【導讀】Inter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(nèi)的緊急事件，例如核戰(zhàn)爭。這項工程被命名為ARPA，它就是Inter的前身。建立此工程的主要應用對象。就是軍事通訊，那些負責ARPA的工程師們當時也沒有想到它將成為“Inter”。根據(jù)定義，一個“Inter”應該由四或者更多的計算機連接起來的網(wǎng)絡。ARPA是通過一種叫TCP/IP的協(xié)議實現(xiàn)連網(wǎng)工作的。國防部很滿意ARPAs的成果，于是決定全力將它培養(yǎng)為。與超過1000臺的主機之間。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。如今，Inter已經(jīng)成為人類歷史上最先進技術的一種。年世界上的每個人，都將擁有Inter接入。Inter下一步將發(fā)展成什么樣子。Inter不僅僅是一件事物。目前使用最廣泛的網(wǎng)頁瀏覽器是Netscape和MSIE。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，

　　

【正文】 line。 tel. A popular tel program for Macintosh is NCSA tel. Any server software (web page daemon, chat daemon) can be accessed via tel, 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 server software, but it39。s easier to use an client (of course). There are millions of WebPages that e 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 it39。s own database of websites. For instance, if you wanted to find a website on dogs, you39。d search for dog or dogs or dog information. Here are a few searchengines. 13 1. Altavista ( Web spider amp。 Indexed 2. Yahoo ( Web spider amp。 Indexed Collection 3. Excite ( Web spider amp。 Indexed 4. Lycos ( Web spider amp。 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 Inter as it39。s own time and speed allows for. An indexed collection uses handadded links. For instance, on Yahoo39。s site. You can click on Computers amp。 the Inter. 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 you39。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 working and multi user systems, security has always been on the mind of system developers and system operators. Since the dawn of ATamp。T and its phone work, 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 working was limited to big corporate panies or government puters who could afford the necessary puter security. The biggest problem nowadays is personal information. Why should you be careful while making purchases via a website? Let39。s look at how the inter 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 puters that make up the Inter backbone. 14 The information is in little chunks, in packages called packets. Here39。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? Bigbrother 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. Browser39。s like Netscape Communicator and Inter Explorer feature encryption support for making online 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 39。crack39。 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 bined effort of 14,000 puters worked over the Inter that took a while to do it, so most hackers don39。t have that many resources available