packet switching and multiplexing technique. 2. octets. With ATM, the length of packets or ________ is fixed at 53 3. One of the advantages of an ATM network is ________ switching, in which the layer 3 address is mapped to a shorter identifier. 4. With ATM, it is possible to provide all different services with a single, ________ network. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. high-definition TV frame relay data rate metropolitan area network 5. 6. 7. 8. 机顶盒 多模光纤 协议堆栈 虚拟路径标识符 172 Computer English Unit 9: Computer Networks (计算机网络) Section A Computer Networks I. INTRODUCTION Computer networks, the widespread sharing of information among groups of computers and their users, are a central part of the information age. The popular adoption of the personal computer (PC) and the local area network (LAN) during the 1980s has led to the capacity to access information on a distant database; download an application from overseas; send a message to a friend in a different country; and share files with a colleague—all from a personal computer. The networks that allow all this to be done so easily are sophisticated and complex entities. They rely for their effectiveness on many cooperating components. The design and deployment of the worldwide computer network can be viewed as one of the great technological wonders of recent 计算机英语 173 decades. II. MODEMS AND COMPUTER BUREAUX1 fragile / 5frAdVail / a. 易损坏的;易碎 的;脆弱的 initiate / i5niFieit / v. 开始;发起 resilience / ri5ziliEns / n. 弹性;复原力 As recently as the 1970s, computers were expensive, fragile machines that had to be looked after by specialists and kept in a controlled environment. They could be used either by plugging in a terminal directly or by using a phone line and modem to gain access from a distance. Because of their high cost, they tended to be centralized resources to which a user had to arrange their own access. During this time, organizations that offered access time on a mainframe computer—computer bureaux—flourished. Computer networks during this period were not commercially available. Even so, one of the most significant developments to shape the modern world of technology was initiated at this time: experimentation by the US Defence Department in distributing computer resources to provide resilience against failure. This work is now known as the Internet. III. LOCAL AREA NETWORKS coaxial / 7kEu5AksiEl / a. 同轴的 carrier / 5kAriE / n. 载波 carrier sense 载波检测, 载波监听 One of the most dramatic events in computer networking has been the introduction and rapid growth of the local area network (LAN) as a way to standardize the system of linking computers used in office systems. As the name suggests, this is a means of connecting a number of computing elements together. At the simplest level, a LAN provides no more than a shared medium (such as a coaxial cable to which all computers and printers are connected) along with a set of rules that govern the access to that medium. The most widely used LAN, Ethernet, uses a mechanism called Carrier Sense Multiple Access-Collision Detect (CSMA-CD2). This means that each connected device can only use the cable when it has established that no other device is using it. If there is contention, the device looking for a connection backs off and tries again later. The Ethernet transfers data at 10M bits/sec3, which is fast enough to make the distance between devices insignificant. They appear to be connected directly to their destination. There are many different layouts (such as bus, star, ring) and a number of different access protocols for LANs. Despite this variety, all LANs share 1 2 3 bureaux:bureau 的复数形式之一,读作 / 5bjuErEuz / 。bureau 的复数形式也可直接加-s。 CSMA-CD:带有冲突检测的载波侦听多路访问(Carrier Sense Multiple Access-Collision Detect 的首字母缩 略)。 10M bits/sec:10 兆位∕秒,M 是组合语素 mega-“兆”的缩写。 174 Computer English the feature that they are limited in range (typically they cover one building) and are fast enough to make the connecting network invisible to the devices that use it. Figure 9A-1: Network configurations In addition to providing shared access, modern LANs can also give users a wide range of sophisticated facilities. Management software packages are available to control the way in which devices are configured on the LAN, how users are administered, and how network resources are controlled. A widely adopted structure on local networks is to have a number of servers that are available to a (usually much greater) number of clients. The former, usually powerful computers, provide services such as print control, file sharing, and mail to the latter, which are usually personal computers. IV. ROUTERS AND BRIDGES The facilities on most LANs are very powerful. Most organizations do not wish to have small isolated islands of computing facilities. They usually want to extend facilities over a wider area so that groups can work without having to be located. Routers and bridges are specialized devices that allow two or more LANs to be connected. The bridge is the more basic device and can only connect LANs of the same type. The router is a more intelligent component that can interconnect many different types of computer network. Many large companies have corporate data networks that are founded on a collection of LANs and routers. From the user’s point of view, this arrangement provides them with a physically diverse network that looks 计算机英语 coherent / kEu5hiErEnt / a. 协调的;一致的 175 like one coherent resource. V. WIDE AREA NETWORKS At some point, it becomes impractical to extend a LAN any further. Physical limitation sometimes drives this, but more often than not there are more convenient or cheaper ways to extend a computer network. Two major components in most real computer networks are the public telephone and data networks. These provide long distance links that extend a LAN into a wide area network. Nearly all of the national network operators offer services for the interconnection of computer networks. These services range from simple, low speed data links that work over the public telephone network to sophisticated high-speed data services that are ideally suited to the interconnection of LANs. These high-speed data services are usually referred to as broadband connections. It is anticipated that they will provide the necessary links between LANs that make what is called the information superhighway a reality. VI. DISTRIBUTED COMPUTING privileged / 5privilidVd / a. 享有特权的;特 许的 extract / ik5strAkt / v. 取出;提取;设 法得到 commonality / 7kCmE5nAlEti / n. 共同特征;共性 It would be easy to assume that computers will all be able to work together once they have broadband connection. But how do you get computers made by different manufacturers in different countries to work together across the world? Until recently, most computers were built with their own interfaces and were structured their own unique way. A computer could talk to one of its own kind but would have difficulty communicating with a “foreigner”. There were only a privileged few with the time, knowledge, and equipment to extract what they wanted from a variety of computing resources. By the 1990s, the level of commonality across different computers reached the stage where they could interwork effectively. This allows virtually anyone to use a remote machine to good effect. The main contributors to this are: ■ Client Server consensus / kEn5sensEs / n. [常作定语]一致 同意;一致(或多 数人)意见 Instead of building computer systems as monolithic systems, there is now general agreement that they should be constructed as client/server systems. The client (a PC user) requests a service (such as printing) and the server (a LAN-connected processor) provides it. This consensus view on the structure of a computer system means that there is a separation of 176 Computer English functions previously bundled together. The implementation details that flow from1 a simple concept go a long way2 to enabling all computers to be treated uniformly. ■ Object Technology premise / 5premis / n. 前提;假设 Another way to build computer systems works from the premise that they should be built from well-defined parts—objects which are encapsulated, defined, and implemented so that they can be independent agents. The adoption of objects as a means of building computer systems has helped to allow interchangeability of parts. ■ Open Systems unbundle / 7Qn5bQndl / v. 分解,分离 entail / in5teil / v. 使成为必要, 需要 site / sait / v. 给…择址;设置 This term covers the general aim of building computer systems so that they can readily be interconnected, and hence distributed. In practice, open systems are all about unbundling all the complexities of a computer system and using similar structure across different systems. And this entails a mixture of standards (which tell the manufacturers what they should be doing) and consortia (groups of like-minded people who help them to do it). The overall effect is that they can talk to each other. The ultimate aim of all of the work in distributed systems is to allow anyone to buy computers from a number of different manufacturers, to site them wherever is convenient, to use broadband connections to link them, and to operate them as one cooperating machine that takes full advantage of the fast links. VII. SECURITY AND MANAGEMENT spectre / 5spektE / n. 鬼怪,幽灵 Having fast computer networks built of machines that can talk to each other is not the end of the story. The spectres of the “information superhighwayman3” and the “information superroadworks4” have yet to be dealt with. ■ Security With ever increasing amounts of important information being 1 2 3 4 flow from:来源于,产生自。 go a long way:有很大作用,大有帮助,后常接介词 to、towards、with。 superhighwayman:highwayman 意为“拦路抢劫的强盗” ,因此文中的 superhighwayman 指的是在信息高速 公路上截取信息的人,其行径如同拦路抢劫的强盗。 superroadworks:roadworks 意为“道路施工”,常见于维修道路而禁止车辆通行的告示牌,因此文中的 superroadworks 指的是信息高速公路发生重大故障,影响信息的传输。 计算机英语 entrust / in5trQst / v. 委托,交托 confidential / 7kCnfi5denFEl / a. 秘密的,机密的 public key 公用密钥,公钥 scramble / 5skrAmbl / v.(加密)编码 intrude / in5tru:d / v. 侵入;侵扰 supervise / 5sju:pEvaiz / v. 监督;管理 177 entrusted to ever more distributed computers, computer security becomes ever more important. In a highly distributed system it would be all too easy for an informed superhighwayman to access confidential information without being seen. The Data Encryption System (DES 1 ) standard for protecting computer data, introduced in the late 1970s, has more recently been supplemented by “public key” systems that allow users to scramble and unscramble their messages easily without a third party intruding. ■ Management It is a full-time job to keep a LAN operating as it should. Keeping a computer network that is distributed across the world running smoothly takes the challenge of network management a step further. The essential concepts for managing distributed and diverse networks have received a lot of attention lately. There are now enough tools and standards for this important aspect of computer networks to allow global networks to be supervised effectively. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The most widely used LAN system is ________, which adopts a form of access known as CSMA-CD. 2. LANs share the feature that they are ________ in range: typically they cover one building. 3. ________ can only connect LANs of the same type. 4. ________ can interconnect many different types of computer network. 5. The public ________ and data networks are the two major components in most real computer networks that provide long distance links that extend a LAN into a(n) ________ area network. 6. The high-speed data services for the interconnection of computer networks are usually referred to as ________ connections. 7. 1 In the building of computer systems, the use of ________ DES:数据加密系统(Data Encryption System 的首字母缩略)。 178 Computer English enables the interchangeability of parts. 8. A(n) ________ system allows users to scramble and unscramble their messages easily without a third party intruding. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. coaxial cable computer networking multiple-access network management software broadband connection confidential information monolithic system star network bus network ring network 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 网络资源 公钥体制 公用电话网 数据加密系统 信息高速公路 信息时代 计算机安全 数据网 数据链路 存取协议 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: bridge limited computer connect disk network topology separate communicate dissimilar protocol link transmit shared convert proper A local area network (LAN) is a group of computers and other devices dispersed ( 分 散 ) over a relatively limited area and connected by a communications ________ that enables any device to interact with any other on the ________. LANs commonly include microcomputers and ________ (often expensive) resources such as laser printers and large hard ________. Most (modern) LANs can support a wide variety of ________ and other devices. Each device must use the ________ physical and data-link protocols for the particular LAN, and all devices that want to ________ with each other on the LAN must use the same upper-level communications ________. Although single LANs are geographically ________ (to a department or an office building, for example), ________ LANs can be connected to form larger networks. Similar LANs are linked 计算机英语 179 by ________, which act as transfer points between networks; ________ LANs are linked by gateways, which both transfer data and ________ it according to the protocols used by the receiving network. The devices on a LAN are known as nodes, and the nodes are ________ by cabling through which messages are ________. Nodes on a LAN can be wired together in any of three basic ________, known as bus, ring, and star. IV. Translate the following passage from English into Chinese: A network, in computer science, is a group of computers and associated devices that are connected by communications facilities. A network can involve permanent connections, such as cables, or temporary connections made through telephone or other communications links. A network can be as small as a local area network consisting of a few computers, printers, and other devices, or it can consist of many small and large computers distributed over a vast geographic area. Small or large, a computer network exists to provide computer users with the means of communicating and transferring information electronically. Some types of communication are simple user-to-user messages; others, of the type known as distributed processes, can involve several computers and the sharing of workloads or cooperative (合作的) efforts in performing a task. 180 Computer English Section B Switched LAN Network Designs A successful switched internetworking solution must combine the benefits of both routers and switches in every part of the network, as well as offer a flexible evolution path from shared-media networking to switched internetworks. In general, incorporating switches in campus network designs results in the following benefits: ● ● ● ● High bandwidth Quality of service (QoS) Low cost Easy configuration 计算机英语 bridging / 5bridViN / n. 桥接,跨接 spanning tree 生成树 181 Switching and bridging sometimes can result in nonoptimal routing of packets. This is because every packet must go through the root bridge of the spanning tree. When routers are used, the routing of packets can be controlled and designed for optimal paths. Cisco1 now provides support for improved routing and redundancy in switched environments by supporting one instance of the spanning tree per VLAN2. 1. General Network Design Principles Good network design is based on many concepts that are summarized by the following key principles: backup / 5bAkQp / n. 备份,后备 profile / 5prEufail / v. 显出…的轮廓; 用数据图表表示 magnitude / 5mAgnitju:d / n. 数量;量值 order of magnitude 数量级 demarcation / 7di:mB:5keiFEn / n. 分界;界线 backplane / 5bAkplein / n. 底板 modular / 5mCdjulE / a. 模块化的 1 2 ● Examine single points of failure carefully—There should be redundancy in the network so that a single failure does not isolate any portion of the network. There are two aspects of redundancy that need to be considered: backup and load balancing. In the event of a failure in the network, there should be an alternative or backup path. Load balancing occurs when two or more paths to a destination exist and can be utilized depending on the network load. The level of redundancy required in a particular network varies from network to network. ● Characterize application and protocol traffic—For example, the flow of application data will profile client-server interaction and is crucial for efficient resource allocation, such as the number of clients using a particular server or the number of client workstations on a segment. ● Analyze bandwidth availability—For example, there should not be an order of magnitude difference between the different layers of the hierarchical model. It is important to remember that the hierarchical model refers to conceptual layers that provide functionality. The actual demarcation between layers does not have to be a physical link—it can be the backplane of a particular device. ● Build networks using a hierarchical or modular model—The hierarchy allows autonomous segments to be internetworked together. Cisco:Cisco 系统公司,企业网络产品的全球领先供应商。 VLAN:虚拟 LAN,虚拟局域网(virtual local area network 的首字母缩略)。 182 Computer English Core Distribution High-speed switching Access Policy-based connectivity Local and remote workgroup access Figure 9B-1: Hierarchical network design model Figure 9B-1 shows a high-level view of the various aspects of a hierarchical network design. A hierarchical network design presents three layers—core, distribution, and access—with each layer providing different functionality. access list 存取表,存取清单, 访问表 The core layer is a high-speed switching backbone and should be designed to switch packets as fast as possible. This layer of the network should not perform any packet manipulation access lists and filtering that would slow down the switching of packets. The distribution layer of the network is the demarcation point between the access and core layers and helps to define and differentiate the core. The purpose of this layer is to provide boundary definition and is the place at which packet manipulation can take place. In the campus environment, the distribution layer can include several functions, such as the following: aggregation / 7Agri5geiFEn / n. 聚集,聚合 multicast / 5mQltikB:st / n. 多播 ● ● ● ● ● ● Address or area aggregation Departmental or workgroup access Broadcast/multicast domain definition VLAN routing Any media transitions that need to occur Security In the non-campus environment, the distribution layer can be a redistribution point between routing domains or the demarcation between static and dynamic routing protocols. It can also be the point at which remote sites access the corporate network. The distribution layer can be summarized as the layer that provides policy-based connectivity. 计算机英语 183 The access layer is the point at which local end users are allowed into the network. This layer may also use access lists or filters to further optimize the needs of a particular set of users. In the campus environment, access-layer functions can include the following: microsegmentation / 5maikrEu7segmEn5teiFEn / n. 微分段 leased line 专线 instantiation / in7stAnFi5eiFEn / n. 例示,实例化 ● ● ● ● Shared bandwidth Switched bandwidth MAC1 layer filtering Microsegmentation In the non-campus environment, the access layer can give remote sites access to the corporate network via some wide-area technology, such as Frame Relay, ISDN, or leased lines. It is sometimes mistakenly thought that the three layers (core, distribution, and access) must exist in clear and distinct physical entities, but this does not have to be the case. The layers are defined to aid successful network design and to represent functionality that must exist in a network. The instantiation of each layer can be in distinct routers or switches, can be represented by a physical media, can be combined in a single device, or can be omitted altogether. The way the layers are implemented depends on the needs of the network being designed. Note, however, that for a network to function optimally, hierarchy must be maintained. With respect to the hierarchical model, traditional campus LANs have followed one of two designs—single router and distributed backbone—as shown in Figure 9B-2. Figure 9B-2: Traditional campus design 1 MAC:媒体接入控制,媒体访问控制,媒体存取控制(media access control 的首字母缩略)。 184 chassis / 5FAsi / n. 底盘,底架, 底板 traverse / 5trAvE:s / v. 横越;穿过 Computer English In the single-router design, the core and distribution layers are present in a single entity—the router. Core functionality is represented by the backplane of the router and distribution is represented by the router. Access for end users is through individual- or chassis-based hubs. This design suffers from scalability constraints because the router can only be in one physical location, so all segments end at the same location—the router. The single router is responsible for all distribution functionality, which can cause CPU overload. The distributed backbone design uses a high-speed backbone media, typically FDDI, to spread routing functionality among several routers. This also allows the backbone to traverse floors, a building, or a campus. 2. Switched LAN Network Design Principles When designing switched LAN campus networks, the following factors must be considered: adversely / 5AdvE:sli / ad. 不利地,有害地 ● Broadcast radiation—Broadcast radiation can become fatal—that is, 100 percent of host CPU cycles can be consumed by processing broadcast and multicast packets. Because of delays inherent in carrier sense multiple access collision detect (CSMA/CD) technologies, such as Ethernet, any more than a small amount of broadcast traffic will adversely affect the operation of devices attached to a switch. Although VLANs reduce the effect of broadcast radiation on all LANs, there is still a scaling issue as to how many hosts should reside on a given VLAN. A router allows for larger network designs because a VLAN can be subsegmented depending on traffic patterns. However, in a nonoptimal network design, a single router can be burdened with large amounts of traffic. ● Well-behaved VLANs—A well-behaved VLAN is a VLAN in which 80 percent or more of the traffic is local to that VLAN. In an example in which the Marketing, MIS 1 , and Engineering departments each have an individual VLAN segment, the 80 percent rule is violated when a user in the Marketing VLAN reads mail from the MIS VLAN, mounts servers from the Engineering VLAN, and sends e-mail to members of the Engineering VLAN. 1 MIS:管理信息系统(Management Information System 的首字母缩略)。 计算机英语 185 ● Available bandwidth to access routing functionality—Inter-VLAN traffic must be routed, so the network design must allocate enough bandwidth to move inter-VLAN traffic from the source, through the device that provides routing functionality, and to the destination. flatten / 5flAtEn / v. 压缩,精简 ● Appropriate placement of administrative boundaries—Switching has the effect of flattening networks, and the deployment of switching outside of your administrative boundary can adversely affect the network within your administrative boundary. Campus network designs are evolving rapidly with the deployment of switching at all levels of the network—from the desktop to the backbone. Three topologies have emerged as generic network designs: flatten / 5flAtEn / v. 压缩,精简 ● Scaled Switching ● Large Switched/Minimal Routing ● Distributed Routing/Switching Figure 9B-3: Scaled switching design 2.1 Scaled Switching The scaled switching design shown in Figure 9B-3 deploys switching at all levels of the network without the use of routers. In this design, each layer consists of switches, with switches in the access layer providing 186 Computer English 10-Mbps1 Ethernet or 16-Mbps Token Ring to end users. Scaled switching is a low-cost and easy-to-install solution for a small campus network. It does not require knowledge of address structure, is easy to manage, and allows all users to communicate with one another. However, this network comprises a single broadcast domain. If a scaled switched network needs to grow beyond the broadcast domain, it can use VLANs to create multiple broadcast domains. Note that when VLANs are used, end users in one VLAN cannot communicate with end users in another VLAN unless routers are deployed. 2.2 Large Switched/Minimal Routing The large switched/minimal routing design deploys switching at the access layer of the network, either ATM switching or LAN switching at the distribution layer of the network, and ATM/LAN switching at the core. Figure 9B-4 shows an example of this network design. Figure 9B-4: Large switched/minimal routing design In the case of ATM in the distribution layer, the following key issues are relevant: ● LANE2 support on routers and switches. ● Support for UNI3 3.X signaling (including point-to-multipoint). ● If redundancy is provided by a virtual PVC4 or SVC5 mesh, the 1 2 3 4 5 Mbps:兆位每秒(Megabits per second 的首字母缩略)。 LANE:局域网仿真(local area network emulation 的首字母缩略)。 UNI:用户网络接口(user network interface 的首字母缩略)。 PVC:永久虚电路(permanent virtual circuit 的首字母缩略)。 SVC:交换虚电路(switched virtual circuit 的首字母缩略)。 计算机英语 187 mesh is a single point of failure. In the case of LAN switching in the distribution layer, the following key issues are relevant: trunking / 5trQNkiN / n. 集群,中继 ● Support for VLAN trunking technology in each device. ● The switches in the distribution layer must run the Spanning-Tree Protocol to prevent loops, which means that some connections will be blocked and load balancing cannot occur. To scale the large switched/minimal routing design, a logical hierarchy must be imposed. The logical hierarchy consists of VLANs and routers that enable inter-VLAN communication. In this topology, routing is used only in the distribution layer, and the access layer depends on bandwidth through the distribution layer to gain access to high-speed switching functionality in the core layer. The large switched/minimal routing design scales well when VLANs are designed so that the majority of resources are available in the VLAN. Therefore, if this topology can be designed so that 80 percent of traffic is intra-VLAN and only 20 percent of traffic is inter-VLAN, the bandwidth needed for inter-VLAN routing is not a concern. However, if inter-VLAN traffic is greater than 20 percent, access to routing in the core becomes a scalability issue. For optimal network operation, scalable routing content is needed at the distribution layer of the network. 2.3 Distributed Routing/Switching The distributed routing/switching design deploys switching in the access layer, routing in the distribution layer, and some form of high-speed switching in the core layer, as shown in Figure 9B-5. Figure 9B-5: Distributed routing/switching design 188 Computer English The distributed routing/switching design follows the classic hierarchical network model both physically and logically. Because it provides high bandwidth for access to routing functionality, this design scales very well. This design is optimized for networks that do not have the 80/20 pattern rule. If servers are centralized, most traffic is inter-VLAN; therefore, high routing content is needed. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. As far as redundancy in a network is concerned, there are two aspects that need to be considered: ________ and ________. 2. A hierarchical network design presents three layers: ________, distribution, and ________. 3. In the designing of campus networks, three topologies have emerged as generic designs: ________ switching, large switched/minimal routing, and ________ routing/switching. 4. In general, incorporating switches in campus network designs can lead to such benefits as high ________, quality of service, low cost, and easy ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. switched internetwork routing protocol carrier sense spanning tree hierarchical network 6. 7. 8. 9. 10. 动态路由选择 虚拟局域网 用户网络接口 校园网 模块模型 计算机英语 189 Section C How Are Networks Used? The fundamental purpose of networks—sharing resources—has evolved over the years to encompass many diverse tasks, and new applications for networking are being developed all the time. In the following sections, we discuss the more popular uses for today’s computer networks. 1. File Sharing ubiquitous / ju:5bikwitEs / a. 普遍存在的 The oldest and most ubiquitous use for networks is sharing data files. One approach to sharing files involves placing the file in a shared location on one computer (acting as a server), and making it available to other computers (acting as clients) on the network. Other users who want access to the file can either open the shared copy directly or copy it over the 190 Computer English network to their own local hard disks. Some database applications use file sharing to store a centralized database file on a server, allowing many users to view and update the file simultaneously. To accommodate this type of application, most NOSs 1 provide functions that enable the application to lock the shared data at the file or data record level. The application can then coordinate access to the data and prevent database updates from stepping on each other. 2. Printer Sharing Traditionally, printers are relatively expensive devices. No matter what era of personal computing you look at, high-end printers can cost more than two or three client computers. (Of course, what constitutes a high-end printer has changed over time.) As a result, sharing printers became a primary use of networks early on2—a tradition that survives today. parallel port 并行端口 To share a printer, you physically connect the printer to a computer acting as a server. (Printers are usually connected directly to the computer’s printer port, also called a parallel port.) Using the NOS, you share the printer over the network. Users can then print to your shared printer as easily as if the printer were directly connected to their own local PCs. Rather than going out the local printer port, the user’s data to be printed travels across the network to the server, and the server sends the data directly to its attached printer. Printer sharing is so pervasive that some printer manufacturers (for example, Hewlett-Packard3) have developed printers that you can directly attach to the network—no server computer required. These printers are sometimes called network printers, because they include a built-in interface to the network. From a user’s perspective, network printers appear and behave just like printers shared by servers on the network. 3. Drive Sharing When large hard disks and CD-ROM drives were relatively expensive devices, network users attached them to servers and shared them over the network. Users could access the contents of one or more shared CD-ROMs, or store and retrieve their own data in a directory on the server’s hard disk. 1 2 3 NOS:网络操作系统(network operating system 的首字母缩略)。 early on:在初期,早先。 Hewlett-Packard:HP 公司,惠普公司。 计算机英语 191 A single hard disk might accommodate many users, each with his or her own private directory. This approach kept the cost of individual PCs lower, and the extra cost of server hardware was spread across many users. As prices of hard disks and CD-ROM drives fell, the tide shifted in the direction of equipping each client computer with plenty of local storage and its own CD-ROM drive. However, more recent trends in cost reduction in some organizations have begun to push the storage devices back to the server, allowing the use of very inexpensive client PCs. Some low-cost client computers don’t even contain hard disks; they rely entirely on storage space supplied by network servers. These low-cost clients are sometimes called diskless workstations. In addition to drives and printers, you can share other devices. All you need is the right device and the right software. For example, intelligent fax machines, modems, scanners, and other devices have been shared over computer networks. We won’t go into the details of each device here. Just remember that the device-sharing concept can reach beyond printers and drives. 4. Application Sharing In its simplest form, application sharing is nothing more than file sharing, where the files just happen to be the executable application files themselves. Instead of installing and running an application on a local hard disk, you place the application once on a server. Users then load and run the application over the network. Keep in mind that not all software vendors design their applications to run in this type of shared environment. group scheduling 成组调度 Another aspect of application sharing involves placing a data file on a server and sharing it among several applications running on the network. (The application files themselves may or may not be shared.) In this environment, the application’s role includes coordinating all access to the shared data file. For example, a group scheduling application running on several networked PCs might store all scheduling data in a single shared file on a server. Likewise, some e-mail applications store all e-mail messages in a set of shared files on a single server computer. Some applications have two distinct parts—a client portion and a server portion. The two parts play specific roles in performing the application’s function. This approach is known as the client-server application model, or simply client-server. A server application lives on a 192 Computer English server computer and runs there exclusively. The client side of the application resides on a client computer and provides the user interface to the server part. The two parts of the application coordinate and exchange data over the network. A good example of this approach is Microsoft SQL Server, a client-server database application that runs on Windows NT Server. One piece of the application runs on a Windows NT Server computer and provides all access to the contents of a database. The client piece runs on each client computer, and makes requests to the server over the network. 5. Remote Access opt / Cpt / v. 选择;作出抉择 commute / kE5mju:t / n. 上下班交通 (路程) telecommuting / 7teli kE5mju:tiN / n. 远程办公,家庭 办公 More and more users these days are hitting the road1 with their laptop PCs in hand. At the same time, many other users are opting to skip the long commute and work from home while staying in touch with the office. (Working at home and communicating with the office electronically has become known as telecommuting.) As all of these users become increasingly dependent on their networks at the office, the need to connect their computers from remote locations has become significantly more important over the last few years. Remote access is a generic term that actually refers to several alternative approaches. In the following sections, we discuss the most popular remote access techniques. ■ REMOTE E-MAIL ACCESS If users need only to send and receive electronic mail messages, they can use a modem to dial in to an e-mail server at the office. Once connected, they can pick up their e-mail messages and compose and send messages to other users. This is a fairly straightforward task, but doesn’t give the user access to any other shared network resources. ■ REMOTE CONTROL If users need remote access to files on their desktop PCs at the office, they can implement an approach called remote control. This approach to remote access requires a special software package that runs on both the remote computer and on the user’s office PC. The software enables the user to take remote control of the office PC. The remote user’s keyboard, mouse, 1 hit the road:启程,动身。系美国俚语用法。 计算机英语 193 and video display act as if they’re directly attached to the PC at the office. The remote control software sends keyboard and mouse actions to the office PC, and receives changes in the display from the office PC. Each remote user takes control of exactly one PC on the office LAN, so each remotely controlled PC requires its own modem and copy of the remote control software. PC AnyWhere1 from Symantec2 is an example of remote control software. ■ REMOTE NODE Users who need full access to shared resources on the LAN at the office must use a remote access approach called remote node. (A node refers to a computer or other device that’s directly attached to the network.) Most modern NOSs, including Windows 98, provide some form of remote node capability. funnel / 5fQnEl / v.(使)流经漏斗; (尤指通过狭窄通 道)传送 With this approach, users can dial in to a remote access server at the office. Once they’re connected, they have complete access to the network—just as if their remote PC were directly connected to the network. Users can remotely access whatever shared resources they would normally be able to access at work. Remote nodes (remote access clients) can dial in to a single remote access server and have a virtual connection to the LAN. In contrast to remote control, the remote node approach funnels all remote users through a single server on the network. In the Microsoft world, remote node is referred to alternatively as RAS 3 (Remote Access Service) and DUN 4 (Dial-Up Networking). Windows 95 included remote access client software, and the Microsoft Plus! 5 pack added a single-modem remote access server. Windows 98 includes both the client and server components, as does Windows NT Workstation. Windows NT Server includes the complete form of RAS, which can handle up to 256 simultaneous remote nodes (that is, when it’s equipped with up to 256 modems). ———————————————— Exercises 1 2 3 4 5 PC AnyWhere:Symantec 公司出品的远程个人计算机控制软件。 Symantec:美国著名软件公司,主要产品有 Symantec C++、Visual Cafe。 RAS:远程访问服务(Remote Access Service 的首字母缩略)。 DUN:拨号联网(Dial-Up Networking 的首字母缩略)。 Microsoft Plus!:Windows 95 的附加软件包。 194 Computer English I. Fill in the blanks with the information given in the text: 1. A printer needs to be physically connected to a computer acting as a(n) ________ in order to be shared. 2. In drive sharing, users can store and retrieve their own data in a(n) ________ on the server’s hard disk. 3. In the text, a(n) ________ refers to a client computer that is not equipped with a hard disk and relies entirely on the storage space supplied by network servers. 4. When a user needs full access to shared resources on the LAN at the office, he can adopt a remote access approach called ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. diskless workstation group scheduling remote node printer port 5. 6. 7. 8. 远程访问 拨号联网 并行端口 网络操作系统 计算机英语 195 Unit 10: Network Infrastructure (网络基础结构) Section A Network Topologies Networks require both network adapter hardware in each device to be connected, and some physical (or wireless) connection to hook them all together. If you consider a two-node network, you can think of the network adapters as the tin cans, and the connection as the string between them. But most real-world networks include more than two nodes, and this leads to many different ways to string them together. predominate / pri5dCmineit / v. 