(完整版)计算机专业英语教程(第5版)翻译完整版

2.1 光存储介质：高密度存储器2.1.1 光盘光盘技术最终可能使磁盘和磁带存储淘汰。

用这种技术，磁存储器所用的读/写头被两束激光代替。

一束激光通过在光盘上刻制微小的凹点，对记录表面进行写；而另一束激光用来从光敏感的记录表面读取数据。

由于光束容易被偏转到光盘上所需要的位置，所以不需要存取臂。

对用户而言，光盘正成为最有吸引力的选择。

它们(光盘)对环境变化不太敏感，并且它们以每兆字节比磁盘低得多的存储器价格提供更多的直接存取存储器。

光盘技术仍在出现，并且还需要稳定；然而，目前有三种主要类型的光盘。

它们是CD-ROM、WORM盘和磁光盘。

CD-ROM1980年引入的，非常成功的CD，或紧密盘是设计来提高音乐的录音重放质量的光盘。

为了制作一张CD，把音乐的模拟声音转换成等价的数字声音，并且存储在一张4.72英寸的光盘上。

在每张光盘上可以用数字格式（用20亿数字位）记录74分钟的音乐。

因为它的巨大存储容量，计算机工业的企业家们立刻认识到光盘技术的潜力。

事实上，任何可以被数字化的东西都能存储在光盘上：数据、正文、声音、静止图象、音乐、图形和视频。

CD-ROM（读作C—D—ROM）是音频CD技术的副产品。

CD-ROM代表紧密盘—只读存储器。

该名字隐含了它的应用。

只读光盘与(能长期播放的) 唱片一样，在工厂里“压制”并带着预先录好的内容(如莎士比亚全集，或电影“飘”的前30分钟部分)，分发出去。

一旦光盘插入光盘驱动器，正文、视频图像等等就能读入主存进行处理或显示；然而，在只读光盘上的数据是固定的—它们不能被改变。

当然，这是与磁盘的读/写能力不同的。

大量的、低成本直接存取存储器（是光盘使之成为可能）已经打开了通向许多新应用的大门。

WORM盘（即，CD—R）写一次，读多次或WORM光盘被那些面向最终用户的公司用来存储它们自己的专用信息。

一旦数据已写到该介质，它们只能读，不能再更新或改变。

WORM盘有可能替代磁带作为档案存储器。

Unit 1A computer system consists of hardware system and software system. The hardware of the computer is usually divided into three major parts or three primary subsystems: the CPU, the memory subsystem, and the I/O subsystem.The CPU performs many operations and controls computer. The memory subsystem is used to store program being executed by the CPU, along with the program’s data. The I/O subsystem allows the CPU to interact with input and output devices such as the keyboard and monitor of a personal computer. The components of the computer are connected to the buses.The part of the computer that performs the bulk of data processing operations is called the central processing unit and is referred to as the CPU. In microcomputer, it is often called the microprocessor. The CPU is made up of three major parts: control unit, ALU, and register set.Memory is also known as internal memory or main memory. It refers to the circuits in the computer that hold whatever programs and data are available for immediate use by the CPU.I/O subsystem includes I/O devices and interface. There are a wide variety of I/O devices, such as mouse, printer, sensor, disk, and so on. Input-output interface provides a method for transferring information between internal storage and external I/O devices. Peripherals connected to a computer need special communication links for interfacing them with the CPU. The purpose of the communication link is to resolve the differences that exist between the central computer and each peripheral.Unit 3(a) A program is a list of instructions or statements for directing the computer to perform a required data processing task. Programming is a multistep process for creating that list of instructions.(b) It is important to understand the difference between a class and an object of that class. A class is simply a specification for creating objects. Thus, a single class may create multiple objects.(c) Java is an object-oriented, network-friendly high-lever programming language that allows programmers to build applications that can run on almost any operating system.(e) Programming involves a great deal of creativity. The design is guide to the function or purpose of each component, but the programmer has great flexibility in implementing the design as code. No matter what language is used, each program component involves at least three major aspects: control structures, algorithms, and data structures.Unit 4The software system can be divided into two broad categories: application software and system software. Application software consists of the program for performing tasks particular to the machine’s utilization. In contrast to application software, system software comprises a large number of programs. These programs start up the computer and function as the principle coordinator of all hardware components and application software. Without system software loaded into RAM of your computer, your hardware and application software are useless.System software can be grouped into three basic parts: operating system, utility software, and language translators. The majority of an installation’s utility software consists of programs for performing activities that are fundamental to computer installations yet not included in the operating system. In a sense, utility software consists of software units that extend the capabilities of the operating system.A computer’s OS is the main collection of programs that manage its activities. The primary chores of an OS are management and control. The OS ensures that all actions requested by a user are valid and processed in an orderly fashion. It also manages the computer system’s resources to perform these operations with efficiency and consistency.Application software is the software designed to help you solve problems specific to business or perform specific business tasks. Application software then is the layer of software closest to you. Basically, there are four categories of application software: productivity software, business and specialty software, entertainment software and education/reference software.Unit 5A computer network is often classified as being either a local area network (LAN), a metropolitan area network (WAN), or a wide area network (WAN). The connection of two or more networks is called an internetwork. The worldwide Internet is a well-known example of an internetwork.LANs are privately owned networks within a single building or campus of up to a few kilometers in size. They are widely used to connect personal computers and workstations in company offices and factories to share resources and exchange information.In general, a given LAN will use only one type of transmission medium. Various topologies are possible for LANs. The most common LAN topologies are bus, ring and star.A MAN is basically a bigger version of a LAN and normally uses similar technology. MAN is designed to extend over an entire city. It may be a single network such as a cable television network, or it may be a means of connecting a number of LANs into a large network so that resources may be shared LAN-to-LAN as well as device-to-device. For example, a company can use a MAN to connect the LANs in all of its offices throughout a city.A WAN spans a large geographical area that may comprise a country, a continent, or even the world. It provides long-distance transmission of data, voice, image, and video information over large geographical area.In contrast to LANs, WANs may utilize public leased, or private communication devices, usually in combinations, and can therefore span an unlimited number of miles.Unit 6Transmission media are used to transfer messages over a network. For instance, the transmission media used in a network may be a privately owned set of cables, the public phone lines, or a satellite system. Transmission media can either be wired or wireless.The three types of wired media most commonly used to carry messages are twisted-pair wire, coaxial cable, and fiber-optic cable. One of the most successful developments in transmission media in recent years has been fiber optics. Fiber-optic cable is commonly used for the high-speed backbone lines of a network, or for Internet infrastructure.Wireless transmission media have become especially popular in recent years. They support communications in situations in which physical wiring is impractical or inconvenient, as well as facilitate mobility. Wireless media are commonly used to connect devices to a network, to share information between computers, to connect wireless mice to a computer, and for handheld PCs, wireless phones, and other mobile devices. Radio signals transferred through the air are the heart of most types of wireless media. In addition to conventional broadcast radio application, the microwave, cellular, and satellite transmission media also use radio signals to transmit data.Radio transmissions require the use of a transmitter to send the radio signals through the air. A receiver (usually containing some type of antenna) accepts the date at the other end. When a device functions as both a receiver and transmitter, it is commonly called a transceiver or transmitter-receiver.Unit 7(a) Since many database systems users are not computer trained, developers hide the complexity from users through several levels of abstraction, to simplify user’s int eractions with the system: physical level, logical level, and view level.(b) A database schema is specified by a set of definitions expressed by a special language called a data-definition language (DDL). The result of compilation of DDL statements is a set of tables that is stored in a special file called data dictionary, or data directory.(c) The structured query language (SQL) is the most widely used and standard query language for relational database management systems. It is a kind of non-procedural language.(d) An entity is a “thing” or “object” in the real world that is distinguishable from other objects. For example, each person is an entity, and bank accounts can be considered to be entities. Entities are described in a database by a set of attributes.(e) Data warehouse is one of the newest and hottest buzzwords and concepts in the IT field and the business environment.A data warehouse is a logical collection of information——gathered from many different operational databases——that supports business analysis activities and decision-making tasks.Unit 9(a) AI is currently being applied in business in the form of knowledge systems, which use human knowledge to solve problems. The most popular type of knowledge-based system is the expert system. An expert system is a computer program that attempts to represent the knowledge of human experts in the form of heuristics. The term heuristic is derived from the same Greek root as the word eureka, which means “to discover”.(b) The user interface enables the manager to enter instructions and information into the expert system and to receive information from it. The instructions specify the parameters that guide the expert system through its reasoning processing. The information is in the form of values assigned to certain variables.(c) The knowledge base contains both facts that describe the problem area and knowledge representation techniques that describe how the facts fit together in a logical manner. The term problem domain is used to describe the problem area.(d) An expert system, also called a knowledge-based system, is an artificial intelligence system that applies reasoning capabilities to reach a conclusion. Expert systems are excellent for diagnostic and prescriptive problems.(e) The DSS is not intended to replace the manager. The computer can be applied to the structured portion of the problem, but the manager is responsible for the unstructured portion——applying judgment or intuition and conducting analyses.1。

