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Our Learning Community June 17: June 30: July
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What is the World Wide Web? WWW or "Web" is system of Internet servers that uses HTTP to transfer specially formatted documents. The documents are formatted in a language called HTML (HyperText Mark-up Language) that supports links to other documents, as well as graphics, audio, and video files. One
can jump from one document to another simply by clicking on hyperlinks.
Not all Internet servers are part of the World Wide Web. What is a web browser? A piece of software which accesses the World Wide Web and looks for information in a simple, clickable interface. Examples include Internet Explorer and Netscape. There are other minor browsers as well (such as Opera). We will use Internet Explorer in this class.What are the parts of the browser?
What is a URL? URL stands for Universal Resource Locator. It is the address where information can be found. In the case of the example http://www.cambridgecollege.edu http:// -- this tells the browser you are looking for a website. On most browsers, this part will be filled in for you. .org -- a Top Level Domain (TLD), indicating that this site is a non-profit organization. This is like saying you live in Vermont. mass4h -- This is the name of the site. This is like saying you live at 123 Any Street, Brattleboro. www -- The name of the computer which hosts the website. This is like saying you live on the 2nd floor or Suite 235. Not all URL's have to have www. For example: www.dell.com -- This is Dell Computer Company's main website. You go here to purchase a computer. support.dell.com -- This is their technical support site. Go here if you are a customer with a support question. There are several Top Level Domains used in web addresses: .com -- Commercial addresses -- www.mcdonalds.com .net -- Networks, usually an Internet Service Provider (ISP) -- www.sover.net .org -- A nonprofit organization -- www.mass4h.org .edu -- An educational institution -- www.cambridgecollege.edu .gov -- A US government site -- www.irs.gov .mil -- A military site -- www.defenselink.mil You will also see foreign websites which end in a two letter extension. For example: .fr = France, .de = Germany, .jp = Japan, .il = Israel, .au = Australia, etc. Indeed, even the US has their code of .us, although it's seldom used here. However, you can find the address in use at many schools and in state government. In fact, the .tv names originally came from the tiny island nation of Tuvalu. They sold the rights to administer those names to a company in California which is now selling and administering those names exclusively. (Tuvalu's main industry is bananas, their population is 10,000, and most people haven't ever seen a computer.) Recently, ICANN (the Internet Convention on Naming and Numbers) approved several new top level domains, including .info, .biz, .coop, .museum, .name, .aero, and .pro. Some are available now, and some will be available in the near future. Starting on the Web In the browser, type the address where you want to go into the box at the top of the screen. Hit "go", and you're there! If you get an error, look for a misspelling first. If the address is not spelled exactly right, with correct punctuation, you're not going anywhere! Try this:
http://www.amazon.com and then hit the Enter key or the "go" button on the browser. How does it all happen? An excellent question! Your computer is often referred to in Information Technology terms, as a "client". Somewhere, one of the wires coming out of your computer is either a phone line, a cable (like TV cable), or another type of line called Ethernet (which is what we use at the Grad Center). These can be thought of as different widths of pipes. The phone line is a thin pipe which doesn't allow very rapid exchange of information, whereas Ethernet is a very fat pipe and allows data to flow very quickly. Cable is closer towards the Ethernet end of things. On the other end of the phone line, cable, or Ethernet is the Internet. It's a networked city of computers from all over the world, all talking to each other at once. Every website has an address in the form of a URL. Think of this as a very easy-to-remember address. All of the rest of the computers have more obscure addresses which are just a bunch of numbers. When you type a URL into your browser, you are giving a command to be taken to a particular computer and view files on that computer. That computer is called a server, because it serves up those files for your viewing. It sends the files back to your browser, which displays the HTML in the format you're used to seeing. (If you want to see the file the server sends to your browser, go to the View menu and pick Source.) The connection from your computer to the Internet is provided by a company like SoverNet, Vermontel, EarthLink, or Adelphia. This is known as an ISP, or Internet Service Provider. Think of them as the spigot, to which you are hooking your hose. You might have heard the buzz about "client/server interactions"? Well, that's all it is, in a nutshell. Now you know. About Links Links can be text based, or a picture may contain a link to another web page. Sometimes, these links are coded to open in the same browser window. Other times, they open in a new browser window. Read more about Links on the EarthLink site. About Email Email is another wonderful application of the Internet. Email allows you to send a personalized message to another person almost instantly. Email is a rapid, low-cost method of communicating with people all over the world. Keep in mind, however, that email is more like a postcard than a sealed letter! Email can potentially read in transit, either legally (i.e. an employer) or illegally (i.e. a hacker). Also, emails have a funny way of rearing their heads after many years. Look at the recent Microsoft Antitrust trial for evidence of that! You also need to be aware of problems arising from email: Spam (after the Monty Python skit) is any piece of unsolicited "junk mail" you might receive. Favorite topics of spam include the usual off-line scams -- get rich quick, erase your bad credit history, porn site advertising, chain letters, pyramid schemes, and many, many more. Generally speaking, you receive this information if you subscribe to newsletters which sell your email address -- just like in the offline world! To avoid getting on an unscrupulous mailing list, be sure to read the privacy policy which comes with most websites. If there is no privacy policy, watch out! Viruses can also be spread through email attachments. Nope, it won't make you sick, but it will make your computer sick if you open the attachment. Often times, just receiving the email won't infect your computer, but stay tuned -- this could change in the future! There are two ways to avoid these viruses lurking in attachments. One is don't open an attachment. This can be inconvenient, particularly if it's email at work and a colleague is sending you a file, though. The other method is to get a good virus checking software package. There are many available, but the big names are Symantec (Norton Antivirus) and McAfee. Run your virus scanner often, check for updates, and use it. |
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