計(jì)算機(jī)科學(xué)與技術(shù)外文文獻(xiàn)翻譯

1、<p><b>　　畢業(yè)設(shè)計(jì)(論文)</b></p><p><b>　　外文文獻(xiàn)翻譯</b></p><p><b>　　信息工程學(xué)院</b></p><p><b>　　1、外文文獻(xiàn)</b></p><p>　　The History of

2、the Internet</p><p>　　The Beginning - ARPAnet</p><p>　　The Internet started as a project by the US government. The object of the project was to create a means of communications between long dist

3、ance points, in the event of a nation wide emergency or, more specifically, nuclear war. The project was called ARPAnet, and it is what the Internet started as. Funded specifically for military communication, the enginee

4、rs responsible for ARPANet had no idea of the possibilities of an "Internet." </p><p>　　By definition, an 'Internet' is four or more computers connected by a network. </p><p>　

5、　ARPAnet achieved its network by using a protocol called TCP/IP. The basics around this protocol was that if information sent over a network failed to get through on one route, it would find another route to work with, a

6、s well as establishing a means for one computer to "talk" to another computer, regardless of whether it was a PC or a Macintosh. </p><p>　　By the 80's ARPAnet, just years away from becoming the

7、 more well known Internet, had 200 computers. The Defense Department, satisfied with ARPAnets results, decided to fully adopt it into service, and connected many military computers and resources into the network. ARPAnet

8、 then had 562 computers on its network. By the year 1984, it had over 1000 computers on its network. </p><p>　　In 1986 ARPAnet (supposedly) shut down, but only the organization shut</p><p>　　dow

9、n, and the existing networks still existed between the more than 1000</p><p>　　computers. It shut down due to a failied link up with NSF, who wanted to</p><p>　　connect its 5 countywide super co

10、mputers into ARPAnet. </p><p>　　With the funding of NSF, new high speed lines were successfully installed</p><p>　　at line speeds of 56k (a normal modem nowadays) through telephone lines</p&g

11、t;<p>　　in 1988. By that time, there were 28,174 computers on the (by then decided) Internet. In 1989 there were 80,000 computers on it. By 1989, there were 290,000. </p><p>　　Another network was buil

12、t to support the incredible number of people</p><p>　　joining. It was constructed in 1992. </p><p>　　Today - The Internet</p><p>　　Today, the Internet has become one of the most imp

13、ortant technological advancements in the history of humanity. Everyone wants to get 'on line' to experience the wealth of information of the Internet. Millions of people now use the Internet, and it's predict

14、ed that by the year 2003 every single person on the planet will have Internet access. The Internet has truly become a way of life in our time and era, and is evolving so quickly its hard to determine where it will go nex

15、t, as computer and net</p><p>　　HOW IT WORKS:</p><p>　　It's a standard thing. People using the Internet. Shopping, playing games,conversing in virtual Internet environments. </p><

16、p>　　The Internet is not a 'thing' itself. The Internet cannot just "crash." It functions the same way as the telephone system, only there is no Internet company that runs the Internet. </p>&l

17、t;p>　　The Internet is a collection of millioins of computers that are all connected to each other, or have the means to connect to each other. The Internet is just like an office network, only it has millions of compu

18、ters connected to it. </p><p>　　The main thing about how the Internet works is communication. How does a computer in Houston know how to access data on a computer in Tokyo to view a webpage? </p><

19、p>　　Internet communication, communication among computers connected to the Internet, is based on a language. This language is called TCP/IP. TCP/IP establishes a language for a computer to access and transmit data ove

20、r the Internet system. </p><p>　　But TCP/IP assumes that there is a physical connecetion between one computer and another. This is not usually the case. There would have to be a network wire that went to eve

21、ry computer connected to the Internet, but that would make the Internet impossible to access. </p><p>　　The physical connection that is requireed is established by way of modems,phonelines, and other modem c

22、able connections (like cable modems or DSL). Modems on computers read and transmit data over established lines,which could be phonelines or data lines. The actual hard core connections are established among computers cal

23、led routers. </p><p>　　A router is a computer that serves as a traffic controller for information. </p><p>　　To explain this better, let's look at how a standard computer might view a webpag

24、e. </p><p>　　1. The user's computer dials into an Internet Service Provider (ISP). The ISP might in turn be connected to another ISP, or a straight connection into the Internet backbone. </p><