第1课计算机基础计算机是一个可编程的机器（或者更准确地说，一个可编程的连续状态机器）。

计算机有两种基本类型：模拟计算机和数字计算机。

模拟计算机是模拟设备，即它们有连续的状态而不是离散的有限状态。

一个模拟计算机可以准确地表示小数或无理数，不进行舍入。

模拟计算机几乎只用于实验环境。

数字计算机是可编程的时序状态机器。

数字计算机使用离散状态。

二进制数字计算机使用两个离散状态（如正/负、高/低、通/断）来表示二进制数0和1。

1. 计算机有什么用？计算机的用途非常广泛。

数据处理是商业和金融的工作。

这包括开票、运输及收货、库存管理和类似的业务以及“电子办公”。

科学处理是用计算机支持科学。

这可以是简单地收集和分析原始数据，也可以是复杂地建立自然现象的模型（如气候模型、热力学、核能等）。

多媒体包括创建内容（创作音乐、演奏音乐、录制音乐、编辑电影和视频、特效、动画、插图、排版印刷材料等）和多媒体播放（游戏、DVD、教学材料等）。

2. 计算机的各部分可以十分粗略简单地认为计算机有三个部件：处理器、内存和I/O（输入/输出）。

这三个术语的边界是十分含糊的、不搭界的和不断变化的。

稍微更简单地可以把计算机部件分为五种：算术和逻辑子系统、控制子系统、主存、输入子系统和输出子系统。

2.1 处理器处理器是计算机实际上进行计算的部件。

有时也称作MPU（主处理器单元）或CPU（中央处理单元或中央处理器）。

处理器通常包括运算器（ALU）、控制器（包括处理器标志、标志寄存器或状态寄存器）、内部总线，有时也有一些特殊作用的单元（最常用的特殊作用单元是用于浮点算法的浮点单元）。