占主导地位 The arrangement of network nodes and connections between them is called the network’s topology. It’s simply a map of the layout of nodes and connections in the network. Three network topologies predominate today—namely, bus, star, and ring. Bus Topology In the bus network topology, you connect each node to the network along a single piece of network cable, called a bus. (If you’re familiar with 196 motherboard / 5mQTEbC:d / n. 主板 tap / tAp / v. 接进 terminator / 5tE:mineitE / n. 终结器;终端 resistor / ri5zistE / n. 电阻器 electrical ground 电器接地端 sever / 5sevE / v. 切断,割断 terminate / 5tE:mineit / v.(使)终止 cabling / 5keibliN / n. [总称]电缆, 连线 Computer English the term bus in the context of motherboards, the idea is similar. The bus provides the path for the data, and devices tap into the bus along its length to communicate with other devices.) As shown in Figure 10A-1, network nodes essentially tap into the bus at convenient locations along the way. Data travels from a node out onto the bus until it reaches the ends of the cable. At each end of the bus, a device called a terminator is installed to prevent data signals from reflecting back onto the bus and causing errors. A terminator is a special resistor device that’s attached to an electrical ground. When the transmitted data hits the terminator, it doesn’t go any farther. Reliability of the bus topology can be a problem in all but the smallest networks. If the single cable acting as the bus is severed at any point, the entire network can go down. Even if many of the nodes are still connected to each other on the bus, a severed cable is no longer terminated correctly. Although it’s the lowest cost topology to implement, I don’t recommend selecting the bus topology unless you’re dealing with a total of three or four computers in the same room, and all the network cabling is easily accessible. Figure 10A-1: The bus network topology connects each node to a single length of cable, terminated at each end. Star Topology In the star network topology, you connect each network node to a central device called a hub. Small LANs with less than eight nodes usually 计算机英语 cohesive / kEu5hi:siv / a. 黏合(或聚合) 在一起的 197 need only one hub. Larger networks can require many hubs, and hubs can be connected to each other to tie all the nodes together into a single network. Figure 10A-2 shows an example of a network using the star topology. The network in this example actually consists of two stars each centered on its own hub. The hubs are tied together to provide a single cohesive network. Figure 10A-2: The star network topology connects each node to a centralized network hub. 198 Computer English Hubs are usually connected together to expand the number of nodes in the network. Hubs typically allow four, eight, or sixteen nodes before another hub is required. In Figure 10A-2, for example, the upper hub uses seven of its eight connections for attaching nodes, and its eighth to connect to the other hub. This approach of connecting stars together is also sometimes used when setting up a WAN. If two branch offices each have their own star topology LANs, you can connect the two LANs together by connecting the two hubs together via a WAN connection. The concept of connecting hubs isn’t restricted to networks. Airlines typically select a handful of major airports as hubs, and create their routes based on traveling through these hubs. You can still get from any city to any other city, but you may have to travel through a hub or two along the way. So it is with the data on a star topology network. Every network node is connected, but data must travel through one or more hubs between its source and destination. One difference between airline hubs and network hubs is the role of the hub itself. Airline hubs, such as the Dallas-Fort Worth International Airport1, for example, can be the beginning or end of a trip. In contrast, a network hub is always between the source and destination of the data. The data source and destination are always network nodes connected to the hub—never the hub itself. You get what you pay for when selecting a network topology. Star topologies are more expensive to implement than bus topologies. You must invest in at least one hub, even if you want to connect only two computers together. Each addition of four, eight, or sixteen nodes to the network may require an additional hub. In contrast, bus topologies require no additional external hardware, beyond the inexpensive terminators at each end of the bus. Ring Topology The ring network topology is shaped just like its name implies—it’s made up of an unbroken circle of network nodes. Essentially, each node is directly connected to its immediate neighbors. Data on the network flows in one direction around the ring, traveling from one node to the next along the way. Figure 10A-3 illustrates the ring topology. 1 Dallas-Fort Worth International Airport:达拉斯-沃思堡国际机场,位于美国得克萨斯州达拉斯和沃思堡两 市之间。 计算机英语 199 Figure 10A-3: The ring network topology connects each node to its neighboring nodes, forming an unbroken ring. plague / 5pleig / v. 使痛苦;给…造 成困难(或麻烦) adjacent / E5dVeisEnt / a. 邻近的,毗连的 Conceptually, a ring is like a bus that has had its two ends brought together. In other words, a ring is like a circular bus, to which all nodes are directly attached. The ring topology can be plagued with reliability problems because it depends on an unbroken link between each adjacent node on the network. If the ring is broken at any point along the way, the entire network stops functioning. Physical and Logical Topologies In the topology discussion so far, I’ve focused on the physical layout of the network in terms of cabling and hubs. This is known as the physical topology of the network. But the physical topology doesn’t really tell the whole story. Each network also has a logical topology, which describes how data actually travels on the network. The physical and logical topology of the network can be the same, but often they aren’t. Think of the physical topology as the network layout you’d see if you looked at the physical network from outside. To understand the physical topology, you completely ignore how the data travels, and focus instead on the appearance of cables, hubs, and nodes that make up the network. To understand the logical topology, you need to become one with the data traveling on the network. Pretend you are the data, and follow the path it 200 Computer English takes. The path you follow defines the network’s logical topology. Why is this important? Well, it turns out that most networks today use a physical star topology, but may have the logical topology of a bus, a star, or a ring. The internal wiring of the cables and hubs determines the network’s logical topology. So there are different types of hubs, connectors, and wiring, depending on the logical topology of the network you’re implementing. Figure 10A-4: A physical star topology can be used to implement a logical ring topology, using an appropriate hub. For example, a physical star topology may be wired with a logical bus 计算机英语 201 topology. Unless the hub itself fails, a break in a single cable won’t bring down the entire network—just the node attached to the broken cable. A physical star topology can also be used to implement a logical ring topology, as shown in Figure 10A-4. Notice that the data travels in one direction only, creating a logical ring. amplify / 5Amplifai / v. 放大,增强 distortion / dis5tC:FEn / n. 失真,畸变 diagnostic / 7daiEg5nCstik / n. [ 常 作 ~s][ 用 作 单]诊断学;诊断法 prevalent / 5prevElEnt / a. 流行的;普遍的 closet / 5klCzit / n. 小房间; (壁)橱 wiring closet 布线室 troubleshoot / 5trQblFu:t / v. 检修,故障诊断, 排故障 Hubs come in1 many different flavors, because they can be wired to implement any of the three basic logical network topologies. For example, a hub that implements a ring topology, such as the one shown in Figure 10A-4, is called a multistation access unit (or MAU 2 or MSAU 3 ). Moreover, a hub can be either passive or active. A passive hub simply acts as a central wiring point, and does nothing to the signals that pass through it. In contrast, an active hub can provide a wide range of features. In its most basic form, an active hub amplifies transmitted signals, to prevent distortion and lost data. High-end active hubs can offer features that include sophisticated network management, diagnostics, and reporting capabilities. Choosing Between Network Topologies The most prevalent physical network topology today is the star topology, even if it’s used to implement a different logical topology. Here’s why the star has become the standard approach to implementing other logical network topologies: ● Convenience—The star configuration causes all network wiring to converge in a central location, typically in a wiring closet or server room. This central location makes it convenient for the network administrator to configure, troubleshoot, and maintain the physical network connections. ● Flexibility—Because each network node is attached via its own dedicated cable, the star approach makes it very easy to add, move, or remove individual nodes from the network without affecting other nodes. ● Intelligence—As manufacturers create increasingly smarter hub devices, star topologies can take advantage of the intelligence built into these devices, including centralized network management and 1 2 3 come in:以…式样(或特征等)供应(或存在) 。 MAU:多站访问单元(multistation access unit 的首字母缩略)。 MSAU:多站访问单元(multistation access unit 的首字母缩略)。 202 Computer English advanced troubleshooting capabilities. Even if a network doesn’t use intelligent hubs today, having the physical star topology in place makes it possible to insert intelligent hubs in the future. Table 10A-1: Comparison of network topologies Characteristics Bus Topology Star Topology External hardware Terminators at each Hub (active or required end of bus passive) Low Moderate Dependent on Dependent on single cable bus central hub(s) Relative hardware cost Reliability Ring Topology MAU hub High Dependent on MAU and cable paths to each node Table 10A-1 presents a summarized comparison of the network topologies I’ve discussed in the previous sections. I’ve included external hardware requirements, relative costs, and reliability. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. A network’s topology is the arrangement of network ________ and ________ between them. 2. The ________, star, and ________ topologies are the three dominant types of network topology. 3. In the bus topology, each node is connected to the network along a single piece of network cable with a(n) ________ at each end. 4. In the star topology, each node is connected to a centralized network ________. 5. In the ring topology, each node is connected to its neighboring nodes, forming an unbroken ________. 6. According to the text, each network has not only a physical topology, but also a(n) ________ one. The two can be the same, but often not. 7. Today most networks use a physical ________ topology. 203 计算机英语 8. A hub can be either ________or ________. The former simply serves as a central wiring point, and does nothing to the signals that pass through it whereas the latter can provide a wide range of features. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. network layout physical topology logical topology star configuration physical network connection high-end active hub passive hub network node electrical ground data flow 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 布线室 多站访问单元 星形拓扑结构 总线拓扑结构 环形拓扑结构 网络拓扑结构 集中式网络管理 智能集线器 网络集线器 物理网络 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: physical node carrier logically traffic standard adapter interfere multiple star approach bus receive desire transmit network Ethernet, originally developed in 1973 at Xerox, is by far the most popular network technology in use today. The logical topology of an Ethernet ________ is always a bus. The predominant ________ topology used to be a bus as well, but has been eclipsed (使暗淡) in recent years by the ________ topology. Because Ethernet is ________ a bus, data is transmitted to every ________ on the network. Each node sees every transmission, and ________ transmissions destined (预定的) for it based on the address of its network ________. This approach to sharing a single cable for all transmissions is known as the ________ access method. Only one node can successfully ________ at any given time, so the nodes must agree on a way to share the cable without ________ with each other. The Ethernet 204 Computer English ________ specifies how the nodes share the bus. Before a node starts transmitting, it briefly listens to the ________ for other traffic. This activity is known as ________ sensing. If another node is already transmitting, the node ________ to transmit tries again later. If there’s no other ________ on the bus, the node begins transmission. This ________ avoids transmissions stepping on each other—in most cases. IV. Translate the following passage from English into Chinese: Token Ring technology uses a very different access method from the Ethernet approach. A special message, called a token, is continuously circulated in one direction around the logical ring. If the token passes by a node that wants to transmit on the network, the node grabs the token, tacks (附加) on the data it wants to send, and puts the message back on the ring. The message continues its journey around the ring until it’s delivered to its destination. Until the message arrives, no other nodes can send any data. A node can’t transmit anything until it sees the token come by again. If a node sees the token but has nothing to say, it simply passes the token on to the next node in the ring. This access method is called token passing. 计算机英语 205 Section B TCP/IP: the Basics I. What Is TCP/IP? Transmission Control Protocol 传输控制协议 Internet Protocol Internet 协议,网际 协议 surfer / 5sE:fE / n. 网上冲浪者 TCP/IP refers to two network protocols (or methods of data transport) used on the Internet. They are Transmission Control Protocol and Internet Protocol, respectively. These network protocols belong to a larger collection of protocols, or a protocol suite. These are collectively referred to as the TCP/IP suite. Protocols within the TCP/IP suite work together to provide data transport on the Internet. In other words, these protocols provide nearly all services available to today’s Net surfer. Some of those services include: ● ● ● ● Transmission of electronic mail File transfers Usenet1 news delivery Access to the World Wide Web There are two classes of protocol within the TCP/IP suite. They are: ● The network-level protocol ● The application-level protocol discrete / 5diskri:t / a. 分离的;离散的 1 2 Network-level protocols manage the discrete mechanics of data transfer.2 These protocols are typically invisible to the user and operate deep beneath the surface of the system. For example, the IP protocol provides packet delivery of the information sent between the user and Usenet:USENET 网(或用户网、友思网),一个具有分布式管理的 UNIX 系统的全球性网络,用于特殊 兴趣讨论组的电子公告牌系统(亦作 UseNET、USENET 或 USEnet)。 Network-level protocols manage the discrete mechanics of data transfer.:网络级协议管理数据传输的离散结 构。 206 sniffer / 5snifE / n. 嗅探者; 监视软件 datagram / 5deitEgrAm / n. 数据报 File Transfer Protocol 文件传输协议 status report 状态报告 suffice / sE5fais / v. 足够 Computer English remote machines. It does this based on a variety of information, most notably the IP address of the two machines. Based on this and other information, IP guarantees that the information will be routed to its intended destination. Throughout this process, IP interacts with other network-level protocols engaged in data transport. Short of 1 using network utilities (perhaps a sniffer or other device that reads IP datagrams), the user will never see IP’s work on the system. Conversely, application-level protocols are visible to the user in some measure2. For example, File Transfer Protocol (FTP) is visible to the user. The user requests a connection to another machine to transfer a file, the connection is established, and the transfer begins. During the transfer, a portion of the exchange between the user’s machine and the remote machine is visible (primarily error messages and status reports on the transfer itself, for example, how many bytes of the file have been transferred at any given moment). For the moment, this explanation will suffice: TCP/IP refers to a collection of protocols that facilitate communication between machines over the Internet (or other networks running TCP/IP). II. The History of TCP/IP imperative / im5perEtiv / a. 必要的 intact / in5tAkt / a. 完整无缺的 requisite / 5rekwizit / n. 必要条件 impervious / im5pE:viEs / a. 不受影响的;不 易损坏的 periodic / 7piEri5Cdik / a. 周期(性)的; 时而发生的 1 2 In 1969, the Defense Advanced Research Projects Agency (DARPA) commissioned development of a network over which its research centers might communicate. Its chief concern was this network’s capability to withstand a nuclear attack. In short, if the Soviet Union launched a nuclear attack, it was imperative that the network remain intact to facilitate communication. The design of this network had several other requisites, the most important of which was this: It had to operate independently of any centralized control. Thus, if one machine was destroyed (or 10, or 100), the network would remain impervious. The prototype for this system emerged quickly, based in part on research done in 1962 and 1963. That prototype was called ARPANET. ARPANET reportedly worked well, but was subject to periodic system crashes. Furthermore, long-term expansion of that network proved costly. A search was initiated for a more reliable set of protocols; that search ended in the mid-1970s with the development of TCP/IP. short of:若无;除…外。 in some measure:在一定程度上,有几分。 计算机英语 meager / 5mi:gE / a. 瘦的;不足的; 贫乏的 translate / trAns5leit / v.(使)转变 dismal / 5dizmEl / a. 令人忧郁的;差 劲的,不怎么样的 compatible / kEm5pAtEbl / n. 兼容机 207 TCP/IP had significant advantages over other protocols. For example, TCP/IP was lightweight (it required meager network resources). Moreover, TCP/IP could be implemented at much lower cost than the other choices then available. Because of these advantages, TCP/IP became exceedingly popular. In 1983, TCP/IP was integrated into release 4.2 of Berkeley Software Distribution (BSD) UNIX. Its integration into commercial forms of UNIX soon followed, and TCP/IP was established as the Internet standard. It has remained so (as of this writing). As more users flock to the Internet, however, TCP/IP is being reexamined. More users translate to greater network load. To ease that network load and offer greater speeds of data transport, some researchers have suggested implementing TCP/IP via satellite transmission. Unfortunately, such research has thus far produced dismal results. TCP/IP is apparently unsuitable for this implementation. Today, TCP/IP is used for many purposes, not just the Internet. For example, intranets are often built using TCP/IP. In such environments, TCP/IP can offer significant advantages over other networking protocols. One such advantage is that TCP/IP works on a wide variety of hardware and operating systems. Thus, one can quickly and easily create a heterogeneous network using TCP/IP. Such a network might have Macs, IBM compatibles, and so on. Each of these can communicate with its peers using a common protocol suite. For this reason, since it was first introduced in the 1970s, TCP/IP has remained extremely popular. III. What Platforms Support TCP/IP? mainstream / 5meinstri:m / a. 主流的 proprietary Most platforms support TCP/IP. However, the quality of that support can vary. Today, most mainstream operating systems have native TCP/IP support (that is, TCP/IP support that is built into the standard operating system distribution). However, older operating systems on some platforms lack such native support. Table 10B-1 describes TCP/IP support for various platforms. If a platform has native TCP/IP support, it is labeled as such. If not, the name of a TCP/IP application is provided. / prEu5praiEtEri / a 专有的,专利的 marginal / 5mB:dVinEl / a. 边缘的;勉强够 格的;少量的 Platforms that do not natively support TCP/IP can still implement it through the use of proprietary or third-party TCP/IP programs. In these instances, third-party products can offer varied functionality. Some offer very good support and others offer marginal support. Table 10B-1: Platforms and their support for TCP/IP 208 Computer English Platform TCP/IP Support UNIX Native DOS Piper/IP by Ipswitch Windows TCPMAN by Trumpet Software Windows 95 Native Windows NT Native Macintosh MacTCP or OpenTransport (Sys 7.5+) OS/2 Native AS/400, OS/400 Native For example, some third-party products provide the user with only basic TCP/IP. For most users, this is sufficient. (They simply want to connect to the Net, get their mail, and enjoy easy networking.) In contrast, certain third-party TCP/IP implementations are comprehensive. These may allow manipulation of compression, methods of transport, and other features common to the typical UNIX TCP/IP implementation. Widespread third-party support for TCP/IP has been around for only a few years. Several years ago, for example, TCP/IP support for DOS boxes was very slim. One interesting point about non-native, third-party TCP/IP implementations is this: Most of them do not provide servers within their distributions. Thus, although a user can connect to remote machines to transfer a file, the user’s machine cannot accept such a request. For example, a Windows 3.11 user using TCPMAN cannot—without installing additional software—accept a file-transfer request from a remote machine. IV. How Does TCP/IP Work? TCP/IP operates through the use of a protocol stack. This stack is the sum total of all protocols necessary to complete a single transfer of data between two machines. (It is also the path that data takes to get out of one machine and into another.) The stack is broken into layers, five of which are of concern here. To grasp this layer concept, examine Figure 10B-1. After data has passed through the process illustrated in Figure 10B-1, it travels to its destination on another machine or network. There, the process is executed in reverse (the data first meets the physical layer and subsequently travels its way up the stack). Throughout this process, a complex system of error checking is employed both on the originating and 计算机英语 209 destination machine. Figure 10B-1: The TCP/IP stack adjoining / E5dVCiniN / a. 贴邻的,毗连的 Each layer of the stack can send data to and receive data from its adjoining layer. Each layer is also associated with multiple protocols. At each tier of the stack, these protocols are hard at work, providing the user with various services. V. TCP/IP Is the Internet TCP/IP basically comprises the Internet itself. It is a complex collection of protocols, many of which remain invisible to the user. On most Internet servers, a minimum of these protocols exist: Internet Control Message Protocol 网间信报控制协议 Address Resolution Protocol 地址解析协议 Network News Transfer Protocol 网络新闻传输协议 Simple Mail Transfer Protocol 简单邮件传输协议 Hypertext Transfer ● ● ● ● ● Transmission Control Protocol Internet Protocol Internet Control Message Protocol Address Resolution Protocol File Transfer Protocol 210 Computer English ● ● ● ● ● The Telnet1 protocol The Gopher2 protocol Network News Transfer Protocol Simple Mail Transfer Protocol Hypertext Transfer Protocol These are only a handful of the protocols run on the Internet. There are actually hundreds of them. Better than half of the primary protocols have had one or more security holes. In essence, the Internet was designed as a system with multiple avenues of communication. Each protocol is one such avenue. As such, there are hundreds of ways to move data across the Net. Until recently, utilizing these protocols called for accessing them one at a time. That is, to arrest a Gopher session and start a Telnet session, the user had to physically terminate the Gopher connection. The HTTP browser changed all that and granted the average user much greater power and functionality. Indeed, FTP, Telnet, NNTP3, and HTTP are all available at the click of a button. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. TCP/IP stands for ________ Control Protocol and ________ Protocol. 2. There are two classes of protocol within the TCP/IP suite: the ________ protocol and the ________ protocol. 3. Today, most mainstream operating systems have ________ TCP/IP support. That is, it is built into the standard operating system distribution. 4. TCP/IP operates through the use of a(n) ________, each layer of which can send data to and receive data from its adjoining layer. 1 2 3 Telnet:远程登录,用于远程联接服务的标准协议或者实现此协议的软件。 Gopher:Gopher 服务器(或“考访”),因特网上搜索文本信息并将结果以层次式菜单的形式告诉用户 的一种实用工具。 NNTP:网络新闻传输协议(Network News Transfer Protocol 的首字母缩略) 。 211 计算机英语 II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. heterogeneous network packet delivery IBM compatible IP datagram DOS box 6. 7. 8. 9. 10. 超文本传输协议 网络新闻传输协议 简单邮件传输协议 安全漏洞 系统崩溃 212 Computer English Section C Network-Level Protocols Network protocols are those protocols that engage in (or facilitate) the transport process transparently. These are invisible to the user unless that user employs utilities to monitor system processes. Important network-level protocols include: ● ● ● ● The Address Resolution Protocol (ARP) The Internet Control Message Protocol (ICMP) The Internet Protocol (IP) The Transmission Control Protocol (TCP) I. The Address Resolution Protocol debut / 5deibju: / n. <法>首次登台演 出;首次出现 The Address Resolution Protocol (ARP) serves the critical purpose of mapping Internet addresses into physical addresses. This is vital in routing information across the Internet. Before a message (or other data) is sent, it is packaged into IP packets, or blocks of information suitably formatted for Internet transport. These contain the numeric Internet (IP) address of both the originating and destination machines. Before this package can leave the originating computer, however, the hardware address of the recipient (destination) must be discovered. (Hardware addresses differ from Internet addresses.) This is where ARP makes its debut. 计算机英语 213 An ARP request message is broadcast on the subnet. This request is received by a router that replies with the requested hardware address. This reply is caught by the originating machine and the transfer process can begin. tidbit / 5tidbit / n. 珍品;常用信息 ARP’s design includes a cache. To understand the ARP cache concept, consider this: Most modern HTML browsers (such as Netscape Navigator1 or Microsoft’s Internet Explorer) utilize a cache. This cache is a portion of the disk (or memory) in which elements from often-visited Web pages are stored (such as buttons, headers, and common graphics). This is logical because when you return to those pages, these tidbits don’t have to be reloaded from the remote machine. They will load much more quickly if they are in your local cache. Similarly, ARP implementations include a cache. In this manner, hardware addresses of remote machines or networks are remembered, and this memory obviates the need to conduct subsequent ARP queries on them. This saves time and network resources. cache / 5kAF / v. 高速缓存 cracker / 5krAkE / n. 非法侵入(计算 机系统)者 hail / heil / v. 招呼(致意) diagnosis / 7daiEg5nEusis / n. 诊断;判断 diagnostic / 7daiEg5nCstik / a.(用于)诊断的; 有助于诊断的 congest / kEn5dVest / v. [ 常 用 于 被 动 语 态]挤满;拥塞 Can you guess what type of security risks might be involved in maintaining such an ARP cache? Address caching (not only in ARP but in all instances) poses a unique security risk. If such address-location entries are stored, it makes it easier for a cracker to forge a connection from a remote machine, claiming to hail from2 one of the cached addresses. II. The Internet Control Message Protocol The Internet Control Message Protocol handles error and control messages that are passed between two (or more) computers or hosts during the transfer process. It allows those hosts to share that information. In this respect, ICMP is critical for diagnosis of network problems. Examples of diagnostic information gathered through ICMP include: ● When a host is down ● When a gateway is congested or inoperable ● Other failures on a network III. The Internet Protocol IP belongs to the network layer. The Internet Protocol provides packet delivery for all protocols within the TCP/IP suite. Thus, IP is the heart of the 1 2 Netscape Navigator:美国 Netscape(网景)公司出品的 Web 浏览器。 hail from:来自。 214 Computer English incredible process by which data traverses the Internet. To explore this process, I have drafted a small model of an IP datagram (see Figure 10C-1). Figure 10C-1: The IP datagram miscellaneous / 7misE5leiniEs / a. 混杂的 bust / bQst / v. 爆裂;打碎 identification / ai7dentifi5keiFEn / n. 识别;标识 void / vCid / n. 空间;真空 decrement / 5dekrimEnt / v. 减少,减缩 1 As illustrated, an IP datagram is composed of several parts. The first part, the header, is composed of miscellaneous information, including originating and destination IP address. Together, these elements form a complete header. The remaining portion of a datagram contains whatever data is then being sent. The amazing thing about IP is this: If IP datagrams encounter networks that require smaller packages, the datagrams bust apart to accommodate the recipient network. Thus, these datagrams can fragment during a journey and later be reassembled properly (even if they do not arrive in the same sequence in which they were sent) at their destination. Even further information is contained within an IP datagram. Some of that information may include identification of the protocol being used, a header checksum, and a time-to-live specification. This specification is a numeric value. While the datagram is traveling the void, this numeric value is constantly being decremented. When that value finally reaches a zero state, the datagram dies. Many types of packets have time-to-live limitations. Some network utilities (such as Traceroute1) utilize the time-to-live field as Traceroute:一种网络实用工具,用来跟踪数据包的路由。 计算机英语 marker / 5mB:kE / n. 标记(符) 215 a marker in diagnostic routines.1 In closing, IP’s function can be reduced to this: providing packet delivery over the Internet. As you can see, that packet delivery is complex in its implementation. IV. The Transmission Control Protocol The Transmission Control Protocol is the chief protocol employed on the Internet. It facilitates such mission-critical tasks as file transfers and remote sessions. TCP accomplishes these tasks through a method called reliable data transfer. In this respect, TCP differs from other protocols within the suite. In unreliable delivery, you have no guarantee that the data will arrive in a perfect state. In contrast, TCP provides what is sometimes referred to as reliable stream delivery. This reliable stream delivery ensures that the data arrives in the same sequence and state in which it was sent. The TCP system relies on a virtual circuit that is established between the requesting machine and its target. This circuit is opened via a three-part process, often referred to as the three-part handshake. The process typically follows the pattern illustrated in Figure 10C-2. Figure 10C-2: The TCP/IP three-way handshake 1 Some network utilities (such as Traceroute) utilize the time-to-live field as a marker in diagnostic routines.:有些 网络实用工具(譬如 Traceroute)在诊断程序里把数据包的生命期字段作为一个标记。 216 full-duplex / 5ful5dju:pleks / a. 全双工的 underway / 5QndE5wei / a. 在进行中的 clean / kli:n / a. 无错误的;畅通 无阻的;顺利的 Computer English After the circuit is open, data can simultaneously travel in both directions. This results in what is sometimes called a full-duplex transmission path. Full-duplex transmission allows data to travel to both machines at the same time. In this way, while a file transfer (or other remote session) is underway, any errors that arise can be forwarded to the requesting machine. TCP also provides extensive error-checking capabilities. For each block of data sent, a numeric value is generated. The two machines identify each transferred block using this numeric value. For each block successfully transferred, the receiving host sends a message to the sender that the transfer was clean. Conversely, if the transfer is unsuccessful, two things may occur: ● The requesting machine receives error information ● The requesting machine receives nothing When an error is received, the data is retransmitted unless the error is fatal, in which case the transmission is usually halted. Similarly, if no confirmation is received within a specified time period, the information is also retransmitted. This process is repeated as many times as necessary to complete the transfer or remote session. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. ARP, the Address Resolution Protocol, serves to map ________ addresses into ________ addresses. 2. Before a message is sent, it is packaged into IP ________, or blocks of information suitably formatted for Internet transport. 3. IP belongs to the ________ layer and provides packet delivery for all protocols within the TCP/IP suite. 4. ________ transmission allows data to travel in both directions at the same time between the sender and the receiver. II. Translate the following terms or phrases from English into 217 计算机英语 Chinese and vice versa: 1. 2. 3. 4. physical address data transfer header checksum stream delivery 5. 6. 7. 8. 虚电路 网络层 全双工传输 地址解析协议 218 Computer English Unit 11: Internet (因特网) Section A How Does the Internet Work? The Internet is based on the concept of a client-server relationship between computers, also called a client/server architecture. In a client/server architecture, some computers act as servers, or information providers, while other computers act as clients, or information receivers. The client/server architecture is not one-to-one—that is, a single client computer may access many different servers, and a single server may be accessed by a number of different client computers. Prior to the mid-1990s, servers were usually very powerful computers such as mainframes or supercomputers, with extremely high processing speeds and large amounts 计算机英语 219 of memory. Personal computers and workstations, however, are now capable of acting as Internet servers due to advances in computing technology. A client computer is any computer that receives information from a server and is often a personal computer. To access information on the Internet, a user must first log on, or connect, to the client computer’s host network. A host network is a network that the client computer is part of, and is usually a local area network (LAN). Once a connection has been established, the user may request information from a remote server. If the information requested by the user resides on one of the computers on the host network, that information is quickly retrieved and sent to the user’s terminal. If the information requested by the user is on a server that does not belong to the host LAN, then the host network connects to other networks until it makes a connection with the network containing the requested server. In the process of connecting to other networks, the host may need to access a router, a device that determines the best connection path between networks and helps networks to make connections. Once the client computer makes a connection with the server containing the requested information, the server sends the information to the client in the form of a file. A special computer program called a browser enables the user to view the file. Examples of Internet browsers are Mosaic1, Netscape, and Internet Explorer. Most Internet files are multimedia documents—that is, text, graphics, photographs, audio, and video may be combined in a single document. Non-multimedia documents do not need browsers to view their text-only contents and many multimedia documents provide access to text-only versions of their files. The process of retrieving files from a remote server to the user’s terminal is called downloading. nonlinear / nCn5liniE / a. 非线性的 1 One of the strengths of the Internet is that it is structured around the concept of hypertext. The term hypertext is used to describe an interlinked system of documents in which a user may jump from one document to another in a nonlinear, associative way. The ability to jump from one document to the next is made possible through the use of hyperlinks—portions of the hypertext document that are linked to other related documents on the Internet. By clicking on the hyperlink, the user is Mosaic:Mosaic 浏览器,第一个流行的图形 Web 浏览器,由伊利诺依大学厄巴纳—尚佩恩分校的国家超 级计算应用中心(National Center for Supercomputing Applications,缩写为 NCSA)于 1993 年初发布在因 特网上。 220 hypermedia / 5haipE7mi:diE / n. 超媒体 Computer English immediately connected to the document specified by the link. Multimedia files on the Internet are called hypermedia documents. I. Accessing the Internet dedicated access 专线访问 dial-up access 拨号访问 Access to the Internet falls into two broad categories: dedicated access and dial-up access. With dedicated access, the computer is directly connected to the Internet via a router, or the computer is part of a network linked to the Internet. With dial-up access, a computer connects to the Internet with a temporary connection, generally over a telephone line using a modem—a device that converts the electrical signals from a computer into signals that can be transmitted over traditional telephone lines. A modem is needed because computers are digital, meaning that their signals are made up of discrete units, while most telephone lines are analog, meaning that they carry signals that are continuous instead of discrete. Once a signal has traveled over the telephone line, a second modem is required at the other end of the line to reconvert the transmitted signals from analog to digital. A great many companies, called Internet Service Providers (ISPs), provide dial-up access to the Internet for a modest fee. Examples of ISPs are America Online (AOL1), the Microsoft Network (MSN2, and CompuServe3. II. Packaging Information data stream 数据流 packet-switching / 5pAkit7switFiN / n. 包交换 address / E5dres / v. 编(址); 寻(址) 1 2 3 All data transmitted over the Internet is divided up into small units of information called packets, each of which is labeled with a unique number indicating its place in the data stream—the flow of information between computing devices. When the various packets that make up a set of data arrive at their destination, they are re-assembled using the unique labels given them. If part of the network over which the packets are sent is malfunctioning, or down, special automatic features of the Internet’s routing equipment re-route the packets so that they travel over functioning portions of the network. Other features make sure that all the data packets arrive intact, automatically requesting that missing or incomplete packets be re-sent from the source. This system, called packet-switching, uses a series of protocols, or rules, known as TCP/IP (Transmission Control Protocol/Internet Protocol). III. Network Addressing AOL:美国在线服务公司(America Online 的首字母缩略)。 