計算機專業(yè)畢業(yè)外文翻譯--internet的歷史

1、<p>　　畢業(yè)設計(論文)外文資料翻譯</p><p>　　學院（系）： ***********（計算機學院） </p><p>　　專 業(yè)： 計算機科學與技術 </p><p>　　姓 名： ** *** </p><p&g

2、t;　　學 號： *********** </p><p>　　外文出處： The History of the Internet </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。</p><p>　　注：請將該封面與附件裝訂成冊。</p><p>　　附件1：

3、外文資料翻譯譯文</p><p>　　Internet的歷史</p><p>　　起源——ARPAnet</p><p>　　Internet是被美國政府作為一項工程進行開發(fā)的。這項工程的目的，是為了建立遠距離之間點與點的通信，以便處理國家軍事范圍內的緊急事件，例如核戰(zhàn)爭。這項工程被命名為ARPAnet，它就是Internet的前身。建立此工程的主要應用對象就是軍事

4、通訊，那些負責ARPAnet的工程師們當時也沒有想到它將成為“Internet”。</p><p>　　根據(jù)定義，一個“Internet”應該由四或者更多的計算機連接起來的網(wǎng)絡。</p><p>　　ARPAnet是通過一種叫TCP/IP的協(xié)議實現(xiàn)連網(wǎng)工作的。此協(xié)議最基礎的工作原理是：如果信息在網(wǎng)絡中的一條路徑發(fā)送失敗，那么它將找到其他路徑進行發(fā)送，就好象建立一種語言以便一臺計算機與其他計

5、算機“交談”一樣，但不注意它是PC，或是Macintosh。</p><p>　　到了20世紀80年代，ARPAnet已經(jīng)開始變成目前更為有名的Internet了，它擁有200臺在線主機。國防部很滿意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，資源共享的服務網(wǎng)絡。到了1984年，它就已經(jīng)超過1000臺主機在線了。</p><p>　　在1986年ARPAnet關閉了

6、，但僅僅是建立它的機構關閉了，而網(wǎng)絡繼續(xù)存在與超過1000臺的主機之間。由于使用NSF連接失敗，ARPAnet才被關閉。NSF是將5個國家范圍內的超級計算機連入ARPAnet。</p><p>　　隨著NSF的建立，新的高速的傳輸介質被成功的使用，在1988年，用戶能通過56k的電話線上網(wǎng)。在那個時候有28，174臺主機連入Internet。到了1989年有80，000臺主機連入Internet。到1989年末，

7、就有290，000臺主機連入了。</p><p>　　另外還有其他網(wǎng)絡被建立，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——Internet</p><p>　　如今，Internet已經(jīng)成為人類歷史上最先進技術的一種。每個人都想“上網(wǎng)”去體驗一下Internet中的信息財富。成千上百的人都用Internet。預計，到了2003年世

8、界上的每個人，都將擁有Internet接入。Internet已經(jīng)真正成為我們這個年代生活的一部分。由于計算機技術和網(wǎng)絡技術每天都在改變，我們很難想象Internet下一步將發(fā)展成什么樣子。</p><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進行購物、玩游戲、聊天等娛樂活動。<

9、/p><p>　　Internet不僅僅是一件事物。Internet也會崩潰。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><p>　　Internet是成千上萬臺計算機互相連接的集合。Internet就像是辦公網(wǎng)絡一樣，不同的是，它有成千上萬臺計算機相連接。</p><p>　　其中最主要的是Internet是如何

10、進行通信的。位于Houston的一臺計算機是如何通過瀏覽網(wǎng)頁而能與位于Tokyo的計算機進行數(shù)據(jù)通信的呢？</p><p>　　Internet信息，擁有信息的計算機連接到Internet，是基于語言。這種語言叫做TCP/IP。TCP/IP建立了一種語言，能使計算機在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電腦之間的物理連接。當然也未必都是

11、這樣。但也必須存在一根網(wǎng)絡線將主機與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DSL）來建立。計算機上的MODEM通過已建立的通信線進行收發(fā)數(shù)據(jù)，通信線可以是電話線或是數(shù)據(jù)線。事實上計算機之間建立連接的硬核被成為路由器。</p><p>　　路由器就是計算機中進行信息交互的

