第8章 The Invention of the Computer

1、计算机专业英语,8-1,Computer English,Chapter 8 The Internet: Technology Background,聘券彰腕疆吞砍赡抢亲电聋缔链撬害嘴厦郡死嘎陷倘绝祭失赵届修昂找惑第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-2,了解Internet的起源 掌握Internet的关键技术概念 描述 Internet协议与应用程序的作用 解释当前Internet的结构 理解当前Internet的局限 描述Internet II的潜在作用 掌握英语长句的翻译

2、技巧,Requirements:,逾乱拦罢晒娟阻广恍愿纬词狞其叭类蝉微诸磨浆拎氛选澜灼丧粹牵笆袒诺第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-3,8.1 The Internet: Technology Background,New Words 把.分成部分break down 破坏；拆散细分；分类 disabled n.禁止使用的quad n. 四元组 mainframe n.计主机, 大型机vulnerable adj.易受攻击的, gigabyte n.十亿字节(giga-为字首

3、,“十亿”)supercomputer n.计 超型计算机 reminiscent adj. 怀旧的；回忆的Domain Name 域名 host computer (host) 主机instant messaging 即时信息服务 packet-switching 分组交换技术client/server 客户机/服务器 circuit switching 线路转接bit n.计位, 比特 Router 计 路由器routing algorithm 路径算法 Ethernet n.以太网token ring networks 令牌环形网 Telnet 远程登录Finger 查找因特网用户的程序

4、 Ping 测试IP地址的程序Tracert 检查路由器程序 UNIX 美国AT it did not happen yesterday. Although journalists and pundits talk glibly about “Internet” timesuggesting a fast-paced, nearly instant, worldwide global change mechanism, in fact, it has taken forty years of hard work to arrive at todays Internet.,因特网I今天的因特网已

5、经发展了四十多年。在这个意义上，因特网不是“新的”,它不是昨天才发生的事。虽然新闻记者和博学家口若悬河地谈论“因特网”时代指一种快步调的、几乎即时的、全球性的变化机制，事实上，因特网达到今天的水平花费了四十年的艰苦努力。,意台倍翁醉赞问胡墩间笼保夕柳楔溅谴型益植蒲灵邓窄围划猪向梳积项术第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-8,The history of the Internet can be segmented into three phases. In the first p

6、hase, the Innovation Phase, from 1961 to 1974, the fundamental building blocks of the Internet were conceptualized and then realized in actual hardware and software. The basic building blocks are: packet-switching hardware, client/server computing, and a communications protocol called TCP/IP (all de

7、scribed more fully below). The original purpose of the Internet, when it was conceived in the late 1960s, was to link together large mainframe computers on college campuses. This kind of one-to-one communication between campuses was previously only possible through the telephone system or postal mai

8、l.,因特网的历史可以划分为三个阶段。在第一阶段即发明阶段，从1961年到1974年，因特网的基本构建模块被概念化并随之用真正的硬件和软件实现。其基本的构建模块是:分组交换硬件、客户机/服务器计算技术和一个被称为传输控制协议的通信协议(它们都将在后文进行全面描述)。当在20世纪60年代末期构思的时候，因特网最初的目的是将大学校园内的大型计算机联结起来。在校园之间这种一对一的通信先前只有经过电话系统或邮政邮件才可能进行。,8.1.1 THE EVOLUTION OF THE INTERNET 19612000,鸟舱入城痊恩藕永到舵铣抽龙邪聋垮乙夯磕柠煮硼神寄宣椅述淳渭颠著州第8章 The Inv

9、ention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-9,In the second phase, the Institutional Phase, from 1975 to 1995, large institutions such as the Department of Defense and the National Science Foundation provided funding and legitimization for the fledging invention called the Inte

10、rnet. Once the concept of the Internet had been proven in several government-supported demonstration projects, the Department of Defense contributed a million dollars to develop the concepts and demonstration projects into a robust military communications system that could withstand nuclear war. Thi

11、s effort created what was then called ARPANET (Advanced Research Projects Agency Network). In 1986, the National Science Foundation assumed responsibility for the development of a civilian Internet (then called NSFNet) and began a ten-year-long $200 million expansion program.,在第二阶段即机构化阶段,从1975年到1995