25、p>　　2. The user launches a web browser like Netscape or Internet Explorer and types in an internet location to go to. </p><p>　　3. Here's where the tricky part comes in. First, the computer sends data

26、 about it's data request to a router. A router is a very high speed powerful computer running special software. The collection of routers in the world make what is called a "backbone," on which all the data

27、 on the Internet is transferred. The backbone presently operates at a speed of several gigabytes per-second. Such a speed compared to a normal modem is like comparing the heat of the sun to the heat of an ice-cube. </

28、p><p>　　Routers handle data that is going back and forth. A router puts small chunks of data into packages called packets, which function similarly to envelopes. So, when the request for the webpage goes throug

29、h, it uses TCP/IP protocols to tell the router what to do with the data, where it's going, and overall where the user wants to go. </p><p>　　4. The router sends these packets to other routers, eventually

30、 leading to the target computer. It's like whisper down the lane (only the information remains intact). </p><p>　　5. When the information reaches the target web server, the webserver then begins to send

31、the web page back. A webserver is the computer where the webpage is stored that is running a program that handles requests for the webpage and sends the webpage to whoever wants to see it. </p><p>　　6. The w

32、ebpage is put in packets, sent through routers, and arrive at the users computer where the user can view the webpage once it is assembled. </p><p>　　The packets which contain the data also contain special in

33、formation that lets routers and other computers know how to reassemble the data in the right order. </p><p>　　With millions of web pages, and millions of users, using the Internet is not always easy for a be

34、ginning user, especially for someone who is not entirely comfortale with using computers. Below you can find tips tricks and help on how to use main services of the Internet. </p><p>　　Before you access webp

35、ages, you must have a web browser to actually be able to view the webpages. Most Internet Access Providers provide you with a web browser in the software they usually give to customers; you. The fact that you are viewing

36、 this page means that you have a web browser. The top two use browsers are Netscape Communicator and Microsoft Internet Explorer. Netscape can be found at www.netscape.com and MSIE can be found at www.microsoft.com/ie. &

37、lt;/p><p>　　The fact that you're reading this right now means that you have a web browser. </p><p>　　Next you must be familiar with actually using webpages. A webpage is a collection of hyperli

38、nks, images, text, forms, menus, and multimedia. To "navigate" a webpage, simply click the links it provides or follow it's own instructions (like if it has a form you need to use, it will probably instruct

39、 you how to use it). Basically, everything about a webpage is made to be self- explanetory. That is the nature of a webpage, to be easily navigatable. </p><p>　　"Oh no! a 404 error! 'Cannot find web

40、 page?'" is a common remark made by new web-users. </p><p>　　Sometimes websites have errors. But an error on a website is not the user's fault, of course.</p><p>　　A 404 error means

41、 that the page you tried to go to does not exist. This could be because the site is still being constructed and the page hasn't been created yet, or because the site author made a typo in the page. There's nothin

42、g much to do about a 404 error except for e-mailing the site administrator (of the page you wanted to go to) an telling him/her about the error.</p><p>　　A Javascript error is the result of a programming err

43、or in the Javascript code of a website. Not all websites utilize Javascript, but many do. Javascript is different from Java, and most browsers now support Javascript. If you are using an old version of a web browser (Net

44、scape 3.0 for example), you might get Javascript errors because sites utilize Javascript versions that your browser does not support. So, you can try getting a newer version of your web browser. </p><p>　　E-

45、mail stands for Electronic Mail, and that's what it is. E-mail enables people to send letters, and even files and pictures to each other. </p><p>　　To use e-mail, you must have an e-mail client, which is

46、 just like a personal post office, since it retrieves and stores e-mail. </p><p>　　Secondly, you must have an e-mail account. Most Internet Service Providers provide free e-mail account(s) for free. Some ser

47、vices offer free e-mail, like Hotmail, and Geocities. </p><p>　　After configuring your e-mail client with your POP3 and SMTP server address (your e-mail provider will give you that information), you are read

48、y to receive mail. </p><p>　　An attachment is a file sent in a letter. If someone sends you an attachment and you don't know who it is, don't run the file, ever. It could be a virus or some other kin

49、d of nasty programs. You can't get a virus just by reading e-mail, you'll have to physically execute some form of program for a virus to strike. </p><p>　　A signature is a feature of many e-mail prog

50、rams. A signature is added to the end of every e-mail you send out. You can put a text graphic, your business information, anything you want. </p><p>　　Imagine that a computer on the Internet is an island in

