Introduction to the Internet

Transcription

1 Introduction to the Internet Sponsored by Greene County Public Library Rev 09/07 1

2 What is the Internet? Introduction to the Internet The internet is a network of computers that are linked around the world. When you use a website, you are using the Internet to connect your computer to information stored on another computer. When you click on the link on the web, you are really sending a message. It goes from your computer, to your modem, then through telephone lines to another computer on a network. The message is then sent along high-speed data lines from computer to computer until it finds its destination. A response is sent back over the network to your computer. The Internet is decentralized meaning that each government, company and organization is responsible for maintaining its own network. For example, Greene County Public Library maintains its network by keeping it current and running so that patrons can access services such as the website and catalog. There is no single organization that controls the Internet. All networks communicate using common protocols or rules known as TCP/IP. TCP/IP is the language computers use to talk with each other. TCP/IP = Transmission Control Protocol/Internet Protocol Why the Internet? In the late 1960s, The U.S. Department of Defense created a network of military computers. The network, called ARPANET, was developed in such a way that if one section of the network was damaged, the remaining computer on the network would still be able to communicate with each other. By the late 1980s, Rev 09/07 2

3 universities saw the advantage of linking up and the National Science Foundation created NSFNET to allow universities and schools to connect to each other. As technology advanced, so did the Internet. In 1976, Queen Elizabeth sends her first and soon after in 1978 the first spam is sent. In 1989, the Internet came into commercial use and the World Wide Web was created. In 1992, a graphical approach to display the information was created. Before graphics, the user needed specific codes and commands to make it work instead of clicking on icons. In 1993, the White House went online and in 1994, commercial services like AOL, CompuServe and Prodigy began providing Internet access to the public. In 1995, the National Science Foundation pulled out of servicing the Internet and commercial providers now service it. Today, more than 50% of U.S. households have Internet access. The World Wide Web The World Wide Web is an international system of computers that store and support items written in a specific format known as HTML (Hyper Text Markup Language). Hypertext = A system in which objects can be linked to each other. The Web consists of a huge collection of documents stored on computers all over the world. These documents, or web pages, are hypertext documents containing links to let you easily jump to other web pages. Using the World Wide Web is the easiest and most common way of accessing information from the Internet. Web pages are now easier to create because there is no longer a need to know Internet language. The information on the Web is constantly changing as the web pages are updated and new pages are created. Rev 09/07 3

4 How Do Computers Communicate? Computers are assigned Internet Protocol (IP) Addresses) and they use these to communicate with each other. IP Addresses are similar to phone numbers in that each one is unique. Computers will connect to another computer s IP address to acquire information. IP addresses always consist of four numbers separated by periods. IP Address = An IP address is then translated into words known as a Uniform Resource Locator (URL) or web address. URL = Parts of a URL Protocol: The rules under which the document or object was built. HTTP stands for Hypertext Transfer Protocol. Domain: Represents the host computer you are contacting that stores the website. Suffix: Indicates what kinds of organization or person owns the website. Directory Path: Contains the name of a specific page within a website. When you click on a link, the directory path will change as you move from document to document. Who Uses What Domain Suffix?.com Commercial.edu Educational.org Not for Profit Rev 09/07 4

5 .mil Military.gov Governmental.info Informational.net Networks Web Page vs. Web Site A web site is a collection of web pages that are linked together and share the same domain name. A web site is much like a magazine and a web page is a like an article within that magazine. Each web page within a web site does not necessarily have to be related in the same way that articles in a magazine are not all about the same topic. A home page is the front page or 1 st page of a web site. Web Browers A web browser is a software program that lets you view, send and receive information on the World Wide Web. Two popular web browsers are Internet Explorer and Mozilla Firefox. A brower is like a television set. The center is the screen, which is where you see snapshots of web pages. The frame around it has the controls. Parts of an Internet Explorer Browser Title Bar Menu Bar Browser Button Tool Bar Address Bar Rev 09/07 5