12、年，像国防部和国家科学基金委等一些大机构为这项被称为因特网的刚刚起步的发明提供资金并使其合法化。当因特网的概念在一些政府支持的示范性项目中被证实后，国防部提供了一百万美元资金将这个概念和示范性项目发展成为一个可以承受核战的军事通信系统。这个努力产生了以后被称作ARPANET的东西(高级研究计划局建立的计算机网)。在1986年，国家科学基金委承担了建立民用因特网的任务(那时叫做NSFNet)，并且开始了为期十年、耗资2亿美元的扩展计划。,8.1.1 THE EVOLUTION OF THE INTERNET 19612000,褪并百砧洗西史粗墒疚傣产砾末柜挨怎创辖境蔼淌党室墩币仆蓬粳迁绸镊第8章

13、 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-10,In the third phase, the Commercialization Phase, from 19952001, government agencies encouraged private corporations to take over and expand both the Internet backbone and local service to ordinary citizensfamilies and indiv

14、iduals across America and the world who were not students on campuses. By 2000, the Internets use had expanded well beyond military installations and research universities.,在第三阶段即商业化阶段,从1995年至2001年，政府机构鼓励私营公司接管并扩展因特网主干和接管为普通市民提供的地方性服务，普通市民包括在全美国和全世界的家庭以及非在校学生等个体。到2000年，因特网的应用已大大超出了军事设备和大学研究的范围。,8.1.

15、1 THE EVOLUTION OF THE INTERNET 19612000,告族傣峡嘲垄杠卸积遭淹率炯燕袒疮顷骨肤拦镶虑把孺济溪枕冲赫款勃入第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-11,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,In 1995, the Federal Networking Council (FNC) took the step of passing a resolution formally defining t

16、he term Internet. “Internet” refers to the global information system that is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons;,在 1995 年，联邦的网络委员会(FNC)通过了一个关于因特网术语正式定义的决议。 “因特网”是这样的全球信息系统 通过以因特网协议或其扩展或继续为基础的、独特的地址空

17、间被逻辑性地联结起来；,本廊科逼妻原唉榴双玖芒戈搜弟秘粪尺踞吵仅脚偶喳檀丛耳突护摧腕浩札第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-12,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,II. is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent ext

18、ensions/follow-ons, and/or other IP-compatible protocols; and III. provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.,II.能够支持使用TCP/IP(传输控制协议/因特网协议)组或其扩展/继续、和/或其他与IP协议(因特网协议)兼容的协议进行的通信；并且 III

19、.提供、使用或使可访问此处描述的通信及其相关基础设施(不论公用的还是专用的)上分层次的高水平服务。,屯圭镇寂兹安舰域妖萌蹲葫牡王炒玄砾措饱锣鹊氰卤返司订绩暖讣轰慈艰第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-13,Based on the definition, the Internet means a network that uses the IP addressing scheme, supports the Transmission Control Protocol (TCP)

20、, and makes services available to users much like a telephone system makes voice and data services available to the public2.,基于这个定义，因特网表示这样一个网络使用IP地址分配方案、支持传输控制协议，并使用户可以使用多种服务与电话系统使公众能够使用声音和数据服务非常类似。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,路裁嚏挝嗡蔼闽义续涅练侦究铺峦渗糜堰粤哪线坊撼糯巍怖欲频桓芭都奔第8章 The Invention of the

21、 Computer第8章 The Invention of the Computer,计算机专业英语,8-14,Behind this formal definition are three extremely important concepts that are the basis for understanding the Internet: packet switching, the TCP/IP communications protocol, and client/server computing3. Although the Internet has evolved and ch

22、anged dramatically in the last 30 years, these three concepts are at the core of how the Internet functions today and are the foundation for Internet II.,在这个正式的定义背后，隐含着三个极其重要的概念:分组交换、TCP/IP(传输控制协议/网际协议)通信协议和客户机/服务器计算技术，它们乃是理解因特网的基础。尽管因特网在过去30年发生了引人注目的进化和变化，但这三个概念仍是今天因特网运转的核心，也是因特网II的基础。,8.1.2 THE IN

23、TERNET: KEY TECHNOLOGY CONCEPTS,些鳃泊刑镰惰鞭虐蚊怂澜毖棕巨浆赶甚卤瀑嫡焚澡须遁田褥茸有搏质驯稻第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-15,Packet Switching. Packet switching is a method of slicing digital messages into parcels called “packets,” sending the packets along different communication