51、 the sea. The sea is filled with millions of islands. This is the Internet. Imagine an island communicates with other island by sending ships to other islands and receiving ships. The island has ports to accept and send

52、out ships. </p><p>　　A computer on the Internet has access nodes called ports. A port is just a symbolic object that allows the computer to operate on a network (or the Internet). This method is similar to t

53、he island/ocean symbolism above. </p><p>　　Telnet refers to accessing ports on a server directly with a text connection. Almost every kind of Internet function, like accessing web pages,"chatting,"

54、 and e-mailing is done over a Telnet connection. </p><p>　　Telnetting requires a Telnet client. A telnet program comes with the Windows system, so Windows users can access telnet by typing in "telnet&qu

55、ot; (without the "'s) in the run dialog. Linux has it built into the command line; telnet. A popular telnet program for Macintosh is NCSA telnet. </p><p>　　Any server software (web page daemon, chat

56、 daemon) can be accessed via telnet, although they are not usually meant to be accessed in such a manner. For instance, it is possible to connect directly to a mail server and check your mail by interfacing with the e-ma

57、il server software, but it's easier to use an e-mail client (of course). </p><p>　　There are millions of WebPages that come from all over the world, yet how will you know what the address of a page you w

58、ant is? </p><p>　　Search engines save the day. A search engine is a very large website that allows you to search it's own database of websites. For instance, if you wanted to find a website on dogs, you&

59、#39;d search for "dog" or "dogs" or "dog information." Here are a few search-engines. </p><p>　　1. Altavista (http://www.altavista.digital.com) - Web spider & Indexed</p&

60、gt;<p>　　2. Yahoo (http://www.yahoo.com) - Web spider & Indexed Collection</p><p>　　3. Excite (http://www.excite.com) - Web spider & Indexed</p><p>　　4. Lycos (http://www.lycos.co

61、m) - Web spider & Indexed</p><p>　　5. Metasearch (http://www.metasearch.com) - Multiple search</p><p>　　A web spider is a program used by search engines that goes from page to page, followin

62、g any link it can possibly find. This means that a search engine can literally map out as much of the Internet as it's own time and speed allows for.</p><p>　　An indexed collection uses hand-added links.

63、 For instance, on Yahoo's site. You can click on Computers & the Internet. Then you can click on Hardware. Then you can click on Modems, etc., and along the way through sections, there are sites available which r

64、elate to what section you're in. </p><p>　　Metasearch searches many search engines at the same time, finding the top choices from about 10 search engines, making searching a lot more effective.</p>

65、<p>　　Once you are able to use search engines, you can effectively find the pages you want. </p><p>　　With the arrival of networking and multi user systems, security has always been on the mind of sys

66、tem developers and system operators. Since the dawn of AT&T and its phone network, hackers have been known by many, hackers who find ways all the time of breaking into systems. It used to not be that big of a problem

67、, since networking was limited to big corporate companies or government computers who could afford the necessary computer security. </p><p>　　The biggest problem now-a-days is personal information. Why shoul

68、d you be careful while making purchases via a website? Let's look at how the internet works, quickly. </p><p>　　The user is transferring credit card information to a webpage. Looks safe, right? Not neces

69、sarily. As the user submits the information, it is being streamed through a series of computers that make up the Internet backbone. The information is in little chunks, in packages called packets. Here's the problem:

70、 While the information is being transferred through this big backbone, what is preventing a "hacker" from intercepting this data stream at one of the backbone points? </p><p>　　Big-brother is not w

71、atching you if you access a web site, but users should be aware of potential threats while transmitting private information. There are methods of enforcing security, like password protection, an most importantly, encrypt

72、ion.</p><p>　　Encryption means scrambling data into a code that can only be unscrambled on the "other end." Browser's like Netscape Communicator and Internet Explorer feature encryption support

73、 for making on-line transfers. Some encryptions work better than others. The most advanced encryption system is called DES (Data Encryption Standard), and it was adopted by the US Defense Department because it was deemed

74、 so difficult to 'crack' that they considered it a security risk if it would fall into another countr</p><p>　　A DES uses a single key of information to unlock an entire document. The problem is, the

75、re are 75 trillion possible keys to use, so it is a highly difficult system to break. One document was cracked and decoded, but it was a combined effort of 14,000 computers networked over the Internet that took a while t