MSN:微软网络,微软提供的网络在线服务(Microsoft Network 的首字母缩略)。 CompuServe:CompuServe 联机服务系统,美国最大的在线信息服务机构之一。 计算机英语 colon / 5kEulEn / n. 冒号 slash / slAF / n. 斜线(号) hostname / 5hEustneim / n. 主机名 name server 名称服务器 domain name 域名 221 To be part of the Internet a computer must have a unique Internet Protocol (IP) network address so that messages can be correctly routed to and from the machine over the Internet. Internet addresses are called URLs1 (Uniform Resource Locators). Some URLs are a string of numbers, but because long strings of numbers are difficult for people to remember, other addressing conventions are also used. An example of this convention is: http://encarta.msn.com/downloads/pryearbk.asp. The http indicates the protocol—in this instance the hypertext transfer protocol—used to access the particular location on the Internet. The name after the colon and double slash (encarta.msn.com) indicates the hostname, which is the name of a specific computer system connected to the Internet. The remaining names after the hostname indicate various files to which the specific URL points. In the example URL, the file pryearbk is located within the directory downloads. Other files located in the same directory will have a similar URL, the only difference being the name of the file, or files, at the end of the address2. Special name servers map IP numbers to domain names (msn.com in the above URL) and guarantee that the correct IP number of the source and the destination are provided for all packets. IV. E-Mail mail server 邮件服务器 list server 列表服务器 online / 5Cn5lain / a. & ad. 联 机 的 (地),在线的(地) 1 2 The most widely used tool on the Internet is electronic mail, or e-mail (see Figure 11A-1). E-mail is used to send written messages between individuals or groups of individuals, often geographically separated by large distances. E-mail messages are generally sent from and received by mail servers—computers that are dedicated to processing and directing e-mail. Once a server has received a message it directs it to the specific computer that the e-mail is addressed to. To send e-mail, the process is reversed. A very convenient and inexpensive way to transmit messages, e-mail has dramatically affected scientific, personal, and business communications. E-mail is the basis of much organized exchange between groups of individuals. List servers, for example, make it possible to address a list of subscribers either in one-way communication, as in keeping interested people up-to-date on a product, or two-way communication, as in online discussion groups. URL:统一资源定位符,统一联网地址(Uniform Resource Locator 的首字母缩略)。 the only difference being the name of the file, or files, at the end of the address:分词作状语,其逻辑主语应与 句子主语一致。否则,分词必须有自己的主语。这种带主语的分词短语,称为分词的独立结构。本句的分 词独立结构起附加说明的作用。 222 Computer English Figure 11A-1: Sending and receiving e-mail news server 新闻服务器 Another use of e-mail is Usenet, in which discussions on a particular subject are grouped together into newsgroups. There are thousands of newsgroups covering an extremely wide range of subjects. Messages to a newsgroup are not posted directly to the user, but are accessible in the form of an ordered list on a dedicated local news server. The networking of these servers makes such discussions available worldwide. Associated software not only enables users to choose which messages they want to read, but also to reply to them by posting messages to the newsgroup. V. Transmission Schemes Before the introduction of the World Wide Web, various standards and types of software existed for transmitting data over the Internet. Many of these are still in use, with Telnet, File Transfer Protocol (FTP), and Gopher among the most popular. Telnet allows an Internet user to connect to a distant computer and use that computer as if he or she were using it directly. FTP is a method of moving files from one computer to another over the Internet, even if each computer has a different operating system or storage format. Gopher is an improvement on FTP, making it easier to list and retrieve files remotely. While these transmission protocols and software are still in use, the WWW is much easier to use and is used much more often than earlier transmission protocols. 计算机英语 223 VI. Bandwidth kilobit / 5kilEbit / n. 千位,千比特 megabit / 5megEbit / n. 兆位,兆比特 The amount of data that a computer network can transmit is called the bandwidth of the network and is usually measured in kilobits per second (Kbps) or megabits per second (Mbps). A bit—the smallest unit of information that computers can process—can have one of two values, either 0 or 1. A kilobit is one thousand bits, while a megabit is one million bits. The transportation of information between routers generally uses communication lines dedicated to this function, with capacities currently ranging from 64 Kbps up to as much as several hundred Mbps. The speed at which information can be transmitted across the Internet depends on the lowest information transporting capacity along the route and the number of people using that route at any given time. A narrow bandwidth somewhere along the route acts as a bottleneck to data transport, and the more people using the line, the less information each of them can transport at any one time. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The Internet is based on the concept of a(n) ________ relationship between computers. 2. To access information on the Internet, a user must first log on to the client computer’s ________ network. 3. Most Internet files are ________ documents, in which text, graphics, photographs, audio, and video may be combined. 4. A user typically connects to the Internet in one of two ways: ________ access and ________ access. 5. A(n) ________ document is an interlinked system of documents in which a user may jump from one document to another in a nonlinear, associative way. 6. ________ are Internet addresses used by Web browsers to locate Internet resources. 7. The ________ of a computer network is the amount of data it can transmit. 224 Computer English 8. The Internet evolved from ________, a large wide area network created in the 1960s by the U.S. Department of Defense Advanced Research Projects Agency. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. list server transmission scheme data packet Mbps hypermedia document FTP host network dedicated access storage format mail server 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 多媒体文件 拨号访问 局域网 检索文件 因特网服务供应商 万维网 统一资源定位符 传输控制协议 数据流 登录 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: development attribute click capability Web language link programming specify promising page system stand navigate view replace Web pages are actually small computer programs, written in a computer language understood by Web browsers. The primary ________ used for Web pages is called HTML, which ________ for HyperText Markup Language. HTML provides a way of describing exactly how a(n) ________ will look when it’s published on the ________. HyperText refers to the ________ of linking pages together so users can quickly ________ through material based on their own interests. (If you’ve used the Windows Help ________ to find the answer to a question, you’ve probably ________ several hypertext links.) Markup refers to the capability to ________ position, size, font, color, and other ________ of elements on the page. Therefore, HTML is a(n) ________ language that enables you to create and ________ together pages, and to specify just 计算机英语 225 about every detail of how the page looks when ________ by a Web browser. HTML isn’t the end of the line for markup languages. ________ of several new languages is under way, to provide more powerful Web publishing capabilities. One of the most ________ is XML, or Extensible Markup Language. Some experts believe it will ________ HTML in the next few years. IV. Translate the following passage from English into Chinese: The Internet provides only the physical and logical infrastructure that connects millions of computers together. Many believe that the World Wide Web (WWW, or simply the Web) provides the killer application (制胜法宝) for this global network. The Web is considered the content of the Internet, providing all sorts of information by using a rich set of tools that manage and link text, graphics, sound, and video. Providing and viewing information on the Web is accomplished using server applications and client applications. If you’ve already explored the Web, you’ll recognize the client-side application as the Web browser. A Web browser receives, interprets, and displays pages of information from the Web. The user can navigate within pages, jump to other pages by clicking hypertext links, and point to just about any page on the Web. 226 Computer English Section B What’s E-Mail? abbreviation / E7bri:vi5eiFEn / n. 缩写(词) In computer science, e-mail is the abbreviation of the term electronic mail, method of transmitting data or text files from one computer to another over an internet, intranet, or the Internet. E-mail enables computer users to send messages and data quickly through a local area network or beyond through a nationwide or worldwide communication network. E-mail came into widespread use in the 1990s and has become a major development in business and personal communications. E-mail users create and send messages from individual computers using commercial e-mail programs or mail-user agents (MUAs1). Most of these programs have a text editor for composing messages. The user sends a message to one or more recipients by specifying destination addresses. When a user sends an e-mail message to several recipients at once, it is sometimes called broadcasting. The address of an e-mail message includes the source and destination of the message. Different addressing conventions are used depending upon the e-mail destination. An interoffice message distributed over an intranet, or internal computer network, may have a simple scheme, such as the employee’s name, for the e-mail address. E-mail messages sent outside of an intranet are addressed according to the following convention: the first part of the address contains the user’s name, followed by the symbol @, the domain name, the institution’s or organization’s name, and finally the country name. A typical e-mail address might be [email protected] In this example sally is the user’s name, abc is the domain name—the specific company, organization, or institution that the e-mail message is sent to or from, and 1 MUA:邮件用户代理(mail-user agent 的首字母缩略)。 计算机英语 suffix / 5sQfiks / n. 后缀 supplementary / 7sQpli5mentEri / a. 增补的,补充的 227 the suffix com indicates the type of organization that abc belongs to—com for commercial, org for organization, edu for educational, mil for military, and gov for governmental. An e-mail message that originates outside the United States or is sent from the United States to other countries has a supplementary suffix that indicates the country of origin or destination. Examples include uk for the United Kingdom, fr for France, and au for Australia. E-mail data travels from the sender’s computer to a network tool called a message transfer agent (MTA1) that, depending on the address, either delivers the message within that network of computers or sends it to another MTA for distribution over the Internet. The data file is eventually delivered to the private mailbox of the recipient, who retrieves and reads it using an e-mail program or MUA. The recipient may delete the message, store it, reply to it, or forward it to others. Modems are important devices that have allowed for the use of e-mail beyond local area networks. Modems convert a computer’s binary language into an analog signal and transmit the signal over ordinary telephone lines. Modems may be used to send e-mail messages to any destination in the world that has modems and computers able to receive messages. footer / 5futE / n. 页脚;脚注 plain text 纯文本(文件) append / E5pend / v. 附加 courier / 5kuriE / n. 信使 E-mail messages display technical information called headers and footers above and below the main message body. In part, headers and footers record the sender’s and recipient’s names and e-mail addresses, the times and dates of message transmission and receipt, and the subject of the message. In addition to the plain text contained in the body of regular e-mail messages, an increasing number of e-mail programs allow the user to send separate files attached to e-mail transmissions. This allows the user to append large text- or graphics-based files to e-mail messages. E-mail has had a great impact on the amount of information sent worldwide. It has become an important method of transmitting information previously relayed via regular mail, telephone, courier, fax, television, and radio. ———————————————— 1 MTA:报文传送代理(message transfer agent 的首字母缩略)。 228 Computer English Exercises I. Fill in the blanks with the information given in the text: 1. The address of an e-mail message includes the source and ________ of the message. 2. The suffixes com, org, edu, mil, and gov appearing in e-mail addresses stand for ________, organization, ________, military, and ________ respectively. 3. The body of a regular e-mail message contains ________ text. 4. In e-mail messages, ________ and ________ contain such information as the sender’s and recipient’s names and e-mail addresses, the times and dates of message transmission and receipt, and the subject of the message. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. plain text destination address mail-user agent message transfer agent graphics-based file 6. 7. 8. 9. 10. 模拟信号 域名 文本文件 文本编辑器 电子邮件地址 计算机英语 229 Section C Videoconferencing Thanks to the constantly evolving world of Internet communication, anybody with a reasonably sophisticated computer system can now videoconferencing experience videoconferencing—speaking, seeing, and sometimes writing / 7vidiEu5kCnfErEnsiN / n.(开)视频会议; to another person simultaneously. 视频会议技术 video camera 摄像机 1 As with other Internet communication software, the problems you may experience with videoconferencing involve the type of equipment you are using and the speed of your Internet connection. If you want to experience all the features of a product like CU-SeeMe1, you must have speakers, a microphone, and a video camera. Fortunately, there are several palm-sized CU-SeeMe:一种视频会议软件系统。注意,这里 CU 的发音同“See You”。在计算机英语中,一些软件或 技术在命名时喜欢用这种方式。例如,著名的网络寻呼软件 ICQ,发音同“I Seek You”。再比如,电子商 务中的 B2B,意思是“Business to Business”。 230 Computer English video cameras available through most1 any computer store, catalog, or Web site for under $100. You must also ensure that you have the correct drivers and any other related software configured properly on your computer in order for these peripherals to work. demo / 5demEu / n. <口> 演示; 示范(产品) (demonstration 及 demonstrator 的缩略) shareware / 5FeEweE / n. 共享软件 freeware / 5fri:weE / n. 免费软件, 自由软件 videoconference / 7vidiEu5kCnfErEns / n. & v.(开)电视 会议 netiquette / 5netiket / n. 网络礼节,网规 (network etiquette 的缩合) conferencing / 5kCnfErEnsiN / n. 开会;会议技术 sweatshirt / 5swetFE:t / n. 宽松无领长袖 运动衫 Additionally, remember that videoconferencing will work best if both parties are on the same kind and speed of Internet connection. Some of the demos, shareware, and freeware listed in this section will not work at all if you have less than a 28.8K 2 -capable modem, so if you plan to use videoconferencing on a regular basis, you should at the least have a 56K modem for adequate video performance. The first time you use videoconferencing, you may be surprised to realize how many people can see you if you simply jump into an existing conference. A typical videoconference is like a chat room, only the image of each person in the conversation is displayed in their window on your monitor. It is always a good idea to participate in a few of these general conferences to get an idea of how you will look and sound, and to see how other people behave. Good videoconferencing netiquette—particularly for business and other related nonpersonal conferencing—involves much more than the general good netiquette you’re expected to use with other kinds of Internet communication. Today’s average computer users are accustomed to knowing that no one else can see them or their office space when they are sending e-mail or participating in a text-only chat session. However, with videoconferencing, both you and much of the room or space around you will be visible to your video camera as well. If you want or need to seem professional to the person you’re calling, you may not want to videoconference in your old college sweatshirt without brushing your hair. Also, look around at your walls, your desk, and anyplace else around your computer that may be photographed by your video camera. Keep this area tidy and clutter-free, and consider moving any questionable decorations such as that Playboy3 calendar. REALISTIC EXPECTATIONS People have waited a long time for videoconferencing to emerge—it 1 2 3 most:在句中作副词,是美国英语口语用法,意为“几乎”、“差不多”,相当于 almost。 K:千比特(kilobyte 的缩略) 。 Playboy:《花花公子》,杂志名。 计算机英语 231 was, in fact, one of the primary plans for TV when it was first developed, and before the concept of broadcast TV took over. The phone companies have spent millions on fascinating studies of videoconferencing, resulting in some demonstration projects and some marketed products, but no videoconferencing system has ever taken off 1 like Internet videoconferencing. The images aren’t necessarily better and the convenience factors haven’t improved much over the best system available previously, but the costs now are substantially better: ● Transmission costs beyond the basic Internet connection are negligible now (versus high, metered, long-distance costs before). ● Video cameras suitable for videoconferencing have dropped in price from thousands of dollars to barely over $100. ● The computer, purchased and used for other purposes, easily takes the place of hundreds of dollars of dedicated electronics that formerly would have had to be purchased. meter / 5mi:tE / v. 用(仪)表计量 electronic / 7ilek5trCnik / n. 电子器件 Keep these advantages in mind when experimenting with current videoconferencing systems. They are interesting, and they work, but you will have to decide if they can adequately handle your personal or business needs. Motion interlaced a. 交织的,交错的; (电视扫描)隔行的 Normal TV images are made up of two interlaced images, each of which is displayed for approximately 1⁄60 of a second. The full motion picture is therefore made up of 30 full frames per second. jerky / 5dVE:ki / a. 忽动忽停的;抽 动的;不平稳的 akin / E5kin / a. 同类的;近似的 In online videoconferencing, images are rarely refreshed more than 20 times per second; in fact, it is not unusual for images to be updated only once or twice per second. Videoconferencing is therefore often at least a bit jerky in depicting motion, and sometimes more akin to a slide show than a movie. As usual, the faster the connection the more frequent the refreshes. / 7intE5leist / Resolution resize / ri:5saiz / v. 调整大小,重定 尺寸 1 Depending on the resolution setting of your computer monitor, your videoconferencing images will be about 2″ by 3″. While most systems let you resize the image, this doesn’t necessarily mean that you will be getting more image information; you will be seeing the same image enlarged. You may at times want to enlarge the image so that you can view it from a take off:开始;开始流行。 232 Computer English greater distance, but do understand that at the same viewing distance the larger image will just look coarser. Uses Online videoconferencing has been used primarily for social interaction. Businesses could benefit from videoconferencing, as long as expectations are realistic. The low resolution and image update frequencies will not allow people’s responses or expressions to be as visible as in a normal TV conference, and definitely not as good as in person. Still, in some cases where these other contacts are out of the question, the videoconference may provide some feel for the other person, and some increased sense of communication. For some purposes, you can use the videoconferencing systems to display things such as appearances of rooms, machines, landscapes, and movements of large and small living things. For many purposes, however, you may need the extra resolution of scanned images or digital still cameras. outlay / 5autlei / n. 费用,支出 Consider the possibilities for a video system that enables you to distribute images for almost no cost after the initial outlay. Monitoring systems, teaching, and scientific research are among thousands of possibilities. HARDWARE CONSIDERATIONS camcorder / kAm5kC:dE / n.(可携式)摄像机 video capture card 视频捕获卡 duplex / 5dju:pleks / a. 双工的 simplex / 5simpleks / a. 单工的 Cameras suitable for black-and-white videoconferencing are sometimes available for prices as low as $50, and color cameras are as low as $100. These cameras usually connect directly to your computer’s input/output ports. Because videoconferencing exchanges images of limited speed and resolution, there is little need to purchase a higher-quality camera. If you currently have a video camera or camcorder you might want to purchase a video capture card to provide your videoconferencing images. The video capture card can better make use of a high quality camera for other uses such as grabbing video images for Web page use. To have two-way conversations (like a telephone) instead of those that only allow one speaker at a time (like a CB radio), you will need a full duplex sound card. These are available in a variety of quality levels and are often not much more expensive than the simplex boards. VIDEOCONFERENCING SYSTEMS 计算机英语 233 The following is information about several videoconferencing systems. CU-SeeMe exceptionally / ik5sepFEnEli / ad. 例外地,格外, 特别 reflector / ri5flektE / n. 反射器;反射镜 plug-in / 5plQgin / a. 插入式的 n. 插件(程序) ;嵌 入组件 monochrome / 5mCnEkrEum / n. & a. 单色(的) lurker / 5lE:kE / n. 潜伏者,伏兵 lurk / lE:k / v. 潜伏;潜行 CU-SeeMe is a free videoconferencing system that is available for Windows 3.1, 95, and NT; Amiga; Mac OS; OS/2; and Linux operating systems. This large operating-system base and the fact that the system is free, easy to use, and has been available longer than most other videoconferencing systems would be enough to make it an exceptionally popular system. There is, however, another feature that adds to its popularity—the use of reflectors. Reflectors enable groups of people to videoconference together. Reflectors work by receiving the video packets from each video camera in the videoconference, and then sending the combined video signals out to all who are viewing the conference. CU-SeeMe can also be used for one-to-one videoconferencing without the use of a reflector site; signals are sent by direct connection (DC) between the two sites. (Private chat requires downloading separate plug-in software.) Most CU-SeeMe videoconferencing is done in monochrome, but an enhanced version is available that supports color conferencing. You can get a feel for videoconferencing by downloading the software and visiting reflector sites as a lurker—a conference viewer without a camera. Some reflector sites discourage lurking because it slows down the reflector, but others accept or encourage lurking. Keep watch for indications at the reflector site of their guidelines on this and other netiquette matters. iVisit1 www.ivisit.com/index.html Another excellent option for one-to-one or small group videoconferencing is iVisit’s software. It is available for free download for Macintosh, Windows 95, and Windows NT platforms. tax / tAks / v. 使负重担;使受 压力;耗费 1 Instead of using reflectors as CU-SeeMe does for groups, iVisit establishes direct connections between each member of the videoconference. This enables private conferences free of concerns about reflector guidelines and over usage. These direct connections, however, do tax the capacity of iVisit:iVisit 公司出品的视频会议软件系统。 234 Computer English your own modem and ISP connection, and the image quality as groups get larger. In addition to the monochrome and color video, iVisit supports simultaneous audio and text chats. Microsoft’s NetMeeting1 http://microsoft.com/netmeeting/ NetMeeting 2.1’s videoconferencing tools are designed to work with any camera or capture card that supports Video for Windows2 to transmit video images. (Viewing videoconferences doesn’t require extra hardware or software beyond NetMeeting itself.) The video component of NetMeeting provides real-time video images when using a 28.8 Kbps or faster modem. These images can be resized and the image quality can be adjusted for the preferred balance between video quality and system performance. RESOURCES interoperable / 7intEr5CpErEbl / a. 可互操作的,能 共同使用的 Because videoconferencing systems use various compression and transmitting standards, most systems are not interoperable with each other. For extra tools, information, and other resources it is usually best to look for sites provided by the software manufacturer or sites that specialize in the videoconferencing system you are interested in. CU-SeeMe cool site www.rocketcharged.com/cu-seeme/ This informal site is an excellent resource for those new to videoconferencing, and specifically to those interested in using the free CU-SeeMe system. The site contains links to software, files of frequently asked questions, and lists of reflectors (used for multiple-user videoconferences). home page 主页 CU-SeeMe home page http://cu-seeme.cornell.edu/ From the source of the CU-SeeMe project at Cornell University3, where CU-SeeMe originated in 1993, you can get information on hardware requirements and software downloads. 1 2 3 NetMeeting:微软集成在 Windows 里的一个实时语音、图像和视频交换程序。 Video for Windows:微软的 Windows 版本视频文件格式,后缀为.avi。 Cornell University: (美国)康奈尔大学,位于纽约州伊萨卡城。 235 计算机英语 Bill Woodland’s CU-SeeMe page http://cu-seeme.cornell.edu/~WCW Bill Woodland provides not only an excellent general resource for CU-SeeMe background information, but also access to one of the best reflector site lists. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. To use videoconferencing on a regular basis, you should at least have a(n) ________ modem for adequate video performance. 2. The resolution and image update frequency of online videoconferencing is usually ________. 3. In online videoconferencing, a full duplex ________ is needed to allow two-way conversations. 4. CU-SeeMe is a free videoconferencing system, in which ________ may be used to enable groups of people to videoconference together. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. full duplex sound card Web page video camera plug-in software 5. 6. 7. 8. 输入∕输出端口 主页 视频捕获卡 聊天室 236 Computer English 计算机英语 Part Four IT and Our Life 237 238 Computer English 第四部分 信息技术与我们的生活 第十二单元 IT 与计算机应用 第十三单元 电子商务 第十四单元 计算机安全 第十五单元 IT 精英如是说 ● 课文 A:信息革命 ● 课文 B:地理信息系统 ● 课文 C:代理技术 ● 课文 A:电子商务 ● 课文 B:电子商务的演变 ● 课文 C:为你的网上商务确立目标 ● 课文 A:计算机安全 ● 课文 B:计算机病毒 ● 课文 C:透过黑客的眼睛 ● 课文 A:比尔·盖茨文摘 ● 课文 B:IT 与中国国有企业改革 ● 课文 C:只有偏执狂才能生存 计算机英语 239 Unit 12: IT and Computer Application (IT 与计算机应用) Section A Information Revolution healer / 5h:lE / n. 信 仰 疗 法 术 士 (指用祈祷或魔术 等方式治病的人) cave painting (旧石器时代的) 洞穴壁画(艺术) accountancy / E5kauntEnsi / n. 会计学 underpin I. Introduction Information Revolution refers to the fundamental changes in the production and use of information, occurring in the late 20th century. Human societies throughout history have had “information specialists” (from traditional healers to newspaper editors); and they have had “information technologies” (from cave painting to accountancy); but two interrelated developments, social and technological, underpin the diagnosis that an information revolution is now occurring. / 7QndE5pin / v. 支持;巩固; 证实 II. Social and Technological Developments 240 Computer English First, there are social and organizational changes. Information-processing has become increasingly visible and important in economic, social, and political life. One familiar piece of evidence is the statistical growth of occupations specializing in information activities. Numerous studies have demonstrated substantial growth in information-based occupations. These occupations now take the largest share of employment in the United States, the United Kingdom, and many other industrial societies. The biggest category is information processors—mainly office workers—followed by information producers, distributors, and infrastructure workers. microelectronics / 5maikrEu i7lek5trCniks/ n. 微电子学 optical disc 光盘 fibre optics [复]光纤;[用作 单]纤维光学 textual / 5tekstjuEl / a. 文本的;正文的 Second, there is technological change. The new information technology (IT) based on microelectronics, together with other innovations such as optical discs and fibre optics, underpins huge increases in the power, and decreases in the costs, of all sorts of information-processing. (The term “information-processing” covers the generation, storage, transmission, manipulation, and display of information, including numerical, textual, audio, and video data.) The information-processing aspects of all work can be reshaped through IT, so the revolution is not limited to information occupations: for example, industrial robots change the nature of factory work. Computing and telecommunications (and also such areas as broadcasting and publishing) used to be quite distinct industries, involving distinct technologies. Now they have converged around certain key activities, such as use of the Internet. Using the same underlying technologies, modern computing and telecommunication devices handle data in digital form. Such data can be shared between, and processed by, many different devices and media, and used in a vast range of information-processing activities. markedly / 5mB:kidli / ad. 明显地,显著地 commonplace / 5kCmEnpleis / a. 普通的,平凡的 The pace of adoption of new IT has been very speedy: it is markedly more rapid than that of earlier revolutionary technologies, such as the steam engine or electric motor. Within 25 years of the invention of the microprocessor, it had become commonplace in practically every workplace and many homes: present not only in computers, but also in a huge variety of other devices, from telephones and television sets to washing machines and children’s toys. III. The Direction of the Information Revolution 计算机英语 commentator / 5kCmEnteitE / n. 时事评论员;评 论者 retrospect / 5retrEu spekt / n. 回顾,回想 241 The outcome of the information revolution is seen by some commentators as likely to be as profound as the shift from agricultural to industrial society. Others see the transformation as essentially a change from one form of industrial society to another, as has happened in earlier technological revolutions. One major issue is how rapidly social institutions adapt to take advantage of the new ways of doing things that new IT makes possible. While some jobs and some areas of people’s lives do seem to have changed rapidly, many others appear to have been affected relatively little. Historians point out that it can take a very long time for what in retrospect seems the obvious way to use a technology to become standard practice.1 For example, electric motors were first used as if they were steam engines, with one centralized motor powering numerous devices, rather than numerous small motors, each powering its own appliance. New IT has often been introduced into well-established patterns of working and living without radically altering them. For example, the traditional office, with secretaries working at keyboards and notes being written on paper and manually exchanged, has remained remarkably stable, even if personal computers have replaced typewriters. Often the technology that gains acceptance is that which most easily fits within traditional ways of doing things. For example, the fax machine, which could take hand-written or typed notes, and was often delegated to a secretary to use, was hugely successful in the 1980s. At the beginning of that decade, it had been predicted that fax would rapidly die out, and e-mail would take its place; but this proved to involve too much organizational change. IV. Trends in Employment afresh / E5freF / ad. 重新 1 The tendency to fit a new technology into established structures, rather than to start afresh every time, has often been documented. It is one reason for the absence of the huge office job losses that were being predicted in the late 1970s and early 1980s, when word processing first began to be taken up Historians point out that it can take a very long time for what in retrospect seems the obvious way to use a technology to become standard practice.:历史学家们指出,事后看起来觉得很明显的使用技术的方法,在 当时可能要花很长时间才能成为通行的做法。在这句话中,由 that 引导的从句系宾语从句,其基本结构为: it(形式主语)+take+time+for sb. (或 sth.) to do sth.(真正主语) 。for what in retrospect seems the obvious way to use a technology 对应 for sth.,而 to become a standard practice 则对应 to do sth.。句中的 in retrospect 系词组,意为“回想起来”、“事后看来”。 242 teleworking / 5teli7wE:kiN / n. 远程工作 outsource / aut5sC:s / v.(将…)外包 (指向外面的 供应商求购) delayering / 7di:5leiEriN / n. 减少层次 flattening / 5flAtEniN / n. 压缩,精简 shop floor (工厂工人的)工作 场所;[总称]工人 fieldworker Computer English on a large scale. However, this is no reason to assume that existing structures will endure. Industrial interest in new forms of organization, such as novel management structures, coordination of activities over large distances by means of telecommunications, teleworking, and other forms of distance working, indicates willingness to consider change. The “hollow firm” is one effort to gain flexibility. The company attempts to dispense with1 the direct ownership and operation of many facilities that would traditionally have belonged to it, instead outsourcing production, distribution, and other tasks to other firms. Many computer companies, for example, buy in many or most of their components from specialist suppliers, and some firms do little more than design the computer for others to assemble. A related idea is “delayering”, or “flattening”, in which the company tries to do away with the numerous layers of middle management and administration that have traditionally processed information, and communication flows between the senior staff and the shop floor or fieldworkers. New information systems are typically used to allow rapid communication across a reduced number of organizational layers. / 5fi:ld7wE:kE / n. 一线工作人员 clerical / 5klerikEl / a. 职员的;文书的 harbinger / 5ha:bindVE / n. 前兆,预示 By the late 1990s the integration of office IT is becoming apparent: material is increasingly exchanged by e-mail (which has finally established itself); many professionals use personal computers directly, often at home and while traveling, as well as in the office; and increasingly, personal computers are networked. Whether a loss of clerical jobs will result remains much debated. Some commentators point to job losses in office-based sectors such as financial services, which use IT intensively, as a harbinger of things to come. Others argue that the unemployment problems of industrial societies are related more to political and economic changes than to the use of new technology. Indeed, new information-related services are emerging, creating new jobs. While some office jobs may have gone, some other traditional clerical jobs have been upgraded to involve new functions made possible with new IT, such as desktop publishing, database management, and customer services. A similar debate has concerned the quality of working life—whether skills have been enhanced or reduced, and whether working conditions have been improved or degraded, in the information revolution. Evidence to date 1 dispense with:摒弃,省掉。 计算机英语 fast food n. 快餐 deskilling / 7di:5skiliN / n. 降低技术性 polarization / 7pEUlErai5zeiFEn / n. 两极化,分化 ensue / in5sju: / v. 接着发生;因而 产生 coincidental / kEu7insi5dentEl / a. 巧合的,碰巧的 243 indicates a mixed picture. There are certainly some areas in which conditions have worsened and skills have been lost, and many low-skill jobs have been created—for example, in cooking and serving fast food. Yet there is also a tendency for more jobs to be upgraded, and new technical skills and skill combinations are in demand. Large-scale deskilling has not taken place. Polarization of the workforce in terms of quality of work and levels of wages has ensued; at the same time a gulf has been opening between employed and unemployed people. Whether this is a result of the information revolution, or of more or less coincidental economic and political factors, the threat is evident of a widening social gulf between the “information-rich” and the “information-poor”. 1 The former have information-processing skills, access to advanced technologies in their work, and the money to invest in IT at home for themselves and their children; the latter do not. V. Information Technology and the Consumer diffuse / di5fju:z / v. 扩散;传播 telework / 5teliwE:k / n. & v. 远程工作 teleshopping / 5teli7FCpiN / n. 远程购物 helpline / 5helplain / n. 服务热线 rudimentary / 7ru:di5mentEri / a. 基本的,初步的; 早期的;未成熟的 At different rates IT is diffusing into the home. The implications of consumer innovations can be substantial. Widespread use of cars facilitated new ways of life, with a growth of suburban living and out-of-town shopping centres, and a decline of train and bus services. The expansion of consumer IT is associated with changes in ways of working (for example, telework), playing (new home entertainment systems), shopping (teleshopping), and learning (multimedia products of various sorts). IT can be used in monitoring body conditions (digital thermometers, pulse meters, and blood-pressure meters are available), and in providing health and lifestyle monitoring and advice (recommending exercise levels, medical check-ups, or diets). Telephone helplines have long offered advice, counselling, and medical services; these and many other services are beginning, sometimes in rudimentary form, to be provided on the Internet. VI. Problems of the Information Revolution Public transport was challenged by the shift to cars, and familiar 1 Whether this is a result of the information revolution, or of more or less coincidental economic and political factors, the threat is evident of a widening social gulf between the “information-rich” and the “information-poor”.:不管这是信息革命的结果,还是经济和政治因素的某种巧合所导致,都存在明显的 征兆,说明“信息富有者”与“信息贫穷者”之间存在着日益加大的社会差距。在这句话中,主句的主语 (the threat)与其定语(of a widening social gulf between the “information-rich” and the “information-poor”) 被谓语(系表结构)分隔开。这种分隔结构在英语中比较常见。 surveillance / sE:5veilEns / n. 监视;监督 alleged / E5ledVd / a. 