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1、河南科技大学本科毕业设计论文外文资料原文The History of the InternetThe Beginning - ArpanetThe Internet started as a project by the US government. The object of the project was to create a means of communications between long distance points, in the event of a nation wide emergency or, more specifically, nuclear war. Th
2、e project was called Arpanet, and it is what the Internet started as. Funded specifically for military communication, the engineers responsible for Arpanet had no idea of the possibilities of an Internet. By definition, an Internet is four or more computers connected by a network. Arpanet achieved i
3、ts 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, as well as establishing a means for one computer to talk to another computer, regardless of whether
4、it was a PC or a Macintosh. By the 80s 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 military computers and resources into the network. Arpane
5、t then had 562 computers on its network. By the year 1984, it had over 1000 computers on its network. In 1986 Arpanet (supposedly) shut down, but only the organization shut down, and the existing networks still existed between the more than 1000 Computers. It shut down due to a failed link up with N
6、SF, who wanted to connect its 5 countywide super computers into Arpanet. With the funding of NSF, new high speed lines were successfully installed at line speeds of 56k (a normal modem nowadays) through telephone lines in 1988. By that time, there were 28,174 computers on the (by then decided) Inter
7、net. In 1989 there were 80,000 computers on it. By 1989, there were 290,000. Another network was built to support the incredible number of people joining. It was constructed in 1992. Today - The InternetToday, the Internet has become one of the most important technological advancements in the histor
8、y 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 its 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
9、and era, and is evolving so quickly its hard to determine where it will go next, as computer and network technology improve every day. HOW IT WORKS:Its a standard thing. People using the Internet. Shopping, playing games, conversing in virtual Internet environments. The Internet is not a thing itsel
10、f. The Internet cannot just crash. It functions the same way as the telephone system, only there is no Internet company that runs the Internet. The Internet is a collection of millions of computers that are all connected to each other, or have the means to connect to each other. The Internet is just
11、 like an office network, only it has millions of computers connected to it. 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? Internet communication, communication among computers connected t
12、o 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 over the Internet system. But TCP/IP assumes that there is a physical connection between one computer and another. This is not usually the case. There woul
13、d have to be a network wire that went to every computer connected to the Internet, but that would make the Internet impossible to access. The physical connection that is required is established by way of modems, phone lines, and other modem cable connections (like cable modems or DSL). Modems on com
14、puters read and transmit data over established lines, which could be phone lines or data lines. The actual hard core connections are established among computers called routers. A router is a computer that serves as a traffic controller for information. To explain this better, lets look at how a stan
15、dard computer might view a webpage. 1. The users 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. 2. The user launches a web browser like Netscape or Internet Explorer and types in an inter
16、net location to go to. 3. Heres where the tricky part comes in. First, the computer sends data about its 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 on
17、 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. Routers handle data that is going back and forth. A router puts small chunks of data int
18、o packages called packets, which function similarly to envelopes. 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 its going, and overall where the user wants to go. 4. The router sends these packets to other routers, even
19、tually leading to the target computer. Its like whisper down the lane (only the information remains intact). 5. When the information reaches the 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 t
20、hat handles requests for the webpage and sends the webpage to whoever wants to see it. 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. The packets which contain the data also contain special informatio
21、n that lets routers and other computers know how to reassemble the data in the right order. With millions of web pages, and millions of users, using the Internet is not always easy for a beginning user, especially for someone who is not entirely comfortable with using computers. Below you can find t
22、ips tricks and help on how to use main services of the Internet. 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 usually give to customers; you. The fact that you are
23、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 and MSIE can be found at The fact that youre reading this right now means that you have a web browser. Next you must be familiar with actu
24、ally 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 its own instructions (like if it has a form you need to use, it will probably instruct you how to use it). Basically, everythi