12、管理器。</p><p>　　為了更好的對它說明，讓我們來看看一臺標準的計算機是怎樣瀏覽網(wǎng)頁的？</p><p>　　1、用戶計算機撥號進入ISP。而此ISP可能還要連接入其他ISP，或是直接進入Internet主干。</p><p>　　2、用戶打開網(wǎng)頁瀏覽器如NETSCAPE或是IE。</p><p>　　3、接下來是進入Internet

13、的棘手部分。首先，用戶計算機相路由器發(fā)出請求。路由器是一種高速高效的計算機運行的專門軟件。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)。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，就像包裹一樣。因此，當請求網(wǎng)頁瀏

14、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)報發(fā)送給其他的路由器，最終轉到目標主機上。就像傳耳語的游戲一樣（當然，只有完整的信息才能被傳送）。</p><p>　　6、當信息到達目標網(wǎng)頁的服務器是，服務器就開始將網(wǎng)頁信息發(fā)送回去。一臺網(wǎng)頁服務器，就是網(wǎng)頁存儲所在的計算機，它能對網(wǎng)頁進行編輯，并將它發(fā)

15、送給用戶。網(wǎng)頁被分成數(shù)據(jù)報，通過路由器，最終到達用戶計算機，這樣，用戶就能瀏覽網(wǎng)頁了。數(shù)據(jù)報中含有相關的數(shù)據(jù)以及一些必須的信息讓路由器或其他計算機知道如何將數(shù)據(jù)報按正確的順序重新組裝成原始的數(shù)據(jù)段。</p><p>　　有了成千上萬的網(wǎng)頁和成千上萬的用戶，對于初學者來說使用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主要服務的幫助。</

16、p><p>　　在你打開網(wǎng)頁之前，你必須有一個網(wǎng)頁瀏覽器用于瀏覽網(wǎng)頁。大部分網(wǎng)絡服務商都會給用戶提供一個網(wǎng)絡瀏覽器。當你在瀏覽網(wǎng)頁時，其實就是在使用瀏覽器。目前使用最廣泛的網(wǎng)頁瀏覽器是Netscape和MSIE。Netscape能自動連接到www.netscape.com，MSIE能自動連接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、

17、圖片、文本、表格、按鈕以及多媒體的集合。只需點擊網(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，旁邊就會有使用這張表的幫助）做，你就可以進行網(wǎng)上沖浪了?；旧?，網(wǎng)頁中的每個元素都可以自我移植。</p><p>　　“哦，不！又是404出錯！‘不能找到相關網(wǎng)頁’”這是上網(wǎng)初學者中很普通的言論。</p><p>　　有時網(wǎng)站也會出錯。當然網(wǎng)站的錯誤跟用戶的操作沒有關系。&l

18、t;/p><p>　　404出錯意思是你想找的那個網(wǎng)頁不存在。這有可能是因為網(wǎng)站仍在建設中，頁面還沒有被創(chuàng)建，或者是因為網(wǎng)站的制作者正在對頁面進行修改。當出現(xiàn)404出錯時，除了對網(wǎng)站管理發(fā)電子郵件，告訴他/她關于出錯的問題，就別無他法了。</p><p>　　Javascript出錯是由于網(wǎng)站中的Javascript的程序代碼出錯造成的。并非所有的網(wǎng)頁都使用Javascript，但有很多是用J

19、avascript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，那是因為你的瀏覽器的版本低于站點使用的Javascript版本。所以，你應該為你的瀏覽器升級到新的版本。</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&g

20、t;　　要使用電子郵件，那你就必須擁有一個電子郵件客戶端，它就像是郵遞員，為你收發(fā)電子郵件。</p><p>　　其次，你必須有一個電子郵件帳戶。大部分網(wǎng)絡服務供應商都會提供給用戶一個免費的電子郵件帳戶。有的網(wǎng)站也提供免費的電子郵箱，如Hotmail和Geocities。</p><p>　　配置好電子郵件客戶端，包括POP3和SMTP服務器地址（電子郵件供應商會給你相關信息）之后，你就可