被说成的;被断 244 Computer English aspects of such public services as education and health could be challenged in the information revolution. Wider concerns over changing relations between private and public activities are reflected in debates about potential or already emerging problems, such as: ● Threats to privacy (unauthorized access to personal data, increasing surveillance of public spaces by security cameras, etc.) ● The alleged growth of “privatism” (a decline in shared activities as individuals pursue their own interests in isolation) ● The scope for participation. (How far can people have a say in the use of IT in ways that affect them? Do new media support the emergence of new social movements, and of new forms of interest groups, lobbying, and mobilization?) ● Questions about the ownership of knowledge. (Who has the right to charge for what kinds of information? Should large parts of the media be controlled by a few large companies? What is the scope for freedom of information to be practised by governments?) All this is in addition to the problems of information inequalities mentioned earlier. The information revolution fundamentally involves a change in the role of information-processing in our society. It is not surprising that fundamental questions are being raised about access to, and the use of, intimate and valuable sorts of information. The outcome of the information revolution depends on social action and social choices as well as on technological developments. Just as industrial societies around the world take various forms, and there are very different ways of life within them, so it is likely that there will be a wide range of information societies. However, as new IT permits more global communication, and more firms expand into global markets, there are also strong forces at work to share elements of different cultures around the world on an unprecedented scale. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The information revolution discussed in the text refers to the 245 计算机英语 fundamental changes in the ________ and use of information, which are currently occurring. 2. According to the text, we can see that an information revolution is now occurring from two interrelated aspects: social and ________ developments. 3. Some commentators say the outcome of the information revolution is likely to be as profound as the shift from ________ to ________ society. 4. Information-based occupations now take the ________ share of employment in many industrial societies such as the United States and the United Kingdom. 5. The biggest category of information-based occupations is information ________. 6. ________ involves the generation, storage, transmission, manipulation, and display of information. 7. Delayering or ________ refers to the efforts to do away with the numerous layers of middle management and administration in a company that have traditionally processed information. 8. The author includes ________ inequalities in the problems of information revolution. He thinks there is a social gulf between the “information-rich” and the “information-poor”. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. electric motor desktop publishing information-related services information-based occupation information processor textual data numerical data audio data fibre optics digital thermometer 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 信息革命 技术革命 全球市场 信息技术 多媒体产品 信息专家 数据库管理 视频数据 信息处理系统 电话服务热线 246 Computer English III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: security issue technology legal challenge volume information banking binary development network international mobility digital integration available It is frequently claimed that the most potent (强有力的) agent of change on present-day society and the economy will prove to be information technology. The so-called ________ revolution whereby information—whether text, sound, or video—can be converted into, and from, ________ digits (bits) and transmitted over global ________ is believed to be likely to transform industries such as ________, telecommunications, and publishing. Advances in light-wave communications ________ based on optical fibres have vastly increased the ________ and speed of information transmission. The ________ of flat-panel displays (平板显示器) has allowed the computer ________ from the desk. Together these have contributed to the ________ of computer and communications technology which, for the user, transcends (超越) space and makes information ________ on demand. As well as rich opportunities, such a major social change presents severe ________. One is how to avoid the creation of a divided society of ________ “haves” and “have nots”. This is both a national and a(n) ________ problem. Others relate to ownership and ________ of information: cyberspace (网络空间) is a new frontier where existing ________ principles and practice are having to be rethought. Yet again, there are moral ________ to be faced about the kinds of information which should be openly available to users of the Internet. IV. Translate the following passage from English into Chinese: The pace of change brought about by new technologies has had a significant effect on the way people live, work, and play worldwide. New and emerging technologies challenge the traditional process of teaching and learning, and the way education is managed. Information technology, while an important area of study in its own right, is having a major impact across 计算机英语 247 all curriculum areas. Easy worldwide communication provides instant access to a vast array of data. Rapid communication, plus increased access to IT in the home, at work, and in educational establishments, could mean that learning becomes a truly lifelong activity—an activity in which the pace of technological change forces constant evaluation of the learning process itself. 248 Computer English Section B Geographic Information System I. What Is a GIS? A geographic information system (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on earth. GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. These abilities distinguish a GIS from other information systems and make it valuable to a wide range of public and private enterprises for explaining events, predicting outcomes, and planning strategies. Mapmaking and geographic analysis are not new, but a GIS performs these tasks better and faster than do the old manual methods. And, before GIS technology, only a few people had the skills necessary to use geographic information to help with decision making and problem solving. Today, GIS is a multibillion-dollar industry employing hundreds of 计算机英语 249 thousands of people worldwide. GIS is taught in schools, colleges, and universities throughout the world. Professionals in every field are increasingly aware of the advantages of thinking and working geographically. II. What Are the Components of a GIS? A working GIS integrates five key components: hardware, software, data, people, and methods. 1. Hardware stand-alone / 5stAndE7lEun / a. 独立的 Hardware is the computer on which a GIS operates. Today, GIS software runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations. 2. Software GIS software provides the functions and tools needed to store, analyze, and display geographic information. Key software components are: ● ● ● ● Tools for the input and manipulation of geographic information A database management system (DBMS) Tools that support geographic query, analysis, and visualization A graphical user interface (GUI) for easy access to tools 3. Data tabular / 5tAbjulE / a.(列成)表格的 in-house / 5in5haus / ad. 在机构内部 spatial / 5speiFEl / a. 空间的;与空间 有关的 Possibly the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or purchased from a commercial data provider. A GIS will integrate spatial data with other data resources and can even use a DBMS, used by most organizations to organize and maintain their data, to manage spatial data. 4. People GIS technology is of limited value without the people who manage the system and develop plans for applying it to real-world problems. GIS users range from technical specialists who design and maintain the system to those who use it to help them perform their everyday work. 5. Methods A successful GIS operates according to a well-designed plan and business rules, which are the models and operating practices unique to each 250 Computer English organization. III. How Does a GIS Work? thematic / Wi5mAtik / a. 主题的;专题的 invaluable / in5vAljuEbl / a. 非常宝贵的;无 法估价的 circulation / 7sE:kju5leiFEn / n. 循环;环流 latitude / 5lAtitju:d / n. 纬度 longitude / 5lCndVitju:d / n. 经度 grid / grid / n. 网格;坐标方格 postal code 邮政编码 geocoding / 7dVi:Eu5kEudiN / n. 地理编码 vector / 5vektE / n. 矢量,向量 raster / 5rAstE / n. 光栅 polygon / 5pCligEn / n. 多边形,多角形 linear / 5liniE / a. 线(性)的 polygonal / pE5ligEnEl / a. 多边(形)的, 多角(形)的 catchment / 5kAtFmEnt / n. 承 水 处 ; 流 域 closed loop 闭环 grid cell 网格单元 A GIS stores information about the world as a collection of thematic layers that can be linked together by geography. This simple but extremely powerful and versatile concept has proven invaluable for solving many real-world problems from tracking delivery vehicles, to recording details of planning applications, to modeling global atmospheric circulation. 1. Geographic References Geographic information contains either an explicit geographic reference, such as a latitude and longitude or national grid coordinate, or an implicit reference such as an address, postal code, or road name. An automated process called geocoding is used to create explicit geographic references (multiple locations) from implicit references (descriptions such as addresses). These geographic references allow you to locate features and events on the earth’s surface for analysis. 2. Vector and Raster Models Geographic information systems work with two fundamentally different types of geographic models—the “vector” model and the “raster” model. In the vector model, information about points, lines, and polygons is encoded and stored as a collection of x,y coordinates. The location of a point feature, such as a bore hole, can be described by a single x,y coordinate. Linear features, such as roads and rivers, can be stored as a collection of point coordinates. Polygonal features, such as sales territories and river catchments, can be stored as a closed loop of coordinates. The vector model is extremely useful for describing discrete features, but less useful for describing continuously varying features such as soil type. The raster model has evolved to model such continuous features. A raster image comprises a collection of grid cells rather like a scanned map or picture. Both the vector and raster models for storing geographic data have unique advantages and disadvantages. Modern GISs are able to handle both models. IV. What Can a GIS Do for You? 1. Performing Geographic Queries and Analysis The ability of GISs to search databases and perform geographic 计算机英语 251 queries has saved many companies literally millions of dollars. GISs have helped reduce costs by: streamline / 5stri:mlain / v. 使成流线型;使 效率更高 logistics / lEu5dVistiks / n. 后勤(学) realtor / 5riEltE / n. 房地产经纪人 tiled / taild / a. 用瓦覆盖的 criterion / krai5tiEriEn / ([复] -ria / -riE / 或 -rions)n. 标准, 准则 ● ● ● ● Streamlining customer service Reducing land acquisition costs through better analysis Reducing fleet maintenance costs through better logistics Analyzing data quickly An example of the last point is: a realtor could use a GIS to find all houses within a certain area that have tiled roofs and five bedrooms, and then list their characteristics. The query could be further refined by adding criteria—the house must cost less than $100 per square foot. You could also list houses within a certain distance of a school. 2. Improving Organizational Integration Many organizations that have implemented a GIS have found that one of its main benefits is improved management of their own organization and resources. Because GISs have the ability to link data sets together by geography, they facilitate interdepartmental information sharing and communication. By creating a shared database, one department can benefit from the work of another—data can be collected once and used many times. 3. Making Better Decisions adage / 5AdidV / n. 谚语;格言 pylon / 5pailEn / n.(飞机场)标塔; (架高压输电线 的)电缆塔 intrusion / in5tru:VEn / n. 侵入;打扰 succinctly / sEk5siNktli / ad. 简明地,简练地 The old adage “better information leads to better decisions” is as true for a GIS as it is for other information systems. A GIS, however, is not an automated decision making system but a tool to query, analyze, and map data in support of the decision making process. GIS technology has been used to assist in tasks such as presenting information at planning inquiries, helping resolve territorial disputes, and siting pylons in such a way as to minimize visual intrusion. A GIS can be used to help reach a decision about the location of a new housing development that has minimal environmental impact, is located in a low-risk area, and is close to a population center. The information can be presented succinctly and clearly in the form of a map and accompanying report, allowing decision makers to focus on the real issues rather than try to understand the data. Because GIS products can be produced quickly, multiple scenarios can be evaluated efficiently and effectively. 4. Making Maps 252 cartography / kB:5tCgrEfi / n. 地图绘制 digitize / 5didVitaiz / v. 使数字化 cartographic / 7kB:tE5grAfik / a. 地图绘制的 atlas / 5AtlEs / n. 地图集 topographic / 7tCpE5grAfik / a. 地形(学)的 Computer English Maps have a special place in GIS (see Figure 12B-1). The process of making maps with GIS is much more flexible than are traditional manual or automated cartography approaches. It begins with database creation. Existing paper maps can be digitized and computer-compatible information can be translated into the GIS. The GIS-based cartographic database can be both continuous and scale free. Map products can then be created centered on any location, at any scale, and showing selected information symbolized effectively to highlight specific characteristics. The characteristics of atlases and map series can be encoded in computer programs and compared with the database at final production time. Digital products for use in other GISs can also be derived by simply copying data from the database. In a large organization, topographic databases can be used as reference frameworks by other departments. Figure 12B-1: A GIS map informed / in5fC:md / a. 了解情况的;有 情报(或资料)根 据的 high-tech / 5hai5tek / a. 高技术的 1 V. Summary In today’s global community, the more information you have at your fingertips 1 , the easier it is to make an informed decision. In today’s high-tech world, information comes in many different ways, from company reports and statistics from down the hall to digital photos and multimedia at one’s fingertips:近在手边;随时可供应用。 253 计算机英语 overwhelming / 7EuvE5hwelmiN / a. 势不可挡的;巨 大的 timely / 5taimli / a. 及时的;适时的 up-to-the-minute / 5QptETE5minit / a. 直到最近的,最 新的 from across the world. Information can be overwhelming and the need for timely decisions calls not only for innovative ways to access accurate, up-to-the-minute information, but also tools to help present the information in useful ways. A geographic information system or GIS allows you to bring all types of data together based on the geographic and locational component of the data. But unlike a static paper map, GIS can display many layers of information that is useful to you. GIS will give you the power to create maps, integrate information, visualize scenarios, solve complicated problems, present powerful ideas, and develop effective solutions like never before. Relationships between the data will become more apparent and your data will become more valuable. GIS is a tool used by individuals, schools, governments, and businesses seeking innovative ways to solve their problems. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. A working GIS contains five key components. They are ________, software, ________, people, and methods. 2. A GIS stores information about the world as a collection of thematic ________ that can be linked together by geography. 3. ________ is an automated process used to create explicit geographic references from implicit references. 4. GISs work with two fundamentally different types of geographic models. They are the ________ model and the ________ model. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. tabular data raster image vector model statistical analysis system 6. 7. 8. 9. 基于计算机的工具 地理信息系统 数据库操作 网格单元 254 Computer English 5. model atmospheric circulation 10. 闭环 计算机英语 255 Section C Agent Technology I. Introduction metaphor / 5metEfE / n. 隐喻;比喻 situated / 5sitjueitid / a. 位于…的,坐落 在…的 proactive / prEu5Aktiv / a. 抢先的,主动的 benevolence / bi5nevElEns / n. 善意,仁慈 intuition / 7intju:5iFEn / n. 直觉 What is an agent? In essence, an agent is a software system which can act on behalf of a human or another system. Agent is a convenient metaphor for describing software systems which we would all like to have—the “intelligent software servant” that is easy to instruct. In research, a more rigorous definition which is often used is: an agent is a software system, situated in some environment, which is capable of behaviour that is proactive, autonomous, communicative, persistent, and timely. Some agents might have additional attributes such as mobility, benevolence, and learning ability. Stronger notions of agency employ concepts such as knowledge, belief, goals and intentions, and provide a logic for reasoning with these concepts. These properties are useful and reflect human intelligence but they are hard to fully realize in a software system. Not all agents have (or need) all these properties, and some agents have these properties in varying degrees. We rely on intuition to perceive and judge the degree of these properties in a software system, since the properties are 256 quantify / 5kwCntifai / v. 确定…的数量, 用数量表示,测量 sociology / 7sEusi5ClEdVi / n. 社会学 artificial life 人工生命 game theory 博弈论,对策论 Computer English generally difficult to quantify or measure. Nevertheless, numerous theories for understanding and modelling properties of agent systems and tools for building agents are being developed in over fifty research laboratories world-wide. The Agent Society (www.agent.org) and AgentLink (www.agentlink.org) are two international organizations formed for the purposes of coordinating agent research and development. Agent research crosses disciplines and has been influenced by areas such as artificial intelligence, distributed computing, software engineering, sociology, economics, object-oriented systems, artificial life, and game theory. In fact, a strength of agent technology is that it combines such areas to build systems more sophisticated than that possible using one technology alone. This strength and the appeal of the agent abstraction accounts in part for the diversity of software solutions possible with the concept of agents. II. Applications sampling / 5sB:mpliN / n. 取样,抽样 impetus / 5impitEs/ n. 推动,促进;推 动力 synthesize / 5sinWisaiz / v. 综合 gargantuan / gB:5gAntjuEn / a. 巨大的,庞大的 hinder / 5hindE / v. 阻碍,妨碍 generalize / 5dVenErElaiz / v. 概 括 , 归 纳 prioritize / prai5Rritaiz / v. 按 优 先 顺 序 列 出;确定…的优先 次序 archive / 5B:kaiv / v. 把…存档 We look at a sampling of agent application areas. ■ The Internet and the World Wide Web The Web provides an impetus for agent research. Information agents naturally fit the role of software assistants which help people find, reason with, synthesize, and manage desired knowledge from the gargantuan Web. While Web documents have some structure, much of the information is still in free text, hindering full understanding of text by agents. However, useful agents for gathering, filtering, sharing, and monitoring Web resources and guiding Web surfers have been built using limited natural language processing and complex keyword-based text searching. Such agent products have been deployed and are being marketed. XML 1 , which generalizes HTML to admit domain-specific tags, provides a standard way of imposing more structure on information. However, the use of XML is still limited compared to HTML. Email filtering and responding is another application where agents prioritize, delete, forward or archive messages for users. Useful tools have been built and marketed without full natural language understanding. ■ Electronic Commerce 1 XML:扩展标记语言(eXtensible Markup Language 的缩略)。 计算机英语 storefront / 5stC:frQnt / n. 店面,铺面 broker / 5brEukE / v. 作为代理行事 nontrivial / nCn5triviEl / n. 重大的,重要的 unambiguously / 7QnAm5bigjuEsli / ad. 不含糊地, 明确地 257 Electronic commerce is an area of growing importance spurred by the popularity of the Internet and the Web. While the Web enables a company to be online twenty-four hours a day and be contactable by the masses, it also provides an electronic storefront with which agents can interact. Intensive agent research is underway to automate product advertising and brokering, merchant brokering, negotiation, purchase and delivery, and customer services. Full and effective automation of electronic commerce is nontrivial and requires not only technological designs but also standards for unambiguously defining commerce-related information such as goods and services, customer and business profiles, and electronic forms. ■ Manufacturing Manufacturing control and factory automation is an area of active research. Agent systems are being developed for designing products, controlling manufacturing robots, and managing factory production processes. ■ And More… informatics / 7infE5mAtiks / n. 信息(科)学 data mining 数据挖掘, 数据采集 roam / rEum / v. 漫游 personal digital assistant 个人数字助理 Other areas of agent research and development include business process management (agent-based systems for streamlining business processes have been developed), telecommunications (e.g. automating network management and efficient service provisioning), medical informatics (e.g. automating decision making in patient monitoring and multi-agent based distributed health care system), entertainment, air traffic control, pilot training, and distributed data mining. III. Mobile Computing—Software and Hardware The increasingly distributed and mobile workforce and enterprise is fueling research into mobile agent systems. The attraction is the ability to send agents to remote hosts, disconnect from these hosts, and reconnect to retrieve answers. For agents to roam the Internet, the capability of “write once, run anywhere” is imperative. Sun’s Java language which has captured the world’s attention via Web applets has provision for platform independent execution, and so, has been used for more than a dozen mobile agent toolkits. With Java being introduced in “soft” embedded devices such as cellular phones, personal digital assistants and handheld terminals, agents might (if need to) roam mobile environments. However, mobile agent research has so far largely been confined to 258 off-the-shelf / 5CfTE5Felf / a. 现成的,非专门 设计(或定制)的 robust / rEu5bQst / a. 强壮的,强健的 Computer English research proposals and prototypes. There is hardly any commercial off-the-shelf mobile agent-based application. Further research in building robust mobile agent applications is still required. Issues such as security and robustness are being tackled—mobile agents might become commonplace in the next decade. IV. Standardization For agents to cooperate, flexible and standard means of agent communication is required. Development and standardization of agent communication languages is being carried out. life cycle 生存周期, 寿命周期 FIPA1 (Foundation for Intelligent Physical Agents) (www.fipa.org), a standards organization in the agent area, has more than forty participants including British Telecom 2 , Hitachi 3 , NEC, Siemens 4 , IBM, and Sun Microsystems. FIPA aims to make available specifications that facilitate inter-operability between agent systems. Specifications for agent management (e.g. directory services, and life cycle) and agent communication have been proposed. The Object Management Group® (OMGTM) (www.omg.org) is also working on standards to allow mobile agent systems to inter-operate. V. Conclusion methodology / 7meWE5dClEdVi / n.(学科的)一套方 法;方法论 Agent technology is a thriving area of research, and it is also an emerging industry. As toolkits and methodologies for developing agent systems emerge, applications where agents will be a key abstraction will increase. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. An agent is essentially a(n) ________ system which can act on behalf of a human or another system. 2. Useful agents for handling Web resources and guiding Web surfers have been built using limited natural language processing and 1 2 3 4 FIPA:智能物理代理基金会(Foundation for Intelligent Physical Agents 的首字母缩略)。 British Telecom:英国电信公司。 Hitachi:(日本)日立公司。 Siemens:(德国)西门子公司。 259 计算机英语 complex ________ text searching. 3. Agent research crosses disciplines and has been influenced by artificial ________, distributed ________, software engineering, and many other areas. 4. Work is now being done to establish standards to facilitate ________ between agent systems. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. domain-specific tag handheld terminal life cycle mobile agent toolkit 5. 6. 7. 8. 扩展标记语言 数据挖掘 博弈论 基于关键字的搜索 260 Computer English Unit 13: Electronic Commerce (电子商务) Section A Electronic Commerce DEFINITION spawn / spC:n / v. 大量产生 Electronic commerce may be defined as the entire set of processes that support commercial activities on a network and involve information analysis. These activities spawn product information and display events, services, providers, consumers, advertisers, support for transactions, brokering systems for a variety of services and actions (e.g., finding certain products, finding cheaply priced products, etc.), security of transactions, user authentication, etc. It involves “the enablement of a business vision supported by advanced information technology to improve efficiency and effectiveness within the trading process”. Although the term itself has gained attention only in recent years, electronic commerce has been around in various forms for over 20 years. 计算机英语 teller / 5telE / n.(银行)出纳员 purveyor / pE5veiE / n. 供应商,提供者 261 Electronic Data Interchange (EDI1) and Electronic Funds Transfer (EFT2) technologies were first introduced in the late 1970s. The growth and acceptance of credit cards, Automated Teller Machines3, and telephone banking in the 1980s are also forms of EC4. While many of these electronic trading technologies have had radical effects within their own markets and created their fair share of publicity, none have attracted the level of hype or have been hailed as purveyors of economic transformation to the extent that electronic commerce has in recent years. REQUIREMENTS AND SERVICES monetary / 5mQnitEri / a. 货币的,金融的 corruption / kE5rQpFEn / n. 毁损,毁坏, 破坏 theft / Weft / n. 偷窃 In order to effectively use electronic commerce, users of such systems require various types of wide-ranging functionalities that include the ability to search for and access relevant information efficiently, make monetary transactions for purchasing and selling products and services, and secure business transactions against intentional and unintentional corruption and theft of data. 1. Acquiring and Storing Information To build a global electronic marketplace, first we need to deal with the problem of digitizing currently available information such as catalogs, books, films, maps, and audio at a variety of quality levels. Data may also already exist in digital form but in a legacy format that must be transformed to be useful. In addition to the technical aspect of this problem, there is also the economic aspect—the costs of digitizing or converting the information. Second, as new information is made available by information providers (individuals, small businesses, large corporations) we need to have mechanisms to capture and store this information. An EC storage system must be capable of storing a large amount of data in a variety of formats and must provide efficient and effective access to this data. 2. Search and Discovery Services Online information search capabilities are important to provide users access to important data such as information about products, services, customers, suppliers, and government agencies. Information search and 1 2 3 4 EDI:电子数据交换(Electronic Data Interchange 的首字母缩略)。 EFT:电子资金传送(系统),电子资金转账(Electronic Funds Transfer 的首字母缩略)。 Automated Teller Machine:自动柜员机,取款机。首字母多小写,常缩略为 ATM。亦作 automatic teller machine。 EC:电子商务(electronic commerce 的首字母缩略)。 262 Computer English discovery services include electronic catalogs (e-catalogs) and directories, information filters, search engines, and software agents. Electronic catalogs organize information based on content and allow users to browse through and select the relevant documents. Such methods, while simple to implement, assume certain organization schemes that may not match the requirement of every user. Furthermore, for systems that require frequent updates, such methods may not be efficient because of the frequency of reorganization required. Information filters are available for users to retrieve the relevant documents to their queries. These filters could be located at the workstation of the end users or at remote sites. Retrieving information from remote sites increases network traffic, and hence it is more efficient to gather metadata rather than to download the data itself. Multimedia information poses additional problems in determining information content and hence in filtering such data. Software agents such as robots, wanderers, and spiders can traverse and locate relevant information. Such programs are based on limited-depth, depth-first algorithms that traverse using hypertext links through HTML documents in the Web in order to locate and retrieve relevant documents. Several open issues persist with the existing discovery and search services. These include the ability to handle new types of data such as multimedia data including video, sound, and 3D1 images; developing more efficient content-based indexing methods; and using parallel processing to conduct multiple searches through the document space. 3. Electronic Payments smart card 智能卡,灵巧卡 accounting / E5kauntiN / n. 会计(制度) ;结 账;结算 settlement / 5setlmEnt / n. 结算;清偿 billing / 5biliN / n. 开(帐)单; 记账 1 EC systems require methods to pay for the delivery of data, products, and services. Electronic payments include digital currencies (smart cards and electronic money), credit card payments, and electronic checks. Smart cards have been developed and are in use for various types of business services—to provide access to financial accounts, to maintain purchase records, and to store personalized information such as shopping preferences and other data. There are two types of smart cards: relationship-based smart cards that allow financial transactions but require accounting settlements at the end of each billing cycle, and electronic 3D:三维的(three-dimensional 的简写形式)。 计算机英语 debit / 5debit / n. 借方;借入 debit card 借方卡 deduct / di5dQkt / v. 扣除,减去 token / 5tEukEn / n. 代币;筹码; 凭证 emulate / 5emjuleit / v. 仿效;仿真 intermittent / 7intE5mitEnt / a. 间歇的 certified check 保付支票, 保兑支票 tamper / 5tAmpE / v. & n. 篡改 fraudulent / 5frC:djulEnt / a. 欺骗性的 encrypt / in5kript / v. 把…加密 expiration / 7ekspi5reiFEn / n. 满期;截止 nonrefutability / 5nCn7refjutE5bilEti / n. 不可批驳性;不 可辩驳性 clear / kliE / v. 结清;结账 micropayment / 7maikrEu5peimEnt / n. 网 络 微 型 支 付 款, (在因特网上付 出的)极少量款项 cost model 成本模型 wholesale / 5hEulseil / n. & a. 批发(的) 263 purses and debit cards that store sums of money and can be used for a variety of services. After each purchase, the value is deducted from the electronic purse, and hence no accounting settlement is necessary. Electronic money (also referred to as digital cash or electronic token) is an electronic payment method that emulates the real-life exchange of goods and services for their equivalent currencies. Thus, electronic tokens could be stored in users’ computers and transmitted through fixed or intermittent network connections. E-money should be bank-certified for their monetary value in order to avoid the risk of insufficient funds. In addition, these should be exchangeable with other forms of payments (such as paper cash and certified checks), must be tamper resistant in order to avoid fraudulent payments, and should be accessible from remote locations. As an alternative to storing electronic tokens in the users’ machines, third-party payment services can process payment transactions. Credit card purchases involve the transmission of encrypted data through computer networks. This includes entering credit card information (card number and expiration date) into the system, having it encrypted by the system, and sending the information over the network. The problem with this type of system is their nonrefutability, which requires the physical presence of the credit card owner for authentication of the signature. Other problems associated with such payment methods are privacy, speed of transactions, and safety. Electronic checks (e-checks) are another mechanism for payments over computer networks. These systems are intended to emulate conventional paper-check processing systems. In this method, a third-party account server acts as a billing service for users. E-checks require digital signatures and authentication services to digitally process information between the payer, payee, and bank. E-checks are suitable for clearing micropayments and are much faster and more efficient than conventional check payment systems. Society has grown accustomed to a wide variety of cost models and financial instruments. EC, however, presents new challenges that are not adequately addressed by these models and instruments. For example, online services presently follow fixed-cost models that are insensitive to changes in data contents and wholesale costs. 4. Security Services 264 sabotage / 5sAbEtB:V / n.(阴谋)破坏 confidentiality / 5kCnfi7denFi5AlEti / n. 机密性 non-repudiation / 5nCnri7pju:di5eiFEn / n. 不拒绝;不否认; 不可抵赖 cryptographic / 7kriptE5grAfik / a. 使用密码的;密 码学的 ciphertext / 5saifEtekst / n.(加)密文(本) decryption / di:5kripFEn / n. 解密,脱密 symmetric / si5metrik / a. 对称的 cryptosystem / 5kriptEu7sistEm / n. 密码系统 message authentication code 信息鉴定码 hash / hAF / n. 散列;无用信息 hash function 散列函数 multiplicity / 7mQlti5plisEti / n. 多样性, 多种多样 predicate / 5predikeit / v. 使基于;使取决 于(on, upon) contend / kEn5tend / v. 争斗;竞争 1 2 Computer English Systems for electronic commerce have to be secured against a number of threats such as fraudulent activities by internal or external sources, theft of valuable information, and sabotage. Hence such systems need to be guarded by some specially designed security system to provide security services such as authentication of data and of the entities accessing the system, unauthorized access control, confidentiality, data integrity, and non-repudiation. Security systems typically consist of a cryptographic system that performs the encryption of plain text data into ciphertext and decryption of ciphertext back into plain text data. Cryptographic systems can be divided into two categories: a symmetric key cryptosystem where the key information is shared and kept secret between the sender and receiver, and a public key cryptosystem where the sender and the receiver do not share the same key (one can be made public while the other is kept secret). Both symmetric key and public key cryptosystems provide security services such as confidentiality, authentication of data source, and integrity. These are achieved through a variety of techniques, namely, message authentication codes and hash functions in symmetric key cryptosystems and the use of public and private keys in public key cryptosystems. Cryptographic systems of today face various challenges, for example, acceptance of such systems by user groups, distribution and management of keys, and the ease of use of effective encryption and decryption mechanisms. 5. Connectivity In an EC environment today, there is a multiplicity of clients. Users may use TV sets, radios, PCs, PDAs1, laptops, and cellular phones for accessing information. The goal of the National Information Infrastructure (NII 2 ) project is to allow universal access to distributed stores of information (digital libraries) and to provide this access at a reasonable cost to every citizen. Widespread use of EC is predicated on, among others, the universal availability of access for a large number of users. EC systems will have to contend with many different information appliances. In such a heterogeneous world of objects, user interfaces, networks, clients, and servers, the issue of interoperability assumes great importance. PDA:个人数字助理(personal digital assistant 的首字母缩略)。 NII:国家信息基础设施(National Information Infrastructure 的首字母缩略)。 计算机英语 cyberspace / 5saibEspeis / n. 电脑空间,虚拟 空间 vigor / 5vigE / n. 活力;精力 civil liberty [常作复]公民自由 ramification / 7rAmifi5keiFEn / n. 衍生结果;后果 obscenity / Eb5senEti / n. 淫秽 cryptography / krip5tCgrEfi / n. 密码学;密码的 使用 contractual / kEn5trAktFuEl / a. 合同(性)的 265 6. Legal and Policy Requirements The legal issues involved in electronic commerce relate to the trouble the Internet itself has in dealing with law in cyberspace. Legal disputes that have been debated for centuries have begun to surface in cyberspace with renewed vigor. Fundamental civil liberties issues demand new attention in a new environment, and the ramifications of past decisions are not the same in a globally networked environment. While governments and individuals struggle to address freedom of speech, obscenity, and privacy issues on the Internet, the legal issues for electronic commerce are numerous as well. Intellectual property, taxation, law enforcement, ubiquitous cryptography, and contractual issues are all unsettled in the growing EC industry. Furthermore, the debate over government involvement in the regulation of electronic business, itself, is still at an immature stage. The issues that require resolution are becoming clear for EC. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Electronic commerce may be defined as the entire set of processes that support ________ activities on a(n) ________ and involve information analysis. 2. In electronic commerce, information search and discovery services include electronic ________ and directories, information filters, search ________, and software agents. 3. Electronic payments include digital ________, credit card payments, and electronic ________. 4. Smart cards can be divided into two types: one is ________ smart cards, and the other is electronic ________ and debit cards. 5. E-checks require digital ________ and authentication services to digitally process information between the payer, payee, and bank. 6. Electronic money is also called digital ________ or electronic ________. 7. Cryptographic systems fall into two classes. They are symmetric 266 Computer English key cryptosystems and ________ key cryptosystems. 8. In ________ key cryptosystems, the key information is shared and kept secret between the sender and receiver. