Basic Computing Using Windows/Networks and the Internet
We have now covered all the basic concepts using a computer. In this chapter we are going to cover the concepts related to networking and using the Internet.
A network is a way of connecting two or more computers together so that they can share peripherals (hardware like printers) and data. The most common form of network uses Ethernet. Ethernet is a system of data transfer that uses two different kinds of wire, the older one being like a cable television wire and the newer one being like telephone wire. The newer one is faster and uses an end called RJ-45, which looks like a fat telephone cable end. Normally, computers are plugged into a hub, or switch using an internal piece of hardware called an Ethernet card or simply a network card and one of these cables. Then they can all communicate with each other.
Once the computers can communicate, each item (i.e. printer or folder) that needs to be accessed on the network must be shared, allowing it to be visible to the other computers. Any shared item may be blocked off from general use by a password. One of the other benefits of networks is email (electronic mail). Email allows users to send messages and files to each other. When a new message is received it goes into the users inbox for storage until it is read, so that a user may receive mail while away from the computer.
Ethernet networks create what is called Local Area Networks (LANs). This means that they are used within one area (i.e. a house or business building) and that is it. All the computers in that area may be connected, but no one else. This can be a problem depending on what you want to do, and a larger network could open up immense possibilities. Enter the Internet. In 1957, just after the USSR launched Sputnik, the American government created ARPA, a scientific research branch for the military. In 1969 ARPA decided to attempt the creation of a national computer network for communications by the military. They did not want to use any standard system, however, not just because of the distance, but because of the fear of nuclear attack. They wanted a network where there was not central hub that could be taken out, but where all remaining parts would function if any other part were destroyed.
After their success, the idea spread. Different government and educational institutions started connecting into the network. Because they all used the same protocol (a set of rules that computers use to communicate, in this case TCP/IP) and the same wires that carried telephone across the country as soon as they plugged in it was the same network. Soon different institutions were creating their own servers (computers that store information meant to be accessed on a network). By 1989 there were more than 100 000 servers on what was becoming known as ‘the Internet’. After the Cold War the American government no longer needed a specifically protected portion of this network they had started for their own and the Internet became completely public domain.
In 1990 Tim Berners-Lee invented a protocol based on TCP/IP that could work with it on the Internet and was more flexible. Soon after this, the NCSA (National Centre for Supercomputing Applications) developed Mosaic, a graphical interface for this protocol called the World Wide Web (WWW).
The rest of this chapter is going to be spent looking at the WWW (or ‘the Web’). To view Web pages (the electronic documents with pictures and formatted text that you view on the Web) you need to have a Web browser. The two most popular browsers are Mozilla Firefox and Internet Explorer. You can use either one or any other Web browser. If you are not sure what you have, then you will still have Internet Explorer, it comes with Windows.
To do anything online (on the Internet), you must first connect to the Internet. If you don’t know how, see Appendix B. After you have connected to the Internet, open your Web browser. Every computer connected to the Internet has an address, called an IP address to identify it. This is a number like ‘220.127.116.11’. To have to remember something like that to access a web page would be a pain, so Domain Names were created. Domain names are names that you can type in the location bar (more on this below) in your browser. The name is then sent to a server on the Internet called a DNS (Domain Name Service) server that then returns the correct IP address.
You should be connected to the Internet and have your browser open. (You may not have access to the Internet where you live. Your teacher will provide a substitute.) First we should identify the parts of a browser so that we know what we’re talking about. Figure 6.1 is a picture of Internet Explorer. If your browser looks a little different, that is okay.
The location bar can also be called the address bar, and it is where you type the URL (Universal Resource Locator or Uniform Resource Locator), which is laid out as follows:
|The protocol name||The domain name||The folder and/or file name on the server|
After you type the URL press the Enter key and you web browser will take you to the page. The first button on the toolbar is the ‘Back’ button. It does the same thing as the ‘< Back’ button that we saw before, it goes to the previous screen you were looking at. In this case, the previous web page you were at. The back arrow on the button is a universal icon. Universal icons are ones that are always used to represent the same function. This is different from a program icon like on your desktop or from an icon that only occurs in one program. Even the ‘< Back’ button has a back arrow, that’s what the ‘<’ is for. Note that universal icons do not always look exactly the same (i.e. the arrow can look different, as long as it points left).
A universal icon also identifies the next button on the toolbar, the ‘Next’ button. If you push the back button, then you can go forwards again by pushing this button. The next button on the toolbar has two universal icons used together. A sheet of paper represents a file. An ‘X’ represents stop. So the sheet of paper with an ‘X’ on it represents stop loading the file, which is what this button does. Some web browsers have just and ‘X’ or have a red stoplight on this button. They mean the same thing, stop.
Two icons are also used on the next toolbar button. The paper means the same thing, and the arrows going around mean refresh or reload. This is actually typically a Microsoft icon, although some other companies also use it. The reload button in Netscape as a bent up-arrow, signifying looking at the server again. This button forces the web browser to look at the server and download all the data for a web page again. This is primarily used for when the cache (the place where a web browser stores web pages on your hard drive for quicker access) has an old version of the page that the web browser is displaying and you want to see the newest version of the page.
The next two buttons on the toolbar are the last ones with universal icons. They have a house, and a magnifying glass. A house represents ‘home’ and this button takes you to your home page. A home page is a web page that you have set up for your browser to take you to when it first starts or when you click this button. The magnifying class represents ‘search’ and this button will take you to a web page from which to search the Internet.
There is one more thing you need to know about if you are going to be using web pages, hyperlinks. Hyperlinks (one is labelled in the picture above) can be either text or pictures. When they are text they are often a different colour and underlined. When you click on them they take you to a different web page. The text ones are a different colour once you have been to the web page they point to. Some text hyperlinks are formatted differently, though, and many hyperlinks are pictures. How can you know if something is a hyperlink? Hover your cursor over it and if it is a hyperlink your cursor will turn into a hand, and usually the URL that the hyperlink (or just link) points to will be displayed in the status bar.
The web is very useful for getting information this way, but what if you don’t know the URL you need? That is why search engines were created. There are more than 10 billion web pages on the Internet, not all of them are catalogued in all search engines and when you search for something you will tend to get pages that have nothing to do with what you want. However there are some ways to improve your search results.
Go to a search engine. They all work much the same but if you don’t know of one go to http://www.google.com. In the text box you can type keywords (words that have something to do with what you want to find). Some search engines have more advanced features that you can explore on your own, but all of them support Boolean operators. The two most useful for web searches are AND and OR. It is best to type them in all caps. AND tells the search engine that the things on both sides must be in the web page (they may be in its text or in its META tags). OR tells the search engine that one or the other must be in the web page. So typing ‘boats AND models’ will look for all pages containing both words, whereas ‘boats OR models’ will find any page with either word. You can also use NOT, ‘boats NOT Titanic’ returns everything containing ‘boats’ that does not contain ‘Titanic’
You can do more complicated strings too, like ‘boats AND models OR ships AND kits’ which finds all pages containing both ‘boats’ and ‘models’ or both ‘ships’ and ‘kits’. You can also do something like this, ‘boats OR ships AND models OR kits’ which finds anything containing the word ‘boats’ or ‘ships’ along with either ‘models’ or ‘kits’.