The
Internet
The
Internet
Lesson Objectives
The Lesson
Let's Get GoingIt's a cold winter morning in New York City. The commercial on Z100 promised that if you visit "empresstrvl.com" you could win a trip to the sunny Bahamas. The subway you take to school is decorated with cardboard advertisements. One of them tells you, if you want to go far, go to Brooklyn: http://www.brooklyn.cuny.edu. Your best friend at school is going to be studying abroad this summer. Can you afford the cost of the long distance phone calls each night? Relax, says your friend, just e-mail me. Lots of places to go, lots of connections to be made, and you never have to leave your desk. Traveling and correspondance today can be done electronically, thanks to your computer and the network technology that has created the world of the Internet.
The Internet - An EvolutionThe Internet began in 1969 at four university sites in California and Utah and was intended to serve the communication needs of the military research community. The Internet has since grown from connecting the original four sites, to a network connecting 300 computers in 1983, to a network of 60 million users by the end of 1997. The Internet, as many people see it today, is an eye-catching, multi-media system of information delivery, often referred to as the World Wide Web. The original Internet, though, was not such a feast for the senses. And the World Wide Web is just one aspect of the Internet. Nonetheless, despite the many developments and enhancements to the electronic network, the most basic precept of the Internet has not changed. The Internet remains a system that allows people located at a distance from each other to use computers connected through telecommunications systems to exchange information easily and quickly.
The World Wide Web: The Main Road on the InternetThe World Wide Web, or the Web, is a visually and aurally enhanced environment where computer users connected to the Internet, talk to each other, find information and data, get software and download files. Computer users can stay in touch with friends through e-mail or visit home pages such as those for Empress Travel and Brooklyn College mentioned at the beginning of the lesson.
Browsers and Links: The Vehicles for Web PagesA computer on the World Wide Web called a Web server can host, or house, Website home pages and transfer these files to a client computer asking to see the site. When you use a browser on your computer to move through the World Wide Web you are using a client computer. In order for your computer to get to and present the text, images and sound that are available on the Web, these different types of files are coded with tags called Hypertext Mark-up Language (HTML). The coding allows for the files to be read as they are intended and for computer users to go from Website to Website. For example, in order to see large lettering, the code <H1> is put in front of text. If you put the code <H1> in front of the word BIG, the word BIG shows up in large letters as you can see in the next line: BIGIn order for you to bring up a home page that you see mentioned on another Website, the name of that home page is labeled in the document you are looking at with the hypertext mark-up language code <a href> and the address of that site. The words leading you to the Website below are coded in this manner. This is the coding <a href="http://www.whitehouse.gov">The Whitehouse </a> that will take you to Files you see on a Web browser are transferred from the Web server to your computer, the client computer, by a hardware/software mechanism called Hypertext Transfer Protocol. Browser software, such as Netscape Navigator or Microsoft Internet Explorer, can read files encoded with HTML and enable computer users connected to the Internet to request the transfer easily. By using a browser, you can go directly to a site you want to visit or go to a search engine site that will help you find the Web pages with the information you need. Browsers allow for the full display of computer files available at a site. A lot of files contain text, but many also contain graphics, both still and animated, and audio or video clips. One of the first browsers, Lynx, allowed computer users on the Internet to access textual information but not the graphical material. Navigator and Explorer both allow access to graphical material. In order to access video and audio, however, the browser software in your computer may require the addition of plug-ins. Most Web home pages connect to other pages through links. These links are embedded in text or images of the Web page as hot spots. Positioning the mouse over these spots and clicking will transport the computer user from one home page to another.
Site Names: The Sign PostsA site on the World Wide Web is identified in two ways: one that is familiar to you and one that you may not recognize. The first means of identifying a site is with its Uniform Resource Locator (URL). The second is with its Internet Protocol (IP) address.
URLsURLs are the names of Web sites that appear as words separated by punctuation such as those given in the introductory paragraphs of this lesson: empresstrvl.com and www.brooklyn.cuny.edu. The URL consists of a fully qualified domain name (FQDN) and any additional path that is needed to reach a desired file. The FQDN is made up of the name of the computer that hosts the site (very often called "www") and the domain name (such as the company, organization or institution name; e.g.: empresstrvl.com and brooklyn.cuny.edu). The suffixes .com and .edu, and others you may have seen such as .net, .org, .gov, and .mil are also referred to as top level domain names (TLDs). Additional, less-well-known TLDs include .firm, .store, .web, .arts, .rec, .info and .nom. .com commercial .edu educational .org non-profit
organization .gov government .mil military
agency .net computer
gateway .firm a
business .store a
retailer .web activities .arts culture or
entertainment .rec recreation .info information
service .nom a
person In addition, Web sites outside of the United States often have country suffixes as part of their domain name. The Chinese University of Hong Kong, for example, has the URL www.cuhk.hk, where the final hk is the country code for Hong Kong. The path that may follow the domain name in a URL is the route to a file on a disk. The route to the file may be through one or more directories or folders, storage areas on a server's disk that help keep files organized. Each directory along the path is proceeded with a foreslash, "/," until the file name is given as the last part of the URL. Files found on the World Wide Web usually end with the file extensions .htm or .html. File extensions are a way of helping to keep files organized by file type.