一些计算机有多个处理器。

这就叫做多处理计算机。

数字处理器的主要种类有：CISC、RISC、DSP以及它们的混合。

CISC代表复杂指令集计算机。

大型计算机和小型计算机有CISC处理器，厂家为了竞争提供了更有用的指令集。

大部分前两代微型处理器都用CISC。

RISC代表精简指令集计算机。

第3单元软件第一部分听力和对话对话：使用多媒体编辑软件制作电子相册(今天是国庆假日后的第一天，Henry在大厅里遇见了Mark.)Henry: 你好，Mark。

国庆假期过得怎么样？Mark: 非常棒！在假期里我和我的家人去了杭州。

那是一座非常美丽的城市，我们照了许多照片并且用DV拍了许多视频。

Henry: 真的吗？听起来真让人兴奋！所有的这些都将是美好的记忆。

我觉得你可以用这些材料将你在杭州的旅程做成电子相册。

这样你可以在任何时刻在电脑上看到它。

此外，如果你喜欢，你可以将它发布在博客上让更多的人分享你的快乐。

Mark: 噢，这是个好主意！但是我不知道怎样去做。

你愿意帮助我吗？Henry: 抱歉，我也是个外行。

但Sophie很擅长多媒体编辑软件，或许她能帮助你。

Sophie: 根据我的经验，图像软件是必不可少的，Mark。

它能帮助你创建、处理和打印图形。

Henry: 它分很多类型，对吧？Sophie: 是的，它包括绘画软件、照片编辑软件、制图软件、3D图形软件、CAD软件、以及演示软件等。

然而，对于你的情况，Mark，Photoshop这样的照片编辑软件就足够了。

Mark: 噢，是的，我听说过这个非常棒的照片编辑软件。

那这些视频呢？Sophie: 别担心，你可以用视频编辑软件编辑这些视频。

它提供了从摄像机传输视频片段到电脑的工具,，裁减掉不想要的片段，按序列拼接视频片段，添加特殊的视觉效果和音轨。

Henry: 我听说一个名叫Adobe Premiere的这种类型的软件。

Sophie: 没错！除此之外，DVD制作软件提供了能够制作好莱坞风格菜单的工具。

例如，Sonic DVDit、ULead DVD MovieFactory、Apple iDVD，以及Adobe Encore DVD。

Mark: 非常感谢你有益的指导，Sophie。

你能告诉我一些怎样使用它们制作电子相册的细节吗？Sophie: 没为题，如果你有时间，我可以为你展示怎样使用这类型的软件。

Unit 8 Computer NetworkingText 1 Data CommunicationsThe end equipment can be computers, printers, keyboards, CRTs, and so on.They are either generates the digital information for transmission or uses the received digital data. This equipment generally operates digital information internally in word units.DTE is data terminal equipment. A station controller STACO is the corresponding unit at the secondaries. At one time, the DTE was the last piece of equipment that belonged to the subscriber in a data link system. Between the DTEs, first is the modem, and then is the communications equipment. The communication equipment is owned and maintained by Telco. Data communications equipment DCE accepts the serial data stream from the DTE. And DCE converts it to some form of analog signal suitable for transmission on voice-grade lines. At the receive end, the DCE performs the reverse function. It converts the received analog signal to a serial digital data stream. The simplest form of DCE is a modem modulator/demodulator or data set. At the transmit end, the modem can be considered a form of digital-to-analog converter.While at the receive end, it can be considered a form of analog-to-digital converter.参考译文数据通信终端设备可以是计算机、打印机、键盘、CRT等;它们可以生成要发送的数字信息,也可以使用所接收的数字数据;这种设备通常在内部以字为单位处理数字信息;DTE一般称为数据终端设备;辅助设备一方的相应设备是工作站控制器STACO;同时,DTE也是数据链路系统中属于用户端的最后一个设备;在两个DTE之间,先是调制解调器,接着是属于Telco电话公司维护的通信设备;数据通信设备DCE从DTE接收串行数据流,并将其转换成适合于在语音线路上发送的某种模拟信号形式;在接收端,DCE完成相反的功能,把接收到的模拟信号转换成串行数字数据流;最简单的DCE是调制解调器或数据传送机;在发送端,调制解调器可以视为一种数/模转换器,而在接收端则可视为一种模／数转换器;Text 2 Architecture of Computer NetworksComputer network is a complex unit, it consists of two or more connected computing units. It is used for the purpose of data communication and resource sharing. Design of a network and its logical structure should comply with a set of design principles. They include: the organization of functions, the description of data formats and procedure.In the following two sections we will discuss two important network architectures, the OSI reference model and the TCP/IP reference model.(1)the OSI reference modelThe OSI open systems interconnection model was created by the ISO. This model is a foundation for comparing protocols; However, more protocols deviate from the rules set up by the OSI model.The OSI model has seven layers. Note that the OSI model itself is not a network architecture.It just tells what each layer should do. However, ISO has also produced standards for all the layers. Each one has been published as a separate international standard.(2)the TCP/IP reference modelTCP/IP is a communication protocol; it provides many different networking services.The TCP/IP Internet protocol suite is formed from two standards: the TCP Transmission Control Protocol and the IP Internet Protocol. TCP means it is on the transport layer. IP means it is on the network layer. On top of the transport layer is the application layer. It contains all the higher-level protocols. The early ones included virtual terminal TELNET, file transfer FTP, electronic mail SMTP and domain name service DNS.As we know, TCP/IP is the foundation of the Internet.These protocols are continually changing and evolving to support the needs of the user community.