76、o do it, so most hackers don't have that many resources available.</p><p><b>　　2、文獻(xiàn)翻譯</b></p><p>　　Internet的歷史</p><p>　　起源——ARPAnet</p><p>　　Internet是被美

77、國政府作為一項(xiàng)工程進(jìn)行開發(fā)的。這項(xiàng)工程的目的，是為了建立遠(yuǎn)距離之間點(diǎn)與點(diǎn)的通信，以便處理國家軍事范圍內(nèi)的緊急事件，例如核戰(zhàn)爭。這項(xiàng)工程被命名為ARPAnet，它就是Internet的前身。建立此工程的主要應(yīng)用對象就是軍事通訊，那些負(fù)責(zé)ARPAnet的工程師們當(dāng)時(shí)也沒有想到它將成為“Internet”。</p><p>　　根據(jù)定義，一個(gè)“Internet”應(yīng)該由四或者更多的計(jì)算機(jī)連接起來的網(wǎng)絡(luò)。</p>

78、;<p>　　ARPAnet是通過一種叫TCP/IP的協(xié)議實(shí)現(xiàn)連網(wǎng)工作的。此協(xié)議最基礎(chǔ)的工作原理是：如果信息在網(wǎng)絡(luò)中的一條路徑發(fā)送失敗，那么它將找到其他路徑進(jìn)行發(fā)送，就好象建立一種語言以便一臺(tái)計(jì)算機(jī)與其他計(jì)算機(jī)“交談”一樣，但不注意它是PC，或是Macintosh。</p><p>　　到了20世紀(jì)80年代，ARPAnet已經(jīng)開始變成目前更為有名的Internet了，它擁有200臺(tái)在線主機(jī)。國防部很

79、滿意ARPAnets的成果，于是決定全力將它培養(yǎng)為能夠聯(lián)系很多軍事主機(jī)，資源共享的服務(wù)網(wǎng)絡(luò)。到了1984年，它就已經(jīng)超過1000臺(tái)主機(jī)在線了。</p><p>　　在1986年ARPAnet關(guān)閉了，但僅僅是建立它的機(jī)構(gòu)關(guān)閉了，而網(wǎng)絡(luò)繼續(xù)存在與超過1000臺(tái)的主機(jī)之間。由于使用NSF連接失敗，ARPAnet才被關(guān)閉。NSF是將5個(gè)國家范圍內(nèi)的超級(jí)計(jì)算機(jī)連入ARPAnet。</p><p>　

80、　隨著NSF的建立，新的高速的傳輸介質(zhì)被成功的使用，在1988年，用戶能通過56k的電話線上網(wǎng)。在那個(gè)時(shí)候有28，174臺(tái)主機(jī)連入Internet。到了1989年有80，000臺(tái)主機(jī)連入Internet。到1989年末，就有290，000臺(tái)主機(jī)連入了。</p><p>　　另外還有其他網(wǎng)絡(luò)被建立，并支持用戶以驚人的數(shù)量接入。于1992年正式建立。</p><p>　　現(xiàn)狀——Interne

81、t</p><p>　　如今，Internet已經(jīng)成為人類歷史上最先進(jìn)技術(shù)的一種。每個(gè)人都想“上網(wǎng)”去體驗(yàn)一下Internet中的信息財(cái)富。成千上百的人都用Internet。預(yù)計(jì)，到了2003年世界上的每個(gè)人，都將擁有Internet接入。Internet已經(jīng)真正成為我們這個(gè)年代生活的一部分。由于計(jì)算機(jī)技術(shù)和網(wǎng)絡(luò)技術(shù)每天都在改變，我們很難想象Internet下一步將發(fā)展成什么樣子。</p><

82、p><b>　　工作原理：</b></p><p>　　現(xiàn)在，人們用Internet是一件很平常的事。他們通過Internet進(jìn)行購物、玩游戲、聊天等娛樂活動(dòng)。</p><p>　　Internet不僅僅是一件事物。Internet也會(huì)崩潰。它的工作原理如同電話通信系統(tǒng)，只不過沒有專門的Internet公司來經(jīng)營Internet。</p><