IP AddressesThe IP address is a numerical way of identifying every computer connected to the Internet. It consists of a string of four number groups separated by periods. As the word address implies, it is a way of finding something. So, just as you would be able to find Empress Travel by looking for its URL, if you knew the IP address of the computer that held the home page file for Empress Travel, you would be able to get to the Empress Travel site by looking for its IP address. Since it's easier for most people to remember strings of words rather than numbers, most people look for Web sites by looking for a URL, rather than by looking for an IP. One of the behind-the-scenes activities of computers on the Internet, though, is finding the corresponding IP address everytime a computer user asks to be taken to a URL. You remember a favorite site by its name (often a simple URL) and this is what you ask for when you search the Web; the behind-the-scenes processes of the computers connected on the network look for a number (the IP address) that matches this name. An IP address, furthermore, may be temporary or permanent. Therefore, if you wanted to get to Web sites by remembering their IP addresses, it would be important that their IP address remain the same. The IP addresses for frequently visited sites usually are permanent. However, chances are that if you get to the Internet through a computer at home, the computer you are using is being identified with a temporary IP address. The IP address for your computer will probably be different the next time you turn on your computer to search the Internet.
Internet Service Providers (ISPs) and Online Services: Toll Takers on the ThruwayThe Internet may appear to be free and thanks to public libraries and school media centers and computer labs, there are many locations where getting on the Internet appears to be as cheap a route to information as pulling paper flyers out of a kiosk. The Internet, nonetheless, is not free, not any more free than it is to have a telephone connection or a magazine subscription bringing information into your home. Internet Service Providers and Online Services, in a sense, act like the telephone company and magazine publishers combined to enable businesses, organizations and individuals to get the information they want from the Internet. A computer uses software to dial into its ISP or Online Service, either through a modem or a local area network connection. The ISP or Online Service provides a connection to the telecommunications system that can access computers on the Internet. Online Services, in addition to general Internet access, give access to discussion forums and subscription-based magazines.
Older Routes on the Internet: Still in Use TodayBefore the Web made Internet travel so appealing, computer users still could connect to distant computer sites, find information and transport files using other technology. These methods of connecting to and using the Internet are now embedded in the Web environment and you may come upon them while using the newer technology. Still present and active (among others) are: telnet, file transfer protocol and gopher. Telnet Telnet allows a computer user to log on to a distant computer directly and run a program based at that far-away computer. A common use of telnet is for accessing the online catalogs of libraries. Before the Web came into use, computer users with telnet software would specify the address of the needed computer either as words punctuated with periods (for example, cunyvm.cuny.edu) or as the IP number. In order to be able to telnet while using the Web, your local area network server or the stand-alone computer you are using must be loaded with a telnet application and your Web browser must be set up or configured to interact with the application when needed. The lesson on the Netscape browser will cover this in more detail. Most home pages that offer a telnet connection will also give you log-on instructions including a log-on ID and a password to use once the telnet connection is made. Gopher Gopher is software that lists broad categories of locations on the Internet and individual files stored on the server running the gopher. The gopher index allows computer users to connect to these locations. A gopher set up on one Web server will usually allow a computer user to link to other gophers established at other sites.
File Transfer Protocol - FTP File Transfer Protocol allows people using computers on the Internet to move files back and forth between a distant computer and their own. Before hypertext transfer protocol (HTTP) allowed for the easy transfer and display of long pieces of text, graphic and audio files in the Web windows environment, FTP file transfer performed these transfers but required knowledge of a command language. Currently, in the Web environment, home page producers (everyone from individuals to corporations) are able to use newer, windows-based FTP software to put their productions on to their Web server and retrieve them in order to change them. Web users who visit these sites see (and possibly hear) these files and can easily make copies of what they see or hear by using the File/Save As command line options in their browser.
Using the Internet For CommunicationIn addition to providing access to files available as pages on the World Wide Web, the Internet has always been a communication mechanism. Methods of using the Internet for communication include electronic mail (e-mail), chat rooms, mailing lists or listservs, newsgroups, bulletin boards and discussion groups. All the methods of communication on the Internet allow you to send messages quickly to one or more people. E-mail is the most popular means of communication. People use e-mail to send, receive and forward electronic messages and files for a wide range of purposes. Chat rooms, listservs, newsgroups, bulletin boards and discussion groups were all developed as methods for people with similar interests to connect and communicate with like-minded people in forum settings. The listserv EAT-L, for example, works as a forum for recipe exchange. The newsgroup alt.tv.law-and-order is a newsgroup for people interested in the television show of the same name. Anyone can join a listserv by subscribing electronically. The list owner defines what sorts of correspondences are suitable contributions to the list. Subscribers then e-mail messages that meet the intentions of the list for all the list subscribers to read. Joining a listserv and reading the messages people send to the list is a way for people in diverse settings often to hear experts in a field make recommendations or notify others of their current work. Access to discussion groups can be restricted so that only invited participants can read the discussion and add their own comments. A discussion group administrator gives the participants instructions for joining. All involved can read any discussion that has transpired and add their comments to the end of the transcript of other people's comments. All the discussion comments will appear on the discussion group Web site. Discussion groups have enabled students and teachers to talk to each other in new sort of electronic classroom. What distingushes chat rooms from other methods of electronic communication is that correspondence in a chat room occurs in real time. This means that as you type in a message on your computer keyboard, your intended audience sees the words appearing and can respond immediately. People who offer comments in a chat room may not spend much time thinking through carefully what they say and therefore the value of the information they share may be limited. Communication through e-mail, a listserv, a newsgroup, a bulletin board or a discussion group requires the intermediary of either a computer or a person playing a role similar to that of a postal worker, distributing correspondences to the people who would want to read them. The correspondence may wind up in some centrally accessible location, such as a bulletin board or on a discussion group Web site, or they may be sent to your electronic mail box through e-mail transfer, or to many electronic mail boxes to all who participate in a listserv. Participants read and respond to correspondences at their own convenience.
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