参考译文计算机网络结构计算机网络是由两个或多个计算机设备互连而成的一种复合系统,它用于数据通信和资源共享;网络设计及其逻辑结构应该遵循一套设计原则,其中包括：功能的组织以及数据格式和过程的说明;在下面的两小节里,我们将讨论两个重要的网络体系结构,即OSI参考模型和TCP/IP参考模型;(1)OSI参考模型OSI模型开放系统互联参考模型是由国际标准化组织ISO开发的一个建议;相对于其他协议来说,此种模式为基础模式;然而,更多的协议是背离OSI模型的;OSI模型有7层;应该注意的是,OSI模型本身并不是一种网络体系结构,它只是说明每一层应该做什么;然而,ISO还是对各层制定了标准,每一层都是作为一个单独的国际标准来颁布的;(2)TCP/IP参考模型TCP/IP参考模型是一种传输协议,提供了许多不同的网络服务;TCP/IP协议组由TCP传输控制协议和IP网际协议两部分组成;TCP表明是处于传输层,IP意为是在网络层;在传输层上面是应用层;应用层包括所有高层协议;早期的协议包括虚拟终端TELNET、文件传送协议FTP、电子邮件SMTP和域名服务DNS;现在我们知道,TCP/IP协议是因特网的基础;这些协议在用户们的支持下不断地改变和进化着;Text 3 Local Area NetworkA LAN Local area data network is a group of computers. The work devices connected together usually within the same building. By definition, the connections must be high-speed and relatively inexpensive . token ring or Ethernet. For example, a LAN may be used to interconnect workstations distributed around offices within a single building or a group of buildings such as a university campus.LANs consist of carefully selected groups of components hardware and software. They are configured for the specific requirements of the organization. A LAN is generally limited to the size of a department or an organization. And a LAN often consists of 2 to 100 devices. LANs usually contain resources such as servers, printers, and connections to other networks through internetworking devices. The internetworking devices include switches and routers.In the next section we will discuss the structure of the different types of LAN.(1)TopologyMost wide area networks, such as the PSTN, use a mesh sometimes referred to as a network topology. With LANs, however, the limited physical separation of the subscriber DTEs allows simpler topologies to be used. The four topologies in common use are star, bus, ring and hub.The most widespread topology for LANs designed to function as data communication subnetworks for the interconnection of local computer-based equipment is the hub topology. It is a variation of the bus andring.(2)Transmission mediaTwisted pair, coaxial cable and optical fibre are the three main types of transmission medium used for LANs.(3)Medium access control methodsTwo techniques have been adopted for use of the medium access control in the LANs. One is carrier-sense-multiple-access with collision detection, and the other is control token.参考译文局域网局域数据网局域网由若干计算机组成;通常是一幢楼内的工作设备被连接在一起;通过定义可知,这种连接一定是高速并且相对廉价的如：令牌网和以太网;例如,一个局域网可以把一幢楼里或像大学校园内楼群里的各个办公室的工作站连在一起;局域网是由精心挑选的各组设备硬件和软件构成的;它们根据组织的各种特殊需要来配置;局域网的大小一般限制在一个部门或者一个组织,由2～100台电脑组成;局域网经常包含一些资源,如一些服务器和打印机,而且可以通过网络设备与其他的网络连接;这些网络设备包括交换机和路由器等;接下来,我们将讨论不同类型局域网的结构;(1)拓扑结构大多数广域网,如公共电话交换网PSTN,使用网状有时称为网络拓扑结构；而局域网由于用户数据终端设备相距很近,可采用简单的拓扑结构;常用的有星形、总线、环形和集线器等4种拓扑结构;应用最广的、用于互连本部门计算机设备以进行数据通信的局域网拓扑结构是集线器拓扑结构;这种拓扑结构是总线和环形拓扑结构的变种;(2)传输媒体双绞线、同轴电缆和光纤是局域网采用的3种主要传输媒体;(3)媒体访问控制方法局域网中采用了两种媒体访问控制技术,一种是载波侦听多路访问／冲突检测技术CSMA/CD,另一种是令牌控制技术;Text 4 InternetThe Internet is used by millions of people across the world to communicate business and personal information. The Internet is huge. Then we will talk about the difference of “an internet”and “ the Internet”.An internet note the lower case "i" is a computer network. It allows computers with distinctive software and hardware to communicate. Many kinds of computers can be connected to an internet. Each computer can serve a specialized role. It offers a wide variety of services to its users.The Internet is specific kind of internet. In The Internet Passport, the Internet will be defined as the network of networks. It follows a set of rules known as the "Internet Protocol IP suite".But what does this mean to you It means that any computer that is connected to the Internet can communicate with any other Internet computer. From the user's perspective, this works much like the telephone system works. You can dial from your phone to any other phone on the system, no matter what kind of telephone you have; you only need to know the phone number of the person you want to reach.With an Internet connection you can get some of the basic services available are:•E-mail. It’s a fast, easy, and inexpensive way to communicate with other Internet users around the world.•Telnet. It allows a user to log into a remote computer as though it were a local system.