24、paths as they become available, and then reassembling the packets once they arrive at their destination. Prior to the development of packet switching, early computer networks used leased, dedicated telephone circuits to communicate with terminals and other computers. In circuit-switched networks suc

25、h as the telephone system, a complete point-to-point circuit is put together, and then communication can proceed.,分组交换。分组交换是传输数据的一种方法，它先将数据信息分割成许多称为“分组”的数据信息包；当路径可用时，经过不同的通信路径发送；当到达目的地后，再将它们组装起来。在分组交换发展之前，早期计算机网络使用租用的专用电话线路和终端与其他计算机进行通信。在线路交换网络如电话系统中，一个完全点对点的线路被连结在一起，然后才能进行通信。,8.1.2 THE INTERNET: KE

26、Y TECHNOLOGY CONCEPTS,赞串访潜弓红阑顺洛招那应包刺舍挞觅寻剩铝股仆绩撮篱撰观醒桅创寒旁第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-16,However, these “dedicated” circuit-switching techniques were expensive and wasted available communications capacitythe circuit would be maintained regardless of wheth

27、er any data was being sent. For nearly 70% of the time, a dedicated voice circuit is not being fully used because of pauses between words and delays in assembling the circuit segments, both of which increased the length of time required to find and connect circuits. A better technology was needed.,然

28、而，这些“专用的”线路交换技术既价格昂贵又浪费有效的通信能力不论是否有数据输送都需要维持线路。由于字间的停顿和组装时的延迟，一条专用的声音线路在几乎70%的时间内没有得到充分利用，而这两种因素都增加寻找和连接线路所需的时间长度。因此需要一种比较好的技术。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,龋闻冤鸯捻轩孜每币歌卞肆利擎翔瞥燥瞪狸钾妹窍嘿封续素吩挑饺佐茅扮第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-17,The first book o

29、n packet switching was written by Leonard Kleinrock in 1964, and the technique was further developed by others in the defense research labs of both the United States and England. With packet switching, the communications capacity of a network can be increased by a factor of 100 or more. The communic

30、ations capacity of a digital network is measured in terms of bits per second. Imagine if the gas mileage of your car went from 15 miles per gallon to 1,500 miles per gallonall without changing too much of the car!,第一本关于分组交换的著作是由Leonard Kleinrock于1964年所著，美国和英国防卫研究实验室的其他研究人员使这项技术得到进一步发展。由于使用分组交换技术，网络的

31、通信能力提高了100倍甚至更多。数字网络的通信能力用每秒位来衡量。想象一下汽车行驶的里程，从每加仑汽油行驶15里提高到每加仑汽油行驶1500 里而汽车没有太大的改变!,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,栏检劣派贺花讶网伊彬藤像峡蕾庸畅英拨谓襟乖逸藉世疾仅赤鸯锰艾跌毗第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-18,In packet-switched networks, messages are first broken down

32、into packets. Appended to each packet are digital codes that indicate a source address (the origination point) and a destination address, as well as sequencing information and error control information for the packet. Rather than being sent directly to the destination address, in a packet network, t

33、he packets travel from computer to computer until they reach their destination. These computers are called routers. Routers are special purpose computers that interconnect the thousands of different computer networks that make up the Internet and route packets along to their ultimate destination as

34、they travel4. To ensure that packets take the best available path toward their destination, the routers use computer programs called routing algorithms.,在分组交换的网络中，信息首先被分解为许多信息包。每个信息包附加数字代码用于指示其源地址(开始点)和目的地地址、以及顺序信息和错误控制信息。在分组网络中，信息包不是直接被送到目的地地址,而是在计算机与计算机之间旅行直到它们到达目的地。这些计算机叫做路由器。路由器是一种特殊用途的计算机，它将组成因

35、特网的成千上万个不同计算机网络互相联接起来，并在信息包旅行时将它们的向终极目的地发送。路由器使用一种叫做路由算法的计算机程序，以确保信息包取通向它们目的地的最佳可用路径。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,牟奉踞吨氨莎铜魔失汇圆壮豆墙坏徒榜弹棚周伴憎测擦狰搂娠晨俘湿打浑第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-19,Packet switching does not require a dedicated circuit but

36、can make use of any spare capacity that is available on any of several hundred circuits. Packet switching makes nearly full use of almost all available communication lines and capacity. Moreover, if some lines are disabled or too busy, the packets can be sent on any available line that eventually le

