Diseases of the Ear

  
Computers
Modem
Telephone
Satellite
Censorship

 
How Things Work: Computers
Answers to common questions by University of Virginia Physics Professor Louis A. Bloomfield.
Complete Guide to the Internet
Fellow ThinkQuest '97 Project with extensive Internet information.
Electronic Privacy Information Center
Watchdog group for personal rights in the Information Age.

By the early ‘90s, commercial applications of the Internet appeared, especially on graphical online information services such as CompuServe and America Online. Today, more than 40 million people use the Internet everyday to communicate with others, conduct business transactions, and receive information easily and effectively.

Technology
Any computer can access the Internet, provided it has the proper hardware, such as a modem, and software support for TCP/IP (Transmission Control Protocol/Internet Protocol). TCP/IP is a standard system for directing network traffic. Every piece of information contains a TCP/IP header, that is read by computers to determine its destination, and routed in the proper direction.

Most home Internet users will use a dial-up software program that instructs their modem to connect, over the phone line, to another modem belonging to their ISP (Internet Service Provider). The ISP acts as a gateway to the network, allowing you to send and receive information. Once your dial-up program has connected, another piece of software, called a client, will be used to display the information you want. There are various types of clients to provide many different services, such as e-mail, World Wide Web, and FTP. To get information, you tell the client what you want. For instance, if you were going to see if you had any electronic mail, the e-mail client would find the server (large computer that provides information to Internet users) that stores your messages, and request permission to download them. The information in your virtual "mailbox" will travel from the server to your computer, where you can view and respond to the messages. The server is always connected to the network, so mail can be sent to you even when you aren’t online (connected to the Internet).

Addresses
Every computer connected to the Internet has a special locator, called an IP address, so other computers can send it information. This address consists of four three digit parts, each numbered between 1 and 255, separated by a period, such as 243.13.3.158. To make the Internet easier to use, a word based address can be used in place of these numbers. The address follows specific guidelines.

First, there is the scheme, an indicator of what type of service the address is for. If you are accessing a web page, you would type http:// (http stands for Hypertext Transfer Protocol), or if you were connected to an FTP server you would type ftp:.

Next you’ll find a similar code for what type of service you are accessing on a single server. This is particularly useful to ISP’s who offer multiple services. A Web page might begin with www., while a gopher site might start with gopher., and so on.

Then you’ll have the name of the organization who owns the server. If you wanted to access a website for Microsoft, you would type http://www.microsoft.com.

The last part of the address tells what type of organization owns the server. In Microsoft’s case, it is a commercial organization, so they add the .com extension. A University would add one for education (.edu), while someone from a country, such as Canada, would have a two letter abbreviation for their country, such as .ca.

Of course, not all addresses have all of these components, and e-mail addresses are radically different. To send someone a letter, you type their user name (also called an alias, which they select when they open their account on the mail server), followed by an @ sign, proceeded by the name of the company and their extension. To send e-mail to Krista Johanson, one of the people who created this site, you would type johanson@fox.nstn.ca. Johanson is her user name, .nstn is the company that provides her with Internet service, and .ca indicates she comes from Canada. The "fox" part of the address simply refers to the actual name of the server NSTN keeps her mail on.

Services
The Internet has dozens of specific services for communicating with others and accessing information. Here are some of the most popular:

Gopher: a type of server that lets users create, search, and view file directories. It allows anyone to view any file available on the server.

World Wide Web: WWW has almost eliminated the usage of gopher services. It allows people to view documents in HTML (Hypertext Mark-up Language). This document format allows the inclusion of other electronic objects, such as pictures, sounds, and animations. It also allows the writer to create links out of photos and text. Whenever a user "click" on that piece of text or photo, they will be automatically transported to another piece of information, such as an additional HTML page, or an e-mail address. The Web has made the Internet engaging and easy to use, resulting in its popularity. The World Wide Web is accessed using a web browser, such as Netscape’s Navigator or Microsoft’s Internet Explorer.

Electronic Mail: or e-mail, allows you to send and receive electronic messages. You simply type a message on your keyboard, address it to another e-mail user, and click Send. You can even attach files to the message, or send the same message to hundreds of people instantaneously. E-mail is the most popular service on the web, and has revolutionized office communications.

File Transfer Protocol: allows you to connect to an FTP server anonymously and transfer files between your computer and the server. This is particularly useful for getting new software programs without purchasing them on disc.

Usenet: or newsgroups, is similar to a public Bulletin Board. You post a message on the group for everyone to read. You can even carry on a conversation by posting back and forth, without having to be on the computer at the exact same time as the other participants.

IRC: or Internet Relay Chat, allows you to connect to a chat server and "talk" with hundreds of other people by typing messages on your keyboard. Various "rooms" are available to discuss certain topics with interested people. This service is being succeeded by new technologies like video conferencing, which allow you to see who you are talking to, and talk into a microphone instead of typing your messages.

All of these services are available to anyone with normal Internet Access. Some companies bundle all of these services into a single easy to use system called an Online Service. These are independent networks such as America Online, CompuServe, and The Microsoft Network. Only people who subscribe to these services (paying a monthly fee) can access them, but all of these services allow their customers to use the public Internet as well. While not as large and free as the Internet, online services are popular with consumers because of their ease of use and added value features, like regular chats with celebrities.

Cyber-Freedom
The great thing about the Internet is that nobody owns it and there are no rules. People from all over the world control and develop the technology, and generally self-govern any problems. This allows people to do what they want, and say what they want easily and effectively. Some people feel this freedom of communication is too much. Many governments want to censor and regulate what can be accessed on the Internet, and many users have been outraged at the attempts. But it does cause many problems. Information that normally isn’t accepted in some areas is readily available to anyone with an Internet account, and because convicting someone of committing a crime when it occurred in "cyberspace" (a popular term used to describe the Internet), it is difficult to prosecute criminals who break local laws on the Internet.