•FTP. It allows a user to transfer virtually every kind of file that can be stored on a computer from one Internet-connected computer to another.•Usenet news. It’s a distributed bulletin board which offers a combination news and discussion service on thousands of topics.•World Wide Web . It’s a hypertext interface to Internet information resources. Also, through an Internet connection, you can:•access online library catalogs.•copy computer files or software from archives.•access databases for teaching or research.•obtain free electronic books.•use educational and information services.•use directory services to find Internet users.•access supercomputer sites.It was estimated that at this rapid growth everyone in the world would have an e-mail address in the near future.参考译文互联网因特网是世界上很多人用来进行商业贸易和个人信息交流的网络,它非常巨大;接下来,我们将讨论互联网及因特网;互联网internet注意小写字母i是一种计算机网络,该网络上的计算机在通信时可以使用不同的软件和硬件;多种计算机都可以连入互联网,每台计算机都可以有一独特作用;一个互联网可以向它的用户提供各式各样的业务;因特网Internet是一种专用互联网;因特网在它的证书中定义为网络的网络,该网络使用了一组叫做互联网协议IP组的规则;但对你来说,这意味着什么呢这表明连接到因特网上的计算机可以与因特网上任何其他计算机通信;从用户的角度来看,其工作方式很像电话系统的工作方式;在电话系统内,可以从你的电话机拨打任何其他电话,而不管你使用什么样的电话机,你只需知道对方的电话号码即可;你可以通过因特网得到的基本服务如下：•电子邮件;它是与世界范围内的因特网用户进行联系的一种快速、方便、廉价的交流方式;•远程登录;允许用户连接到远程计算机上,就像这台远程计算机是本地机一样;•文件传输协议;该协议可以将存储在计算机上的各种文件,从因特网上的一台计算机传送给另一台计算机;•新闻组网络系统;一种分布式的电子公告牌,它能提供有关上千种话题的新闻和讨论服务;•万维网;一种因特网信息资源的超文本界面;•访问在线图书馆目录;•从计算机档案库存储器中拷贝文件或软件;•访问教学或科研数据库;•获取免费电子图书;•使用教育和信息服务;•使用目录服务以查找因特网用户;•访问超级计算机站点;估计以这样的高速发展,在不久的将来世界上每个人都将拥有至少一个电子邮件地址;Text 5 The World Wide WebThe World Wide Web also known as or Web is one of the fastest-growing Internet software applications. It is an architectural framework. It linked documents spread out over thousands of machines for accessing all over the Internet.The World Wide Web ties the computers together into a vast collection of interactive multimedia resources. The is a way of exchange information between computers on the Internet.The Web is built around hypertext and hypermedia. A hypertext document has certain keywords or phrases linked to other online documents. A person reading a hypertext document about mobile phone, for example, might be able to select the highlighted word “Nokia 3310”, and he call up another document giving more information about that particular type. With documents intertwined by links into a web of information, you can select paths to browse online resources, a process often referred to as surfing.Hypermedia extends the concept of hypertext to other forms of information. They include: images, sounds, and even video clips. If a person read a hypermedia document about mobile phones, then he might select a video show of a phone and hear the ring of it.The World Wide Web also subsumes previous Internet information systems such as Gopher and FTP. These resources can still be accessed through the Web. But the Web offered by these more restricted connection methods. Now the Web provides a wealth of additional capabilities.Thousands of computers around the world are now connected to the Web. They offer a huge variety of information and services to visitors. These online documents are generally referred to as pages. They are composed and supported by various people and organizations. Web pages are available for an amazing variety of tasks ranging from the playful to the serious. You can get many services access Web pages. For example, you can search database of mailing lists, you can see pictures of your favorite band and their concert schedule, or you can take a “tour” through a foreign country. Thousands of links to new services are added to the Web each day, and its growth has been explosive.参考译文万维网万维网又称或Web是因特网上发展最快的应用软件之一;它是一种结构化框架,用于访问遍布在因特网上的成千上万台机器中的链接文档;万维网把这些计算机连接成了一个巨大的交互式多媒体资源库,它是因特网上的计算机之间进行信息交流的一种方式;Web是用超文本和超媒体设计的;超文本文档中的一些关键词或短语被链接到了其他的在线文档中;例如,某人在阅读一篇有关移动电话的超文本文档时,如果他选择高亮显示的词“诺基亚3310”,就能链接到另一篇有关这一类型移动电话的文章,从而可以获取更多的信息;网络文章通过链接形成了一个网络信息资源库,用户可以选择路径来浏览这些在线资源,这种行为通常被称为“网上冲浪”;超媒体将超文本的概念扩展到了其他的信息形式,其中包括图片、声音,甚至是录像剪辑;在超媒体文档中阅读有关移动电话的文章时,读者可以选择关于该电话的视频演示,还能听见铃声;万维网也包括了以前的因特网信息系统,如Gopher 和FTP;这些资源仍然可以通过网络访问,但是以前那些连接方式的局限性很大,现在的网络提供了许多先辈们没能提供的功能;现在世界上成千上万的计算机都连接到了网络上,而且为访问者提供了相当多的信息和服务;这些由不同的人和组织编写和支持的在线文档被称为网页;Web网页可以跨越从诙谐到严肃的各种风格;通过访问网页,用户可以查看邮件数据库,查阅自己喜爱的乐队的图片和他们的演出时间表,或去国外周游一圈;现在每天都会增加上千种新的服务链接,万维网已经飞速发展起来了;。