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. user authentication electronic purse information filter data integrity smart card HTML symmetric key cryptosystem message authentication code unauthorized access control electronic catalog 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 电子货币 搜索引擎 数字签名 用户界面 电子资金转帐 公钥密码系统 个人数字助理 超文本链接 三维图像 信用卡 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: option product cost transaction customer retailer credit technology payment practice secure e-commerce online electronic storefront standard The term electronic commerce encompasses the entire process of buying, selling, and advertising products and services using electronic communications media. But when people talk about ________ today, they’re usually referring to the emerging marketplace on the Internet. ________ of all kinds are now scrambling (争夺) to establish themselves and reach ________ in this new marketplace. The major obstacle to e-commerce is the problem of how to pay for ________ and services online. How can electronic ________ be made convenient, reliable, and ________ for consumers and retailers alike? As with every other Internet ________, a global standard for online ________ must emerge before e-commerce becomes a widely accepted ________. 计算机英语 267 The drive to establish a standard for ________ money is well underway. Software developers, banks, and ________ card companies are all pushing transaction systems to ________ merchants, each betting that their system will become the ________ way to pay for things online. As a Web ________ owner, you must investigate all the ________ and offer as many choices to your customers as they demand, while keeping ________ and complexities from getting out of hand. IV. Translate the following passage from English into Chinese: Your business’s Web site is a passive form of marketing. In order to get people to visit it, you have to promote your Web site aggressively. And if you want to ensure that people return, you’ll have to offer valuable services or content. Marketing practices on the Internet may differ dramatically from marketing methods that you are accustomed to using. Online marketing focuses more on generating publicity and creating a reputation for your Web site rather than on generating sales. Your marketing efforts must be creative, interesting, and constantly changing in order to make your site stand out. And you must obey long-standing rules if you want to avoid boycotts (联合 抵制) or offending potential customers. Web site promotion efforts should be ongoing. Don’t think that just because you registered your site on all the search engines, you’re done. Constantly be on the lookout for new, creative ways to promote your site, and keep up with emerging trends. 268 Computer English Section B The Evolution of e-Business scramble / 5skrAmbl / v. 争夺,抢夺 imperative / im5perEtiv / n. 必要的事 competitor / kEm5petitE / n. 竞争者;对手 payoff / 5peiCf / n. 报偿;报应 From the smallest company to the largest enterprise, the Internet has forced virtually every business to reconsider the way it operates. In every sector, companies are scrambling to establish services on the Web. Now a new imperative has emerged: Drive toward a business model that provides tailored services for customers or risk losing business to competitors who will. The payoff for businesses that make the transition will be huge. At Intel, a new Web e-Business service brought in over $1 billion in orders in its first month. The secure, Web-based product ordering and tracking system has lowered transaction costs and sped delivery for business partners worldwide. Perhaps most important, it delivers customized information to each customer. Intel did more than just bolt a Web front-end onto its existing order-taking systems.1 Sales, marketing and IT staffs worked together to craft an electronic business solution that automates the order process and 1 Intel did more than just bolt a Web front-end onto its existing order-taking systems.:Intel 所做的不止是将 Web 前端栓定到其现存的订货系统上。 269 计算机英语 craft / krB:ft / v. 精心制作;周密 制订 strengthens business relationships. It won’t be long before many of your customers will demand this kind of service. Take the Stage centric / 5sentrik / a. 中心的 prosper / 5prCspE / v. 兴旺;成功 perish / 5periF / v. 丧生;毁灭 foresight / 5fC:sait / n. 预见;深谋远虑 overview / 5EuvEvju: / n. 概述;概观 aggregate / 5Agrigeit / v.(使)聚集 For IT professionals, the transition from a traditional vendor-centric model to one focused on the customer will prove a crucial test. Companies will prosper or perish based on their ability to deploy and support customer-oriented e-Business systems that make their business partners more competitive. IT managers will play a driving role in this effort, as business management turns to IT for the tools, knowledge and foresight needed to transform and extend business processes for the Internet Age. As a leader in Internet and business technologies, Intel sees the evolution of e-Business following a four-stage progression. Most important, businesses today face the crucial transition from a vendor-centric model to the emerging customer-centric business model. The table below provides a quick overview of the four stages of e-Business: Table 13B-1: The four stages of e-Business Stage Description Approach Time Stage 1 Establishing Web Presence Vendor-centric Widely deployed Stage 2 Conducting E-Commerce Vendor-centric Underway, widely deployed Stage 3 Data Usage Customer-centric Deploying Stage 4 Automation Customer-centric Emerging How will this transition help your customers? Imagine being able to see an aggregated view of all the partners you do business with, rather than viewing one partner’s Web site at a time. Data will be delivered in binary formats—rather than rigid HTML text—eliminating the need to copy and paste text into systems. Ultimately, customer applications will interact with your business systems. Your customers will receive personalized data, relying on your systems to make them more competitive. The table below shows some key changes that occur in a customer-centric environment: 270 Computer English Table 13B-2: Evolving from vendor-centric to customer-centric e-Business brochure / 5brEuFE / n. 小册子;情况介 绍手册 value chain 价值链 Vendor-centric (Stages 1 & 2) Customer-centric (Stages 3 & 4) ● Surfing the Web ● Tight inter-business linkages suppliers and customers ● Brochures and storefronts ● Automated business processes ● Exclusively synchronous, human-driven (Customers come to look for information when they want it) ● Synchronous and asynchronous, rule-driven (Binary data is shipped to customers) ● Vendor-centric value chain ● Customer-centric value chain ● Multiple processes enterprise cull / kQl / v. 挑出;挑选 warehousing / 5weE7hauziN / n. 存库,仓贮 within an and with inter-business ● Multiple enterprises within a single process This customer-centric environment expands the horizons of Web commerce. A customer checking on product deliveries might cull data from your production and warehousing facilities, your shippers’ tracking systems, and its own receiving department—all using a single interface. What’s more, this information can be delivered in real-time, providing always-on decision support. The IT Angle telematics / 7teli5mAtiks / n. 远程通信及信息 处理技术 scrap / skrAp / v. 废弃;抛弃 1 “Essentially, every business needs to become an information services company,” says Mike Ledford, Chief Technical Officer-Telematics for Ford Motor Company1. “You need to do more than just answer the phones, make the sales, and ship the products. You have to give your customers what they want, when they want it, and how they want it—even if that means integrating your processes with other businesses. If you don’t, somebody else will.” To form links with business partners over the Internet, companies may have to scrap existing business processes and create new ones. It will also require changes to the computing infrastructure. Among the key issues for IT managers to consider: acumen / E5kju:men / n. 敏锐;聪明 Ford Motor Company:福特汽车公司。 middleware / 5midlweE / n. 中间件 back-end / 5bAk5end / a. & n. 后端(的) stability / stE5bilEti / 271 计算机英语 • Develop robust support systems and in-house technical acumen to meet customer requests for enhanced information delivery. • Deploy middleware software and servers to support advanced services while maintaining back-end stability. • Plan the infrastructure to scale to demand, particularly as new services emerge and the number of active connections grow. • Ensure ample performance headroom to allow flexibility and scalability at the client and server. IT and business management must work together closely to tailor processes and deliver solutions, says Joyce M. Wrenn, Vice President Information Technologies and CIO1 for Union Pacific Railroad Company2. “There are a lot of opportunities out there, but company senior management and IT departments need to start planning now. You can’t deploy advanced e-Business services without shaking up3 your business and information infrastructure. It’s hard work, but the payoff will be well worth it.” What Intel Is Doing Intel is working hard to enable this vision of the future, by actively fostering the development of customer-centric solutions. Among the key activities: • Active engagement with businesses to deploy advanced e-Business systems. • Investing in solutions. • Exploring rapid application assembly technologies to enable client-side solutions. • Enabling high-performance, affordable, standard high volume server building blocks. • Investing in and optimizing crucial applications and middleware to run on the Intel Architecture4. technologies that encourage customer-centric These efforts are already starting to bear fruit. Today, Intel is working with businesses to streamline the delivery of status information. One large company is developing a Stage 3 delivery solution to manage extremely 1 2 3 4 CIO:首席信息官(chief information officer 的首字母缩略)。该缩略语是仿照 CEO(chief executive officer, 首席执行官)而创造,并流行于 IT 行业。 Union Pacific Railroad Company:(美国)联合太平洋铁路公司。 shake up:改组,重组。 Intel Architecture:Intel 体系结构。 272 Computer English high server loads produced by customers checking its Web site for status information. The new system automatically sends updates in binary form, controlling the load on the company’s servers while improving customer service. Intel is also helping independent software vendors (ISVs1) develop products that deliver customer-centric solutions. For instance, companies are facilitating the integration of packaged, legacy and custom applications into the business process. This technology can help ensure collaboration over the Internet with multiple business partners, including resellers, distributors, manufacturers and customers. Independent Stage 3 efforts are also underway. Users can already select from Web-based services and products that pull real-time stock quotes and other financial information over the Internet. Software automatically pours the data into spreadsheets or other documents. inventory / 5invEntEri / n. 存货清单;库存 code generator 代码生成器 uplift / Qp5lift / v. 提高,促进 agility / E5dVilEti / n. 敏捷,灵活 On the customer side of the fence, emerging server and client components allow knowledge workers to build decision-support applications using office productivity tools. Imagine being able to pull product inventory and order-tracking information off your vendor’s servers from within your spreadsheet. Today, Intel is demonstrating a code generator that produces the necessary scripts, enabling components to be used in a variety of client applications. In between, there is a real need to uplift the computing infrastructure to manage custom data delivery. Middleware servers and applications will provide the glue between back-end systems and custom front-ends. These services will allow substantial agility in delivering information while maintaining a stable back-end platform. As customers request additional formats or application support, IT managers can deploy application services to fit their customer’s needs. Middleware on the client will also reduce complexity. Building Foundations The transition to Stage 4 is still just emerging, but IT managers need to position their companies now for a customer-centric future. Ultimately, businesses must realize that one global network—the Internet—will connect 1 ISV:独立软件推销商(或开发商) (independent software vendor 的首字母缩略)。 273 计算机英语 subsume / sEb5sju:m / v. 把…包括在内 formulate / 5fC:mjuleit / v. 构想出;系统地 阐述 with and subsume all others. By the same token 1 , the drive to share business processes will blur the lines between enterprises. IT managers cannot expect to simply jump to this endpoint, of course. The tools and processes to enable this capability are still being developed. But by carefully formulating e-Business strategies and deploying infrastructures now, IT managers can get started on building capabilities more quickly. New technologies will make it easier for companies to initiate business relationships, while at the same time making relationships more fruitful over the long haul2. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. According to Intel, there are ________ stages in the evolution of e-Business. 2. A company’s ability to deploy and support customer-oriented ________ systems will be of vital importance to its prosperity. 3. Today businesses face the crucial transition from a traditional ________ business model to the emerging ________ business model. 4. The deployment of advanced e-Business services should be accompanied with changes in the computing ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 1 2 vendor-centric model Web site Web surfing middleware server back-end platform 6. 7. 8. 9. 10. 电子商务策略 二进制格式 面向客户的电子商务系统 独立软件推销商 信息基础结构设施 by the same token:由于同样原因,同样地;而且。 over the long haul:长远地,从长远的观点看(亦作 for the long haul 或 in the long haul) 。 274 Computer English Section C Setting Goals for Your Online Business overwhelm / 7EuvE5hwelm / v. 使受不了;使不 知所措;征服;压倒 Most businesses realize that they need some kind of Web presence, but they don’t know what that Web presence should be. Other businesses become so overwhelmed by the limitless possibilities of being on the Web that they try to do everything they can, or end up doing nothing at all. The only way to successfully create a presence for your business on the Internet is to establish goals for going online, and then tailor your Web site to fit your goals. Think of establishing goals as creating a business plan for your Web site. Determine ahead of time what you want to accomplish by moving your business online. The business plan will save time and money and ensure a more efficient, productive Web site. The Internet is here to stay, so your goals should focus on the long-term benefits of having a Web site rather than the immediate effects. You probably shouldn’t expect to start making money on the Web right away. However, you may get other results from going online that aren’t 计算机英语 275 immediately measurable, such as product promotion or building a new customer base. When creating a business plan, you should know something about the reasons for your business to get on the Web and the types of online businesses. Besides, you should study how similar businesses use the Web. Visiting your competitors’ Web sites and learning what they’re doing online can help you focus your goals. Why take your business online? When most people think of opening a Web business, the first thing that springs to mind is selling products or services online. However, online retail is a very small part of what business Web sites are doing. You may not have realized how many other ways a Web site can benefit your business. There are many reasons for your business to get on the Web: ● Sell products and services. If your product or service translates well to online retail, you can create a Web site for taking and processing orders. offline / 5Cf5lain / a. & ad. 脱 机 的 (地),离线的(地) value-added / 5vAlju:5Adid / a. 增值的 ● Advertise products and services. Even if you don’t use your Web site to sell goods or services directly, you can still promote what you are selling offline. A Web site is often more effective as a marketing tool than a selling tool. The site can provide in-depth information, multimedia demos, and other promotion materials that just aren’t possible in print advertising. ● Provide customer services. You can use your Web site to communicate with customers, 24 hours a day, 7 days a week. For example, you can provide company information, product news and updates, and customer support. Value-added services, such as order tracking and financing applications, help maintain good customer relations. A Web site is also a convenient way for customers to get in touch with you. ● Contact new customers. Millions of people use the Web to research interests and needs. A Web site is an efficient tool for reaching out to new customers and telling them about your business or product. ● Product and market analysis. Every visitor to your Web site can 276 Computer English give valuable feedback on products and services. You can survey the potential market for a new product or find out how customers are using an existing product. If your product can easily be delivered online, such as software, you can even test it on potential customers. ● Open the international marketplace. The global Internet is an effective way to expand your business to an international market. You can easily get in touch with customers and partners overseas, and your Web site is open to them even when your offices are not. ● Communicate with partners. The Web is an efficient and fast communication medium. Use it to connect with business partners, vendors, employees, and others with whom you do business. media outlet 媒体渠道,媒介 kit / kit / n. 成套工具;套件, 软件包 electronic press kit 电子版发行包 disseminate / di5semineit / v. 散布;传播 press release (通讯社或政府机 构等发布的)新闻稿 ● Communicate with the press. Many media outlets now accept electronic press kits. Use your Web site to disseminate press releases and to update materials as needed, without the costs of printing and mailing. ● Recruit employees. Many people are turning to the Web to search for jobs. For relatively little money, you can list available jobs and collect resumes from a broad talent base. Which of these goals do you want your Web site to accomplish? Don’t try to do them all, at least not at first. An effective online business concentrates on one or two goals. Later, your Web site can grow to do even more. Types of online businesses Most businesses don’t use Web sites to make money or generate sales, at least not directly. Creating a Web site to provide customer services or publish company information contributes to sales via other channels. For example, many potential customers use the Web to research a product before buying it elsewhere. profitable / 5prCfitEbl / a. 有(赢)利的 1 However, a lot of businesses do want to make money off their Web sites.1 Several models have been developed for creating profitable online businesses: However, a lot of businesses do want to make money off their Web sites.:然而,不少公司确实想靠其网站赚钱。 该句中的 off 为介词,意思相当于“以…为依靠”。 计算机英语 mail-order / 5meil7C:dE / a. 邮购的 portal / 5pC:tEl / n. 门,入口,入门 subscription / sEb5skripFEn / n. 订阅;订购 stockbroker / 5stCk7brEukE / n. 股票(或证券) 经纪人 real estate 不动产,房地产 listing / 5listiN / n. 列表;一览表 ad / Ad / n. <口> 广告 classified ad 分类广告 277 ● Web storefronts. Some products are particularly well adapted to selling online, such as mail-order items. Web storefronts encompass the entire purchasing process, from providing product information, to taking orders and payments, to processing orders and tracking inventory. ● Content providers. Online publishing is a fast-growing medium. You can easily translate print publications, such as newspapers or magazines, into Web publications. Or you can create an information resource just for online access—a portal such as Yahoo!1 (www.yahoo.com) is a good example of this kind of service. Online content providers make money in two ways: advertisements and subscriptions. The advertising method works well for general information resources, while more specialized resources are better suited to selling subscriptions directly to the targeted audience. ● Free-based services. If you can enhance your service with a Web site, you can reach more customers and do more business electronically. For example, stockbrokers, real estate listings, job listings, and classified ads are all free-based services that translate well into online services. ● Consulting services. Many kinds of consulting services benefit from being online, such as Web site design and promotion services. You can reach a wider client base, exchange files, and communicate electronically, cutting mail and phone costs. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. When most people think of opening a Web business, the first thing that springs to mind is selling products or ________ online. 2. A Web site is often more effective as a(n) ________ tool than a selling tool. 3. The author lists four types of online businesses. They are Web ________, content providers, free-based services, and ________ services. 1 Yahoo!:(美国)雅虎公司,以因特网上的目录信息检索服务而著称。 278 Computer English 4. Online content providers make money in two ways: ________ and ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. Web storefront electronic press kit online retail multimedia demo 5. 6. 7. 8. 联机访问 增值业务 产品推销 通信媒体 计算机英语 279 Unit 14: Computer Security (计算机安全) Section A Computer Security THREATS TO COMPUTER SECURITY break-in / 5breikin / n. 闯入;盗窃 Threats to computer security are computer crimes (including viruses and electronic break-ins) and natural and other hazards. 1. Computer Criminals perpetrator / 5pE:pitreitE / n. 犯罪者 A computer crime is an illegal action in which the perpetrator uses special knowledge of computer technology. Computer criminals are of four types: ■ Employees The largest category of computer criminals consists of those with the easiest access to computers—namely, employees. Sometimes the employee 280 resentment / ri5zentmEnt / n. 忿恨,怨恨 Computer English is simply trying to steal something from the employer—equipment, software, electronic funds, proprietary information, or computer time. Sometimes the employee may be acting out of resentment and is trying to “get back” at the company. ■ Outside Users password / 5pB:swE:d / n. 口令 Not only employees but also some suppliers or clients may have access to a company’s computer system. Examples are bank customers who use an automatic teller machine. Like employees, these authorized users may obtain confidential passwords or find other ways of committing computer crimes. ■ “Hackers” and “Crackers” destructive / dis5trQktiv / a. 破坏(性)的, 毁灭(性)的 legitimate / li5dVitimEt / a. 合法的;正当的 gambling / 5gAmbliN / n. 赌博 counterfeiter / 5kauntE7fitE / n. 伪造者(尤指伪 造货币的人) disgruntled Some people think of these two groups as being the same, but they are not. Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes. They may intend to steal technical information or to introduce what they call a “bomb”—a destructive computer program—into the system. ■ Organized Crime Organized crime has discovered that computers can be used just like legitimate business people use them, but for illegal purposes. For example, computers are useful for keeping track of stolen goods or illegal gambling debts. In addition, counterfeiters and forgers use microcomputers and printers to produce sophisticated-looking documents such as checks and driver’s licenses. 2. Computer Crime / dis5grQntld / a. 不满的 notoriety / 7nEutE5raiEti / n. 声名狼藉;名声 远扬 variant / 5veEriEnt / n. 变体;变种 worm / wE:m / n. 蠕虫(病毒) replicate / 5replikeit / v. 复制 clog / 5klCg / v. 塞满;阻塞 Computer crime can take various forms, including: ■ Damage Disgruntled employees sometimes attempt to destroy computers, programs, or files. In recent years, computer viruses have gained wide notoriety. Viruses are programs that “migrate” through networks and operating systems and attach themselves to different programs and databases. A variant on the virus is the worm. This destructive program fills a computer system with self-replicating information, clogging the system so 计算机英语 infamous / 5infEmEs / a. 臭名昭著的 bulletin / 5bulitin / n. 公告,布告 electronic bulletin board 电子公告板 281 that its operations are slowed or stopped. The most infamous is known as the Internet Worm. In 1988, it traveled across North America, stopping thousands of computers along its way. Viruses typically find their way into microcomputers through copied floppy disks or programs downloaded from electronic bulletin boards. Because viruses can be so serious—certain “disk-killer” viruses can destroy all the information on one’s system—computer users are advised to exercise care in accepting new programs and data from other sources. Detection programs called virus checkers are available to alert users when certain kinds of viruses enter the system. Unfortunately, new viruses are being developed all the time, and not all viruses can be detected. There are recommended procedures to reduce the risk of catching a computer virus and to minimize its potential damage. ■ Theft Theft can take many forms—of hardware, of software, of data, of computer time. Thieves steal equipment, of course, but there are also “white-collar crimes.” Thieves steal data in the form of confidential information such as preferred client lists. They also use (steal) their company’s computer time to run another business. piracy / 5paiErEsi / n. 侵犯版权,盗版, 剽窃 pirate / 5paiErEt / v. 剽窃,盗用,非 法翻印 incidence / 5insidEns / n. 发生率 Thailand / 5tailAnd / n. 泰国 prankster / 5prANkstE / n. 恶作剧者 Unauthorized copying—a form of theft—of programs for personal gain is called software piracy. Pirated software accounts for 40 percent of software used in the United States. The incidence of pirated software is even higher overseas in such countries as Italy (82 percent) and Thailand (92 percent). ■ Manipulation Finding entry into someone’s computer network and leaving a prankster’s message may seem like fun, which is why hackers do it. It is still against the law. Moreover, even if the manipulation seems harmless, it may cause a great deal of anxiety and wasted time among network users. 3. Other Hazards hurricane / 5hQrikEn / n. 飓风 tornado / tC:5neidEu / n. 龙卷风 There are plenty of other hazards to computer systems and data besides criminals. They include the following: ■ Natural Hazards Natural forces include fires, floods, wind, hurricanes, tornadoes, and 282 strife / straif / n. 冲突;争斗 terrorism / 5terErizEm / n. 恐怖主义 unrest / 7Qn5rest / n. 动乱;动荡 brownout / 5braunaut / n. 负载偏重期,电 压不足 blackout / 5blAkaut / n. 断电,停电 primary storage 主存储器 disturbance / dis5tE:bEns / n. 干扰 surge / sE:dV / n. 浪涌;电涌 spike / spaik / n. 尖峰 surge protector 浪涌电压保护器 activate / 5Aktiveit / v. 激活,启动 circuit breaker 断路器 catastrophe / kE5tAstrEfi / n. 灾难,灾祸 inadvertently / 7inEd5vE:tEntli / ad. 漫不经心地,粗 心大意地 sloppy / 5slCpi / a. 马虎的;凌乱的 Computer English earthquakes. Even home computer users should store backup disks of programs and data in safe locations in case of fire or storm damage. ■ Civil Strife and Terrorism Wars, riots, and other forms of political unrest are real risks in some parts of the world. Even people in developed countries, however, must be mindful that acts of sabotage are possible. ■ Technological Failures Hardware and software don’t always do what they are supposed to do. For instance, too little electricity, caused by a brownout or blackout, may cause the loss of data in primary storage. Too much electricity, as when lightning or other electrical disturbance affects a power line, may cause a voltage surge, or spike. This excess of electricity may destroy chips or other electronic components of a computer. Most microcomputer users buy a surge protector, a device that separates the computer from the power source of the wall outlet. When a voltage surge occurs, it activates a circuit breaker in the surge protector, protecting the computer system. Another technological catastrophe is when a hard-disk drive suddenly “crashes,” or fails, perhaps because it has been bumped inadvertently. If the user has forgotten to make backup copies of data on the hard disk, data may be lost. ■ Human Errors Human mistakes are inevitable. Data-entry errors are probably the most commonplace. Programmer errors also occur frequently. Some mistakes may result from faulty design, as when a software manufacturer makes a deletion command closely resembling another command. Some errors may be the result of sloppy procedures. One such example occurs when office workers keep important correspondence under filenames that no one else in the office knows. MEASURES TO PROTECT COMPUTER SECURITY Security is concerned with protecting information, hardware, and software. Security measures consist of encryption, restricting access, anticipating disasters, and making backup copies. 1. Encrypting Messages 计算机英语 intercept / 7intE5sept / v. 拦截;截取 wiretap / 5waiEtAp / v. 搭线窃听 clipper chip 加密芯片 key escrow chip 密钥托管芯片 safeguard / 5seifgB:d / v. 保护,维护 283 Whenever information is sent over a network, the possibility of unauthorized access exists. The longer the distance the message has to travel, the higher the security risk is. For example, an e-mail message on a LAN meets a limited number of users operating in controlled environments such as offices. An e-mail message traveling across the country on the National Information Highway affords greater opportunities for the message to be intercepted. Businesses have been encrypting, or coding, messages for years. They have become so good at it that some law enforcement agencies are unable to “wiretap” messages from suspected criminals. Some federal agencies have suggested that a standard encryption procedure be used so that law enforcement agencies can monitor suspected criminal communications. The government is encouraging businesses that use the National Information Highway to use a special encryption program. This program is available on a processor chip called the clipper chip and is also known as the key escrow chip. Individuals are also using encryption programs to safeguard their private communications. One of the most widely used personal encryption programs is Pretty Good Privacy. 2. Restricting Access identification / ai7dentifi5keiFEn / n. 身份证明 oftentimes / 5CfEntaimz / ad. <古> 经常;通 常(=often) punch / pQntF / v. 按键输入 buffer / 5bQfE / n. 缓冲区,缓冲器 Security experts are constantly devising ways to protect computer systems from access by unauthorized persons. Sometimes security is a matter of putting guards on company computer rooms and checking the identification of everyone admitted. Oftentimes it is a matter of being careful about assigning passwords to people and of changing them when people leave a company. Passwords are secret words or numbers that must be keyed into a computer system to gain access. In some “dial-back” computer systems, the user telephones the computer, punches in the correct password, and hangs up. The computer then calls back at a certain preauthorized number. Most major corporations today use special hardware and software called firewalls to control access to their internal computer networks. These firewalls act as a security buffer between the corporation’s private network and all external networks, including the Internet. All electronic communications coming into and leaving the corporation must be evaluated by the firewall. Security is maintained by denying access to unauthorized 284 Computer English communications. 3. Anticipating Disasters Companies (and even individuals) that do not make preparations for disasters are not acting wisely. Physical security is concerned with protecting hardware from possible human and natural disasters. Data security is concerned with protecting software and data from unauthorized tampering or damage. Most large organizations have a disaster recovery plan describing ways to continue operating until normal computer operations can be restored. hindrance / 5hindrEns / n. 妨碍,障碍 lax / lAks / a. 松(弛)的 sprinkler / 5spriNklE / n. 喷洒器; 喷水装置 sprinkler system 喷洒灭火系统 cooperative Hardware can be kept behind locked doors, but often employees find this restriction a hindrance, so security is lax. Fire and water (including the water from ceiling sprinkler systems) can do great damage to equipment. Many companies therefore will form a cooperative arrangement to share equipment with other companies in the event of catastrophe. Special emergency facilities called hot sites may be created if they are fully equipped computer centers. They are called cold sites if they are empty shells in which hardware must be installed. 4. Backing up Data / kEu5CpErEtiv / a. 合作的,协作的 irreplaceable / 7iri5pleisEbl / a. 不能替代的;失 去后无法补偿的 audit / 5C:dit / v. 审核;检查 Equipment can always be replaced. A company’s data, however, may be irreplaceable. Most companies have ways of trying to keep software and data from being tampered with in the first place. They include careful screening of job applicants, guarding of passwords, and auditing of data and programs from time to time. The safest procedure, however, is to make frequent backups of data and to store them in remote locations. 5. Security for Microcomputers If you own a microcomputer system, there are several procedures to follow to keep it safe: ■ Avoid Extreme Conditions Don’t expose the computer to extreme conditions. Direct sun, rain from an open window, extreme temperatures, cigarette smoke, and spilled drinks or food are harmful to microcomputers. Clean your equipment regularly. Use a surge protector to protect against voltage surges. ■ Guard the Computer Put a cable lock on the computer. If you subscribe or belong to an 计算机英语 social security 社会保险 285 online information service, do not leave passwords nearby in a place accessible by others. Etch your driver’s license number or social security number into your equipment. That way it can be identified in the event it is recovered after theft. ■ Guard Programs and Data Store disks properly, preferably in a locked container. Make backup copies of all your important files and programs. Store copies of your files in a different—and safe—location from the site of your computer. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. According to the text, the largest category of computer criminals is ________. 2. People who gain unauthorized access to a computer system for fun and challenge are called ________. 3. People who gain unauthorized access to a computer system for malicious purposes are called ________. 4. Computer crime can take the forms of ________, theft, and ________. 5. A(n) ________ is a destructive program that fills a computer system with self-replicating information, clogging the system so that its operations are slowed or stopped. 6. gain. ________ is the unauthorized copying of programs for personal 7. Security measures for computer systems consist of encryption, restricting ________, anticipating disasters, and making ________ copies. 8. Secret words or numbers that must be keyed into a computer system to gain access are called ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 286 Computer English 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. encryption program deletion command authorized user backup copy voltage surge circuit breaker electronic component data-entry error electronic break-in power line 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 检测程序 电源 破坏性计算机程序 计算机病毒 软件侵权 硬盘驱动器 病毒检查程序 主存储器 电子公告板 浪涌电压保护器 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: contain cost-cutting create virus programmer file clock employment timer event trigger infect system program replicate list A virus or other unwelcome surprise can lurk in your computer system for days or months without discovery. A time bomb is a computer program that stays in your ________ undetected until it is triggered by a certain ________ in time, such as when the computer system ________ reaches a certain date. A time bomb is usually carried by a(n) ________ or Trojan horse. For example, the Michelangelo virus ________ a time bomb designed to damage ________ on your hard disk on March 6, the birthday of artist Michelangelo. A logic bomb is a computer program that is ________ by the appearance or disappearance of specific data. For example, suppose a(n) ________ in a large corporation believes that she is on the ________ of employees to be terminated during the next ________ campaign. Her hostility ( 敌 意 ) overcomes her ethical ( 道 德 的 ) judgment, and she ________ a logic bomb program that checks the payroll (在职人员名单) file every day to make sure her ________ status is still active. If the programmer’s status changes to “terminated,” her logic bomb activates a(n) ________ that destroys data on the computer. A time bomb or logic bomb might do mischief (祸害) in your computer long before the ________ goes off. If the bomb contains a virus, it could 计算机英语 287 ________ and spread to other files. Meanwhile, you might send files from your computer to other computers, not knowing that they are ________. IV. Translate the following passage from English into Chinese: A computer virus is a program that “infects” computer files (usually other executable programs) by inserting in those files copies of itself. This is usually done in such a manner that the copies will be executed when the file is loaded into memory, allowing them to infect still other files, and so on. Viruses often have damaging side effects, sometimes intentionally, sometimes not. A virus that propagates (传播) itself across computer networks is sometimes referred to as a “Worm”, especially if it is composed of many separate segments distributed across the network. A “Trojan Horse”, though technically not a virus, is a program disguised as something useful, which when run does something equally devious (阴险的) to the computer system while appearing to do something else. 288 Computer English Section B Computer Virus I. What Is a Virus? Since the first PC virus was found in 1986, the total number of virus has been rocketing to an enormous figure. As many may have known, computer virus is a piece of malicious program, which is able to affect the normal operation of a computer system. disastrous / di5zB:strEs / a. 灾难性的 complicate / 5kCmplikeit / v. 使复杂化 macro virus 宏病毒 When a virus strikes, the results range from merely annoying screen displays to disastrous and extensive data corruption. With the growing popularity of microcomputers, the threat of virus should definitely not be negligible. To further complicate the story, a new type of virus, named “Macro Virus”, emerged into the computing world in 1995. Its ability to infect 计算机英语 ubiquity / ju:5bikwEti / n. 普遍存在 notwithstanding / 7nCtwiW5stAndiN / ad. & prep. 尽管 infection / in5fekFEn / n.(病毒)传染; 感染 boot sector 引导(扇)区 master boot record 主引导记录 interrupt / 7intE5rQpt / n. 