83、p>　　Internet是成千上萬臺(tái)計(jì)算機(jī)互相連接的集合。Internet就像是辦公網(wǎng)絡(luò)一樣，不同的是，它有成千上萬臺(tái)計(jì)算機(jī)相連接。</p><p>　　其中最主要的是Internet是如何進(jìn)行通信的。位于Houston的一臺(tái)計(jì)算機(jī)是如何通過瀏覽網(wǎng)頁而能與位于Tokyo的計(jì)算機(jī)進(jìn)行數(shù)據(jù)通信的呢？</p><p>　　Internet信息，擁有信息的計(jì)算機(jī)連接到Internet，是基于

84、語言。這種語言叫做TCP/IP。TCP/IP建立了一種語言，能使計(jì)算機(jī)在Internet系統(tǒng)中傳送數(shù)據(jù)。</p><p>　　但是TCP/IP的取得也必須具備兩臺(tái)電腦之間的物理連接。當(dāng)然也未必都是這樣。但也必須存在一根網(wǎng)絡(luò)線將主機(jī)與Internet連接起來，但做到這樣，還是不可能與Internet連接的。</p><p>　　物理連接要求通過MODEM，電話線和其他類似MODEM的連接（如

85、DSL）來建立。計(jì)算機(jī)上的MODEM通過已建立的通信線進(jìn)行收發(fā)數(shù)據(jù)，通信線可以是電話線或是數(shù)據(jù)線。事實(shí)上計(jì)算機(jī)之間建立連接的硬核被成為路由器。</p><p>　　路由器就是計(jì)算機(jī)中進(jìn)行信息交互的管理器。</p><p>　　為了更好的對它說明，讓我們來看看一臺(tái)標(biāo)準(zhǔn)的計(jì)算機(jī)是怎樣瀏覽網(wǎng)頁的？</p><p>　　1、用戶計(jì)算機(jī)撥號(hào)進(jìn)入ISP。而此ISP可能還要連接入

86、其他ISP，或是直接進(jìn)入Internet主干。</p><p>　　2、用戶打開網(wǎng)頁瀏覽器如NETSCAPE或是IE。</p><p>　　3、接下來是進(jìn)入Internet的棘手部分。首先，用戶計(jì)算機(jī)相路由器發(fā)出請求。路由器是一種高速高效的計(jì)算機(jī)運(yùn)行的專門軟件。世界上所有路由的連接便形成了Internet的主干，在這里傳送Internet上的所有數(shù)據(jù)。目前主干網(wǎng)上的處理速度為每秒幾千兆字節(jié)

87、。這樣的速度分配到一只MODEM上，就好比太陽光的熱量分配到一塊冰上的熱量一樣。</p><p>　　4、路由器發(fā)送或接受數(shù)據(jù)。它將一小段數(shù)據(jù)分別打包，形成數(shù)據(jù)報(bào)，就像包裹一樣。因此，當(dāng)請求網(wǎng)頁瀏覽是，就用TCP/IP協(xié)議告訴路由器如何處理這些數(shù)據(jù)，將這些數(shù)據(jù)發(fā)送去哪里，用戶主要想去哪里。</p><p>　　5、路由器將這些數(shù)據(jù)報(bào)發(fā)送給其他的路由器，最終轉(zhuǎn)到目標(biāo)主機(jī)上。就像傳耳語的游戲一

88、樣（當(dāng)然，只有完整的信息才能被傳送）。</p><p>　　6、當(dāng)信息到達(dá)目標(biāo)網(wǎng)頁的服務(wù)器是，服務(wù)器就開始將網(wǎng)頁信息發(fā)送回去。一臺(tái)網(wǎng)頁服務(wù)器，就是網(wǎng)頁存儲(chǔ)所在的計(jì)算機(jī)，它能對網(wǎng)頁進(jìn)行編輯，并將它發(fā)送給用戶。網(wǎng)頁被分成數(shù)據(jù)報(bào)，通過路由器，最終到達(dá)用戶計(jì)算機(jī)，這樣，用戶就能瀏覽網(wǎng)頁了。數(shù)據(jù)報(bào)中含有相關(guān)的數(shù)據(jù)以及一些必須的信息讓路由器或其他計(jì)算機(jī)知道如何將數(shù)據(jù)報(bào)按正確的順序重新組裝成原始的數(shù)據(jù)段。</p>