第4章操作系统第一部分阅读和翻译A部分 Windows 71. 简介Windows 7是微软最新发布的windows版本,这一系列微软制造的操作系统主要用于个人电脑,其中包括家庭和商业台式电脑、笔记本电脑、上网本、平板电脑、和媒体中心电脑。

(见图4.1)Windows 7于2009年7月22日开始生产,并在2009年10月22日零售,这个时间距其推出其前任Windows Vista不到三年时间。

与Windows 7相对应的Windows server 2008 R2,也是同年发布。

不像其前一操作系统vista，windows7 引入了大量的新特性，更集中于增量升级的windows线，目标是兼容已经在vista中兼容的应用程序和硬件。

微软在2008年的报告中关注于对于多点触控的支持，以及一个重新设计的windows shell和一个新的任务栏，并将其称之为Superbar，还有一个称之为家庭组的网络系统，注重性能改进。

之前版本的windows 系统中的一些标准的应用程序，包括windows日历，windows邮件，windows movie maker，和windows相片画廊在windows 7中并没有包含进来，而大多数是作为Windows Live Essentials套件单独免费进行提供的。

2. 发展最初，微软计划用一个代号为Blackcomb的windows版本来继承Windows XP(代号惠斯勒)和Windows Server 2003。

微软计划在Blackcomb中设计的主要功能包括在搜索中的加强，查询数据以及一个先进的存储命名系统。

然而，一个临时的，更小的，代号为Longhorn 的版本在2003年发布了。

微软在2003年中旬推迟发布了Blackcomb，但是Longhorn获得了大部分当初试图在Blackcomb中实现的特性。

在2003年，相继有三个主要病毒暴露了windows操作系统的一些漏洞，微软改变了其的发展重点，搁置了Longhorn的主要开发工作，主要开发windows xp和windows server 2003的服务包。

第5单元程序开发和编程语言第一部分听力和对话对话：认识Java运行时环境（JRE）和Java虚拟机（JVM）（在Java编程的第一课之前，Mark下载了一个简单的Java小应用程序进行示例学习，但他发现，它无法正常运行。