中断 289 document files has broken the golden rule that “virus can affect program files only”. Also, the ubiquity of interchanging documents among computer users has fuelled up the spreading of the macro virus further. Notwithstanding, with appropriate counter-measures in place, we are still able to prevent/minimize the loss from computer infection. II. Types of Virus ■ Boot Sector Virus Until the mid-1990s, boot sector viruses were the most prevalent virus types, spreading primarily in the 16-bit DOS world via floppy disk. Boot sector viruses infect the boot sectors on floppy disks and hard disks, and can also infect the master boot record (MBR) on a user’s hard drive. Once the machine is infected, it attempts to infect every floppy disk that is inserted into the computer and accessed. Boot sector viruses work like this: by hiding on the disk, the virus is loaded into the memory before system files are loaded. This allows it to gain complete control of DOS interrupts so that it can spread and cause damage. Typical example: diskette / 5disket / n. 软磁盘,软盘 Michelangelo1 is an infamous boot sector virus. It infects both boot sectors of diskettes and MBR of hard disks. Once it becomes memory resident, it is able to infect all non-write protected diskettes as they are accessed. In addition to infecting, the virus attempts to delete all the files within the infected system on March 6th. ■ File Infector Virus parasitic / 7pArE5sitik / a. 寄生的 File infectors, also known as parasitic viruses, operate in memory and usually infect executable files. They activate every time infected files are executed: They copy themselves into other executable files and can remain in memory long after the virus has activated. Thousands of different file infecting viruses exist, but similar to boot sector viruses, the vast majority operate in DOS 16-bit environment. A simple method of removing file infector virus is by using anti-virus software to scan and clean it. However, you cannot clean system files under 1 Michelangelo:米开朗琪罗病毒,一种臭名昭著的引导扇区病毒,在意大利文艺复兴时期著名画家和雕刻 家米开朗琪罗(1475~1564)的生日 3 月 6 号发作。 290 Computer English Windows because they are locked in Windows mode. In this case, you have to boot your computer to DOS mode and then run the anti-virus software to clean the infected files. Typical example: EXE file 可执行文件 corrupt / kE5rQpt / v. 毁损,毁坏, 破坏 Flash BIOS 可擦写 BIOS multi-partite / 7mQlti5pB:tait / a. 分成多部分的 CIH 1 infects EXE files in Windows 95/98 and has a couple destructive payloads that are triggered on the 26th day. On that day, it attempts to overwrite the system’s hard disk with some random data, and that makes data recovery very difficult. It also tries to corrupt data stored in the Flash BIOS. ■ Multi-Partite Virus Multi-partite viruses have characteristics of both boot sector viruses and file infector viruses. ■ Macro Virus attachment / E5tAtFmEnt / n. 附件 Unlike other virus types, macro viruses aren’t specific to an operating system and spread with ease via email attachments, floppy disks, Web downloads, file transfers, and cooperative applications. Macro viruses are, however, application-specific. They infect macro utilities that accompany such applications as Microsoft Word and Excel. Macro viruses are written in “every man’s programming language” such as Visual Basic or Corel Draw, and these types of programming languages are relatively easy to create. Typical example: template / 5templit / n. 模板 global template 共用模板 illicit / i5lisit / a. 非法的; 不正当的 1 2 3 4 JulyKiller2 spreads through MS Word 97 documents via VB3 macro. When an infected document is opened, it will first infect the global template (normal.dot4) and thus, opening other documents would result in infection of this virus. This virus has a destructive payload. If the current month is July, it will delete all your files in c:\. ■ Trojan/Trojan Horse A Trojan or Trojan Horse is a program that appears legitimate, but performs some malicious and illicit activity when it is run. It may be used CIH:CIH 病毒,一种恶性计算机病毒。 JulyKiller:七月杀手,一种恶性计算机病毒。 VB:可视化 Basic 语言(Visual Basic 的首字母缩略)。 normal.dot:Word 的模板文件。 计算机英语 sneak / sni:k / v. 偷偷地走,溜 291 as a hacker tool to leak a user’s password information or it may simply destroy programs or data on the hard disk. Contrary to a virus, a Trojan does not replicate itself. It stays in the computer doing its damage or allowing somebody from a remote site to take control of the computer. Trojans often sneak in by attaching to a free game or other utility. Typical example: console / 5kCnsEul / n. 控制台 Back Orifice1 is a Trojan released in 1998. It is a Windows remote administration tool, which allows a user to remotely control a computer across a TCP/IP connection using a simple console or GUI application. ■ Worm proliferation / prEu 7lifE5reiFEn / n. 激增;扩散 A worm is a program that spreads over network. Unlike a virus, a worm does not attach itself to a host program. It uses up the computer resources, modifies system settings and eventually puts the system down. With the proliferation of the Internet, a worm can utilize email systems to replicate, e.g. by emailing itself out as an attachment to other users, within a short period of time. Typical example: spam / spAm / v.(向…)发送电子 垃圾 Discovered in June 1999, Worm.ExploreZip is an auto-spamming worm. When executed, it sends email with itself as an attachment, to recipients in the Windows address book. Once the attachment is clicked upon in any Windows environment, this worm executes automatically. In Windows 95/98 environment, this worm copies itself to the c:\windows\system directory as ‘Explore.exe’. It will also modify the WIN.INI2 file in order to execute itself each time the system is rebooted. III. How Can Virus Affect Us? Computer virus affects the health of your computer just like their biological counterparts make you sick. Typical payload of computer virus includes creating some annoyances (e.g. affects your mouse/keyboard), removing files from your hard disk and formatting your hard disk. It’s only the discovery of CIH virus that corruption to BIOS data has been added to the list of payloads. Computer virus may seem remote from you. It may be true in the old 1 2 Back Orifice:一种黑客程序,黑客可以通过它控制受感染的计算机。 WIN.INI:Windows 系统文件之一,用于存放初始化信息。 292 Computer English days, when few of us have a PC at home and virus spread slowly with the exchange of floppy disks. But time has changed; virus can now reach us through a number of routes. They may arrive from the shared files in the server, mails from your colleagues, files downloaded from the Internet and BBS1. And worse still, some vendors deliver the machines/CD-ROMs with virus pre-installed. So, you are at stake. outbreak / 5autbreik / n. 爆发,突然发生 This is illustrated by the results of a survey conducted by ICSA2 (International Computer Security Agency, a US-based company) in 1998 over 580,000 desktop workstations and 12,000 application and file servers. ICSA found that virtually all large and midsize North American corporations (>99%) have encountered computer infections. In addition, the outbreak of the Melissa3 virus proved that virus could spread around the globe just within hours. Do you still think that virus is remote to you? IV. How to Detect Virus? New viruses are being developed every day. New techniques may render existing preventive measures insufficient. The only truth in the virus and anti-virus field is that there is no absolute security. However, we can minimize the damage by identifying virus infections before they carry out their payload. The following lists some ways to detect virus infections: ● Watch out for any changes in machine behavior. Any of the following signs could be symptoms of virus activity. Programs take longer time than usual to execute or there is a sudden reduction in the available system memory or disk space. memory-resident / 5memEri 5rezidEnt/ a. 内存驻留的 virus signature 病毒特征代码 ● A memory-resident anti-virus software can be employed to continuously monitor the computer for viruses. ● Scan your hard disk with anti-virus software. You should make sure that an up-to-date virus signature has been applied and you should update the signature at least once a month. ● Employ server-based anti-virus software to protect your network. You should also consider employing application-based anti-virus software (e.g. those running on Lotus Notes4) to further protect 1 2 3 4 BBS:公告板系统(bulletin board system 的首字母缩略)。 ICSA:国际计算机安全代理公司(International Computer Security Agency 的首字母缩略)。 Melissa:“梅利莎”病毒,一种恶性计算机病毒,通过电子邮件传播,受感染的计算机会自动将其复制, 发给通讯簿中前 50 个地址。 Lotus Notes:Lotus 公司出品的群件系列软件。 293 计算机英语 your machine. V. How to Clean Virus? Virus has been found? Don’t panic! Some pieces of advice about removing computer virus are given below: detach / di5tAtF / v. 使分开,使分离 ● All activities on the infected machine should be stopped (and it should be detached from the network) as the payload may be triggered at any time. Continuing the use of the infected machine helps the suspected virus spread further. ● Recover from backup is the most secure and effective way to recover the files. partition table 分区表 ● In some cases, you may recover the boot sector, partition table and even the BIOS data using the emergency recovery disk. ● In case you do not have the latest backup of your files, you may try to remove the virus using anti-virus software. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Before the appearance of the ________ virus, computer virus could only affect program files. 2. Michelangelo is a(n) ________ virus. 3. File infectors are also called ________ viruses. 4. A(n) ________ is a program that appears legitimate, but does something harmful when it is run. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. partition table host program anti-virus software global template virus signature 6. 7. 8. 9. 10. 公告板系统 数据毁损 主引导记录 引导扇区 宏病毒 294 Computer English Section C Through a Hacker’s Eyes indiscriminate / 7indis5kriminEt / a. 不加区别的;不 加选择的;任意的 intruder / in5tru:dE / n. 侵入者;闯入者 1 If you ask system professionals why network security measures are necessary, most will answer, “To protect against hackers.” Hackers spend a great deal of time and energy exploring systems and networks, searching for ways of penetrating system defenses, often utilizing the access they gain to disastrous effect. News accounts of hacker exploits are routine, with many government, corporate, and organizational systems on the list of sites taken out of commission1 for days, even weeks. Although one still sees hackers celebrated as evil geniuses, that perception is changing as the list of victims grows longer and the damage associated with the attacks becomes more indiscriminate. If you are charged with protecting a system, understanding the approach intruders take as they carry out an attack can sometimes be out of commission:不能使用,不在使用中。 计算机英语 295 helpful. This knowledge is valuable for a number of reasons. proactively / prEu5Aktivli / ad. 抢先地 vulnerability / 7vQlnErE5bilEti / n. 易 遭 攻 击 的 地 方;脆弱(性) stance / stAns / n. 姿态,态度 hack / hAk / v. & n. 非 法 闯 入 (计算机网络) self-aggrandizement / 7selfE5grAndizmEnt / n.(在名利、权势等 方面的)自我扩张 tangible / 5tAndVEbl / a. 可触摸的;有形 的;明确的 incentive / in5sentiv / n. 刺激;动机 seizure / 5si:VE / n. 抓住;夺取 fascination / 7fAsi5neiFEn / n. 强烈的爱好,迷 恋;魅力 ● It enables you to spot certain activity patterns as they happen, recognizing the elements of an attack. ● It enables you to look at your systems proactively before the attacker gets to them, correcting vulnerabilities that would be found by any attacker searching your site. ● It gives you the insight necessary to make good decisions about protection strategies. Numerous products are marketed for the purpose of protecting systems. Some are a better fit for your environment than others. ● It enables you to make wiser decisions in managing your systems and your users. Security management is a constant balancing act between accommodating needs for access and honoring needs for protection. A knowledge of the threat from one attempting to attack your system gives you a better sense of the impact of tightening or loosening security stances. Identifying a Victim The first step in a system hack is to decide which system to attack. Two major attack motivations become apparent at this stage of the attack. The first motivation is entertainment or challenge, and the victim selection is almost random. Here the attacker (or a group of cooperating attackers) might use vulnerability scanners to search part of the IP address space, recording hosts that have security vulnerabilities. The second motivation for selecting a hacking target is self-aggrandizement or other tangible incentives (including intellectual property theft and discovery of sensitive information). Here the targeting of the victim is much more focused, with the attacker gaining knowledge of the victim system through research and information collection. This is usually followed by a more deliberate search and seizure of the desired information. The motivation for targeting your site can include the following: ● You may be in business competition with the hacker or an entity that has employed that hacker. ● The hacker may have some personal interest in your site, for example, a relative who is an employee of your firm, or a fascination with a product your organization produces. 296 Computer English / 7aidiEu 5lCdVikEl / ● Your site may have an odd or amusing domain name. ● Your site may have received press coverage. ● Your organization may be involved in a political or ideological matter of interest to the hacker. a. 思想上的;意识 形态的 Casing the Joint1 coverage / 5kQvEridV / n. 新闻报道;覆盖 范围 ideological Once the target of the hack is identified, the hacker determines the goal of the attack. In cases where a particular site has been identified as the target, this determination is likely to include collecting information about the system. The information can come from the InterNIC2 and other public sources and can include items such as the system platforms (both hardware and operating system), personnel involved in the management of the system, telephone numbers, MX3 records, registered servers, and other information. If the attacker hasn’t done it already, he or she may run a vulnerability assessment tool against the site, recording the results. Gaining Access social engineering (应用社会学原理 以达成某种特殊或 认定的社会目标 的)社会工程 dupe / dju:p / v. 欺骗,愚弄 unwitting / 7Qn5witiN / a. 不知道的,不知 情的 expertise / 7ekspE:5ti:z / n. 专门知识(或技 能),专长 documentation / 7dCkjumen5teiFEn / n. 文献资料,文档 1 2 3 With the victim selected and sufficient information gathered to identify possible approaches to attacking the site, the attention of the attacker is likely to shift to gaining access to a site system. In many cases the vulnerability assessment tool run as part of casing the site has identified a vulnerability that allows the attacker to log on. In cases where no vulnerabilities were found, the hacker has several options. The attacker could utilize social engineering techniques for gaining entry. This approach consists of steps such as making telephone calls to users, pretending to be system maintenance or network management personnel, asking for passwords or information. Another option is to introduce a Trojan horse into the system, accomplished by duping an unwitting authorized user into installing the Trojan horse by including it on a disk or network download containing data or software, or by sending it as an email attachment. Should these measures fail, the next step depends on the determination and expertise levels of the attacker. If both are high, he or she is likely to undertake a more systematic, rigorous, analysis of the target system. For instance, the hacker might review all the system documentation, searching case the joint:<俚>(行窃前)探路,侦察地形。 InterNIC:Internet 网络信息中心(NSFnet (Internet) Network Information Center 的缩和)。 MX:邮件交换(mail exchange 的缩略)。 计算机英语 297 for known problems. If the operating system or applications source code is available, she or he might search it for vulnerabilities. If the attacker has a system on which to test possible attacks, he or she might construct several test attacks, checking to see whether any were indeed successful. off-hour / 5Cf5auE / a. 休息时间的;非 工作时间的 Once an avenue into the system is isolated, the final item in the strategy is to determine the timing of the attack. Many attackers time attacks for late night or early morning when they believe that no one is likely to be using the system. As globalization of organizations with time zone differences has increased the possibility that someone will be utilizing the system at almost any time, day or night, off-hour timing might not be as feasible as before. In any event, some attackers target attacks for peak hours so that their activity will blend into the “noise floor” of other system activity.1 Executing the Attack optimization / 7Cptimai5zeiFEn / n. 最佳化,最优化 finger / 5fiNgE / n. finger 命令,远程 用户信息服务命令 daemon / 5di:mEn / n. 后台程序,守护 程序 user ID 用户标识 superuser / 5sju:pE 7ju:zE / n. 超级用户,特权 用户 carte blanche / 5kB:t5blCnF / n. <法> 全权,自由 处理权 After the strategy is set, it’s time to actually execute the attack. Some attackers, utilizing intrusion scripts and other process optimizations, are able to launch a targeted attack and then cover their tracks in a matter of minutes, even seconds. Others, who wish to take a more leisurely approach, might watch the system activities, waiting until the system has no other users logged on to proceed. On UNIX systems in which the finger daemon is enabled, executing a finger command with the name of the targeted system (“[email protected]”) returns a list of current users who are logged on the system. When the attacker determines that the coast is clear2, she or he will actually use an intrusion script or “borrowed” user IDs and passwords to log on to the machine. Depending on the privilege level of the account, the attacker might be in the system with user privilege. In this case, the attacker may utilize additional hacker tools to try to gain superuser privilege, which will provide carte blanche access to the entire system. A. Installing a Back Door The first thing that some hackers do after they have entered the machine as superusers is install back doors, system utilities equipped with 1 2 In any event, some attackers target attacks for peak hours so that their activity will blend into the “noise floor” of other system activity.:不管怎样,有些攻击者将攻击时间选定在最繁忙的时候,这样他们的活动就会和系 统中其他活动的“背景噪声”混在一起。 the coast is clear:无人阻碍;危险已过。 298 Computer English custom vulnerabilities that allow the hacker to access the machine at a later time. More expert hackers import precompiled system Trojan horses with back doors, devised so that the file statistics do not differ from the original system binaries. Furthermore, the transfer of these Trojan horses may be done with remote commands that are not logged by the system. Part of this step can include installing “Trojaned” versions of critical system binaries that log information about system processes and network connections. These binaries are altered to hide the presence of the attacker. B. Covering Tracks obscure / Eb5skjuE / v. 使变模糊,掩盖 publicize / 5pQblisaiz / v. 引起公众对…的 注意;宣传 juvenile / 5dVu:vEnail / n. 少年 prosecution / 7prCsi5kju:FEn / n. 起诉 compensate / 5kCmpenseit / v. 补偿,赔偿 predator / 5predEtE / n. 捕食者;掠夺者 prey / prei / n. 捕获物;牺牲品 Obscuring the evidence associated with the attack is a critical part of most attack strategies. Attackers have two separate sets of concerns: ● Covering those tracks that might lead a victim or investigator back to the attacker ● Eliminating evidence internal to the system indicating that the attack occurred C. Publicizing the Result For some hackers, especially those operating as part of a group, the final step in an attack is publicizing the exploit to others. This step is more likely to occur if ● Your site has high name recognition (such as a popular e-commerce site, a major newspaper, or a government agency). ● The attacker is a juvenile, or otherwise not subject to criminal prosecution for the offense. This publicity and resulting notoriety are often considered part of the motivation for the hack. If the hacker is a professional who was compensated for taking intellectual property or other sensitive information from your site, you will probably never see this stage of the attack. D. Studying Predator and Prey As you encounter and deal with intrusions in your environment, you may see many variations on the themes presented in this article. My point in presenting this information is that your ability to understand the goals of intrusion detection and the suitability of various monitoring and detection strategies depends on your understanding of the threats you hope to counter. Although the ability to hack a system doesn’t necessarily indicate a similar 299 计算机英语 adversary / 5AdvEsEri / n. 对手,敌手 ability to protect the system, those who can best protect the system do understand how an attacker approaches the system. Only by studying the approaches taken by your adversary can you shift the balance of power in your favor. Knowledge is the key to changing your role in this relationship from prey to predator. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The author thinks that understanding how an attacker approaches your computer system can help you ________ it. 2. According to the text, there are two major motivations for selecting a hacking target. One is ________ or ________, and the other is self-aggrandizement or other tangible incentives. 3. A hacker might use vulnerability scanners to search part of the ________ space, recording hosts that have security vulnerabilities. 4. When hackers enter a computer system as superusers, the first thing that they sometimes do is to install ________, which enable them to access the system at a later time. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. system platform install back doors email attachment vulnerability assessment tool 5. 6. 7. 8. 网络安全措施 系统维护人员 邮件交换记录 非法闯入系统 300 Computer English Unit 15: Remarks by IT Giants (IT精英如是说) Section A Remarks by Bill Gates1 (1): Why the PC Will Not Die Computers will take many forms, but there will always be a place for the all-purpose machine we've come to depend on. imminent / 5iminEnt / a. 临近的,即将发 生的 demise / di5maiz / n. 死亡;终止 ritual / 5ritjuEl / n. 仪式;例行公事 defy / di5fai / v.(公然)违抗 prophet / 5prCfit / n. 预言者;先知 doom / 5du:m / n. 命运;毁灭 empowerment / im5pauEmEnt / n. 授权;给人能力 Predicting the imminent demise of the personal computer has become an annual ritual in recent years—and each year the PC has defied the prophets of doom. This year looks set for a repeat performance. 2 Predictions for first-quarter global sales were bad; the PC era was finally ending. In fact, sales grew at a healthy 19 percent annual rate. Worldwide, well over 100 million PCs will be sold this year. That means the world now buys almost as many PCs as color TVs. The PC’s growing popularity isn’t surprising. Prices have fallen sharply while the power of the hardware and software has kept increasing. Consumers and businesses everywhere are rushing to get on the Web, and the PC makes that easy. But what really sets the PC apart is the incredible empowerment and flexibility it offers in a single, economical package. Sitting at your PC, you can do your taxes, surf the Web, write letters, e-mail friends, play games, plan a business, buy a car, do your homework … in fact, do whatever you want. The PC has given the average American the kind of computing power that 10 years ago was found only in large corporations. Yet people now take this for granted—and want more. They want to do many of the things they 1 2 Bill Gates:比尔·盖茨(1955~),微软公司董事会主席和首席工程师,18 岁入读哈佛大学,读到二年级 时辍学,后来创立微软公司。 This year looks set for a repeat performance.:今年看来又要重演一次。在本句中,look 为连系动词,set for a repeat performance 为形容词短语,充当表语。set 作形容词时,可表示“很有可能的”、 “即将发生的”,后 接动词不定式。 计算机英语 Auto PC 自动个人电脑 WebTV / 5web5ti:5v: / n. 网络电视机 portfolio / 7pC:t5fEuliEu / n. 投资组合 tandem / 5tAndEm / n. 纵列套在马车上 的两匹马 dealership / 5di:lEFip / n. 商品特许经销商 morph / mC:f / v. 变化,改变 tablet / 5tAblit / n. 便笺簿; (图形) 输入板;药片 tablet PC 便笺簿式个人电脑 1 2 301 can do on their PC regardless of where they are or what device they are using—whether it’s a palm-size computer, a Web-enabled cell phone, an Auto PC or a smart television like WebTV. A combination of sophisticated software, powerful microprocessors, wireless technology and high-bandwidth connectivity is starting to make that a reality. For most people at home and at work, the PC will remain the primary computing tool; you’ll still want a big screen and a keyboard to balance your investment portfolio, write a letter to Aunt Agnes, view complex Web pages, and you’ll need plenty of local processing power for graphics, games and so on. But the PC will also work in tandem1 with other cool devices. You’ll be able to share your data—files, schedule, calendar, e-mail, address book, etc.—across different machines; you won’t have to think about it; it will be automatic. If you want to find the best price for a new car—and check out your budget to see if you can afford it—you’ll be able to do that at the dealership, on the device you have with you. Wherever you are, whatever you want to do, you’ll have all the information you need. At the same time—and many who doubt the PC’s staying power miss this point—the PC itself will be getting more powerful, more reliable and simpler to use. Even though the underlying hardware, networks and software will become more complex, that complexity will be hidden from users. There will be a simpler user interface that adapts to your needs, with voice recognition and natural-language processing. There will be “instant-on,” so you won’t have to wait for your PC to come to life. When the PC is at the center of a home network (probably connected to a broader network that will constantly monitor performance, update software and download device drivers and the like), it will be incredibly easy to administer, automatic in operation and maintenance-free. And the PC will morph into many new forms, such as book-size “tablet PCs.” But they’ll still be PCs underneath, with all the benefits of the universal PC model. That model will play a vital role in this new world of anytime, anywhere computing. The PC’s high-volume, low-cost approach will be adopted by many of the new smart devices, because it offers amazing value to consumers. The cost of innovation is spread widely, so everyone benefits from billions of dollars of R & D2. And the PC’s broadly accepted technical standards—and open Internet standards—mean that when you buy a new in tandem:一前一后地;协同地,联合地。 R & D:研究与开发(research and development 的缩略)。 302 Computer English device, you’ll know it will function with your existing equipment. In this new “PC-plus” era connectivity will be king, and the PC model’s common standards will be more important than ever. PCs gave the world a whole new way to work, play and communicate. The PC-plus era will be just as revolutionary. It will take the PC’s power and make it available almost anywhere, on devices that haven’t yet been dreamed up. Given my job, it’s hardly surprising that I’d say this. But I’m betting Microsoft’s future on it. ———————————————— Remarks by Bill Gates (2): Everyone, Anytime, Anywhere The next step for technology is universal access. lexicon / 5leksikEn / n.(某一语言、作 家、学科的)特殊 词汇,专门词汇 gadget / 5gAdVit / n. 精巧的装置;小 玩意儿 spectrum / 5spektrEm / n. 频谱 agnostic / Ag5nCstik / a. 不可知论 (者)的 1 Amazingly, it’s been more than 20 years since the concept of “convergence” entered the high tech lexicon. For most of that time, convergence has meant two things: the coming together of the computer, consumer electronics, and telecommunications industries and the merging of gadgets such as the PC, TV, and telephone. But as the 21st century approaches, sophisticated digital technologies and the promise of exploding bandwidth are combining to create a third kind of convergence—one that will change our lives more dramatically than anything we’ve seen so far. It will deliver the power of the information age into the hands of everyone, anytime, anywhere. We live in an age where voice, data, and video are just bits, ones and zeros to be pushed down the broadest pipe or around the most accommodating slice of spectrum.1 Bits are agnostic. They don’t care how they get where they’re going—only that they arrive in the right order We live in an age where voice, data, and video are just bits, ones and zeros to be pushed down the broadest pipe or around the most accommodating slice of spectrum.:我们生活在这样一个时代:声音、数据和图像都不过 是比特,是要通过最宽的管道或最具有容纳力的频段传递的 1 和 0。 计算机英语 empower / im5pauE / v. 授权给;使能够 hybridization / 7haibridai5zeiFEn / n. 杂交;混合 envision / in5viVEn / v. 想像,展望 cable modem 电缆调制解调器 exponential / 7ekspEu5nenFEl / a. 指数的;可用指 数函数表示的 303 and at the right moment.1 The ubiquity of bits is already empowering the kind of hybridization that most people have envisioned for consumer electronics these past two decades—multifunctional devices such as modern PCs, WebTV, cable modems, and smart phones. But this is only the start. Combine digital technology with advanced software, smaller and more powerful microprocessors, and exponential growth in fiber and wireless bandwidth, and you get something far more useful—seamless, universal connectivity. This turns convergence on its head.2 It means that although computer, telecommunications, and consumer electronics technologies will come together, the next generation of smart devices mostly won’t. Universal connectivity will bring together all the information and services you need and make them available to you regardless of where you are, what you are doing, or the kind of device you are using. Call it “virtual” convergence—everything you want is in one place, but that place is wherever you want it to be, not just at home or in the office. The result is that there’ll be a proliferation of smart, connected devices, from palm-sized and tablet PCs to Web-enabled phones and AutoPCs. Your files, schedule, address book, and everything else you need will automatically be replicated onto each of these devices, because everything that can think will link. ballpark / 5bC:lpB:k / n. 球场;(连同看 台的)棒球场 hot dog 热狗,红肠面包 tax return 纳税申报单 itinerary / ai5tinErEri / n. 旅程;路线;旅 行计划 1 2 Virtual convergence will take the power on your desktop and make it available wherever you want it. But to help avoid information overload, it will do this intelligently. If you’re watching a game in the ballpark on a Saturday afternoon, the network will know that player profiles or an online form to order a hot dog are what you need on your palm-sized computer—not your tax return or tomorrow’s travel itinerary. A lot still needs to be done to make this a reality. First, in the same way that people must speak the same language if they are to understand each other and collaborate, smart devices also need to speak a common language to communicate effectively. The best way to achieve this is by using existing open Internet standards. The industry is starting down that route, They don’t care how they get where they’re going—only that they arrive in the right order and at the right moment.:它们不关心如何到达所要去的地方——它们所关心的只是在适当的时刻按适当的顺序到达。句 子后半部分的 that 从句是宾语从句,在 only 前省略了 they care。 This turns convergence on its head.:这使结合的趋势颠倒过来。on one’s head 系习语,意为“倒立地”、 “颠 倒地”。 304 Computer English but there’s still a long way to go. Second, a massive amount of investment is still required if high-speed, broadband communications are to be widely available throughout the United States. joint venture 合资企业 viable / 5vaiEbl / a. 切实可行的;可 实施的 To make all this happen, we’ll see more deals, alliances, and joint ventures involving computing, consumer electronics, telecommunications, Internet, and cable companies. And chances are that as everyone faces the challenge of developing a viable business model, some of those ventures will fail in the marketplace. But two things are certain: Ubiquitous wireless and high-bandwidth data networks are going to get built, and the various smart devices required to provide access to these networks will soon be on the market. Together, they will make the potential of virtual convergence a reality. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. According to Bill Gates, the world now buys almost as many PCs as ________. 2. One of the reasons for the PC’s growing popularity is that consumers and businesses everywhere are rushing to get on the ________, and the PC makes that easy. 3. The PC has given the average American the kind of computing power that 10 years ago was found only in large ________. 4. In the so-called “PC-plus” era, ________ will be of vital importance. 5. According to Bill Gates, the next step for technology is universal ________. 6. Up to now, convergence has mostly taken two forms: the combination of the computer, consumer electronics, and ________ industries and the merging of gadgets such as the PC, TV, and ________. 7. To make virtual convergence a reality, we need ubiquitous ________ and ________ data networks and various smart devices to provide access to them. 8. Smart devices need common standards to communicate 305 计算机英语 effectively and the author thinks it is best to use existing open ________ standards. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. PC-plus era cable modem universal PC model multifunctional device information overload high-bandwidth connectivity consumer electronics investment portfolio virtual convergence tablet PC 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 语音识别 智能电视 研究与开发 在网上冲浪 自动个人计算机 给同事发电子邮件 具有上网功能的手机 数字技术 无线技术 宽带通信 III. Fill in each of the blanks with one of the words given in the following list, making changes if necessary: interactive download software technology cell electronic hardware automatically online possible commonplace microprocessor device network available product At home, you’ll be able to operate your PC by talking to it. It will ________ back up all your information, update its own ________ and synchronize itself with your TV, ________ phone, handheld (掌上电脑), and all the devices on your home ________. The refrigerator in your kitchen will know how well stocked it is, suggest recipes (食谱) based on what’s ________, and order more food from your ________ grocer. Your TV will double as a(n) ________ shopping mall (大型购物中心), letting you buy advertised ________ or clothes you saw in a sitcom (情景戏剧). And if you don’t want to watch TV, you’ll be able to read a(n) ________ book that knows your favorite authors and automatically ________ their latest novels. If you decide to read one of them, your bank account will be debited (计入…的借方). Sounds like science fiction? Just a few years ago, it was. But thanks to 306 Computer English the________ and to all the incredible innovations in software, ________, the Internet and telecommunications, everything I’ve described is already ________. And although you can’t yet buy all these ________ at your local computer retailer, the incredible speed at which ________ is advancing means that it won’t be long before they’re as ________ as the PC. IV. Translate the following passage from English into Chinese: But the really amazing thing is that we’re still only at the dawn of the digital age. In the past two decades, the power of microprocessors has increased more than one million times. But 20 years from now, microprocessors will probably be more than a million times again as powerful as they are today. And they’ll contain up to one billion transistors. Over the next few years the PC will remain the main computing tool for most people, but it will be joined by all kinds of new, microprocessor-powered devices that will make your life even easier. For example, when you’re traveling you’ll be able to call up your itinerary, send an e-mail postcard, book an appointment with your doctor or balance your bank account using a handheld PC that will know what information you need, and when and where you need it. And you’ll be able to get a map, hotel guide or the news from the Web via new kinds of cell phones. 计算机英语 307 Section B Louis V. Gerstner Jr.1: IT and the Reformation of Chinese State-Owned Enterprises (excerpts) China is very special to me. I’ve had the privilege of visiting your country many, many times over the past 20 years. And I believe you know how proud we are of our business here, and the IBM China team led by my colleague, Henry Chow. We employ about 2,000 people in IBM China. We’ve established 7 joint ventures with an additional 3,000 employees in areas including application software, software development, and manufacturing. We enjoy relationships with hundreds of local Chinese business partners, and we continue to invest very heavily in China. Our storage business is among IBM’s most strategic and fastest-growing, and China is home to developments and manufacturing facilities that feed our assembly plants all over the world. …… Mandarin / 5mAndErin / n.(中国)官话; (中 国)国语 Last fall, I was personally honored to host President Jiang during his trip to the United States. And at his request, we demonstrated some of IBM’s latest technologies, including one we are extremely proud of: a speech recognition program for Mandarin—a fantastic product developed right here in our advanced research laboratory in Beijing. Yesterday, I had the pleasure of meeting with President Jiang once again. We shared a lot of positive ideas of how we can strengthen IBM’s relationship with China and serve China’s interest in the reformation of Chinese state-owned enterprises. IBM has enjoyed a relationship with China that has endured for more 1 Louis V. Gerstner Jr.:小路易斯·V·格斯特纳,亦译作郭士纳,1965 年在哈佛商学院获工商管理硕士学位。 1993 年开始任 IBM 董事会主席兼首席执行官。 308 sweeping / 5swi:piN / a. 全面的;势不可 挡的 underscore / 7QndE5skC: / a. 强调;加强 Computer English than half a century. But I do not believe there has ever been a more exciting time to be doing business here, as vast new opportunity is created by your sweeping modernization and ambitious, government-led reform programs for thousands of state-owned enterprises. This transformation, I believe, will underscore the critical importance of information technology as a driver of competitive success and real economic growth for China. …… Today, in almost every industry in almost every part of the world there are many examples of enterprises applying this technology to seize competitive advantage and to create enormous challenges for their competitors. I think we’re seeing information technology reach the point that all transformational technologies reach when they are no longer controlled by just a small group of skilled professionals, and they cross over to mass acceptance and ubiquity. infancy / 5infEnsi / n. 