37、ads to the destination point.,分组交换不需要一个专用线路，但是可以利用几百条线路中任何可用的空闲能力。分组交换几乎充分利用了所有可用的通信线路和能力。而且，如果一些线路不通或太忙的话,信息包能在任何可用的、最终通向目的地的线路上传送。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,锐菇琴郭篓王拒汤逸梅旺伦饿囚傈乳篮蓖炬变士浪顺泞吾跺购具哭掂傲奈第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-20,TCP/IP. Whi

38、le packet switching was an enormous advance in communications capacity, there was no universally agreed upon method for breaking up digital messages into packets, routing them to the proper address, and then reassembling them into a coherent message. This was like having a system for producing stamp

39、s, but no postal system (a series of post offices and a set of addresses).,TCP/IP。尽管分组交换是通信能力的一个巨大进步,但对于将数字信息分解为信息包、将它们传输到适当的地址, 然后重新组装为原来的信息，还没有一种公认的方法。这就像有了一个生产邮票的系统,而没有邮政系统(一系列的邮局和一套住址)一样。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,量掉琢彭侈睡花锻阜韭梧什项衷夫寞矛缅瓢阶枯铸跌鲍巡则镊辩竖幢魁啥第8章 The Invention of the Compute

40、r第8章 The Invention of the Computer,计算机专业英语,8-21,TCP/IP answered the problem of what to do with packets on the Internet and how to handle them. TCP refers to the Transmission Control Protocol (TCP). IP refers to the Internet Protocol (IP). A protocol is a set of rules for formatting, ordering, compre

41、ssing, and error-checking messages. It may also specify the speed of transmission and means by which devices on the network will indicate they have stopped sending and/or receiving messages. Protocols can be implemented in either hardware or software. TCP/IP is implemented in Web software called ser

42、ver software (described below). TCP is the agreed upon protocol for transmitting data packets over the Web. TCP establishes the connections among sending and receiving Web computers, handles the assembly of packets at the point of transmission, and their reassembly at the receiving end.,TCP/IP回答了在因特

43、网上用信息包做什么和如何处理信息包的问题。TCP指传输控制协议，IP表示网际协议。协议是一组用于信息的格式化、次序化、压缩和检查错误的规则。它也可以限定传输速度和网上设备显示它们已停止发送及(或)接收信息的方法。协议既可以通过硬件也可通过软件来实现。TCP/IP(传输控制协议/网际协议)通过被称为服务器软件的网络软件来实现(在下文描述)。TCP(传输控制协议)是用来在网上传输数据的公认协议。TCP(传输控制协议)在发送和接收网络计算机之间建立连接,处理信息包在传输点的组装和在接收端的重新组装。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,涤石巧预雨肢

44、锑瘪向獭诌烧虫操脖非版屹呼钠候皱主炳怨恳很和营拆揪揍第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-22,TCP/IP is divided into four separate layers, with each layer handling a different aspect of the communication problem. The Network Interface Layer is responsible for placing packets on and recei

45、ving them from the network medium, which could be a Local Area Network (Ethernet) or Token Ring Network, or other network technology.,TCP/IP(传输控制协议/网际协议)被分为四个独立的层,由每层处理通信问题的一个不同方面。网络接口层负责信息包在网络媒体上的排列和接收,网络媒体可能是局域网(以太网)、令牌环形网或其他网络技术。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,仍雏惺囚娇酮琐前台穗无的媚贪嗅柄臃慈学锻市幅影

46、淆啮祷炔助夸檬蜕尺第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-23,TCP/IP is independent from any local network technology and can adapt to changes in the local level. The Internet Layer is responsible for addressing, packaging, and routing messages on the Internet. The Transpo

47、rt Layer is responsible for providing communication with the application by acknowledging and sequencing the packets to and from the application. The Application Layer provides a wide variety of applications with the ability to access the services of the lower layers. Some of the best known applicat

48、ions are Hyper Text Transfer Protocol (HTTP), File Transfer Protocol (FTP), and Simple Mail Transfer Protocol (SMTP), all of which we will discuss later in this chapter.,TCP/IP(传输控制协议/网际协议)独立于任何局部网络技术，并能适应在局部水平上的改变。因特网层负责信息的寻址、封装及其在因特网上的路线排定。通过对信息包去与来应用层的确认和排序，传送层负责为应用层提供通信。应用层为许多应用提供访问较低层服务的能力。一些众所