89、<p>　　有了成千上萬的網(wǎng)頁和成千上萬的用戶，對于初學(xué)者來說使用Internet將不再那么容易，尤其是那些不太精通電腦的人。接下來，你將能找到一些上網(wǎng)的小技巧和使用Internet主要服務(wù)的幫助。</p><p>　　在你打開網(wǎng)頁之前，你必須有一個(gè)網(wǎng)頁瀏覽器用于瀏覽網(wǎng)頁。大部分網(wǎng)絡(luò)服務(wù)商都會(huì)給用戶提供一個(gè)網(wǎng)絡(luò)瀏覽器。當(dāng)你在瀏覽網(wǎng)頁時(shí)，其實(shí)就是在使用瀏覽器。目前使用最廣泛的網(wǎng)頁瀏覽器是Netscape

90、和MSIE。Netscape能自動(dòng)連接到www.netscape.com，MSIE能自動(dòng)連接www.microsoft.com。</p><p>　　接下來你就必須熟悉如何使用網(wǎng)頁。網(wǎng)頁是超鏈接、圖片、文本、表格、按鈕以及多媒體的集合。只需點(diǎn)擊網(wǎng)頁提供的連接或是按照網(wǎng)頁的步驟（比如，如果你需要用網(wǎng)頁中的一張表，旁邊就會(huì)有使用這張表的幫助）做，你就可以進(jìn)行網(wǎng)上沖浪了?；旧?，網(wǎng)頁中的每個(gè)元素都可以自我移植。<

91、/p><p>　　“哦，不！又是404出錯(cuò)！‘不能找到相關(guān)網(wǎng)頁’”這是上網(wǎng)初學(xué)者中很普通的言論。</p><p>　　有時(shí)網(wǎng)站也會(huì)出錯(cuò)。當(dāng)然網(wǎng)站的錯(cuò)誤跟用戶的操作沒有關(guān)系。</p><p>　　404出錯(cuò)意思是你想找的那個(gè)網(wǎng)頁不存在。這有可能是因?yàn)榫W(wǎng)站仍在建設(shè)中，頁面還沒有被創(chuàng)建，或者是因?yàn)榫W(wǎng)站的制作者正在對頁面進(jìn)行修改。當(dāng)出現(xiàn)404出錯(cuò)時(shí)，除了對網(wǎng)站管理發(fā)電子郵件，告

92、訴他/她關(guān)于出錯(cuò)的問題，就別無他法了。</p><p>　　Javascript出錯(cuò)是由于網(wǎng)站中的Javascript的程序代碼出錯(cuò)造成的。并非所有的網(wǎng)頁都使用Javascript，但有很多是用Javascript的。Javascript不同于JAVA，目前大部分瀏覽器都支持Javascript。如果你現(xiàn)在用的是舊版的網(wǎng)頁瀏覽器，那么就有可能出現(xiàn)Javascript出錯(cuò)，那是因?yàn)槟愕臑g覽器的版本低于站點(diǎn)使用的Ja

93、vascript版本。所以，你應(yīng)該為你的瀏覽器升級(jí)到新的版本。</p><p>　　電子郵件即電子方式的郵件。電子郵件能使人們互相收發(fā)信件，甚至是文件和圖片。</p><p>　　要使用電子郵件，那你就必須擁有一個(gè)電子郵件客戶端，它就像是郵遞員，為你收發(fā)電子郵件。</p><p>　　其次，你必須有一個(gè)電子郵件帳戶。大部分網(wǎng)絡(luò)服務(wù)供應(yīng)商都會(huì)提供給用戶一個(gè)免費(fèi)的電子郵

94、件帳戶。有的網(wǎng)站也提供免費(fèi)的電子郵箱，如Hotmail和Geocities。</p><p>　　配置好電子郵件客戶端，包括POP3和SMTP服務(wù)器地址（電子郵件供應(yīng)商會(huì)給你相關(guān)信息）之后，你就可以準(zhǔn)備收郵件了。</p><p>　　附件是與信一起發(fā)過來的文件，如果有人發(fā)給你帶有附件的郵件，但你不知道他是誰，就不要打開那個(gè)附件。它有可能是病毒或是其他惡意的程序。用戶不會(huì)通過閱讀郵件而被傳染

95、病毒，你不得不運(yùn)行殺毒軟件來防止病毒感染。</p><p>　　簽名是很多電子郵件程序的一個(gè)特征。簽名加在郵件的末尾。你可以將生動(dòng)的文本，你職業(yè)信息或是其他你喜歡的東西作為簽名。</p><p>　　設(shè)想在國際互聯(lián)網(wǎng)中的電腦就像海中的島嶼。那么海洋中就充滿了數(shù)百萬的島嶼。這就是國際互聯(lián)網(wǎng)。設(shè)想島與島之間是通過發(fā)送和接收船只來聯(lián)絡(luò)的。那么島嶼就有接收和發(fā)送船只的港口。</p>