婴儿期;初期 cable television 有线电视 Networking technology is still in its infancy, yet it’s reached already the point where we can call it a new mass medium. Consider that in the U.S.: Radio took about 30 years to attract 50 million users. Television took 13 years. Cable television took 10 years. The Internet did it in half that. Less than 5 years after the birth of the World Wide Web, some 90 million people are online around the world, and that number will be hundreds of millions before too long. Of course, right now, the U.S. has embraced the Net more fully than other nations, both in terms of individual users, and business use. But, clearly, this is a global medium. Very soon there will be equal numbers of people accessing the Web in English and other languages. Five countries other than the U.S. have around ten percent of their populations using the Web. Here in China, the number of Internet users has nearly doubled since just last October, to more than 1 million users. And I’ve seen statistics that say your Internet population will exceed 7 million people by the year 2001. Some people are talking about a phenomenon they call “Internet 计算机英语 leapfrog / 5li:pfrCg / n. & v.(作)跳背 游戏 astute / E5stju:t / a. 敏锐的,精明的 bypass / 5baipB:s / v. 绕过;越过 equate / i5kweit / v.(认为…)等同 309 Leapfrog”, a high-stakes game in which countries that make the most astute use of networked technologies quickly bypass other regions in production, productivity, and profitable growth. Today, this contest of Internet Leapfrogging is played on a wide-open field. We have about 90 million connected users and some equate that with universal connectivity. But consider that if just 4 percent of the populations of your nation and India got connected tomorrow, the worldwide number of Internet users would double. These numbers are interesting, but the real important question is: “What are all these individuals, and the world’s leading institutions, doing on the Net?” Not too long ago, the prevailing view was that the Net was about looking up information, or that it was a medium for interpersonal communication, a replacement for the telephone or post office. Today, it’s evident that the Net represents a transformation far more profound than online “chat” groups or giving people access to sports scores and weather reports. It has emerged as a powerful means for parties of every type to conduct interactions of every type. Certainly, it’s changing the way things are bought and sold. Electronic commerce is booming. Even the most conservative estimates say that it will be at least a $200 billion marketplace by the turn of the century (which is only 500 days away)—most of that volume in business to business transactions. And while 86 percent of Internet commerce was generated inside the U.S. last year, the rest of the world is getting into the game in a serious way. Internet commerce generated outside the U.S. will represent more than 35 percent of the world total by the year 2002. But what’s going on isn’t just limited to commerce, to buying and selling. At IBM, we use a slightly more descriptive term. We talk about e-business to describe all of the vital transactions that will be conducted on the Net. E-business includes transactions among employees inside an enterprise; among trading partners in a supply chain; and of course, the networked transactions that transform the way educators teach students, physicians treat patients, and the way governments deliver services to citizens. 310 Computer English All of these interactions will become digital. They won’t necessarily replace the kind of physical transactions we know today, but they will augment them. …… embark / em5bB:k / v. 着手,开始工作 (on, upon) align / E5lain / v. 调整;使结盟 China is embarking on an extraordinary new stage of its economic and industrial development. The restructuring of the state-owned enterprises is as big a transformation as any country has ever seen, let alone implemented. The process of transformation of the state-owned enterprises is well underway, as we discussed with Minister Sheng and President Jiang yesterday. Today it is working at the first stage of enterprise restructuring, which is to align industries, align assets, merge companies, and to create an industry infrastructure that is organizationally capable of becoming a globally successful enterprise or globally successful industry. However, there’s another phase to economic reform of state-owned enterprises that goes beyond structure, that goes beyond merging, that goes beyond aligning. It’s about the processes by which the enterprises are managed. benchmarking / 5bentFmB:kiN / n.(企业管理上的) 标杆学习 The systems of cost control, of accounting, of inventory management, of supply chain management, of cash management, of customer relationships, and of benchmarking—these are all systems that aren’t created through structural change. They’re created through process and cultural change. And underpinning all of those systems—what drives the creation of those systems—is information technology.1 Information technology is the science—the underlying science—of institutional restructuring. It is the science you use to restructure institutions. It is the basis and the tools by which you build systems that allow institutions to be efficient and globally competitive. China’s information technology industry needs to evolve today along with the state-owned enterprises to support the transformation of China’s enterprises. 1 And underpinning all of those systems—what drives the creation of those systems—is information technology.:而 所有那些系统的基础——那些系统建立的驱动力——都离不开信息技术。本句为倒装句,主语是 information technology。 计算机英语 311 Today China’s information technology industry is principally a hardware-based industry. But it is absolutely critical that China build a software and services industry along with its hardware industry if the transformation of the state-owned enterprises is going to take place. Because what we need in China are applications. We already have the computers, but what China needs now are the applications that run on the computers that will allow the state-owned enterprises to achieve this transformation. I’m not talking about simple, unsophisticated software like spreadsheets, word processing, or games. I’m talking about large, complex software that allows these companies to do all the things I talked about before: transaction processing, data management, billing, cash management, managing platforms, e-business opportunities. China needs to build the industry that will adapt applications for and build new applications out of the intellectual capital of the Chinese people. And then a services industry has to emerge that will help China’s institutions apply these technologies to their state-owned enterprises. And finally there is, in my opinion, a very big opportunity for China to lead in the transformation of small and medium sized companies, including smaller state-owned enterprises—because what will happen in the future is that software applications that allow companies to become efficient and globally competitive will be embedded in a network. telecom / 5telikCm / n. 电信 Small and medium sized companies will not have to build those applications. They will not have to pay for those applications. If China’s telecom industry develops in the way we expect it will, and if focus is given to these Chinese applications, small and medium sized businesses will be able to, in effect, rent the applications, dial up on their telephone, and have a billing application, an accounting application, or an e-business application, to use without having to build it, pay up front1, or maintain it. But again, this requires a focus in China on the next stage of development of the information technology industry, which is to move beyond just making PCs and hardware to making intellectual capital, to making the real heart of an information technology system, which is the application, not the hardware. 1 up front:<口> 预先,先期。 312 Computer English So it’s interesting to see how China’s extraordinarily important priority of restructuring the state-owned enterprises aligns very clearly and carefully with the next stage of development of the information technology industry in China. It aligns very clearly with the next phase of the information technology, which is e-business. And through the evolution of Chinese-based applications, building on the e-business concept, there’s a lot of opportunity and, I think, a lot of optimism about the success of the state-owned enterprise reformation program. Thank you very much. ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. Not too long ago, it was generally thought that the Internet was a medium for people to look up ________, or to conduct interpersonal ________. 2. At IBM, the term ________ is used to describe all of the vital transactions conducted on the Internet. 3. According to Gerstner, information technology is the basis and underlying science of institutional ________. 4. The real heart of an information technology system is not the hardware, but the ________. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. 5. networking technology assembly plant state-owned enterprise economic reform supply chain 6. 7. 8. 9. 10. 有线电视 成本控制 合资企业 应用软件 库存管理 计算机英语 313 Section C Andrew S. Grove1: Only the Paranoid Survive Sooner or later, something fundamental in your business world will change. motto / 5mCtEu / n. 箴言,格言 paranoid / 5pArEnCid / a. 患偏执狂的;多 疑的 paranoia / 7pArE5nCiE / n. 偏执狂;多疑症 inculcate / 5inkQlkeit / v. 反复灌输 guardian / 5gB:diEn / n. 守卫者,保护者 prematurely / 7premE5tjuEli / ad. 不成熟地 morale / mC5rB:l / n. 士气;道德 slack / slAk / v. 放松,松弛 displace / dis5pleis / v. 取代,替代 inflection / in5flekFEn / n. 拐折;回折点 inflection point 拐点,回折点 1 2 I’m often credited with the motto, “Only the paranoid survive.” I have no idea when I first said this, but the fact remains that, when it comes to business, I believe in the value of paranoia. Business success contains the seeds of its own destruction. The more successful you are, the more people want a chunk of your business and then another chunk and then another until there is nothing left. I believe that the prime responsibility of a manager is to guard constantly against other people’s attacks and to inculcate this guardian attitude in the people under his or her management. The things I tend to be paranoid about vary. I worry about products getting screwed up, and I worry about products getting introduced prematurely. I worry about factories not performing well, and I worry about having too many factories. I worry about hiring the right people, and I worry about morale slacking off2. And, of course, I worry about competitors. I worry about other people figuring out how to do what we do better or cheaper, and displacing us with our customers. But these worries pale in comparison to how I feel about what I call strategic inflection points. I’ll describe what a strategic inflection point is a bit later in this book. For now, let me just say that a strategic inflection point is a time in the life of a business when its fundamentals are about to change. That change can mean an opportunity to rise to new heights. But it may just as likely signal Andrew S. Grove:安德鲁·S·葛洛夫(1936~),英特尔公司前总裁。本文系其 1996 年 9 月出版的 IT 经典著作“Only the Paranoid Survive”的前言部分。该书的中译本《只有偏执狂才能生存》已于 1997 年 5 月由《光明日报》出版社出版。 slack off:松弛,懈怠。 314 Computer English the beginning of the end. insidiously / in5sidiEsli / ad. 阴险地;不知不 觉间加剧地;隐伏地 mince / 5mins / v. 装作高雅地说 deadly / 5dedli / a. 致命的 adept / E5dept / a. 熟练的,擅长的 incumbent / in5kQmbEnt / n. 现任者,在职者 dedicate / 5dedikeit / v. 把…献给,把… 用于 Strategic inflection points can be caused by technological change but they are more than technological change. They can be caused by competitors but they are more than just competition. They are full-scale changes in the way business is conducted, so that simply adopting new technology or fighting the competition as you used to may be insufficient. They build up force so insidiously that you may have a hard time even putting a finger on1 what has changed, yet you know that something has. Let’s not mince words2: A strategic inflection point can be deadly when unattended to. Companies that begin a decline as a result of its changes rarely recover their previous greatness. But strategic inflection points do not always lead to disaster. When the way business is being conducted changes, it creates opportunities for players who are adept at operating in the new way. This can apply to newcomers or to incumbents, for whom a strategic inflection point may mean an opportunity for a new period of growth. You can be the subject of a strategic inflection point but you can also be the cause of one. Intel, where I work, has been both. In the mid-eighties, the Japanese memory producers brought upon us an inflection point so overwhelming that it forced us out of memory chips and into the relatively new field of microprocessors. The microprocessor business that we have dedicated ourselves to has since gone on to cause the mother of all inflection points for other companies, bringing very difficult times to the classical mainframe computer industry. Having both been affected by strategic inflection points and having caused them, I can safely say that the former is tougher. I’ve grown up in a technological industry. Most of my experiences are rooted there. I think in terms of technological concepts and metaphors, and a lot of my examples in this book come from what I know. But strategic inflection points, while often brought about by the workings of technology, are not restricted to technological industries. The fact that an automated teller machine could be built has changed banking. If interconnected inexpensive computers can be used in medical diagnosis and consulting, it may change medical care. The possibility that all entertainment content can be created, stored, transmitted and displayed 1 2 put a finger on:多作 put one’s finger on,意为“明确地指出”。 mince words:常用于否定句,意为“说话婉转”。 计算机英语 315 in digital form may change the entire media industry. In short, strategic inflection points are about fundamental change in any business, technological or not. pulsate / 5pQlseit / v.(心脏、动脉等) 搏动,跳动 moat / mEut / n. 护城河;深沟 verge / vE:dV / n. 边,边缘 constructive / kEn5strQktiv / a. 建设性的 energetic / 7enE5dVetik / a. 精力充沛的;充 满活力的 well-being / 5wel5bi:iN / n. 康乐,安康 cataclysmic / 7kAtE5klizmik / a. 灾难性的;剧烈 的;巨变的 engulf / in5gQlf / v. 吞没,淹没 1 2 We live in an age in which the pace of technological change is pulsating ever faster, causing waves that spread outward toward all industries. This increased rate of change will have an impact on you, no matter what you do for a living. It will bring new competition from new ways of doing things, from corners that you don’t expect. It doesn’t matter where you live. Long distances used to be a moat that both insulated and isolated people from workers on the other side of the world. But every day, technology narrows that moat inch by inch. Every person in the world is on the verge of1 becoming both a coworker and a competitor to every one of us, much the same2 as our colleagues down the hall of the same office building are. Technological change is going to reach out and sooner or later change something fundamental in your business world. Are such developments a constructive or a destructive force? In my view, they are both. And they are inevitable. In technology, whatever can be done will be done. We can’t stop these changes. We can’t hide from them. Instead, we must focus on getting ready for them. The lessons of dealing with strategic inflection points are similar whether you’re dealing with a company or your own career. If you run a business, you must recognize that no amount of formal planning can anticipate such changes. Does that mean you shouldn’t plan? Not at all. You need to plan the way a fire department plans: It cannot anticipate where the next fire will be, so it has to shape an energetic and efficient team that is capable of responding to the unanticipated as well as to any ordinary event. Understanding the nature of strategic inflection points and what to do about them will help you safeguard your company’s well-being. It is your responsibility to guide your company out of harm’s way and to place it in a position where it can prosper in the new order. Nobody else can do this but you. If you are an employee, sooner or later you will be affected by a strategic inflection point. Who knows what your job will look like after cataclysmic change sweeps through your industry and engulfs the company you work for? Who knows if your job will even exist and, frankly, who will care besides you? on the verge of:接近于,濒于。 much the same:差不多一样,几乎一样。 316 Computer English Until very recently, if you went to work at an established company, you could assume that your job would last the rest of your working life. But when companies no longer have lifelong careers themselves, how can they provide one for their employees? layoff / 5leiCf / n.(尤指临时)解雇 proprietor / prEu5praiEtE / n. 所有人,业主 As these companies struggle to adapt, the methods of doing business that worked very well for them for decades are becoming history. Companies that have had generations of employees growing up under a no-layoff policy are now dumping 10,000 people onto the street at a crack1. The sad news is, nobody owes you a career. Your career is literally your business. You own it as a sole proprietor. You have one employee: yourself. You are in competition with millions of similar businesses: millions of other employees all over the world. You need to accept ownership of your career, your skills and the timing of your moves. It is your responsibility to protect this personal business of yours from harm and to position it to benefit from the changes in the environment. Nobody else can do that for you. Having been a manager at Intel for many years, I’ve made myself a student of strategic inflection points. Thinking about them has helped our business survive in an increasingly competitive environment. I’m an engineer and a manager, but I have always had an urge to teach, to share with others what I’ve figured out for myself. It is that same urge that makes me want to share the lessons I’ve learned. memoir / 5memwB: / n. 回忆录;自传 arena / E5ri:nE / n. 竞技场; 活动场所 camouflage This book is not a memoir. I am involved in managing a business and deal daily with customers and partners, and speculate constantly about the intentions of competitors. In writing this book, I sometimes draw on observations I have made through such interactions. But these encounters didn’t take place with the notion that they would make it into any public arena. They were business discussions that served a purpose for both Intel and others’ businesses, and I have to respect that. So please forgive me if some of these stories are camouflaged in generic descriptions and anonymity. It can’t be helped. / 5kAmuflB:V / v. 伪装;掩饰 anonymity / 7AnE5nimEti / n. 匿名 1 at a crack:瞬间。 What this book is about is the impact of changing rules. It’s about finding your way through uncharted territories. Through examples and reflections on my and others’ experiences, I hope to raise your awareness of what it’s like to go through cataclysmic changes and to provide a framework in which to deal with them. 317 计算机英语 ———————————————— Exercises I. Fill in the blanks with the information given in the text: 1. The author defines a strategic inflection point as a time in the life of a business when its ________ are about to change. 2. Strategic inflection points can not only lead to disaster but also create ________. 3. Although strategic inflection points are often brought about by the workings of ________, they are not restricted to ________ industries. 4. Because of competition from the Japanese, IBM was forced out of the field of ________ and into the field of ________ in the mid-eighties. II. Translate the following terms or phrases from English into Chinese and vice versa: 1. 2. 3. 4. strategic inflection point media industry mainframe computer problem diagnosis 5. 6. 7. 8. 技术概念 自动柜员机 存储芯片 竞争环境 318 Computer English Appendix I Glossary (词汇表) A a priori / 7eiprai5C:rai / ad. abbreviation / E7bri:vi5eiFEn / n. abstract / Ab5strAkt / v. abstraction / Ab5strAkFEn / n. access list accessory / Ek5sesEri / n. accommodate / E5kCmEdeit / v. accountancy / E5kauntEnsi / n. accounting / E5kauntiN / n. acronym / 5AkrEnim/ n. activate / 5Aktiveit / v. actualization / 7AktFuElai5zeiFEn / n. acumen / E5kju:men / n. ad / Ad / n. adage / 5AdidV / n. adapter / E5dAptE / n. address / E5dres / v. address bus Address Resolution Protocol addressee / 7Adre5si: / n. adept / E5dept / a. adjacent / E5dVeisEnt / a. adjoining / E5dVCiniN / a. administer / Ed5ministE / v. administrator / Ed5ministreitE / n. advent / 5Advent / n. adversary / 5AdvEsEri / n. adversely / 5AdvE:sli / ad. affirmation / 7AfE5meiFEn / n. afresh / E5freF / ad. aggregate a. / 5AgrigEt / & v. / 5Agrigeit / aggregation / 7Agri5geiFEn / n. agility / E5dVilEti / n. agnostic / Ag5nCstik / a. akin / E5kin / a. algorithm / 5AlgEri TEm / n. align / E5lain / v. alleged / E5ledVd / a. alleviate / E5li:vieit / v. allocate / 5AlEkeit / v. allot / E5lCt / n. <拉> 用演绎方法,经推理(8C) 缩写(词)(11B) 把…抽象出来;提出,抽出(5B) 抽象;提取(4B) 存取表,存取清单,访问表(9B) 附件,配件(1B) 容纳;使适应(2B) 会计学(12A) 会计(制度);结账;结算(13A) 首字母缩拼词(2C) 激活,启动(14A) 实现(8A) 敏锐;聪明(13B) <口> 广告(13C) 谚语;格言(12B) 适配器(3C) 对付,处理(4A)∕编(址);寻(址) (11A) 地址总线(2A) 地址解析协议(10B) 收信人;收件人(8A) 熟练的,擅长的(15C) 邻近的,毗连的(10A) 贴邻的,毗连的(10B) 掌管;实施(6A) (系统)管理员(6C) 出现,到来(1A) 对手,敌手(14C) 不利地,有害地(9B) 肯定(8B) 重新(12A) 聚集的(6A)∕(使)聚集(13B) 聚集,聚合(9B) 敏捷,灵活(13B) 不可知论(者)的(15A) 同类的;近似的(11C) 算法(6A) 调整;使结盟(15B) 被说成的;被断言的;所谓的(12A) 减轻,缓解(5C) 分配;分派(6B) 分配;分派(3A) 计算机英语 ambiguous / Am5bigjuEs / a. ample / 5Ampl / a. amplify / 5Amplifai / v. analog(ue) / 5AnElCg / a. analogous / E5nAlEgEs / a. analytical / 7AnE5litikEl / a. Analytical Engine ancestor menu 含糊不清的,模棱两可的(4A) 充裕的,足够的(13B) 放大,增强(10A) 模拟的(1A) 相似的;可比拟的(7A) 分析的(1A) 分析机,解析机(1A) 祖辈菜单(面向对象编程术语,指所有的菜单都 要继承该菜单的属性、方法、事件等特征)(5C) 异常(现象);不按常规(7A) 匿名(15C) 附加(11B) 小应用程序(4C) 近似(值)(1A) 神秘的,晦涩难解的;秘密的(4C) 考古学家(1B) 把…存档(12C) 竞技场;活动场所(15C) 变元,自变量(5C) 一系列,大量(3A)∕数组,阵列(4A) 巧妙办法(7C) 人工智能(1A) 人工生命(12C) (电视、电影图像的)高宽比,纵横比(2C) 汇编程序(5A) 汇编码(4C) 汇编语言(4A) 赋值语句(4A) 敏锐的,精明的(15B) 不同时的;异步的,非同步的(6A) 地图集(12B) 在…顶上(5B) 附件(14B) 审核;检查(14A) 扩大;增加(8C) 验证,认证(6A) 经授权的(6A) 自动个人电脑(15A) (使)自动化(5A) 自动化(1A) 自治的;独立存在的(6A) 自主主体(6A) anomaly / E5nCmEli / n. anonymity / 7AnE5nimEti / n. append / E5pend / v. applet / 5AplEt / n. approximation / E7prCksi5meiFEn / n. arcane / B:5kein / a. archeologist / 7B:ki5ClEdVist / n. archive / 5B:kaiv / v. arena / E5ri:nE / n. argument / 5B:gjumEnt / n. array / E5rei / n. artifice / 5B:tifis / n. artificial intelligence artificial life aspect ratio assembler / E5semblE / n. assembly code assembly language assignment statement astute / E5stju:t / a. asynchronous / ei5siNkrEnEs / a. atlas / 5AtlEs / n. atop / E5tCp / prep. attachment / E5tAtFmEnt / n. audit / 5C:dit / v. augment / C:g5ment / v. authentication / C:7Wenti5keiFEn / n. authorized / 5C:WEraizd / a. Auto PC automate / 5C:tEmeit / v. automation / 7C:tE5meiFEn / n. autonomous / C:5tCnEmEs / a. autonomous agent B backbone / 5bAkbEun / n. back-end / 5bAk5end / a. & n. backplane / 5bAkplein / n. backup / 5bAkQp / n. 319 骨干;基础;骨干网(8B) 后端(的)(13B) 底板(9B) 备份,后备(9B) 320 Computer English ballpark / 5bC:lpB:k / n. bandwagon / 5bAnd7wAgEn / n. bandwidth / 5bAndwidW / n. basic / 5beisik / n. benchmark / 5bentFmB:k / n. benchmarking / 5bentFmB:kiN / n. benevolence / bi5nevElEns / n. beta / 5bi:tE / n. beta testing better / 5betE / ad. bill / bil / v. billing / 5biliN / n. binary / 5bainEri / a. & n. bit / bit / n. blackout / 5blAkaut / n. blinding / 5blain diN / a. block / blCk / n. blockbuster / 5blCk7bQstE / n. blur / blE: / v. bombsight / 5bCmsait / n. bookkeeping / 5buk7ki:piN / n. boot / bu:t / v. & n. boot sector bottleneck / 5bCtlnek / n. bound / baund / n. bounds checking break-in / 5breikin / n. bridge / bridV / n. bridging / 5bridViN / n. briefcase / 5bri:fkeis / n. broadband / 5brC:dbAnd / a. brochure / 5brEuFE / n. broker / 5brEukE / n. & v. brownout / 5braunaut / n. browse / brauz / v. browser / 5brauzE / n. buffer / 5bQfE / v. & n. bug / bQg / n. building block bulletin / 5bulitin / n. bursty / 5bE:sti / a. bus / bQs / n. bust / bQst / v. buzzword / 5bQzwE:d / n. bypass / 5baipB:s / v. byte / bait / n. bytecode / 5baitkEud / n. 球场;(连同看台的)棒球场(15A) 乐队彩车;浪潮,时尚(5B) 带宽(8B) [常作~s] 基本原理;基本因素(4B) 基准(尺度);基准程序;基准测试(3C) (企业管理上的)标杆学习(15B) 善意,仁慈(12C) 希腊语的第二个字母(B,β);测试版(1B) β测试(1B) 多(于)(than)(10B) 给…开账单;把…登帐(8A) 开(帐)单;记账(13A) 二进制的(1A)∕二进制(3C) 位,比特(1A) 断电,停电(14A) 眩目的,使人眼花缭乱的(3B) (字、信息、程序、数据等的)块;分程序(2A) 重磅炸弹;了不起的人(或事物)(2C) 使模糊不清(8A) 轰炸瞄准器(1A) 簿记,登录账目(3A) (亦作 boot up)引导,启动(1C) 引导(扇)区(14B) 瓶颈,障碍(7A) [常作~s] 边界;界限,界线(4C) 边界检查(4C) 闯入;盗窃(14A) 网桥,桥接器(6A) 桥接,跨接(9B) 公文包(1A) 宽带的(8C) 小册子;情况介绍手册(13B) 代理者;代理程序(4C)∕作为代理行事(12C) 负载偏重期,电压不足(14A) 浏览(4C) 浏览器(4C) 缓冲,缓存(3B)∕缓冲区,缓冲器(14A) (程序)错误,缺陷,故障(5A) 积木块,构造快(13B) 公告,布告(14A) 猝发的,突发的(8C) 总线(1A) 爆裂;打碎(10C) 玄妙的术语;时髦词语(6B) 绕过;越过(15B) 字节(1A) 字节码(4C) C 计算机英语 cable modem cable television cabling / 5keibliN / n. cache / 5kAF / n. & v. camcorder / kAm5kC:dE / n. camouflage / 5kAmuflB:V / v. carrier / 5kAriE / n. carrier sense carte blanche / 5kB:t5blCnF / n. cartographic / 7kB:tE5grAfik / a. cartography / kB:5tCgrEfi / n. cartridge / 5kB:tridV / n. cataclysmic / 7kAtE5klizmik / a. catastrophe / kE5tAstrEfi / n. catchment / 5kAtFmEnt / n. categorize / 5kAtigEraiz / v. cathode / 5kAWEud / n. cathode ray tube caution / 5kC:FEn / n. cave painting cell / sel / n. cell phone cellular / 5seljulE / a. cellular telephone Celsius / 5selsiEs / a. census / 5sensEs / n. centric / 5sentrik / a. certificate / sE5tifikEt / n. certified check character code character set chassis / 5FAsi / n. checksum / 5tFeksQm / n. child window chunk / tFQNk / n. ciphertext / 5saifEtekst / n. circuit breaker circuitry / 5sE:kitri / n. circulation / 7sE:kju5leiFEn / n. civil liberty clarity / 5klArEti / n. class hierarchy classified ad clean / kli:n / a. clear / kliE / v. clerical / 5klerikEl / a. click / klik / v. & n. click-on / 5klikCn / a. clip / klip / n. & v. 321 电缆调制解调器(15A) 有线电视(15B) [总称] 电缆,连线(10A) 高速缓冲存储器(3C)∕高速缓存(10C) (可携式)摄像机(11C) 伪装;掩饰(15C) 载波(9A) 载波检测,载波监听(9A) <法> 全权,自由处理权(14C) 地图绘制的(12B) 地图绘制(12B) 盒,匣(5A) 灾难性的;剧烈的;巨变的(15C) 灾难,灾祸(14A) 承水处;流域(12B) 将…分类(8A) 阴极(2A) 阴极射线管(2A) 小心,谨慎(7B) (旧石器时代的)洞穴壁画(艺术)(12A) 单元;单元格(8C) 蜂窝电话,移动电话,手机(1B) 蜂窝状的,多孔的(8A) 蜂窝电话,移动电话,手机(8A) (温度)摄氏的(4B) 人口普查(1A) 中心的(13B) 证(明)书(6A) 保付支票,保兑支票(13A) 字符代码(5C) 字符集(5C) 底盘,底架,底板(9B) 检查和,校验和,检验和(3C) 子窗口(4B) (大)块;程序块;组块(7A) (加)密文(本)(13A) 断路器(14A) 电路(1A) 循环;环流(12B) [常作复] 公民自由(13A) 清晰,明晰(4C) 类层次(4B) 分类广告(13C) 无错误的;畅通无阻的;顺利的(10C) 结清;结账(13A) 职员的;文书的(12A) 鼠(标点)击(1B)∕(鼠标的)点击(4B) (鼠标)点击(式)的(3A) 夹子,夹具(2A)∕(用夹子、回形针等)夹住, 322 clipper chip clog / 5klCg / v. clone / klEun / n. closed loop closet / 5klCzit / n. clustered / 5klQstEd / a. clutter / 5klQtE / n. coaxial / 7kEu5AksiEl / a. code / kEud / v. code generator code set coexist / 7kEuig5zist / v. coherent / kEu5hiErEnt / a. cohesive / kEu5hi:siv / a. coincidental / kEu7insi5dentEl / a. collaborate / kE5lAbEreit / v. collaboration / kE7lAbE5reiFEn / n. collaborative / kE5lAbEreitiv / a. collision detection colon / 5kEulEn / n. combobox / 5kCmbEubCks / n. command line commence / kE5mens / v. commentator / 5kCmEnteitE / n. commonality / 7kCmE5nAlEti / n. commonplace / 5kCmEnpleis / a. commute / kE5mju:t / n. compact / kEm5pAkt / a. compact disc compatible / kEm5pAtEbl / a. & n. compensate / 5kCmpenseit / v. competitor / kEm5petitE / n. compile / kEm5pail / v. compiled code compiled language compiler / kEm5pailE / n. compliance / kEm5plaiEns / n. compliant / kEm5plaiEnt / a. complicate / 5kCmplikeit / v. comply / kEm5plai / v. component code computation / 7kCmpju:5teiFEn / n. computational / 7kCmpju:5teiFEnEl / a. compute / kEm5pju:t / v.& n. computing / kEm5pju:tiN / n. conceive / kEn5si:v / v. conceptual / kEn5septjuEl / a. conceptual model conceptually / kEn5septjuEli / ad. Computer English 扣住(1B) 加密芯片(14A) 塞满;阻塞(14A) 克隆;克隆机,兼容机(3A) 闭环(12B) 小房间;(壁)橱(10A) 成簇的(7B) 凌乱,杂乱;杂乱的东西(4C) 同轴的(9A) 编码,编程序(4B) 代码生成器(13B) 代码集(5C) 共存;同时存在(6A) 协调的;一致的(9A) 黏合(或聚合)在一起的(10A) 巧合的,碰巧的(12A) 合作,协作(3B) 合作,协作(3A) 合作的,协作的(6A) 冲突检测(8B) 冒号(11A) 组合框(5B) 命令行(3A) 开始(6A) 时事评论员;评论者(12A) 共同特征;共性(9A) 普通的,平凡的(12A) 上下班交通(路程)(9C) 小巧的;紧密的(1B) 光盘(3A) 兼容的(3A)∕兼容机(10B) 补偿,赔偿(14C) 竞争者;对手(13B) 汇编;编译(1A) 编译执行的代码(4C) 编译执行的语言(5A) 编译程序,编译器(4A) 遵从;顺从(3B) 遵从的,顺从的(5C) 使复杂化(14B) 遵从,顺从(with)(5C) 组件编码(6A) 计算(2A) 计算(机)的(2A) 计算(6B) 计算(技术)(1A) (构)想出(1A) 概念的(6B) 概念模型(6C) 概念上(1A) 计算机英语 concurrency / kEn5kQrEnsi / n. concurrent / kEn5kQrEnt / a. concurrently / kEn5kQrEntli / ad. conditional statement conditioning / kEn5diFEniN / n. conferencing / 5kCnfErEnsiN / n. confidential / 7kCnfi5denFEl / a. confidentiality / 5kCnfi7denFi5AlEti / n. configuration / kEn 7figju5reiFEn / n. configure / kEn5figE / v. confine / 5kCnfain / n. conform / kEm5fC:m / v. congest / kEn5dVest / v. congestion / kEn5dVestFEn / n. conjecture / kEn5dVektFE / n. connotation / 7kCnE5teiFEn / n. consensus / kEn5sensEs / n. console / 5kCnsEul / n. consortium / kEn5sC:tjEm / n. constrain / kEn5strein / v. constraint / kEn5streint / n. constructive / kEn5strQktiv / a. contend / kEn5tend / v. contention / kEn5tenFEn / n. context switching contraction / kEn5trAkFEn / n. contractual / kEn5trAktFuEl / a. control / kEn5trEul / n. converge / kEn5vE:dV / v. convergence / kEn5vE:dVEns / n. conversion / kEn5vE:FEn / n. convoluted / 5kCnvElu:tid / a. cooperative / kEu5CpErEtiv / a. coral / 5kCrEl / n. cordless telephone corporate / 5kC:pErEt / a. corrupt / kE5rQpt / v. corruption / kE5rQpFEn / n. cost effectiveness cost model cost-effective / 5kCsti5fektiv / a. counterfeiter / 5kauntE7fitE / n. counterpart / 5kauntEpB:t / n. courier / 5kuriE / n. coverage / 5kQvEridV / n. crack / krAk / v. cracker / 5krAkE / n. craft / krB:ft / v. credit card 323 同时发生,并发,并行性(6A) 同时发生的,并发的,并行的 (7A) 同时发生地,并发地,并行地(4C) 条件语句(4A) 调节,调整(8A) 开会;会议技术(11C) 秘密的,机密的(9A) 机密性(13A) 配置(2B) 配置(2B) [常作~s] 界限,范围(6A) 遵照;符合(to, with)(3B) [常用于被动语态]挤满;拥塞(10C) 拥挤;拥塞(8C) 推测,猜想(1A) 内涵意义,隐含意义;内涵(6B) [常作定语]一致同意;一致(或多数人)意见(9A) 控制台(14B) ([复]-tia / -tjE / 或 -tiums)联营企业; (国际)财团,联盟(2C) 限制,约束(4C) 约束;限制(7A) 建设性的(15C) 争斗;竞争(13A) 争用;争夺(6A) 上下文转换(3A) 缩约词;缩约形式;缩约(8B) 合同(性)的(13A) 控件,控制器(4B) 收敛,会聚(8A) 收敛,会聚;(数码技术与模拟技术的)结合(8A) 转换;转变(2C) 盘绕的;盘错的,错综复杂的(4C) 合作的,协作的(14A) 珊瑚(1B) 无绳电话(8A) 公司的;社团的(6A)∕共同的;一致的(7C) 毁损,毁坏,破坏(14B) 毁损,毁坏,破坏(13A) 成本效益(6A) 成本模型(13A) 有成本效益的;合算的(6B) 伪造者(尤指伪造货币的人)(14A) 对应的物(或人)(5A) 信使(11B) 新闻报道;覆盖范围(14C) 破译(1A) 非法侵入(计算机系统)者(10C) 精心制作;周密制订(13B) 信用卡(8A) 324 criterion / krai5tiEriEn / n. crop / krCp / v. cryptic / 5kriptik / a. cryptographic / 7kriptE5grAfik / a. cryptography / krip5tCgrEfi / n. cryptosystem / 5kriptEu7sistEm / n. cull / kQl / v. cursor / 5kE:sE / n. custom / 5kQstEm / a. customization / kQstEmai5zeiFEn / n. customize / 5kQstEmaiz / v. cut-through / 5kQtWru: / a. cutting-edge / 5kQtiNedV / a. cyberspace / 5saibEspeis / n. Computer English ([复] -ria / -riE / 或 -rions)标准,准则(12B) 裁切,裁剪(2C) 隐含的;意义含糊的(4C) 使用密码的;密码学的(13A) 密码学;密码的使用(13A) 密码系统(13A) 挑出;挑选(13B) 光标(2A) 定制的(4B) 定制,用户化(7B) 定制,使用户化(4B) 穿越式的,直通的(8C) 尖端的,先进的(1B) 电脑空间,虚拟空间(13A) D daemon / 5di:mEn / n. data bus data declaration data mining data set data stream data-aware / 5deitEE7weE / a. database / 5deitEbeis / n. database manager datagram / 5deitEgrAm / n. dataset / 5deitEset / n. datum / 5deitEm / n. de facto / di:5fAktEu / a. deadly / 5dedli / a. dealership / 5di:lEFip / n. debit / 5debit / n. debit card debug / di:5bQg / v. debugger / di:5bQgE / n. debut / 5deibju: / n. decentralize / 7di:5sentrElaiz / v. decimal / 5desimEl / a. decipher / di5saifE / v. deck / dek / n. decode / 7di:5kEud / v. decrement / 5dekrimEnt / v. decryption / di:5kripFEn / n. dedicate / 5dedikeit / v. dedicated / 5dedikeitid / n. dedicated access deduce / di5dju:s / v. deduct / di5dQkt / v. 后台程序,守护程序(14C) 数据总线(2A) 数据声明(4A) 数据挖掘;数据采集(12C) 数据集(3A) 数据流(11A) 数据敏感的,数据感知的(7C) 数据库(1A) 数据库管理器(7A) 数据报(10B) 数据集(7C) ([复]data)数据(1A) <拉> 实际的,事实上的(4C) 致命的(15C) 商品特许经销商(15A) 借方;借入(13A) 借方卡(13A) 调试,排除(程序)中的错误(5A) 调试程序,调试器,排错程序(5A) <法> 首次登台演出;首次出现(10C) 分散(6A) 十进制的(1A) 破译,译解(8A) 叠;卡片叠,卡片组(5A) 译(码),解(码)(8A) 减少,减缩(10C) 解密,脱密(13A) 把…献给,把…用于(15C) 专用的(1A) 专线访问(11A) 推论,推断(4A) 扣除,减去(13A) 计算机英语 deem / di:m / v. default / di5fC:lt / n. defy / di5fai / v. degrade / di5greid / v. delayering / 7di:5leiEriN / n. delve / delv / v. demarcation / 7di:mB:5keiFEn / n. demise / di5maiz / n. demo / 5demEu / n. demodulate / di:5mCdjuleit / v. demodulator / di:5mCdjuleitE / n. demultiplex / 7di:5mQltipleks / v. denote / di5nEut / v. depict / di5pikt / v. deploy / di5plCi / v. deregulate / di:5regjuleit / v. deskilling / 7di:5skiliN / n. desktop / 5desktCp / a. & n. destructive / dis5trQktiv / a. detach / di5tAtF / v. device driver diagnosis / 7daiEg5nEusis / n. diagnostic / 7daiEg5nCstik / a./n. dialog box dial-up access Difference Engine differential / 7difE5renFEl / a. differentiate / 7difE5renFieit / v. diffuse / di5fju:z / v. digit / 5didVit / n. digitize / 5didVitaiz / v. dinosaur / 5dainEsC: / n. diode / 5daiEud / n. directory / di5rektEri / n. disastrous / di5zB:strEs / a. disclose / dis5klEuz / v. discrete / 5diskri:t / a. disgruntled / dis5grQntld / a. diskette / 5disket / n. dismal / 5dizmEl / a. disparity / dis5pArEti / n. displace / dis5pleis / v. disseminate / di5semineit / v. distortion / dis5tC:FEn / n. disturbance / dis5tE:bEns / n. dizzying / 5diziiN / v. documentation / 7dCkjumen5teiFEn / domain / dE5mein / n. n. 325 认为;相信(5B) 默认,缺省,系统设定值(5A) (公然)违抗(15A) 降低;退化(3C) 减少层次(12A) 搜索,翻查(4C) 分界;界线(9B) 死亡;终止(15A) <口> 演示;示范(产品)(demonstration 及 demonstrator 的缩略)(11C) 解调(8A) 解调器(2A) 分路,把…分成多路(8C) 表示;意思是(6B) 描绘;描写(6B) 部署;配置(3C) 撤销对…的管制规定,解除对…的控制(8B) 降低技术性(12A) 桌面的;台式的(1A)∕桌面;台式(计算)机(1C) 破坏(性)的,毁灭(性)的(14A) 使分开,使分离(14B) 设备驱动程序(5A) 诊断;判断(10C) (用于)诊断的;有助于诊断的(10C) / [常作~s; 用作单] 诊断学;诊断法(10A) 对话框(4B) 拨号访问(11A) 差分机(1A) 差分的;微分的(1B) 区分,区别(6B) 扩散;传播(12A) 数字(1A) 使数字化(12B) 恐龙;(尤指废弃过时的)庞然大物(4C) 二极管(2C) 目录(4C) 灾难性的(14B) 透露;揭露(1B) 分离的;离散的(10B) 不满的(14A) 软磁盘,软盘(14B) 令人忧郁的;差劲的,不怎么样的(10B) 不同,差异(6C) 取代,替代(15C) 散布;传播(13C) 失真,畸变(10A) 干扰(14A) 使人头晕目眩的;使人困惑的(6B) 文献资料,文档(14C) 领域,域(6A) 326 Computer English domain name doom / 5du:m / n. DOS box down side download / 7daun5lEud / v. & n. drive / draiv / n. driver / 5draivE / n. droplet / 5drCplit / n. drum / drQm / n. dual / 5dju:El / a. duke / dju:k / n. dupe / dju:p / v. duplex / 5dju:pleks / a. duplication / 7dju:pli5keiFEn / n. 域名(11A) 命运;毁灭(15A) DOS 箱,DOS 机(10B) 不利的一面,缺点(8B) 下载(2B) 驱动器(1C) 驱动器,驱动程序(1C) 小滴(2A) 磁鼓(2A) 双的;双重的(2C) 公爵(4C) 欺骗,愚弄(14C) 双工的(11C) 重复;复制(7A) E editor / 5editE / n. electrical contact electrical ground electronic / 7ilek5trCnik / n. electronic bulletin board electronic press kit elusive / i5lu:siv / a. embark / em5bB:k / v. embed / im5bed / v. embedded / im5bedid / a. empower / im5pauE / v. empowerment / im5pauEmEnt / n. emulate / 5emjuleit / v. emulator / 5emjuleitE / n. encapsulate / in5kApsEleit / v. encapsulation / in7kApsE5leiFEn / n. encipher / in5saifE / v. encode / en5kEud / v. encompass / in5kQmpEs / v. encrypt / in5kript / v. encryption / in5kripFEn / n. endoscopic / 7endE5skCpik / a. energetic / 7enE5dVetik / a. engulf / in5gQlf / v. enhance / in5hB:ns / v. ensue / in5sju: / v. entail / in5teil / v. entity / 5entiti / n. entrust / in5trQst / v. envision / in5viVEn / v. equate / i5kweit / v. erase / i5reiz / v. 编辑器,编辑程序(4B) 电触点(1A) 电器接地端(10A) 电子器件(11C) 电子公告板(14A) 电子版发行包(13C) 难以捉摸的;令人困惑的(1B) 着手,开始工作(on, upon) (15B) 把…嵌入(1A) 嵌入(式)的,内嵌的(7A) 授权给;使能够(15A) 授权;给人能力(15A) 仿效;仿真(13A) 仿真器;仿真程序(3B) 封装(4B) 封装(4C) 把…译成密码(1A) 把…编码;把…译成电码(或密码) (5A) 包含,包括(6A) 把…加密(13A) 加密(6A) 内窥镜的;(用)内窥镜检查的(1B) 精力充沛的;充满活力的(15C) 吞没,淹没(15C) 增强(1A) 接着发生;因而产生(12A) 使成为必要,需要(9A) 实体(6B) 委托,交托(9A) 想像,展望(15A) (认为…)等同(15B) 擦除,清除(2A) 计算机英语 ergonomics / 7E:gE5nCmiks / n. [用作单或复] 人机工程学,人类工程学, 工效学(1B) 本质,实质(4A) 蚀刻(1A) 事件驱动的(4B) 例外地,格外,特别(11C) 可执行文件(14B) 可执行文件(5C) 执行,运行(1A) 奇异的(8B) 专门知识(或技能),专长(14C) 满期;截止(13A) 解释的,说明的(4B) 明确的;详述的(8C) 明确地;直言地(4C) 指数的;可用指数函数表示的(15A) 表达式(4A) 可扩展性,可扩充性(6A) 扩展名(5C) 取出;提取;设法得到(9A) essence / 5esEns / n. etch / etF / v. event-driven / i5vent7drivEn / a. exceptionally / ik5sepFEnEli / ad. EXE file executable / 5eksikju:tEbl / n. execution / 7eksi5kjuFEn / n. exotic / ig5zCtik / a. expertise / 7ekspE:5ti:z / n. expiration / 7ekspi5reiFEn / n. explanatory / ik5splAnEtEri / a. explicit / ik5splisit / a. explicitly / ik5splisitli / ad. exponential / 7ekspEu5nenFEl / a. expression / ik5spreFEn / n. extensibility / ik7stensE5bilEti / n. extension / ik5stenFEn / n. extract / ik5strAkt / v. F fabricate / 5fAbrikeit / v. facilitate / fE5siliteit / v. facsimile / fAk5simili / n. Fahrenheit / 5fArEnhait / a. fascination / 7fAsi5neiFEn / n. fast food n. fault tolerance n. fiber / 5faibE / n. fiber-optic / 5faibEr5Cptik / a. fibre optics field / fi:ld / n. & v. fieldworker / 5fi:ld7wE:kE / n. File Transfer Protocol fill / fil / n. finger / 5fiNgE / n. firewall / 5faiEwC:l / n. firmware / 5fE:mweE / n. Flash BIOS flat file flatbed scanner flatten / 5flAtEn / v. flattening / 5flAtEniN / n. flaw / flC: / n. fledged / fledVd / a. floppy / 5flCpi / a. 制作(1A) 使变得(更)容易;促进(7A) 传真(8A) 华氏(温度计)的(4B) 强烈的爱好,迷恋;魅力(14C) 快餐(12A) 容错(6A) 光纤(8B) 光纤的(8A) [复]光纤;[用作单]纤维光学(12A) 字段,域,信息组(2B)∕派…上场;实施; 产生(4C) 一线工作人员(12A) 文件传输协议(10B) 填充(8C) finger 命令,远程用户信息服务命令(14C) 防火墙(6A) [总称] 固件(2A) 可擦写 BIOS(14B) 平面文件(7C) 平板扫描仪(2A) 压缩,精简(9B) 压缩,精简(12A) 缺点,瑕疵(4C) 羽毛已长成的;成熟的(3B) (松)软的(2A) 327 328 Computer English floppy disk n. flux / flQks / n. focal / 5fEukEl / a. font / fCnt / n. footer / 5futE / n. foreign key foresight / 5fC:sait / n. formulate / 5fC:mjuleit / v. forum / 5fC:rEm / n. foster / 5fCstE / v. fragile / 5frAdVail / a. frame / freim / n. frame relay fraudulent / 5frC:djulEnt / a. fraught / frC:t / a. free memory freeware / 5fri:weE / n. front-end / 5frQnt5end / a. & n. full-duplex / 5ful5dju:pleks / a. function call function statement functional language functionality / 7fQNkFE5nAlEti / n. funnel / 5fQnEl / v. fuse / fju:z / v. 软(磁)盘(2A) (不断的)变动(5B) 焦点的(7A) 字体(5C) 页脚;脚注(11B) 外键(7B) 预见;深谋远虑(13B) 构想出;系统地阐述(13B) 论坛(1C) 培养,促进(13B) 易损坏的;易碎的;脆弱的(9A) 帧;单幅画面(2B) 帧中继(8C) 欺骗性的(13A) [一般作表语] 充满的,伴随着的(with)(2B) 自由内存,闲置内存(5A) 免费软件,自由软件(11C) 前端(的)(5C) 全双工的(10C) 函数调用(4B) 函数语句(4A) 函数式语言(4A) 功能性(1B) (使)流经漏斗;(尤指通过狭窄通道)传送(9C) 熔化;熔合;熔接;熔凝(2A) G gadget / 5gAdVit / n. gaggle / 5gAgl / n. gambling / 5gAmbliN / n. game theory gargantuan / gB:5gAntjuEn / a. gateway / 5geitwei / n. generalize / 5dVenErElaiz / v. generic / dVi5nerik / a. geocoding / 7dVi:Eu5kEudiN / n. gigabit / 5dVigEbit / n. global template grand / grAnd / n. graphic(al) / 5grAfik(El) / a. graphical user interface graphics / 5grAfiks / n. grid / grid / n. grid cell group scheduling guardian / 5gB:diEn / n. 精巧的装置;小玩意儿(15A) (紊乱而有联系的)一堆(4C) 赌博(14A) 博弈论,对策论(12C) 巨大的,庞大的(12C) 网关(5B) 概括,归纳(12C) 通用的;一般的;类属的(5C) 地理编码(12B) 吉位,千兆比特(3C) 共用模板(14B) [常单复同]<美俚> 一千美元(1B) 图形的(2A) 图形用户界面(3A) 图形,图形显示(1A) 网格;坐标方格(12B) 网格单元(12B) 成组调度(9C) 守卫者,保护者(15C) 计算机英语 H hack / hAk / v. & n. hacker / 5hAkE / n. hail / heil / v. hand-held scanner handler / 5hAndlE / n. handshake / 5hAndFeik / n. harbinger / 5ha:bindVE / n. hard-code / 5hB:dkEud / v. hash / hAF / n. hash function header / 5hedE / n. headroom / 5hedru:m / n. healer / 5h:lE / n. 