Oooooh, Magic!!

It's very easy to believe that the Internet is a mysterious place full of wonders and treasures - not unlike Aladdins cave.

But the truth of the matter is far simpler. As we saw in Module 1, the Internet is about pieces of information (packets) being transferred from one computer to another. Download and Upload are the terms that are used to describe the primary direction that these packets are traveling in. This is not as complicated as it sounds. If you request information from another computer then it will be passed down to you. You will have Downloaded it. If you are sending information to another computer, then you are passing it up. You are uploading it.

 

So Why Up and Down

Why, indeed!! Time for a picture.

It's all about hierarchies. You, via your ISP, send a request for information from another computer on the WWW, and that computer passes on the request until it arrives at the computer that has the information (say, in Belgium). (Information, games and Web Pages are stored on special computers that are called servers. These are both expensive, and owned by someone who is not you). For the sake of argument we will call our server computer in Belgium General Bob. If General Bob agrees to pass the information on to you, it will arrive via the proper chain of command (of course). He passes the information onto Colonel Jim, who passes it on to Captain Ahab, etc, until it finally arrives at your computer.

Access to server computers is limited to the number of incoming modems that are available at any time. Not everybody can get access all the time, and in some cases you need passwords or special authorities to get access. These special authorities will be looked at in Net Security . Even if you can download almost anything you want from the Internet, you need special access to upload. Uploading is the passing through the chain of command to get permission to put something ON a server. Remember, this is someone else's computer. And they may not want to catch your Virus!!

When to Download

You are doing it now!! Each time you turn to another page in this module you are 'downloading' information from a computer. Each border and every picture. In fact, even the words are being sent from your hard drive to this application.

The same is true on the Internet. Each time you call a page to your browser, every item on that page is sent from a server computer. General Bob sends you everything you see, hear or read.

There is, however, a special type of downloading. This is the deliberate requesting of a document or application.

For example: If you wish to download a InterMod Training Module from my Web Page you would do the following steps.

1. Request my home page using your browser http://www2.eis.net.au/~statham
2. Select the InterMod page from the available selections
3. Check to find the Module you required amongst the selection, and
4. Single mouse click on the Download button (or on the links).

This pattern is basically the same for anything you wish to download. Your browser then commences the transfer, and you go off to make a cup of coffee. If the download is large, you might wish to make dinner, or go to bed.

 

Things to Note

1. Your download will most likely be compressed when it arrives. This is the next topic.
2. Your download could arrive from a special section on a server called an ftp site, in which case the way it arrives, where it is stored on your hard drive when it arrives, and the display on the progress bar or download box on your browser while it arrives may not give you any information other than the fact that a download is taking place.
3. There may also be security issues to consider