96、<p>　　在國際互聯(lián)網(wǎng)中的電腦有被叫做“港口”的端口。端口只是一個(gè)象征性的對象，它使得電腦能在網(wǎng)絡(luò)（或是國際互聯(lián)網(wǎng)）上運(yùn)轉(zhuǎn)。這種方法與上面提到的“島嶼、海洋”形象論類似。</p><p>　　遠(yuǎn)程登陸涉及到在服務(wù)器上直接用文本連接來使用端口。</p><p>　　幾乎每種互聯(lián)網(wǎng)活動(dòng)，如訪問網(wǎng)頁、聊天、以及發(fā)電子郵件都是依托遠(yuǎn)程登陸來實(shí)現(xiàn)的。</p><p&g

97、t;　　遠(yuǎn)程登陸需要一個(gè)遠(yuǎn)程登陸客戶服務(wù)器。遠(yuǎn)程登陸程序兼容于Windows系統(tǒng)，所以Windows用戶可以通過在對話窗口鍵入telnet（不加's）來接入遠(yuǎn)程登陸軟件。Linux系統(tǒng)則將它創(chuàng)建在命令行里：鍵入telnet。用于Macintosh的普通遠(yuǎn)程登陸程序是NCSA遠(yuǎn)程登陸軟件。 </p><p>　　任何一個(gè)服務(wù)軟件（網(wǎng)頁端口監(jiān)督程序，聊天端口監(jiān)督程序）都可以通過遠(yuǎn)程登陸被接入，即使這些軟件不經(jīng)

98、常以這種方法被接入。</p><p>　　舉例來說，直接與郵件服務(wù)器連接并通過與郵件服務(wù)軟件交流來校對你的郵件是可能的，但用電子郵件客戶服務(wù)器卻更簡單（當(dāng)然如此）。</p><p>　　世界各地有數(shù)百萬的網(wǎng)頁，那么你如何知道哪個(gè)網(wǎng)頁的地址是你需要的呢？</p><p>　　搜索工具能節(jié)約時(shí)間。搜索工具是一個(gè)非常龐大的網(wǎng)站，它使你能夠搜尋它自有的網(wǎng)站數(shù)據(jù)庫。</

99、p><p>　　舉例來說，如果你要找關(guān)于“狗”的網(wǎng)站，你可以搜索“狗”或“狗的信息”。這里有一些搜索引擎：</p><p>　　1. Altavista (http://www.altavista.digital.com) - Web spider & Indexed</p><p>　　2. Yahoo (http://www.yahoo.com) - Web

100、 spider & Indexed Collection</p><p>　　3. Excite (http://www.excite.com) - Web spider & Indexed</p><p>　　4. Lycos (http://www.lycos.com) - Web spider & Indexed</p><p>　　5

101、. Metasearch (http://www.metasearch.com) - Multiple search</p><p>　　網(wǎng)絡(luò)蜘蛛是一種搜索引擎使用的程序，它隨著可能找到的任何鏈接從一個(gè)網(wǎng)頁到另一個(gè)網(wǎng)頁。</p><p>　　這意味著只要它自己的時(shí)間和速度允許，搜索引擎就能盡可能多地在網(wǎng)絡(luò)上逐字搜尋信息。編入索引的收集使用手動(dòng)附加鏈接。比如雅虎網(wǎng)站。你可以點(diǎn)擊“電腦和網(wǎng)絡(luò)”

102、，再點(diǎn)擊“硬件”，然后點(diǎn)擊“貓”（調(diào)制解調(diào)器）等等。那么通過分類的過程，與你要的類別相關(guān)的網(wǎng)站就找到了。</p><p>　　Metasearch 同時(shí)搜索許多搜索引擎，從十個(gè)引擎中找出最上面的搜索結(jié)果，使得搜索變得有效很多。一旦你能夠使用搜索引擎，你就能有效的找到你要的網(wǎng)頁。伴隨著網(wǎng)絡(luò)系統(tǒng)和多用戶系統(tǒng)時(shí)代的來臨，安全總是系統(tǒng)開發(fā)和系統(tǒng)操作人員考慮的問題。</p><p>　　從美國電報(bào)電