21、以準備收郵件了。</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，就不要打開那個附件。它有可能是病毒或是其他惡意的程序。用戶不會通過閱讀郵件而被傳染病毒，你不得不運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特征。簽名加在郵件的末尾。你可以將生動的文本，你職業(yè)信息或是其他你喜歡的東西作為簽名。</p>

22、;<p>　　設想在國際互聯(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)。設想島與島之間是通過發(fā)送和接收船只來聯(lián)絡的。那么島嶼就有接收和發(fā)送船只的港口。</p><p>　　在國際互聯(lián)網(wǎng)中的電腦有被叫做“港口”的端口。端口只是一個象征性的對象，它使得電腦能在網(wǎng)絡（或是國際互聯(lián)網(wǎng)）上運轉。這種方法與上面提到的“島嶼、海洋”形象論類似。</p><p&g

23、t;　　遠程登陸涉及到在服務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，如訪問網(wǎng)頁、聊天、以及發(fā)電子郵件都是依托遠程登陸來實現(xiàn)的。</p><p>　　遠程登陸需要一個遠程登陸客戶服務器。遠程登陸程序兼容于Windows系統(tǒng)，所以Windows用戶可以通過在對話窗口鍵入telnet（不加's）來接入遠程登陸軟件。Linux系統(tǒng)則將它創(chuàng)建在命令行里：鍵入t

24、elnet。用于Macintosh的普通遠程登陸程序是NCSA遠程登陸軟件。 </p><p>　　任何一個服務軟件（網(wǎng)頁端口監(jiān)督程序，聊天端口監(jiān)督程序）都可以通過遠程登陸被接入，即使這些軟件不經(jīng)常以這種方法被接入。</p><p>　　舉例來說，直接與郵件服務器連接并通過與郵件服務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器卻更簡單（當然如此）。</p><

25、p>　　世界各地有數(shù)百萬的網(wǎng)頁，那么你如何知道哪個網(wǎng)頁的地址是你需要的呢？</p><p>　　搜索工具能節(jié)約時間。搜索工具是一個非常龐大的網(wǎng)站，它使你能夠搜尋它自有的網(wǎng)站數(shù)據(jù)庫。</p><p>　　舉例來說，如果你要找關于“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

26、.altavista.digital.com) - Web spider & Indexed</p><p>　　2. Yahoo (http://www.yahoo.com) - Web spider & Indexed Collection</p><p>　　3. Excite (http://www.excite.com) - Web spider & In

27、dexed</p><p>　　4. Lycos (http://www.lycos.com) - Web spider & Indexed</p><p>　　5. Metasearch (http://www.metasearch.com) - Multiple search</p><p>　　網(wǎng)絡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

28、從一個網(wǎng)頁到另一個網(wǎng)頁。</p><p>　　這意味著只要它自己的時間和速度允許，搜索引擎就能盡可能多地在網(wǎng)絡上逐字搜尋信息。編入索引的收集使用手動附加鏈接。比如雅虎網(wǎng)站。你可以點擊“電腦和網(wǎng)絡”，再點擊“硬件”，然后點擊“貓”（調制解調器）等等。那么通過分類的過程，與你要的類別相關的網(wǎng)站就找到了。</p><p>　　Metasearch 同時搜索許多搜索引擎，從十個引擎中找出最上面的搜

29、索結果，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)絡系統(tǒng)和多用戶系統(tǒng)時代的來臨，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>　　從美國電報電話公司和它的電話網(wǎng)組建開始，黑客已為許多人所知。黑客就是一直尋找途徑侵入系統(tǒng)的人。這過去不是一個大問題，因為網(wǎng)絡系統(tǒng)對于那些能夠提供必要的電腦安全措施的大型法人公司和政府的電腦來說是有限的。</p><