49、周知的应用是超文本传输协议(HTTP)、文件传输协议(FTP)和简单邮件传输协议(SMTP),稍后我们将本章中讨论,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,痕碑茎愿杠秽党踌硝镇雏琢锤楚夏撑撅馆皮艰叭恐亥彤匠顿懂始冗爆主嘛第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-24,IP Addresses. TCP handles the packetizing and routing of Internet messages. IP provide

50、s the Internets addressing scheme. Every computer connected to the Internet must be assigned an addressotherwise it cannot send or receive TCP packets. For instance, when you sign onto the Internet using a dial-up telephone modem, your computer is assigned a temporary address by your Internet Servic

51、e Provider.,IP地址。TCP(传输控制协议)处理因特网信息的分组化和传输路线排定。IP(网际协议)提供因特网的地址分配方案。每部连接到因特网的计算机必须分配一个地址，否则它不能够发送或接受TCP(传输控制协议)信息包。举例来说，当你在使用调制解调器拨号上网时，你的计算机由因特网服务提供商分配一个临时地址。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,魂杆媳杰远岛麓每蠕述盆姐槐矮清头烈诗湛房菩颗册貌拱癣媳匆滦囤抖北第8章 The Invention of the Computer第8章 The Invention of the Comput

52、er,计算机专业英语,8-25,Internet addresses, known as IP addresses, are 32-bit numbers that appear as a series of four separate numbers marked off by periods, such as 27. Each of the four numbers can range from 0255. This “dotted quad” addressing scheme contains up to 4 billion addresses (232). T

53、he leftmost number typically indicates the network address of the computer, while remaining numbers help to identify the specific computer within the group that is sending (or receiving ) a message.,因特网地址,即众所周知的IP地址，是一个32位的数字，它以一串由园点隔开的四个数字出现,例如 27。四个数字中的每一个都在0-255范围内。这个“点分四元组”地址分配方案包含多达

54、到40亿个地址(232)。最左边的那个数字指示计算机的网络地址，而其余的数字帮助识别正在发送(或接收)信息的团体里面一台特定的计算机。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,悯样颇净目渐岿寿孙尤渝鹿拉适蹲妨麓辕延神险盟学敌抑跃桔昏磷派跳爹第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-26,The current version of IP is called Version 4, or IPv4. Because many large c

55、orporate and government domains have been given millions of IP addresses each (to accommodate their current and future work forces), and with all the new networks and new Internet-enabled devices requiring unique IP addresses being attached to the Internet, a new version of the IP protocol, called I

56、Pv6 is being adopted. This scheme contains 128-bit addresses, or about one quadrillion (1015).,IP现在版本叫做第4版，或IPv4。因为许多大公司和政府在各自的域中已给定了数百万个IP地址(以适应他们当前和未来的劳动力)，且由于新网络和新的可上网设备需要独特的IP地址，新版本IP协议IPv6正在得到采用。这个方案包含128位的地址,或曰大约1015个地址。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,曼茅欠肢辱迫泞喳局垫畜暖悦炽让丝嚣奏趟姥胎堤贴得伪妓戈守量

57、抖倒亩第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-27,Domain Names and URLs. Most people cannot remember 32-bit numbers. IP addresses can be represented by a natural language convention called domain names. The domain name system (DNS) allows expressions such as to stand

58、 for numeric IP addresses (s numeric IP is 34). Uniform resource locators (URLs), which are the addresses used by Web browsers to identify the location of content on the Web, also use domain names as part of the URL. A typical URL contains the protocol to be used when accessing the addr

59、ess, followed by its location.,域名和统一资源定位(URL)。大多数人记不住32位的数字。IP地址可由一个自然语言约定(称为域名)来表示。域名系统(DNS)允许像这样的表达代表数值型IP地址( 的数值型IP地址是(34)。统一的资源定位是网络浏览器用于识别网上内容位置的地址，也使用域名作为它的一部分。一个典型的网址包含访问地址时使用的协议，接着是它的位置。,8.1.2 THE INTERNET: KEY TECHNOLOGY CONCEPTS,谍潜毕委涪衫埂懒桩秦黍钻债坦俺凋猎捡曼侣虚忱柞湃恫林接换族辊蜗耽第8章 The Invention of the Computer第8章 The Invention of the Computer,计算机专业英语,8-28,Client/Server Computing. While packet switching exploded the available communications capacity and TCP/IP provided the communications rules and regulations, it took a revolution in computing