）Mark：对不起，Henry和Sophie。

你们能帮助我吗？Henry：当然可以。

什么问题？Mark：为什么这个Java小应用程序不能运行？它的源代码是正确的。

Sophie：你的计算机是否安装了Java运行环境[1]？Mark：还没有。

什么是Java运行环境？Henry：简称JRE,是一个由太阳微系统公司开发的软件平台，可以让计算机运行由Java 编程语言编写的Java小应用程序和应用程序。

[2]Sophie：它包含Java虚拟机、Java库和一些其他组件。

Mark：Java虚拟机是做什么用的？Sophie: Java虚拟机（简称JVM)是一套计算机软件程序和数据结构，它使用虚拟机模型来执行其他计算机程序和脚本。

它可以隐藏能够运行程序的计算机硬件的细节。

[3]Mark：JVM和JRE是什么关系？[4]Henry：JVM是JRE的实例，当执行Java程序时开始起作用。

当执行完成后，这个实例具有垃圾回收机制。

JVM与一套能够实现Java API（Application Program Interface，应用程序接口）的标准类库一起发行。

虚拟机和API必须彼此一致，因此它们被捆绑成为JRE.[5]Sophie：因此，这可以被视为一个虚拟的计算机，其中虚拟机是处理器，并且API是用户界面。

Henry： JVM是Java平台一个至关重要的组件。

使用所有平台的相同字节码可将Java描述成“编译一次，到处运行”Mark: 字节码？Henry：是的。

JVM在通常称为Java字节码的一种中间语言上运行，这种中间语言通常是由Java源代码产生的，但也不一定。

打算在JVM上运行的程序，必须编译成这种标准化的可移植的二进制格式。

1.1 A Closer Look at the Processor and PrimaryStorage仔细看看处理器和主存储器We have learned that all computers have similar capabilities and perform essentially the same functions, although some might be faster than others. We have also learned that a computer system has input, output, storage, and processing components; that the processor is the “intelligence” of a computer system; and that a single computer system may have several processors. We have discussed how data are represented inside a computer system in electronic states called bits. We are now ready to expose the inner workings of the nucleus of the computer system — the processor.我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。

我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。

我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。

第10单元计算机安全与隐私第一部分听力和对话对话：使用杀毒软件（Sophie的电脑不幸感染了恶意的电子邮件附件。

现在，她正努力寻找一些措施，用来有效地治疗和保护她的计算机不受病毒感染。

）Mark：我认为杀毒软件在上网时是一个主要的措施。

Henry：是的。

我同意。

杀毒软件是这样一种实用程序软件，它能够寻找并去除病毒、木马、蠕虫和恶意软件。

它适用于所有类型的计算机和数据存储设备，包括智能手机、平板电脑、个人计算机、闪存、服务器、PC机和Mac机。

Sophie：你能否推荐任何有信誉的杀毒软件让我使用？Mark：没问题。

流行的杀毒软件包括Norton AntiVirus、Kapspersky Anti-Virus、F-Secure Anti-Virus、Windows Defender和Avast等。

Sophie：杀毒软件如何起作用？Henry：现代的杀毒软件在幕后运行，并且企图识别存在于设备内的作为下载、电子邮件、附件或网页的恶意软件。

查找恶意软件的过程有时称为扫描或实现病毒扫描。

要识别恶意软件，杀毒软件可以查找病毒特征值或实现启发式分析。

Sophie：当查到恶意软件后会怎样呢？Mark：当杀毒软件查到恶意软件后，它可以试图去除感染，将这个文件放到隔离区，或仅仅是删除这个文件。

Mark：尽管偶尔查不到，但是杀毒软件和其他的安全软件模块能够不断地删去感染设备的恶意软件。

要点是使用安全软件，但是进行额外的预防措施也很重要，如定期备份数据，并且避开靠不住的软件销售商店。

Sophie：我如何保证我的杀毒软件正在运行？Mark：杀毒软件往往是我们习以为常的数字生活的一部分。

我们假定它已安装并执行它的工作。

Henry：但是杀毒软件可能无意中被禁用。

它的配置可以被通过设法潜入设备的恶意软件所改变。

在试用或订阅到期后，杀毒软件会失效。

保证杀毒软件正确地执行也许需要用户定期的介入。

Mark：而且许多杀毒产品在任务栏或通告区会显示一个图标。

1.1仔细看看处理器和主存储器我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。

我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。

我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。

计算机的内部操作很有意思，但确实没有什么神秘可言。

所谓的神秘只是存在于那些听信传闻和相信科幻小说作家的人的意识中。

计算机就是一种没有思想的需要接通电源的电子设备而已，与烤面包机和台灯差不多。

不加夸张地讲，市场上有几百种不同类型的计算机在销售.每种电脑在复杂性上可能有很大区别，但归根结底,每种处理器，有时称为中央处理器即cpu，只有两个基本部分:控制单元和计算逻辑单元.主内存在处理器内部操作中也是一个不可缺少的部分.这三个部件--主内存，控制单元和计算逻辑单元--一起工作.然我们看看它们(各自的)功能和它们之间的联系主存与其他的辅助存储器（如：磁带、硬盘）不一样的是，主存不含有运转部件。