30、;p>　　現(xiàn)今最大的問題是個人信息。為什么當你通過網(wǎng)絡購物時應該小心？讓我們快速地看一看國際互聯(lián)網(wǎng)時如何工作的。用戶將信用卡的信息傳遞到網(wǎng)頁上?？雌饋戆踩瑢幔科鋵嵨幢?。當用戶提交信息時，它就會流過組成互聯(lián)網(wǎng)主干網(wǎng)的一系列的電腦。信息是小塊的一包包的，被稱作信息包。</p><p>　　這里有個問題：當信息通過這巨大的支柱被傳遞時，怎樣防止黑客在支柱的某一點上攔截數(shù)據(jù)流？你接入網(wǎng)站時哥哥不會看著你，但用戶

31、在傳遞私人信息時應該清楚潛在的威脅。</p><p>　　加強安全有很多方法，如密碼保護，一種最重要的措施：加密。加密指將數(shù)據(jù)攪亂成只能在另一終端才能譯出的密碼。像Netscape Communicator和Internet Explore這樣的瀏覽器為在線傳遞提供了特色的加密支持。</p><p>　　一些加密措施比其他工作地更好。最先進的加密系統(tǒng)被稱作DES（數(shù)據(jù)加密準則），且它被美國

32、安全局采納，因為它被認為是如此難以非法侵入以至他們認為如果它落入其它國家手中會有安全風險。</p><p>　　DES用單獨的信息鑰匙來開啟一整個文件。問題是有75萬億可能的鑰匙可用，所以它是一個很難破壞的系統(tǒng)。一個文件被侵入并被解碼，但這是一個需14000臺電腦進入互聯(lián)網(wǎng)系統(tǒng)的綜合的努力過程，并需要花一段時間來做。所以大部分黑客沒有那么多的資源。</p><p><b>　　附

33、件2：外文原文</b></p><p>　　The History of the Internet</p><p>　　The Beginning - ARPAnet</p><p>　　The Internet started as a project by the US government. The object of the project wa

34、s to create a means of communications between long distance 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. Fund

35、ed specifically for military communication, the engineers responsible for ARPANet had no idea of the possibilities of an "Internet." </p><p>　　By definition, an 'Internet' is four or more c

36、omputers connected by a network. </p><p>　　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

37、 one route, it would find another route to work with, as 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

38、the 80's ARPAnet, just years away from becoming the more well known Internet, had 200 computers. The Defense Department, satisfied with ARPAnets results, decided to fully adopt it into service, and connected many mil

39、itary computers and resources into the network. ARPAnet 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, b

40、ut only the organization shut</p><p>　　down, 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&

41、lt;/p><p>　　connect its 5 countywide super computers into ARPAnet. </p><p>　　With the funding of NSF, new high speed lines were successfully installed</p><p>　　at line speeds of 56k (a

42、 normal modem nowadays) through telephone lines</p><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 2

43、90,000. </p><p>　　Another network was built to support the incredible number of people</p><p>　　joining. It was constructed in 1992. </p><p>　　Today - The Internet</p><p&

44、gt;　　Today, the Internet has become one of the most important technological advancements in the history of humanity. Everyone wants to get 'on line' to experience the wealth of information of the Internet. Millio

45、ns of people now use the Internet, and it's predicted 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 evolvin

46、g so quickly its hard to determine where it will go next, as computer and net</p><p>　　HOW IT WORKS:</p><p>　　It's a standard thing. People using the Internet. Shopping, playing games,conver

47、sing in virtual Internet environments. </p><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

48、Internet company that runs the Internet. </p><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 jus

49、t like an office network, only it has millions of computers 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

50、a computer in Tokyo to view a webpage? </p><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

51、language for a computer to access and transmit data over 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.