非法闯入(计算机网络)(14C) 黑客(4C) 招呼(致意)(10C) 手持式扫描仪(2A) 处理程序(4B) 握手(信号)(2B) 前兆,预示(12A) 硬编码(5C) 散列;无用信息(13A) 散列函数(13A) 页眉;标头(4C) 净空(高度)(13B) 信仰疗法术士(指用祈祷或魔术等方式 治病的人)(12A) 希伯来语(5C) 服务热线(12A) 各种各样;非均匀性;多相性(6A) 各种各样的;混杂的;异构的(6A) 分级的,分层的,层次的(8B) 层次,分层(结构),分级(结构)(4A) 高清晰度的(8C) 高端的,尖端的 (3A) 突出显示,强光显示(4B) 高技术的(12B) 阻碍,妨碍(12C) 妨碍,障碍(14A) 主页(11C) 同种类的;同性质的;同构的(6A) 跳跃;转发;信程(8C) 主机(7A) 主机语言(7A) 主机名(11A) 热狗,红肠面包(15A) 外壳,外罩(1B) (轮)毂; (网络)集线器(2B) 匈牙利的(1A) 飓风(14A) 杂种的;混合的(6B) 杂交;混合(15A) 天花乱坠的广告宣传;大肆宣传(5B) 超链接(5B) 超媒体(11A) 超文本(6A) 超文本传输协议(10B) Hebrew / 5hi:bru: / n. helpline / 5helplain / n. heterogeneity / 7hetErEudVi5ni:Eti / n. heterogeneous / 7hetErEu5dVi:niEs / a. hierarchical / 7haiE5rB:kikEl / a. hierarchy / 5haiE7rB:ki / n. high-definition / 5haidefi5niFEn / a. high-end / 5hai5end / a. highlight / 5hailait / v. high-tech / 5hai5tek / a. hinder / 5hindE / v. hindrance / 5hindrEns / n. home page homogeneous / 7hCmEu5dVi:niEs / a. hop / hCp / n. host / hEust / n. host language hostname / 5hEustneim / n. hot dog housing / 5hauziN / n. hub / hQb / n. Hungarian / hQN5geEriEn / a. hurricane / 5hQrikEn / n. hybrid / 5haibrid / a. hybridization / 7haibridai5zeiFEn / n. hype / haip / n. hyperlink / 5haipEliNk / n. hypermedia / 5haipE7mi:diE / n. hypertext / 5haipEtekst / n. Hypertext Transfer Protocol I 329 330 Computer English icon / 5aikCn / n. identification / ai7dentifi5keiFEn / n. identifier / ai5dentifaiE / n. ideological / 7aidiEu 5lCdVikEl / a. illicit / i5lisit / a. illuminate / i5lu:mineit / v. illusion / i5lu:VEn / n. imaging / 5imidViN / n. imminent / 5iminEnt / a. imperative / im5perEtiv / a. & n. impervious / im5pE:viEs / a. impetus / 5impitEs/ n. implementer / 5implimentE / n. implicit / im5plisit / a. impulse / 5impQls / n. inadvertently / 7inEd5vE:tEntli / ad. incentive / in5sentiv / n. incidence / 5insidEns / n. incompatibility / 5inkEm7pAtE5bilEti / n. inconsistency / 7inkEn5sistEnsi / n. incorporate / in5kC:pEreit / v. incremental / 7inkri5mentEl / a. inculcate / 5inkQlkeit / v. incumbent / in5kQmbEnt / n. indiscriminate / 7indis5kriminEt / a. infamous / 5infEmEs / a. infancy / 5infEnsi / n. infection / in5fekFEn / n. inference engine inflection / in5flekFEn / n. inflection point informatics / 7infE5mAtiks / n. informed / in5fC:md / a. infrastructure / 5infrE7strQktFE / n. inherent / in5hiErEnt / a. in-house / 5in5haus / a. & ad. INI file initialization / i7niFElai5zeiFEn / initiate / i5niFieit / v. ink cartridge inkjet / 5iNkdVet / a. innate / 7i5neit / a. innovation / 7inE5veiFEn / n. innovative / 5inE7veitiv / a. input stream insidiously / in5sidiEsli / ad. installer / in5stC:lE / n. instance variable n. 图标,图符(3A) 识别;标识(10C)∕身份证明(14A) 标识符(8C) 思想上的;意识形态的(14C) 非法的;不正当的(14B) 照明;照射(2C) 错觉,幻觉(1B) 成像(技术)(8C) 临近的,即将发生的(15A) 必要的(10B)∕必要的事(13B) 不受影响的;不易损坏的(10B) 推动,促进;推动力(12C) 实现者;实现程序(8B) 不言明的;含蓄的;无疑问的(6C) 脉冲(8A) 漫不经心地,粗心大意地(14A) 刺激;动机(14C) 发生率(14A) 不可兼容性(2C) 不一致(7A) 包含(1A) 增量的;递增的(6A) 反复灌输(15C) 现任者,在职者(15C) 不加区别的;不加选择的;任意的(14C) 臭名昭著的(14A) 婴儿期;初期(15B) (病毒)传染;感染(14B) 推理机(5A) 拐折;回折点(15C) 拐点,回折点(15C) 信息(科)学(12C) 了解情况的;有情报(或资料)根据的(12B) 基础结构(6A) 内在的;固有的(6A) 存在(或起源)于机构内部的;内部的; 自用的(8B)∕在机构内部(12B) 初始化文件(initialization file 的缩略)(5C) 初始化,赋初值(4B) 开始;发起(9A) 墨盒(5A) 喷墨的(2A) 固有的;天生的(8C) 革新,创新(3A) 革新的,新颖的;富有革新精神的(1B) 输入(信息)流(1A) 阴险地;不知不觉间加剧地;隐伏地(15C) 安装程序(3B) 实例变量(5C) 计算机英语 instantaneous / 7instEn5teinjEs / n. instantiate / in5stAnFieit / v. instantiation / in7stAnFi5eiFEn / n. instruction set insulate / 5insjuleit / v. intact / in5tAkt / a. integer / 5intidVE / n. integrated network integrator / 5intigreitE / n. integrity / in5tegrEti / n. interact / 7intEr5Akt / v. interactive / 7intEr5Aktiv / a. intercept / 7intE5sept / v. interface / 5intEfeis / n. & v. interlaced / 7intE5leist / a. intermediate language intermittent / 7intE5mitEnt / a. internet / 5intEnet / n. Internet Control Message Protocol Internet Protocol internetwork / 7intE5netwE:k / n. internetworking / 7intE5netwE:kiN / n. interoperability / 5intEr7CpErE5bilEti / n. interoperable / 7intEr5CpErEbl / a. interoperate / 7intEr5CpEreit / v. interpreted code interpreted language interpreter / in5tE:pritE / n. interpreter program interrupt / 7intE5rQpt / n. intertwine / 7intE5twain / v. interwork / intE5wE:k / v. & n. intranet / intrE5net / n. intrinsically / in5trinsikEli / ad. intrude / in5tru:d / v. intruder / in5tru:dE / n. intrusion / in5tru:VEn / n. intuition / 7intju:5iFEn / n. intuitive / in5tju:itiv / a. invaluable / in5vAljuEbl / a. inventory / 5invEntEri / n. inverse / 5invE:s / a. invocation / 7invE5keiFEn / n. involved / in5vClvd / a. irreplaceable / 7iri5pleisEbl / a. isochronous / ai5sCkrEnEs / a. itinerary / ai5tinErEri / n. 331 瞬间的,即刻的(4C) 例示,实例化(5C) 例示,实例化(9B) 指令集(1A) 使绝缘;隔离(6C) 完整无缺的(10B) 整数(5C) 综合网络(8C) 积分器(1A) 完整(性)(7A) 互相作用;互相影响(2A) 交互(式)的(8A) 拦截;截取(14A) 界面;接口(1B)∕(使)联系;(使)接合(4B) 交织的,交错的; (电视扫描)隔行的(11C) 中间语言,中级语言(4A) 间歇的(13A) 互联网,互连网(8B) 网间信报控制协议(10B) Internet 协议,网际协议(10B) 互联网(8B) 互联网(技术) (8B) 互操作性,互用性(6A) 可互操作的,能共同使用的(11C) 互操作,互用(8C) 解释执行的代码(4C) 解释执行的语言(5A) 解释程序,解释器(3A) 解释程序(5A) 中断(14B) (使)缠结,(使)缠绕在一起(4C) 配合工作,互工作(8C) 企业内部(互联)网,内联网(1B) 固有地;本质上;内在地(6A) 侵入;侵扰(9A) 侵入者;闯入者(14C) 侵入;打扰(12B) 直觉(12C) 直觉的;凭直觉获知的(3A) 非常宝贵的;无法估价的(12B) 存货清单;库存(13B) 反的,逆的(8C) 启用,调用(6A) 复杂(难懂)的(7C) 不能替代的;失去后无法补偿的(14A) 同步的,等时的(2B) 旅程;路线;旅行计划(15A) J 332 Computer English jerky / 5dVE:ki / a. joint venture joystick / 5dVCistik / n. jumper / 5dVQmpE / n. juvenile / 5dVu:vEnail / n. 忽动忽停的;抽动的;不平稳的(11C) 合资企业(15A) 控制杆,操纵杆,游戏杆(2A) 跳线,跨接线(2B) 少年(14C) K kernel / 5kE:nEl / n. key / ki: / n. key escrow chip kickstart / 5kik7stB:t / n. & v. kilobit / 5kilEbit / n. kit / kit / n. know-how / 5nEuhau / n. Korean / kE5riEn / n. (果核或果壳内的)仁;核心(3B) 键值;关键字(7B) 密钥托管芯片(14A) (用)脚踏起动器(启动) (8B) 千位,千比特(11A) 成套工具;套件,软件包(13C) 技术;实际知识(8B) 朝鲜语(5C) L land / lAnd / n. laptop / 5lAptCp / n. & a. latency / 5leitEnsi / n. latitude / 5lAtitju:d / n. lax / lAks / a. layer / 5leiE / v. layering / 5leiEriN / n. layoff / 5leiCf / n. leapfrog / 5li:pfrCg / n. & v. leased line legacy / 5legEsi / a. legitimate / li5dVitimEt / a. lever / 5li:vE / n. lexicon / 5leksikEn / n. library / 5laibrEri / n. library routine life cycle light pen linear / 5liniE / a. linguistic / liN5gwistik / a. linker / 5liNkE / n. liquid crystal display list server listing / 5listiN / n. literally / 5litErEli / ad. load balancing 凸区,槽脊(2C) 膝上型计算机,便携式计算机(1A)∕膝上型的, 便携式的(2A) 潜伏时间,等待时间(8C) 纬度(12B) 松(弛)的(14A) 使分层(8B) 分层(2C) (尤指临时)解雇(15C) (作)跳背游戏(15B) 专线(9B) 旧版本的,老化的(8C) 合法的;正当的(14A) (杠)杆;控制杆(2A) (某一语言、作家、学科的)特殊词汇,专门 词汇(15A) 程序库,库(3B) 库程序(5A) 生存周期,寿命周期(12C) 光笔(2A) 线(性)的(12B) 语言(学)的(4A) 连接程序,链接程序(4C) 液晶显示(器)(2A) 列表服务器(11A) 列表;一览表(13C) 确实地,不加夸张地;逐字地(6B) 负载平衡(6B) 计算机英语 local area network local database logical element logistics / lEu5dVistiks / n. longitude / 5lCndVitju:d / n. loom / lu:m / n. loop / lu:p / n. & v. loudspeaker / 5laud5spi:kE / n. lurk / lE:k / v. lurker / 5lE:kE / n. 局域网(3B) 本地数据库(7C) 逻辑元件(1A) 后勤(学)(12B) 经度(12B) 织机(1A) 循环(体)(4B) 扬声器,喇叭(2B) 潜伏;潜行(11C) 潜伏者,伏兵(11C) M macro / 5mAkrEu / n. macro virus magneto-optical / mAg7ni:tEu5CptikEl / a. magnitude / 5mAgnitju:d / n. mail server mail-order / 5meil7C:dE / a. main memory mainframe / 5meinfreim / n. mainstream / 5meinstri:m / a. malicious / mE5liFEs / a. Mandarin / 5mAndErin / n. mandate / 5mAndeit / v. manipulate / mE5nipjUleit / v. manipulation / mE7nipju5leiFEn / n. map / mAp / v. marginal / 5mB:dVinEl / a. maritime / 5mAritaim / a. markedly / 5mB:kidli / ad. marker / 5mB:kE / n. master boot record matrix / 5meitriks / n. maximize / 5mAksimaiz / v. meager / 5mi:gE / a. media outlet mediate / 5mi:dieit / v. megabit / 5megEbit / n. megabyte / 5megEbait / n. memoir / 5memwB: / n. memory / 5memEri / n. memory-resident / 5memEri 5rezidEnt/ a. merge / mE:dV / v. mesh / meF / n. message authentication code messaging / 5mesidViN / n. messy / 5mesi / a. metadata / 7metE5deitE / n. 宏,宏指令(4A) 宏病毒(14B) 磁光的(2A) 数量;量值(9B) 邮件服务器(11A) 邮购的(13C) 主存(储器)(3A) 主机,大型机(1A) 主流的(10B) 恶意的(4C) (中国)官话;(中国)国语(15B) 批准,授权(5B) 操作;处理(1A) 操作,处理(10B) 映射,使变换(8C) 边缘的;勉强够格的;少量的(10B) 海的;海上的(1B) 明显地,显著地(12A) 标记(符)(10C) 主引导记录(14B) ([复]-trices / -trisi:z / 或 -trixes)(矩)阵(2A) 使增加(或扩大)到最大限度(6A) 瘦的;不足的;贫乏的(10B) 媒体渠道,媒介(13C) 调解;传递(6A) 兆位,兆比特(11A) 兆字节(1C) 回忆录;自传(15C) 存储器,内存(1A) 内存驻留的(14B) 合并;结合(4A) 网格;网孔;网状结构(8C) 信息鉴定码(13A) 通信,消息接发(6A) 凌乱的,杂乱的(5B) 元数据(7A) 333 334 Computer English metaphor / 5metEfE / n. meter / 5mi:tE / v. methodology / 7meWE5dClEdVi / n. metropolitan / 7metrE5pClitEn / a. microchip / 5maikrEutFip / n. microcomputer / 5maikrEukEm5pju:tE/ n. microelectronics / 5maikrEu i7lek5trCniks/ n. microminiaturization / 5maikrEu7minitFErai5zeiFEn / micron / 5maikrCn / n. micropayment / 7maikrEu5peimEnt / n. microprocessor / 7maikrEu5prEusesE / n. microsecond / 5maikrEu7sekEnd / n. microsegmentation / 5maikrEu7segmEn5teiFEn / microwave / 5maikrEweiv / a. & n. middleware / 5midlweE / n. migrate / mai5greit / v. mimic / 5mimik / v. mince / 5mins / v. miniature / 5minitFE / a. minicomputer / 7minikEm5pju:tE / n. minimal / 5minimEl / a. minimize / 5minimaiz / v. miscellaneous / 7misE5leiniEs / a. moat / mEut / n. mobilization / 7mEubilai5zeiFEn / n. modeling / 5mCdEliN / n. modem / 5mEudem / n. modifier / 5mCdifaiE / n. modular / 5mCdjulE / a. modulate / 5mCdjuleit / v. modulator / 5mCdjuleitE / n. module / 5mCdju:l / n. mom / mCm / n. monetary / 5mQnitEri / a. monochrome / 5mCnEkrEum / n. & a. monolithic / 7mCnE5liWik / a. morale / mC5rB:l / n. morph / mC:f / v. motherboard / 5mQTEbC:d / n. motto / 5mCtEu / n. mouse / maus / n. multicast / 5mQltikB:st / n. multicast protocol multimedia / 7mQlti5mi:diE / a. multi-partite / 7mQlti5pB:tait / a. multiplex / 5mQltipleks / v. & n. multiplexing / 5mQltipleksiN / n. multiplicity / 7mQlti5plisEti / n. multitasking / 5mQlti7tB:skiN / n. n. n. 隐喻;比喻(12C) 用(仪)表计量(11C) (学科的)一套方法;方法论(12C) 大城市的,大都会的(8C) 微芯片(1A) 微型计算机(1A) 微电子学(12A) 微小型化,超小型化(1A) 微米(2C) 网络微型支付款,(在因特网上付出的)极少量 款项(13A) 微处理器(1A) 微秒,10-6 秒(8C) 微分段(9B) 微波(的)(8A) 中间件(13B) 移居;迁徙;移植(5C) 模仿(1A) 装作高雅地说(15C) 小型的,微小的(1B) 小型计算机(1A) 最小的;最低限度的(6A) 使减少到最低限度(3A) 混杂的(10C) 护城河;深沟(15C) 动员(12A) 建模,模型化(7A) 调制解调器(2A) 限定语符;修改量(4B) 模块化的(9B) 调制(8A) 调制器(2A) 模块(2A) <主美口> 妈妈(4C) 货币的,金融的(13A) 单色(的)(11C) 单块的,单片的(6B) 士气;道德(15C) 变化,改变(15A) 主板(10A) 箴言,格言(15C) 鼠标(1B) 多播(9B) 多址通信协议(6A) 多媒体的(2C) 分成多部分的(14B) 多路复用,多路传输(8C) 多路复用,多路传输(8B) 多样性,多种多样(13A) 多任务处理,同时执行多项任务(3A) 计算机英语 multithreaded / 5mQlti7Wredid / a. multithreading / 5mQlti7WrediN / n. 335 多线程的(4C) 多线程操作(4C) N name server native code navigate / 5neivigeit / v. negligible / 5neglidVEbl / a. netiquette / 5netiket / n. network / 5netwE:k / v. Network News Transfer Protocol networking / 5net7wE:kiN / n. neural / 5njuErEl / a. neural network news server newsgroup / 5nju:zgru:p / n. node / nEud / n. nonlinear / nCn5liniE / a. nonrefutability / 5nCn7refjutE5bilEti / n. non-repudiation / 5nCnri7pju:di5eiFEn / n. nontrivial / nCn5triviEl / n. nonvolatile memory notation / nEu5teiFEn / n. notoriety / 7nEutE5raiEti / n. notwithstanding / 7nCtwiW5stAndiN / ad. & prep. novice / 5nCvis / n. null / nQl / a. & n. numeric / nju:5merik / a. numerical / nju:5merikEl / a. 名称服务器(11A) 本机代码(4C) 航行(于) ; (为…)领航;指引(1B) 可略而不计的(6A) 网络礼节,网规(network etiquette 的缩合) (11C) 联网(3A) 网络新闻传输协议(10B) 联网,建网(1A) 神经的(1A) 神经(元)网络(1A) 新闻服务器(11A) 新闻组(11A) 节点(6A) 非线性的(11A) 不可批驳性;不可辩驳性(13A) 不拒绝;不否认;不可抵赖(13A) 重大的,重要的(12C) 非易失性存储器(2A) (系统成套的)记号;标记法(5A) 声名狼藉;名声远扬(14A) 尽管(14B) 新手,初学者(1C) 空的∕空值(7B) 数字的;数值的(7B) 数字的;数值的(1A) O object code obscenity / Eb5senEti / n. obscure / Eb5skjuE / v. obtuse / Eb5tju:s / a. obviate / 5Cbvieit / v. octet / Ck5tet / n. offense / E5fens / n. off-hour / 5Cf5auE / a. offline / 5Cf5lain / a. & ad. offload / 5CflEud / v. offshoot / 5CfFu:t / n. off-the-shelf / 5CfTE5Felf / a. oftentimes / 5CfEntaimz / ad. ongoing / 5Cn7gEuiN / a. online / 5Cn5lain / a. & ad. 目标(代)码(5A) 淫秽(13A) 使变模糊,掩盖(14C) 不被明显感知的;(感觉)迟钝的(4B) 排除;避免(8C) 八位位组,八位元(8C) 冒犯;攻击(4C) 休息时间的;非工作时间的(14C) 脱机的(地),离线的(地)(13C) 卸载(3C) 支族,旁系;衍生事物(4C) 现成的,非专门设计(或定制)的(12C) <古> 经常;通常(= often)(14A) 正在进行的(1A) 联机的(地),在线的(地)(11A) 336 Computer English on-the-fly / 5CnTE5flai / ad. opt / Cpt / v. optic / 5Cptik / n. optical disc optimal / 5CptimEl / a. optimization / 7Cptimai5zeiFEn / n. optimize / 5Cptimaiz / v. optimum / 5CptimEm / a. order of magnitude orient / 5C:rient / v. originate / E5ridVEneit / v. outbreak / 5autbreik / n. outgrowth / 5autgrEuW / n. outlast / 7aut5lB:st / v. outlay / 5autlei / n. outright / 5autrait / a. & ad. outsource / aut5sC:s / v. outweigh / aut5wei / v. overhead / 5EuvEhed / n. overlap / 7EuvE5lAp / v. oversee / 7EuvE5si: / v. overshadow / 7EuvE5FAdEu / v. overturn / 7EuvE5tE:n / v. overview / 5EuvEvju: / n. overwhelm / 7EuvE5hwelm / v. overwhelming / 7EuvE5hwelmiN / a. overwrite / 7EuvE5rait / v. 自由地;随意地(2B) 选择;作出抉择(9C) 光学仪器(2C) 光盘(12A) 最适的,最佳的(= optimum)(6C) 最佳化,最优化(14C) 使优化,使最佳化(3C) 最适的,最佳的(6B) 数量级(9B) 给…定向;使适应;使面向(3A) 发源;产生;创始(8C) 爆发,突然发生(14B) 发展结果;产物(4A) 比…持久(6A) 费用,支出(11C) 完全的,彻底的(6A)∕完全地,彻底地(5B) (将…)外包(指向外面的供应商求购)(12A) 在价值(或重要性、影响等)方面超过(4C) 开销;经常(或管理、间接)费用(4C) 重叠,层叠(3A) 监视;检查;管理(3A) 使相形见绌(1A) 推翻;废除(1A) 概述;概观(13B) 使受不了;使不知所措;征服;压倒(13C) 势不可挡的;巨大的(12B) 改写,重写(2A) P packet / 5pAkit / n. packet radio packet switching packet-switching / 5pAkit7switFiN / padding / 5pAdiN / n. pager / 5peidVE / n. palmtop / 5pB:mtCp / n. paper-tape reader parallel port parameter / pE5rAmitE / n. paranoia / 7pArE5nCiE / n. paranoid / 5pArEnCid / a. parasitic / 7pArE5sitik / a. parity / 5pArEti / n. parity function parse / pB:z / v. partition / pB:5tiFEn / n. & v. partition table password / 5pB:swE:d / n. n. 包,数据包,信息包(2B) 无线电包通信,无线电分组通信(3B) 包交换(8B) 包交换(11A) 填充(8C) 寻呼机(8A) 掌上型计算机(1A) 纸带阅读器(1A) 并行端口(9C) 参数,参量(4A) 偏执狂;多疑症(15C) 患偏执狂的;多疑的(15C) 寄生的(14B) 奇偶性;校验(8B) 奇偶校验功能(8B) (从语法上)分析(4B) 分区,分割,划分(3C) 分区表(14B) 口令(14A) 计算机英语 patent / 5peitEnt / n. payload / 5peilEud / n. payoff / 5peiCf / n. pay-per-view / 5peipE5vju: / n. peer / piE / n. pending / 5pendiN / a. perceptible / pE5septEbl / a. perforated / 5pE:fEreitid / a. periodic / 7piEri5Cdik / a. peripheral / pE5rifErEl / n. perish / 5periF / v. permutation / 7pE:mju5teiFEn / n. perpetrator / 5pE:pitreitE / n. persistence / pE5sistEns / n. persistent / pE5sistEnt / a. personal digital assistant pervasive / pE5veisiv / a. phosphorescent / 7fCsfE5resEnt / a. photocopier / 7fEutEu5kCpiE / n. photodetector / 7fEutEudi5tektE / n. physical memory pinpoint / 5pinpCint / v. pipe / paip / n. piracy / 5paiErEsi / n. pirate / 5paiErEt / v. pit / pit / n. pitch / pitF / n. plague / 5pleig / v. plain text player piano Plug ’n Play Plug and Play plug-in / 5plQgin / a. & n. plus / plQs / n. pointer / 5pCintE / n. polarization / 7pEUlErai5zeiFEn / n. poll / pEul / n. & v. polycarbonate / 7pCli5kB:bEnit / n. polygon / 5pCligEn / n. polygonal / pE5ligEnEl / a. polymorphism / 7pCli5mC:fizEm / n. populate / 5pCpjuleit / v. port / pC:t / n. portable / 5pC:tEbEl / a. portal / 5pC:tEl / n. portfolio / 7pC:t5fEuliEu / n. postal code prankster / 5prANkstE / n. preamble / pri:5Ambl / n. precompiler / 7pri:kEm5pailE / n. 专利(权)(1A) 有效载荷(2B) 报偿;报应(13B) 付费节目服务,有偿点播服务(8C) 同位体,同级设备,对等层(6A) 未决的;在进行中的;行将发生的(2B) 可感知的;可察觉的(3A) 穿孔的(1A) 周期(性)的;时而发生的(10B) 外围设备(2B) 丧生;毁灭(13B) 排列;置换;改变(6C) 犯罪者(14A) 持续性,持久性(6A) 持续的,持久的(6A) 个人数字助理(12C) 遍布的;普遍的(6A) 发磷光的(2A) 复印机(2A) 光电探测器(2C) 物理内存(3C) 精确地确定…的位置(7B) 管道(符)(2B) 侵犯版权,盗版,剽窃(14A) 剽窃,盗用,非法翻印(14A) 凹区,凹槽(2A) 音高(8A) 使痛苦;给…造成困难(或麻烦)(10A) 纯文本(文件)(11B) 自动钢琴(5A) 即插即用(= Plug and Play)(2B) 即插即用(3C) 插入式的∕插件(程序);嵌入组件(11C) 好处,有利因素(5B) 指针(光标)(2A) 两极化,分化(12A) 轮询,探询(2B) 聚碳酸酯(2C) 多边形,多角形(12B) 多边(形)的,多角(形)的(12B) 多态性,多形性(4C) 充填;置入(5C) 端口,通信口(3B) 可移植的;便携的(4A) 门,入口,入门(13C) 投资组合(15A) 邮政编码(12B) 恶作剧者(14A) 前同步码,前同步信号(8C) 预编译程序(7A) 337 338 Computer English precursor / 7pri:5kE:sE / n. predator / 5predEtE / n. predicate / 5predikeit / v. predominantly / pri5dCminEntli / ad. predominate / pri5dCmineit / v. prefix / 5pri:fiks / n. prematurely / 7premE5tjuEli / ad. premise / 5premis / n. preprocessor / pri:5prEusesE / presentation manager press release prevalent / 5prevElEnt / a. prey / prei / n. primary key primary storage prioritize / prai5Rritaiz / v. privacy / 5praivEsi / n. privatism / 5praivEtizEm / n. n. privileged / 5privilidVd / a. proactive / prEu5Aktiv / a. proactively / prEu5Aktivli / ad. probe / prEub / v. procedural language procedure call profile / 5prEufail / v. profitable / 5prCfitEbl / a. profound / prE5faund / a. programmatically / 7prEugrE5mAtikEli / programming / 5prEugrAmiN / n. proliferation / prEu 7lifE5reiFEn / n. prompt / prCmpt / v. & n. prone / prEun / a. prophet / 5prCfit / n. proprietary / prEu5praiEtEri / a proprietor / prEu5praiEtE / n. prosecution / 7prCsi5kju:FEn / n. prosper / 5prCspE / v. protocol / 5prEutEkCl / n. protocol stack protocol suite prototype / 5prEutEtaip / n. prover / pru:vE / n. provision / prEu5viVEn / v. public key publicize / 5pQblisaiz / v. pull-down / 5puldaun / a. pull-down menu pulsate / 5pQlseit / v. ad. 先驱(1A) 捕食者;掠夺者(14C) 使基于;使取决于(on, upon)(13A) 占主导地位地;主要地(5B) 占主导地位(10A) 前缀(7B) 不成熟地(15C) [~s] 房屋(及其附属建筑、基地 等)(8C)∕前提;假设(9A) 预处理程序,预处理器(4C) 表示管理程序(3A) (通讯社或政府机构等发布的)新闻稿(13C) 流行的;普遍的(10A) 捕获物;牺牲品(14C) 主键(7B) 主存储器(14A) 按优先顺序列出;确定…的优先次序(12C) 隐私;秘密(1A) 只关心个人生活(或个人利害)的态度; 隐遁主义(12A) 享有特权的;特许的(9A) 抢先的,主动的 (12C) 抢先地(14C) 探查,探测(1B) 过程语言(4A) 过程调用(6A) 显出…的轮廓;用数据图表表示(9B) 有(赢)利的(13C) 深邃的;深刻的(3C) 用编程方法(7A) 节目的播送;编程(8A) 激增;扩散(14B) 提示(符)(4B) 有…倾向的,易于…的(2B) 预言者;先知(15A) 专有的,专利的(10B) 所有人,业主(15C) 起诉(14C) 兴旺;成功(13B) 协议(3B) 协议(堆)栈(8C) 协议组,协议族(8B) 原型;样品(1A) 证明程序(4C) 供应,提供(8C) 公用密钥,公钥(9A) 引起公众对…的注意;宣传(14C) 下拉(式)的(3A) 下拉(式)菜单(4B) (心脏、动脉等)搏动,跳动(15C) 计算机英语 punch / pQntF / v. punched card punctuation / 7pQNktju5eiFEn / purport / pE:5pC:t / v. purveyor / pE5veiE / n. pylon / 5pailEn / n. 339 按键输入(14A) 穿孔卡片(1A) 标点符号(4A) 声称;自称(6C) 供应商,提供者(13A) (飞机场)标塔; (架高压输电线的)电缆塔(12B) n. Q quantify / 5kwCntifai / v. query / 5kwiEri / v.& n. query language query optimization 确定…的数量,用数量表示,测量(12C) 查询(2B) 查询语言(7A) 查询优化(7A) R radio frequency radio telephone ramification / 7rAmifi5keiFEn / n. random / 5rAndEm / a. raster / 5rAstE / n. real estate realign / 7ri:E5lain / v. realtor / 5riEltE / n. reapportion / 7ri:E5pC:FEn / v. reassuring / 7ri:E5FuEriN / a. recipient / ri5sipiEnt / n. redirector / 7ri:di5rektE / n. redundancy / ri5dQndEnsi / n. reef / ri:f / n. reference / 5refErEns / v. refinery / ri5fainEri / n. reflector / ri5flektE / n. reformat / 7ri:5fC:mAt / v. register / 5redVistE / n. registry / 5redVistri / n. registry access regulatory / 5regjulEtEri / a. relational language relay / ri:5lei / v. release / ri5li:s / n. reliance / ri5laiEns / n. rendering / 5rendEriN / n. repetitive / ri5petEtiv / a. replicate / 5replikeit / v. report / ri5pC:t / n. repository / ri5pCzitEri / n. 射频;无线电频率(1B) 无线电话(8A) 衍生结果;后果(13A) 随机的(2A) 光栅(12B) 不动产,房地产(13C) 重新调整(5A) 房地产经纪人(12B) 重新分派;重新按比例分配(6B) 安慰(性)的,鼓励(性)的(5B) 接受者;收件人(6A) 呼叫转移器,重定向器(3C) 冗余(2B) 礁(1B) 引用;参照(4C) 提炼厂(1B) 反射器;反射镜(11C) 重新定义格式;重新格式化(5A) 寄存器(2B) 注册表(1C) 注册表存取(3C) 管理的;调整的(8B) 关系语言,相关语言(4A) 接力传送;传递(5B) 版本;发布(3A) 依靠,依赖(6A) 渲染(计算机图形处理术语,专指诸如 3D 等图形 效果处理运算)(3C) 重复的(5A) 复制(14A) 报表(7A) 仓库,储存库(5B) 340 Computer English requisite / 5rekwizit / n. resentment / ri5zentmEnt / n. reserve / ri5zE:v / a. reside / 5rizaid / v. resilience / ri5ziliEns / n. resistor / ri5zistE / n. resize / ri:5saiz / v. resolution / rezE5lu:FEn / n. resourceful / ri5sC:sful / a. résumé / 5rezju:mei / n. retrieval / ri5tri:vEl / n. retrieve / ri5tri:v / v. retrospect / 5retrEu spekt / n. revolve / ri5vClv / v. rigorous / 5rigErEs / a. ritual / 5ritjuEl / n. roam / rEum / v. robust / rEu5bQst / a. root hub route / 5ru:t / v. router / 5ru:tE / n. routine / ru:5ti:n / n. routing / 5ru:tiN / n. routing algorithm royalty / 5rCiElti / n. rudimentary / 7ru:di5mentEri / a. runtime / 5rQntaim / n. 必要条件(10B) 忿恨,怨恨(14A) 保留的;后备的(8C) 居住;存在(5B) 弹性;复原力(9A) 电阻器(10A) 调整大小,重定尺寸(11C) 分辨率;清晰度(2C) 善于随机应变的;足智多谋的;资源丰富的(6C) (亦作 resume)摘要;简历(5B) 检索(2A) 检索(2A) 回顾,回想(12A) 旋转;围绕(4C) 严密的;严格的(4A) 仪式;例行公事(15A) 漫游(12C) 强壮的,强健的(12C) 根集线器(2B) (按特定路线)发送(8C) 路由器(8C) 例(行)程(序);程序(5A) 路由选择(6A) 路由算法(6A) (著作的)版税(7B) 基本的,初步的;早期的;未成熟的(12A) 运行时刻(4C) S sabotage / 5sAbEtB:V / n. safeguard / 5seifgB:d / v. salvage / 5sAlvidV / n. sampling / 5sB:mpliN / n. scalability / 7skeilE5bilEti / n. scalable / 5skeilEbl / a. scale / skeil / v. scaling / 5skeiliN / n. scanner / 5skAnE / n. scenario / si5nB:riEu / n. scheduler / 5Fedju:ElE; 5skedVu:ElEr / n. scheduling / 5Fedju:EliN; 5skedVu:EliN / n. schematic / ski5mAtik / a. scramble / 5skrAmbl / v. scramble / 5skrAmbl / v. scrap / skrAp / v. scratch / skrAtF / n. script / skript / n. scroll / skrEul / v. & n. (阴谋)破坏(13A) 保护,维护(14A) 海上救助(1B) 取样,抽样(12C) 可缩放性(3C) 可缩放的,可扩缩的,可升级的(3C) 缩放(7C) 缩放(6C) 扫描仪(2A) 方案;设想(3C) 调度程序,计划任务程序(3A) 调度;安排(8C) 图表的;图解的;纲要的(6B) (加密)编码(9A) 争夺,抢夺(13B) 废弃;抛弃(13B) 起跑线;零分(3B) 脚本,过程(文件)(5C) 滚动(4B) 计算机英语 scroll bar seamless / 5si:mlis / a. seemingly / 5si:miNli / ad. segmentation / 7segmen5teiFEn / n. segregate / 5segrigeit / v. seizure / 5si:VE / n. self-aggrandizement / 7selfE5grAndizmEnt / semantically / si5mAntikEli / ad. sensor / 5sensE / n. sequential / si5kwenFEl / a. serial / 5siEriEl / a. settlement / 5setlmEnt / n. set-top box setup / 5setQp / n. sevenfold / 5sevEnfEuld / ad. sever / 5sevE / v. shaft / FB:ft / n. shareware / 5FeEweE / n. ship / Fip / v. shop floor silicon / 5silikEn / n. Simple Mail Transfer Protocol simplex / 5simpleks / a. simulate / 5simjuleit / v. simultaneously / 7simEl5teiniEsli / ad. site / sait / v. site license situated / 5sitjueitid / a. skip / skip / v. slack / slAk / v. slash / slAF / n. sleek / sli:k / a. sloppy / 5slCpi / a. slot / slCt / n. smart card snapshot / 5snApFCt / n. snapshot scanner sneak / sni:k / v. sniffer / 5snifE / n. snorkeler / 5snC:kElE / n. social engineering social security sociology / 7sEusi5ClEdVi / n. socket / 5sCkit / n. software overhead software package sophistication / sE7fisti5keiFEn / n. source code source file n. 滚动条(4B) 无缝的(3B) 表面上;看来(4C) (分)段,分割(6A) 隔离;分开(4C) 抓住;夺取(14C) (在名利、权势等方面的)自我扩张(14C) 在语义上(4C) 传感器(1B) 顺序的(6A) 串行的;连续的(2A) 结算;清偿(13A) 机顶盒,顶置盒(8C) 设置;安装;建立(2B) 七倍地(2C) 切断,割断(10A) 轴(1A) 共享软件(11C) 推出(产品)(5C) (工厂工人的)工作场所;[总称]工人(12A) 硅(1A) 简单邮件传输协议(10B) 单工的(11C) 模拟;模仿(5A) 同时(发生)地(2A) 给…择址;设置(9A) 站点许可证(7C) 位于…的,坐落在…的(12C) 略过,跳过(2C) 放松,松弛(15C) 斜线(号)(11A) 光滑的;线条明快的,造型优美的(3A) 马虎的;凌乱的(14A) (插)槽(2B) 智能卡,灵巧卡(13A) 快照;快相(2B) 快照扫描仪(2B) 偷偷地走,溜(14B) 嗅探者;监视软件(10B) 使用水下呼吸管潜游者(1B) (应用社会学原理以达成某种特殊或认定的社会 目标的)社会工程(14C) 社会保险(14A) 社会学(12C) 插座;插槽(1C) 软件开销(6A) 软件包(4C) 复杂性;尖端性(4A) 源(代)码(3B) 源文件(5A) 341 342 source program spam / spAm / v. span / spAn / v. spanning tree spatial / 5speiFEl / a. spawn / spC:n / v. -specific / spi5sifik / comb. form specific / spi5sifik / n. specification / 7spesifi5keiFEn / n. specs / speks / n. spectre / 5spektE / n. spectrum / 5spektrEm / n. spike / spaik / n. spiral / 5spaiErEl / n. spoof / spu:f / v. spreadsheet / 5spredFi:t / n. sprinkler / 5spriNklE / n. sprinkler system stability / stE5bilEti / n. stall / stC:l / v. stance / stAns / n. stand-alone / 5stAndE7lEun / a. standing / 5stAndiN / n. state of the art statement / 5steitmEnt / n. status report still camera stock quote stockbroker / 5stCk7brEukE / n. storage engine storage register storefront / 5stC:frQnt / n. straightforward / 7streit5fC:wEd / a. streamline / 5stri:mlain / v. strife / straif / n. strive / straiv / v. stylus / 5stailEs / n. submarine / 7sQbmE5ri:n / n. subroutine / 5sQbru:7ti:n / n. subscribe / sEb5skraib / v. subscriber / sEb5skraibE / n. subscription / sEb5skripFEn / n. substantive / 5sQbstEntiv / a. substrate / 5sQbstreit / n. subsume / sEb5sju:m / v. subtle / 5sQtl / a. succinctly / sEk5siNktli / ad. suffice / sE5fais / v. suffix / 5sQfiks / n. suite / swi:t / n. Computer English 源程序(5A) (向…)发送电子垃圾(14B) 横跨,跨越(8C) 生成树(9B) 空间的;与空间有关的(12B) 大量产生(13A) 表示“限定的”,“特有的” (3A) [~s] 详情,细节(4B) [常作~s] 规格,规范;明确说明(1B) [复]<口> 规格(1B) 鬼怪,幽灵(9A) 频谱(15A) 尖峰(14A) 螺旋(形)(2C) 哄骗,欺骗(4C) 电子数据表,电子表格(3A) 喷洒器;喷水装置(14A) 喷洒灭火系统(14A) 稳定(性)(13B) 拖延,推迟(2B) 姿态,态度(14C) 独立的(12B) 级别;地位(6B) 最新水平,发展水平(8B) 语句(4A) 状态报告(10B) 静物照相机(2B) 股票行情(5B) 股票(或证券)经纪人(13C) 存储引擎(7A) 存储寄存器(4A) 店面,铺面(12C) 简单的;直截了当的(4B) 使成流线型;使效率更高(12B) 冲突;争斗(14A) 努力,奋斗(1B) ([复]-luses 或 -li / -lai / )输入笔,光笔(2A) 潜艇(1A) 子例程,子(例行)程序(5A) 订购;订阅(8C) 用户;订户(8B) 订阅;订购(13C) 根本性的,本质的(8B) 衬底,基底(1A) 把…包括在内(13B) 微妙的;细微的(5C) 简明地,简练地(12B) 足够(10B) 后缀(11B) (软件的)套件;(同类物的)系列,套(5C) 计算机英语 supercomputer / 5sju:pEkEmpju:tE / n. superconductivity / 5sju:pE7kCndQk5tivEti / n. superfluous / sju:5pE:fluEs / a. superuser / 5sju:pE 7ju:zE / n. supervise / 5sju:pEvaiz / v. supplementary / 7sQpli5mentEri / a. surf / 5sE:f / v. surfer / 5sE:fE / n. surge / sE:dV / n. surge protector surgeon / 5sE:dVEn / n. surpass / sE5pB:s / v. surveillance / sE:5veilEns / n. swap / 5swCp / n. & v. swap space sweatshirt / 5swetFE:t / n. sweeping / 5swi:piN / a. switch / 5switF / n. symmetric / si5metrik / a. sync / siNk / a. sync bit synchronization / 7siNkrEnai5zeiFEn / n. synchronize / 5siNkrEnaiz / v. synchronous / 5siNkrEnEs / a. syntactic / sin5tAktik / a. syntax / 5sintAks / n. synthesize / 5sinWisaiz / v. system call 343 超级计算机,巨型计算机(1A) 超导(电)性(1A) 多余的;过剩的(4C) 超级用户,特权用户(14C) 监督;管理(9A) 增补的,补充的(11B) 浏览,(在…上)冲浪(1C) 网上冲浪者(10B) 浪涌;电涌(14A) 浪涌电压保护器(14A) 外科医生(1B) 超过;优于(5C) 监视;监督(12A) 交换(1C) 交换空间(3B) 宽松无领长袖运动衫(11C) 全面的;势不可挡的(15B) 交换(设备)(1A) 对称的(13A) <口> 同步的(= synchronous) (8C) 同步位(8C) 同步(2B) (使)同步(2B) 同时的;同步的(6A) (按照)句法的(4C) 句法(4A) 综合(12C) 系统调用(5A) T tablet / 5tAblit / n. tablet PC tabular / 5tAbjulE / a. tailor / 5teilE / v. tamper / 5tAmpE / v. & n. tandem / 5tAndEm / n. tangible / 5tAndVEbl / a. tap / tAp / v. tapestry / 5tApistri / n. tax / tAks / v. tax return techie / 5teki / n. telecom / 5telikCm / n. telecommunication / 5telikE7mju:ni5keiFEn / n. telecommuting / 7teli kE5mju:tiN / n. telegraph / 5teligrB:f / n. telematics / 7teli5mAtiks / n. 便笺簿;(图形)输入板;药片(15A) 便笺簿式个人电脑(15A) (列成)表格的(12B) 针对特定目的(或对象)作修改,使适应 (特定需要)(4C) 篡改(13A) 纵列套在马车上的两匹马(15A) 可触摸的;有形的;明确的(14C) 接进(10A) 花毯;挂毯(5A) 使负重担;使受压力;耗费(11C) 纳税申报单(15A) (尤指计算机方面的)技术人员;计算机迷(1B) 电信(15B) 电信(2C) 远程办公,家庭办公(9C) 电报(机)(8A) 远程通信及信息处理技术(13B) 344 teleshopping / 5teli7FCpiN / n. telework / 5teliwE:k / n. & v. teleworking / 5teli7wE:kiN / n. teller / 5telE / n. template / 5templit / n. temple / 5templ / n. tempt / tempt / v. terminate / 5tE:mineit / v. termination / 7tE:mi5neiFEn / n. terminator / 5tE:mineitE / n. terminology / 7tE:mi5nClEgVi / n. terrorism / 5terErizEm / n. text editor textbox / 5tekstbCks / n. textual / 5tekstjuEl / a. Thailand / 5tailAnd / n. theft / Weft / n. thematic / Wi5mAtik / a. theorem / 5WiErEm / n. theorem prover thermal / 5WE:mEl / a. thin-client computer thread / Wred / n. throughput / Wru:5put / n. tidbit / 5tidbit / n. tier / tiE / n. tiered / tiEd / a. tiering / 5tiEriN / n. tiled / taild / a. timely / 5taimli / a. time-slice / 5taimslais / n. tinker / 5tiNkE / v. tip / tip / n. token / 5tEukEn / n. token ring toner / 5tEunE / n. toolkit / 5tu:lkit / n. topographic / 7tCpE5grAfik / a. topology / tE5pClEdVi / n. tornado / tC:5neidEu / n. torpedo / tC:5pi:dEu / n. touch-sensitive / 5tQtF7sensitiv / a. trackball / 5trAkbC:l / n. trailer / 5treilE / n. transaction / trAn5zAkFEn / n. transient / 5trAnziEnt / a. transistor / trAn5sistE / n. transition / trAn5siVEn / n. translate / trAns5leit / v. translator / trAns5leitE / n. Computer English 远程购物(12A) 远程工作(12A) 远程工作(12A) (银行)出纳员(13A) 模板(14B) 太阳穴,鬓角(1B) 引诱,诱惑(5C) (使)终止(10A) 结束,终止(6A) 终结器;终端(10A) [总称] 术语(6B) 恐怖主义(14A) 文本编辑器,文本编辑程序(5A) 文本框(5B) 文本的;正文的(12A) 泰国(14A) 偷窃(13A) 主题的;专题的(12B) 定理(4C) 定理证明程序,定理证明器(4C) 热的;热量的(6B) 瘦客户机(1B) 线程,线索(4C) 吞吐量,吞吐率(3C) 珍品;常用信息(10C) (一)层(7A) 分层的,层叠的(7A) 层叠(7A) 平铺(式)的(3A)∕用瓦覆盖的(12B) 及时的;适时的(12B) 时间片(3A) 修补,摆弄(1C) 指点;技巧(1C) 权标,令牌(2B)∕代币;筹码;凭证(13A) 权标环,令牌环(3B) 色粉,墨粉(2A) (软件)工具箱(5C) 地形(学)的(12B) 拓扑(结构)(2B) 龙卷风(14A) 鱼雷(1A) 触敏的(2A) 跟踪球,轨迹球(2A) 尾部(信息)(8C) 交易;业务(1A) 短暂的;临时的(6A) 晶体管(1A) 过渡;转变(6B) (使)转变(10B) 翻译程序,翻译器(5A) 计算机英语 Transmission Control Protocol traverse / 5trAvE:s / v. trigger / 5trigE / n. trigger / 5trigE / v. Trojan / 5trEudVEn /(horse) n. troubleshoot / 5trQblFu:t / v. trunking / 5trQNkiN / n. trustworthiness / 5trQst7wE:Tinis / n. trustworthy / 5trQst7wE:Ti / a. tweak / twi:k / v. 传输控制协议(10B) 横越;穿过(9B) 触发器(7B) 触发,引起(8A) 特洛伊木马程序(或病毒)(4C) 检修,故障诊断,排故障(10A) 集群,中继(9B) 值得信任;可信;可靠(6A) 值得信任的;可信的;可靠的(4C) 微调,调理(1C) U ubiquitous / ju:5bikwitEs / a. ubiquity / ju:5bikwEti / n. unambiguously / 7QnAm5bigjuEsli / ad. unauthorized / 7Qn5C:WEraizd / a. unbundle / 7Qn5bQndl / v. underlie / QndE5lai / v. underlying / 7QndE5laiiN / a. underpin / 7QndE5pin / v. underscore / 7QndE5skC: / a. underway / 5QndE5wei / a. unify / 5ju:nifai / v. uninitialized / 7Qni5niFElaizd / a. uninitiated / 7Qni5niFieitid / a. unobtrusive / 7QnEb5tru:siv / a. unprecedented / 7Qn5presidEntid / a. unrest / 7Qn5rest / n. unwitting / 7Qn5witiN / a. upcoming / 5Qp7kQmiN / a. update / Qp5deit / v. upgrade / Qp5greid / v. uplift / Qp5lift / v. upstream / 5Qp5stri:m / a. up-to-the-minute / 5QptETE5minit / a. user ID user-friendly / 5ju:zE5frendli / a. utility / ju:5tilEti / n. utility program 普遍存在的(9C) 普遍存在(14B) 不含糊地,明确地(12C) 未经授权的(4C) 分解,分离(9A) 构成…的基础;支持(6A) 基本的,根本的(6A) 支持;巩固;证实(12A) 强调;加强(15B) 在进行中的(10C) 使成一体;统一(6A) 未初始化的(2B) 缺乏某种特定知识和经验的(3B) 不唐突的;考虑周到的(1B) 无前例的,空前的,前所未闻的(12A) 动乱;动荡(14A) 不知道的,不知情的(14C) 即将来到的(8A) 更新;修改(1C) 使升级;改善(3A) 提高,促进(13B) 向上流的(8C) 直到最近的,最新的(12B) 用户标识(14C) 用户友好的,使用方便的(1B) 实用程序(3B) 实用程序,工具程序(5A) V vacuum tube validity / vE5lidEti / n. value chain value-added / 5vAlju:5Adid / variant / 5veEriEnt / n. a. 真空管(1A) 有效性(7A) 价值链(13B) 增值的(13C) 变体;变种(14A) 345 346 vector / 5vektE / n. vein / vein / n. vendor / 5vendE / n. verge / vE:dV / n. versatile / 5vE:sEtail / a. versatility / 7vE:sE5tilEti / n. versus / 5vE:sEs / prep. viable / 5vaiEbl / a. vice versa / 7vaisi5vE:sE / ad. video camera video capture card video display videoconference / 7vidiEu5kCnfErEns / n. & v. videoconferencing / 7vidiEu5kCnfErEnsiN / n. video-on-demand / 7vidiEuCndi5mB:nd / n. view / vju: / n. vigor / 5vigE / n. virtual memory virtualize / 5vE:tFuElaiz / v. virus signature visualize / 5vizjuElaiz / v. void / vCid / n. volatile / 5vClEtail / a. volatile memory voltage transition vulnerability / 7vQlnErE5bilEti / n. vulnerable / 5vQlnErEbl / a. Computer English 矢量,向量(12B) 静脉;血管(1B) 卖主;厂商(1B) 边,边缘(15C) 多用途的,通用的(1A) 多用途;通用性(4A) 对;与…相比(2C) 切实可行的;可实施的(15A) 反之亦然(6C) 摄像机(11C) 视频捕获卡(11C) 视频显示(器)(2A) (开)电视会议(11C) (开)视频会议;视频会议技术(11C) 视频点播(8B) 视图(7B) 活力;精力(13A) 虚拟内存(3A) 使虚拟化(8B) 病毒特征代码(14B) 使可视化,使可见;使直观化(4B) 空间;真空(10C) 易失的(2A) 易失性存储器(2A) 电压翻转(2B) 易遭攻击的地方;脆弱(性)(14C) 脆弱的;易受攻击的(4C) W walkie-talkie / 5wC:ki5tC:ki / n. warehousing / 5weE7hauziN / n. warrant / 5wCrEnt / v. wearable / 5weErEbl / n. Web site WebTV / 5web5ti:5v: / n. well-being / 5wel5bi:iN / n. well-defined / 5weldi5faind / a. whereby / weE5bai / ad. whim / wim / n. wholesale / 5hEulseil / n. & a. wide area network window / 5windEu / v. Windows socket wiretap / 5waiEtAp / v. wiring closet workstation / 5wE:k7steiFEn / n. worm / wE:m / n. 步话机(8A) 存库,仓贮(13B) 证明…是正当(或有理);授权给;保证(6C) 佩带式计算机(1B) 网站,站点(1C) 网络电视机(15A) 康乐,安康(15C) 明确的;界线分明的(6B) 靠那个;借以(3A) 突然产生的念头;异想天开的念头,怪念头(6B) 批发(的)(13A) 广域网(8B) 把…分隔成多个窗口(3A) Windows 套接字接口(5B) 搭线窃听(14A) 布线室(10A) 工作站(1A) 蠕虫(病毒)(14A) 347 计算机英语 Appendix II Abbreviations (缩略语表) 3D three-dimensional 三维的(13A) AAL ATM adaptation layer 异步传输模式适配层(8C) ACK acknowledgement 确认,应答(2B) ADO ActiveX Data Object ActiveX 数据对象(7C) AI artificial intelligence 人工智能(5A) AIX advanced interactive executive 高级交互执行系统(3A) ALGOL Algorithmic Language ALGOL 语言,算法语言(4A) AM amplitude modulation 调幅(8B) ANSI American National Standards Institute 美国国家标准协会(5C) AOL America Online 美国在线服务公司(11A) API Application Program Interface 应用程序接口(4B) ARP Address Resolution Protocol 地址解析协议(10B) ARPANET Advanced Research Projects Agency net ARPA 网,阿帕网(8B) ASCII American Standard Code for Information Interchange ASCII 码,美国国家信息交换标准代码(5C) ASP Active Server Pages 活动服务器网页(3C) AT&T American Telephone and Telegraph 美国电话电报公司(3A) ATM Asynchronous Transfer Mode 异步传输模式(3B) ATM automated (或 automatic) teller machine 自动柜员机,取款机(13A) BASIC Beginner’s All-purpose Symbolic Instruction Code BASIC 语言,初学者通用符号指令码(4A) BBS bulletin board system 公告板系统(14B) BDE Borland Database Engine Borland 数据库引擎(7C) BIOS Basic Input Output System 基本输入输出系统(2A) BSD Berkeley Software Distribution 伯克利软件发行中心(3A) CB citizens band 或 Citizens’ Band 民用波段,民用电台频带(8A) CD compact disc 光盘(2C) CD-R compact disc-recordable 可刻录光盘(2C) CD-ROM compact disc read-only memory 只读光盘(存储器)(2A) CD-RW compact disc-rewritable 可擦写光盘(2C) CIO chief information officer 首席信息官(13B) COBOL Common Business-Oriented Language COBOL 语言,面向商业的通用语言(4A) 348 Computer English COM Component Object Model 组件对象模型(3C) CORBA Common Object Request Broker Architecture 公用对象请求代理程序体系结构(4C) CPU central processing unit 中央处理器(1B) CRC cyclic redundancy check 循环冗余码校验(8C) CRC Cyclic Redundancy Code 循环冗余代码(2B) CRT cathode ray tube 阴极射线管(2A) CSMA-CD Carrier Sense Multiple Access-Collision Detect 带有冲突检测的载波侦听多路访问(9A) DARPA Defense Advanced Research Projects Agency (美国)国防部高级研究计划局(8B) DBCS Double Byte Character Set 双字节字符集(5C) DBMS database management system 数据库管理系统(7A) DC direct connection 直接连接(11C) DCOM Distributed Component Object Model 分布式组件对象模型(7C) DEC Digital Equipment Corporation (美国)数字设备公司(2B) DES Data Encryption System 数据加密系统(9A) DLL dynamic-link library 动态链接库(5C) DML Data Modification Language 数据修改语言(7A) DOS disk operating system 磁盘操作系统(3A) DQDB distributed queue dual bus 分布式队列双总线(8C) DSL Digital Subscriber Line 数字用户线路(8A) DUN Dial-Up Networking 拨号联网(9C) DVD digital video disk 数字视盘(1B) digital versatile disk 数字多功能光盘(1B) DVD-R digital versatile disk-recordable 可刻录 DVD 光盘(2C) DWDM Dense Wave Division Multiplexing 密集波分多路技术(8B) EBONE European Backbone 欧洲骨干网(8B) EC electronic commerce 电子商务(13A) EDI Electronic Data Interchange 电子数据交换(13A) EFT Electronic Funds Transfer 电子资金传送(系统),电子资金转账(13A) ENIAC Electronic Numerical Integrator And Computer 电子数字积分计算机,ENIAC 计算机(1A) ERD entity relationship diagram 实体关系图(7A) FAQ frequently asked questions 经常提出的问题,常见问题(1C) FDDI fiber-distributed data interface 光纤分布式数据接口(8C) FIPA Foundation for Intelligent Physical Agents 智能物理代理基金会(12C) FM frequency modulation 调频(8B) FORTRAN Formula Translation FORTRAN语言,公式翻译程序语言(4A) FTP File Transfer Protocol 文件传输协议(3B) G7 Group of Seven 西方七(大工业)国(8B) 349 计算机英语 GB gigabyte 吉字节,千兆字节(2C) Gbps gigabits per second 吉位每秒,每秒千兆位(3C) GII Global Information Infrastructure 全球信息基础设施(8B) GIS geographic information system 地理信息系统(12B) GPS Global Positioning System 全球卫星定位系统(1B) GUI graphical user interface 图形用户界面(1B) HDLC high-level data link control 高级数据链路控制规程(8C) HTML Hypertext Markup Language 超级文本标签语言(5B) HTTP Hypertext Transfer Protocol 超文本传输协议(6A) I/O input/output 输入∕输出(1B) IBM International Business Machines (美国)国际商用机器公司(2B) IC integrated circuit 集成电路(1A) ICMP Internet Control Message Protocol 网间信报控制协议(10B) ICSA International Computer Security Agency 国际计算机安全代理公司(14B) ID identification 身份证明(7B) IEEE Institute of Electrical and Electronics Engineers (美国)电气和电子工程师协会(8C) InterNIC NSFnet (Internet) Network Information Center Internet 网络信息中心(14C) IP Internet Protocol Internet 协议,网际协议(8B) IPX Internetwork Packet Exchange 网间报文交换,互联网络包交换(3B) IS International Standard 国际标准(2C) ISA Industry Standard Architecture 工业标准结构(2B) ISDN Integrated Services Digital Network 综合业务数字网(3B) ISO International Standards Organization 国际标准化组织(6A) ISP Internet service provider 因特网服务提供者(3B) ISV independent software vendor 独立软件推销商(或开发商)(13B) IT information technology 信息技术(12A) K kilobyte 千比特(11C) KB/sec kilobyte/second 千字节∕秒(2C) Kbps Kilobits per second 千比特每秒(11A) LAN local area network 局域网(1B) LANE local area network emulation 局域网仿真(9B) LAPD link access procedures on the D channel D 信道连接访问程序(8C) LCD liquid crystal display 液晶显示(器)(1B) LISP List Processing LISP 语言,表处理语言(4A) LSI large-scale integrated 大规模集成(1A) MAC media access control 媒体接入控制,媒体访问控制, 媒体存取控制(9B) 350 Computer English MAN metropolitan area network 市域网,城域网(8C) MAU multistation access unit 多站访问单元(10A) MB megabyte 兆字节(1C) Mb/s megabit/second 兆位∕秒(8C) MB/sec megabyte/second 兆字节/秒(2B) Mbps Megabits per second 兆位每秒(9B) MBR master boot record 主引导记录(14B) MFC Microsoft Foundation Class 微软基础类(4B) MIS Management Information System 管理信息系统(9B) MPEG Moving Pictures Experts Group 运动图像专家组(2C) MSAU multistation access unit 多站访问单元(10A) MS-DOS Microsoft Disk Operating System 微软(公司)磁盘操作系统(3A) msec millisecond 毫秒(2B) MSN Microsoft Network 微软网络(微软提供的网络在线服务) (11A) MTA message transfer agent 报文传送代理(11B) MTS Microsoft Transaction Server 微软事务服务器(7C) MUA mail-user agent 邮件用户代理(11B) MX mail exchange 邮件交换(14C) NAK negative acknowledgement 否定确认,否定应答(2B) NCP Network Control Program 网络控制程序(8B) NEC Nippon Electric Company 日本电气公司(2B) NII National Information Infrastructure 国家信息基础设施(13A) NIIAC Advisory Council on the National Information Infrastructure (美国)国家信息基础设施顾问 委员会(8B) NNTP Network News Transfer Protocol 网络新闻传输协议(10B) NOS network operating system 网络操作系统(9C) ns nanosecond 纳秒,毫微秒,10 9 秒(8C) NSFNET National Science Foundation Network (美国)国家科学基金会网络(8B) NTFS NT File System NT 文件系统(3C) OCX OLE custom control OLE 定制控件(5B) ODBC open database connectivity 开放式数据库连接(性)(5B) OLE object linking and embedding 对象链接和嵌入(5B) OMG Object Management Group 对象管理组(6A) OS operating system 操作系统(3A) PARC Palo Alto Research Center (施乐公司)帕洛阿尔托研究中心(3A) PBD PowerBuilder DLL PowerBuilder 动态链接库(5C) _ 351 计算机英语 PBL PowerBuilder library PowerBuilder 库(5C) PC personal computer 个人计算机(6A) PCI Peripheral Component Interconnect 外部设备互连(总线),外围元件互连(2B) PDA personal digital assistant 个人数字助理(13A) PID Packet Identification 包类型标识(2B) PLIP Parallel Line Interface Protocol 并行线路接口协议(3B) POP Post Office Protocol 邮局协议(3B) POSIX Portable Operating System Interface for UNIX 可移植的 UNIX 操作系统(3B) PROLOG Programming in Logic PROLOG 语言,逻辑程序设计语言(4A) PSTN public-switched telephone network 公用交换电话网(8C) PVC permanent virtual circuit 永久虚电路(9B) QoS quality of service 服务质量(9B) R&D research and development 研究与开发(15A) RAM random access memory 随机(访问)存储器(2A) RAS Remote Access Service 远程访问服务(9C) RDO Remote Data Object 远程数据对象(5B) RF radio frequency 射频;无线电频率(1B) RISC reduced instruction set computing 精简指令集计算机(3A) ROM read only memory 只读存储器(1A) RPC remote procedure call 远程过程调用(6B) SIMULA Simulation Language SIMULA 语言,仿真语言,模拟语言(4A) SMB Server Message Block 服务器消息块(3C) SMP symmetric multiprocessing 对称多(任务)处理(3C) SNA system network architecture 系统网络体系结构(8B) SNMP Simple Network Management Protocol 简单网络管理协议(3B) SOF Start Of Frame 帧首(2B) SQL structured query language 结构化查询语言(4A) SVC switched virtual channel 交换式虚拟通道(8C) SVC switched virtual circuit 交换虚电路(9B) SVGA Super Video Graphics Array 超级视频图形阵列(3B) TCO total cost of ownership 总拥有成本(3C) TCP Transmission Control Protocol 传输控制协议(8C) TCP/IP Transmission Control Protocol/Internet Protocol TCP/IP 协议,传输控制协议∕网际协议(3B) TMP temporary memory 暂(时)存(储)器(1C) UNI user network interface 用户网络接口(9B) URL Uniform Resource Locator 统一资源定位符,统一联网地址(11A) USB Universal Serial Bus 通用串行总线(2B) 352 Computer English UTP unshielded twisted pair 非屏蔽双绞线(8C) VAX virtual address extension 虚(拟)地址扩充系统(8B) VB Visual Basic 可视化 Basic 语言(14B) VBX Visual Basic custom control 可视 Basic 定制控件(5B) VCI virtual channel identifier 虚拟通道标识符(8C) VCL Visual Component Library (Delphi 的)可视化组件库(7C) VGA Video Graphics Array 视频图形阵列(3B) VLAN virtual local area network 虚拟 LAN,虚拟局域网(9B) VLSI very large-scale integrated 超大规模集成(1A) VPI virtual path identifier 虚拟路径标识符(8C) WAN wide area network 广域网(5B) WAP Wireless Application Protocol 无线应用协议(1B) WIMP windows-icons-menus-pointing device 窗口-图标-菜单-指点设备(3A) WWW World Wide Web 万维网,WWW 网(3B) XML eXtensible Markup Language 扩展标记语言(12C)
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
advertisement