25、ng about a webpage is made to be self- explanatory. That is the nature of a webpage, to be easily navigatable. Oh no! a 404 error! Cannot find web page? is a common remark made by new web-users. Sometimes websites have errors. But an error on a website is not the users fault, of course.A 404 error m
26、eans that the page you tried to go to does not exist. This could be because the site is still being constructed and the page hasnt been created yet, or because the site author made a typo in the page. Theres nothing much to do about a 404 error except for e-mailing the site administrator (of the pag
27、e you wanted to go to) an telling him/her about the error.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. If you are using an ol
28、d 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 version of your web browser. E-mail stands for Electronic Mail, and thats what it is. E-mail enables pe
29、ople to send letters, and even files and pictures to each other. 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. Secondly, you must have an e-mail account. Most Internet Service Providers provide free e-mail account(s) f
30、or free. Some services offer free e-mail, like Hotmail, and Geocities. After configuring your e-mail client with your POP3 and SMTP server address (your e-mail provider will give you that information), you are ready to receive mail. An attachment is a file sent in a letter. If someone sends you an a
31、ttachment and you dont know who it is, dont run the file, ever. It could be a virus or some other kind of nasty programs. You cant get a virus just by reading e-mail, youll have to physically execute some form of program for a virus to strike. A signature is a feature of many e-mail programs. A sign
32、ature is added to the end of every e-mail you send out. You can put a text graphic, your business information, anything you want. 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 oth
33、er island by sending ships to other islands and receiving ships. The island has ports to accept and send out ships. 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
34、 the island/ocean symbolism above. Telnet refers to accessing ports on a server directly with a text connection. Almost every kind of Internet function, like accessing web pages,” chatting, and e-mailing is done over a Telnet connection. Relenting requires a Telnet client. A telnet program comes wit
35、h the Windows system, so Windows 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. Any server software (web page daemon, chat daemon) can be accessed via telnet, alth
36、ough 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-mail server software, but its easier to use an e-mail client (of course). There are millions of WebPages that come from all
37、 over the world, yet how will you know what the address of a page you want is? Search engines save the day. A search engine is a very large website that allows you to search its own database of websites. For instance, if you wanted to find a website on dogs, youd search for dog or dogs or dog inform
38、ation. Here are a few search-engines. 1. AltaVista () - Web spider & Indexed2. Yahoo () - Web spider & Indexed Collection3. Excite () - Web spider & Indexed4. Lycos () - Web spider & Indexed5. Metasearch () - Multiple searchA web spider is a program used by search engines that goes from page to page
39、, following any link it can possibly find. This means that a search engine can literally map out as much of the Internet as its own time and speed allows for.An indexed collection uses hand-added links. For instance, on Yahoos site. You can click on Computers & the Internet. Then you can click on Ha
40、rdware. Then you can click on Modems, etc., and along the way through sections, there are sites available which relate to what section youre in. Metasearch searches many search engines at the same time, finding the top choices from about 10 search engines, making searching a lot more effective.Once
41、you are able to use search engines, you can effectively find the pages you want. With the arrival of networking and multi user 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, hacke
42、rs who find ways all the time of breaking 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. The biggest problem now-a-days is personal information. Why should you be
43、 careful while making purchases via a website? Lets look at how the internet works, quickly. The user is transferring credit card 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 Int
44、ernet backbone. The information is in little chunks, in packages called packets. Heres 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 backbone points? Big-brother is not watching you if y
45、ou 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, encryption.Encryption means scrambling data into a code that can only be unscrambled on the other end.
46、Browsers like Netscape Communicator 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 adopted by the US Defense Department because it was de
47、emed so difficult to crack that they considered it a security risk if it would fall into another countries hands. A DES uses a single key of information to unlock an entire document. The problem is, there are 75 trillion possible keys to use, so it is a highly difficult system to break. One document
48、 was cracked and decoded, but it was a combined effort of 14,000 computers networked over the Internet that took a while to do it, so most hackers dont have that many resources available.外文资料译文Internet的历史起源ArpanetInternet是被美国政府作为一项工程进行开发的。这项工程的目的，是为了建立远距离之间点与点的通信，以便处理国家军事范围内的紧急事件，例如核战争。这项工程被命名为Arpanet，它就是Internet的前身。建立此工程的主要应用对象就是军事通讯，那些负责Arpanet的工程师们当时也没有想到它将成为“Internet”。根据定义，一个“Internet”应该由四或者更多的计算机连接起来的网络。Arpanet是通过一种叫TCP/IP的协议实现连网工作的。此协议最基础的工作原理是：如果信息在网络中的一条路径发送失败，那么它将找到其他路径进行发送，就好象建立一种语言以便一台计算机与其他计算机“交谈”一样，但不注意它是PC，或是Ma