internet的历史--毕业设计外文翻译.doc

外文资料原文
The History of the Internet

The Beginning - Arpanet
The 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. The 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 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, as well as establishing a means for one computer to "talk" to another computer, regardless of whether it was a PC or a Macintosh.
By the 80's Arpanet, just years away from becoming the more well known Internet, had 200 computers. The Defense Department, satisfied with Arpanet’s results, decided to fully adopt it into service, and connected many military 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.
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 NSF, 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) Internet. 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 Internet
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. Millions 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 evolving so quickly its hard to determine where it will go next, as computer and network technology improve every day.
HOW IT WORKS:
It's a standard thing. People using the Internet. Shopping, playing games, conversing in virtual Internet environments.
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.
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 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 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 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 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.
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 computers 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, let's look at how a standard computer might view a webpage.
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.
2. The user launches a web browser like Netscape or Internet Explorer and types in an internet location to go to.
3. Here's where the 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 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 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 into 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 it's going, and overall where the user wants to go.
4. The 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).
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 that 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 information 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 tips 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 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 you're reading this right now means that you have a web browser.
Next you must be familiar with actually 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 it 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- 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 user's fault, of course.
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 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.
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 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 version of your web browser.
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.
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) for 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 attachment and you don't know who it is, don't run 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.
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.
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 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 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 with 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, 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-mail server software, but it's easier to use an e-mail client (of course).
There are millions of WebPages that come from all 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 it's own database of websites. For 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.
1. AltaVista () - Web spider & Indexed
2. Yahoo () - Web spider & Indexed Collection
3. Excite () - Web spider & Indexed
4. Lycos () - Web spider & Indexed
5. Metasearch () - Multiple search
A web spider is a program used 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.
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 way through sections, there are sites available which relate to what section you're 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 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, hackers 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 careful while making purchases via a website? Let's 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 Internet backbone. The information is in little chunks, 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 backbone points?
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, like password protection, an most importantly, encryption.
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 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 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 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 don't have that many resources available.
外文资料译文
Internet的历史

起源——Arpanet
Internet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Macintosh。
到了20世纪