由于没有机械运转的需要，主存种数据访问可以达到电子的速度，或接近于光速。

当今计算机的主存大多数使用DRAM（动态随机存取存储器）技术。

目前最新的工艺水平是：一块只有大约1/8张邮票大小的DRAM芯片却可以存储大约256,000,000位，约25,6000,000个字符的数据。

主存储器，也就是说内存，用于为处理器暂时存放程序和数据。

所有的程序和数据在被操作之前必须从输入设备（如VDT）或者辅助存储器转存到主存储器中。

主存储器存储容量通常是相当有限的，因此，在一个程序执行结束，它所占用的存储空间必须被重新分配给其它正在等待执行操作的程序。

图 1-1描述了输入/输出设备与主存储器间的读和写过程。

在图中，VDT发出一个输入请求，请求是以消息模式通过通道（如同轴电缆）发送到主存储器。

计算机体系结构弗林在1972年提出的计算机体系结构的分类法在今天仍然是对并行计算机分类的最为广泛使用的方法。

弗林根据计算机使用单还是多数据流、单还是多指令流来划分计算机（表格1-1）。

表格1-1 弗林的分类体系结构。

另一方面，一个多指令单数据流计算机会对从内存中取出来的每个数据执行多条指令。

遵从这种模型的计算机还没有制造出来。

弗林四个组群中的第三个是单指令多数据流。

在一个单指令多数据流计算机中，许多个处理器同时地执行相同的指令，但是处理的数据是不同的。

例如，如果指令是把A和B相加，这里的A和B都是矩阵，那么每一个处理器把B中的属于该处理器的元素加到A中相应的元素上。

到目前为止，这种类型的性能最显著的计算机是分布式阵列处理器（Distributed Array Processor,DAP）,连接机器（the Connection Machine,CM）等等。

这些机器由一些很简单的处理单元（PE）构成，但一台机器可以用很多个PE来补偿因其简单带来的不足。

一个单一的主处理器把程序指令广播给单一的处理单元，这些处理单元针对它们自己的数据执行指令。

处理单元可以被临时地被禁用以保证操作在部分数据上被执行；这提供了一种使计算是数据依赖的方式，就像大多数语言中的IF语句。

各处理单元之间也可以传输数据。

在DAP中，处理单元被连接在一个方阵列中。

每一个处理单元可以同时地向一个方向移动一位的数据并从相反的方向接受一位的数据。

重复的移动可以从网格中的任何部分移动大量数据到网格中的其它任何部分。

单指令多数据流计算机的一个特点是，随着处理单元的增加，处理单元之间的连接数也会增加，因此机器的总通信带宽与它的规模成比例增加。

这样的伸缩性在多指令多数据流计算机中也是一个重要的考虑因素。

经验表明单指令多数据流计算机在某些方面做的很好，在其它的某些方面却是无效率的。

例如，很多被用在图像处理中的算法涉及到对图像的每一个像素执行相同的操作，像求一些值的加权平均，与某个值最接近的四个值。

计算机专业英语翻译及课后答案Unit Nine: The InternetUnit Nine/Section AI. Fill in the blanks with the information given in the text:1. research2. ICANN或the Internet Corporation for Assigned Names and Numbers3. router; gateway4. temporary/dial-up; permanent/dedicated5. ISP或Internet service provider6. network; host7. decimal8. mnemonicII. Translate the following terms or phrases from English into Chinese and vice versa:1. cell phone 蜂窝电话，移动电话，手机2. IP address 网际协议地址，IP地址3. autonomous system 自主系统4. dial-up connection 拨号连接5. network identifier 网络标识符6. binary notation 二进制记数法7. mnemonic name 助记名，缩写名8. Internet-wide directory system 因特网范围的目录系统9. name server 名称服务器10. Internet infrastructure 因特网基础结构11. 助记地址mnemonic address12. 网吧cyber cafe13. 宽带因特网访问broadband Internet access14. 顶级域名top-level domain (TLD)15. 因特网编址Internet addressing16. 点分十进制记数法dotted decimal notation17. 因特网服务提供商Internet service provider (ISP)18. 专用因特网连接dedicated Internet connection19. 主机地址host address20. 硬件与软件支持hardware and software supportIII. Fill in each of the blanks with one of the words given in the following list, making changes if necessary:Early computer networks used leased telephone company lines for their connections. Telephone company systems of that time established a single connection between sender and receiver for each telephone call, and that connection carried all data along a single path. Whena company wanted to connect computers it owned at two different locations, the company placed a telephone call to establish the connection, and then connected one computer to eachend of that single connection.The U. S. Defense Department was concerned about the inherent risk of thissingle-channel method for connecting computers, and its researchers developed a differentmethod of sending information through multiple channels. In this method, files and messagesare broken into packets that are labeled electronically with codes for their origins, sequences,and destinations. In 1969, Defense Department researchers in the Advanced Research ProjectsAgency (ARPA) used this network model to connect four computers into a network called theARPANET. The ARPANET was the earliest of the networks that eventually combined to become what we now call the Internet. Throughout the 1970s and 1980s, many researchers in the academic community connected to the ARPANET and contributed to the technological developments that increased its speed and efficiency.IV. Translate the following passage from English into Chinese: 因特网只是提供了将许许多多的计算机连接在一起的物理与逻辑基础结构。