6 Parts of a Browser Explained Title Bar = This is the blue bar across the top of the screen that tells you the name of the web page you are currently viewing and the type of program you are using. Menu Bar = This is the grey bar below the title bar that contain commands and options. Each item gives you a list of choices when you click on it. Included in the menu bar is Help. This is a great place to get information about using Internet Explorer. Tool Bar = This is the second grey bar just below the menu bar that contains the pictures or icons. These icons are called browser buttons and they represent shortcut to frequently used commands. The name of the function will appear when you hover your pointer over any of the buttons. Brower Buttons (in order) Back: Goes to the last web page you visited Forward: If you clicked back, this will take you forward again Stop: Use to cancel a web page from loading Refresh: Retransmits the web page. This is useful if your page did not load correctly, or if you are at a sire that changes frequently. Home: Your browser is set to always open to the same page. Clicking Home will return to that page. Search: Opens a separate web search page Favorites: You can save frequently visited sites into your favorites so that you don t need to memorize them or write them down. Clicking on this button retrieves your favorites list. History: Shows you a list of the web sites you have visited. Print: Prints exactly what is on your screen Address Bar = This is the long white box below the toolbar. This will give you the web address of the web site currently on Rev 09/07 6

7 your screen. This is also the place where you can type in a different web address to visit another web site. Main Browser Window = This is your viewing screen where web pages you visit will appear. Scroll Bar = These are the long, skinny bars to the right and/or bottom of the screen. If the web page is too large to fit in your screen, the scroll bar will allow you to scroll through it. Status Bar = This is the bar at the very bottom the screen that tells you the progress of the browser while it downloads files to the web page, where links go to when you move over them, whether or not a document is secure, and any other information that the program feels is necessary for you to know. Location Bar Arrow = This is the drop down arrow to the right of the address bar. Clicking this will show you a list of previously visited web sites. You can move down that list and click on an address to get back to it. Hyperlinks Hyperlinks can be words or images. What they have in common is that your mouse pointer will turn into a pointing white hand when you hover over one. Often, they are underlined. Rev 09/07 7

8 Printing To print an entire Web page, click on FILE, and choose PRINT. Click OK in the Print Dialog Box. (Beware: this will print the entire Web page which may turn out to be many printed pages.) To print selected text from a Web page, use your mouse to select the portion of the Web page that you wish to print. Click on FILE, and choose PRINT. In the Page Range section of the Print dialog box, click Selection, then the OK button. To print selected pages from a Web site, check the length of the document before printing by clicking on FILE, then PRINT PREVIEW. The Web page appears as it will look when printed. If there is more than one page of information, click on the NEXT PAGE arrow to see that page. You can choose to PRINT from here or CLOSE. If you choose PRINT, a box will open asking to print all or various pages. Using LANDSCAPE: If you have a chart or picture that will not fit on a vertical 8 ½ by 11 page, you might want to try this. When you go to FILE, then PRINT, click on PROPERTIES. Under the Basics tab locate PORTRAIT and LANDSCAPE. The default is PORTRAIT, so click on LANDSCAPE to change the way the page will print. Library policy on printing: The libraries charge $.15 per page for printing any full text item. To Save a Web Document as Text 1. In Internet Explorer, click on the File menu, choose Save As Make the Save In box display the A: drive by clicking on the down arrow to the right of the Save In box and choosing 3 ½ Floppy (A:). 3. Determine whether you want to accept the name in the File Name box. You can change the name by typing over the name that s there. 4. Click on the down arrow to the right of the box that says Save as type, choose Text File (*.txt) 5. Click the Save button. Rev 09/07 8

9 To Save a Web Document as HTML When you choose Web Page, HTML only (*.htm, *.html) in the Save As type box, you save the HTML file that makes up most of what you see on the screen minus the images. When you choose Web Page, complete (*.htm, *.html) in the Save As type box, you save the HTML file AND all of the images that appear on the page. This can be many files. To Save an Image 1. Move your cursor over an image and click the button on the right-side of your mouse. 2. Select Save Picture As... from the pop-down menu. This will bring up the standard Windows Save As dialog box. 3. Make the Save In box display the A: drive by clicking on the down arrow to the right of the Save In box and choosing 3 ½ Floppy (A:). 4. Take note of the name of the image file. Image files commonly end in.gif or.jpg 5. Click the Save button. NOTE: Although you can save only to the A: drive at the Greene County Public Library computers, you have the option of saving to the hard drive (C: drive) on your home computer. Rev 09/07 9