52、 There would have to be a network wire that went to every computer connected to the Internet, but that would make the Internet impossible to access. </p><p>　　The physical connection that is requireed is est

53、ablished by way of modems,phonelines, and other modem cable 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 ha

54、rd core connections are established among computers called routers. </p><p>　　A router is a computer that serves as a traffic controller for information. </p><p>　　To explain this better, let

55、9;s look at how a standard computer might view a webpage. </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

56、connection into the Internet backbone. </p><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 t

57、he tricky part comes in. First, the computer sends data 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

58、is called a "backbone," on which all the data 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 comparin

59、g the heat of the sun to the heat of an ice-cube. </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 enve

60、lopes. So, when the request for the webpage goes through, 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

61、router sends these packets to other routers, eventually leading to the target computer. It's like whisper down the lane (only the information remains intact). </p><p>　　5. When the information reaches th

62、e target web server, the webserver then begins to send 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 w

63、hoever wants to see it. </p><p>　　6. The webpage 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

64、 packets which contain the data also contain special information 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 o

65、f users, using the Internet is not always easy for a beginning 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

66、Internet. </p><p>　　Before you access webpages, 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 usuall

67、y give to customers; you. The fact that you are viewing 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.netsca

68、pe.com and MSIE can be found at www.microsoft.com/ie. </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 actual

69、ly using webpages. A webpage is a collection of hyperlinks, images, text, forms, menus, and multimedia. To "navigate" a webpage, simply click the links it provides or follow it's own instructions (like if i

70、t has a form you need to use, it will probably instruct 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>&l

71、t;p>　　"Oh no! a 404 error! 'Cannot find web 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 fa

72、ult, of course.</p><p>　　A 404 error means 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

73、site author made a typo in the page. There's nothing 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>

74、　　A Javascript error is the result of a programming error 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

75、. If you are using an old version of a web browser (Netscape 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

76、 version of your web browser. </p><p>　　E-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>　　

77、To use e-mail, you must have an e-mail client, which is 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 Prov

78、iders provide free e-mail account(s) for free. Some services 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

79、 provider will give you that information), you are ready 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 ru

80、n the file, ever. It could be a virus or some other kind 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>

81、<p>　　A signature is a feature of many e-mail programs. 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>　　

82、Imagine that a computer on the Internet is an island in 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 re

83、ceiving ships. The island has ports to accept and send 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

84、 network (or the Internet). This method is similar to the island/ocean symbolism above. </p><p>　　Telnet refers to accessing ports on a server directly with a text connection. Almost every kind of Internet f

85、unction, like accessing web pages,"chatting," 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 Windo

86、ws users can access telnet by typing in "telnet" (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>

87、<p>　　Any server software (web page daemon, chat 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

88、server and check your mail by interfacing with the e-mail 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,

89、 yet how will you know what the address of a page you want 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

90、instance, if you wanted to find a website on dogs, you'd search for "dog" or "dogs" or "dog information." Here are a few search-engines. </p><p>　　1. Altavista (http://www.a

91、ltavista.digital.com) - Web spider & Indexed</p><p>　　2. Yahoo (http://www.yahoo.com) - Web spider & Indexed Collection</p><p>　　3. Excite (http://www.excite.com) - Web spider & Inde

92、xed</p><p>　　4. Lycos (http://www.lycos.com) - Web spider & Indexed</p><p>　　5. Metasearch (http://www.metasearch.com) - Multiple search</p><p>　　A web spider is a program used

93、by search engines that goes from page to page, following 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>

94、<p>　　An indexed collection uses hand-added links. 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

95、way through sections, there are sites available which relate 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 en

96、gines, making searching a lot more effective.</p><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 us

97、er systems, security has always been on the mind of system 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 breakin

98、g into systems. It used to not be that big of a problem, since networking was limited to big corporate companies or government computers who could afford the necessary computer security. </p><p>　　The bigges

99、t problem now-a-days is personal information. Why should 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

100、 information to a webpage. Looks safe, right? Not necessarily. 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 chun

101、ks, in packages called packets. Here's the problem: While the information is being transferred through this big backbone, what is preventing a "hacker" from intercepting this data stream at one of the backb

102、one points? </p><p>　　Big-brother is not watching 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,

103、 like password protection, an most importantly, encryption.</p><p>　　Encryption means scrambling data into a code that can only be unscrambled on the "other end." Browser's like Netscape Commun

104、icator and Internet Explorer feature encryption support 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 ado