Vol. 4, Issue 6, Nov/Dec 1996	Previous Issues Subscribe to AT Messenger Download PDF Viewer
	PDF (for printing) Large Print (pdf) Text Version

The Internet: A Trip into Cyberspace

by Michael Meyreles
Rehab Engineer, New Castle County ATRC

The Internet-what is it? The Internet is a mystery to many people as well as an intricate part of daily life to many others. This article will discuss what the Internet is, the parts of the Internet, and how to connect to the Internet.

The Internet can trace its beginnings to the late 1960s when the U.S. Department of Defense began an experimental network allowing scientists to communicate with each other. This beginning network consisted of four computers, three located at different locations in California and one located in Utah. Today, the Internet is a worldwide "network of networks" that can communicate with each other. Each of these networks has been developed and maintained either by organizations such as government agencies, educational institutions, major corporations, and commercial on-line services like America Online and CompuServe, or by individuals from the privacy of their homes.

With so many networks and computers connected to each other, a common language or protocol was developed to allow communication between computers. This protocol is called Transmission Control Protocol/Internet Protocol (TCP/IP). TCP breaks the information into small chunks called packets that are transferred from computer to computer. For example, a single document may be broken down into numerous packets, each containing parts of the document, as well as the destination address. The destination address is the IP part of the protocol used for communication.

Communication between computers is accomplished with a modem. A modem is a device that connects a computer to a data transmission line, typically a telephone line. A modem acts like a translator; it converts the digital information to an analog signal to be transmitted over a standard telephone line. The modem transmits data as bits, the smallest representation of computer information, over telephone lines at speeds (baud rate) up to 28,800 bits per second (28.8Kbps.) Standard modem speeds range from a baud rate of 2400bps to 28.8Kbps, but there is a newer type of modem that takes advantage of a digital telephone service. This service is called ISDN (Integrated Services Digital Network). With an ISDN telephone line and an ISDN modem coupled to a computer with the appropriate software, a person can connect to the Internet at 56Kbps. Standard modem prices range up to approximately $200, while ISDN modems can cost up to $600. Also, there is an additional cost of adding an ISDN telephone line.

There are many components that make up the Internet. The most popular is the World Wide Web. Other components include E-Mail, File Transfer Protocol (FTP), Gopher, and Usenet Newsgroups. Client software is the term used to describe the software applications needed to access the different parts of the Internet. There is a wide variety of client software available to browse the World Wide Web, send E-Mail, and download files via FTP.

The World Wide Web is a network of computers from all around the world that are connected through the Internet. These computers or servers contain files that can be accessed by any other computer-located anywhere in the world-if that computer has the necessary software, usually called a web browser. Three specifications are needed to connect servers with client software: URL-Uniform Resource Locator, HTML-HyperText Markup Language, and HTTP-HyperText Transfer Protocol. When a person connects to the World Wide Web, a home page or document is loaded into the browser. This page can contain graphic, sound, and text files. It also contains links to other World Wide Web pages. The URL is the address of a document on a network server. HTTP is the protocol in which both the client software and the server can communicate. The document itself is coded in HTML, which allows the browser to identify the elements of the document and then render it.

E-Mail (electronic mail) is a popular way for persons to communicate over the Internet. E-Mail operates in much the same manner as the U.S. Postal Service. When a letter is drafted and sent out using the U.S. Postal Service, the letter is passed from one post office to the next until it reaches the town in which the person lives, at which time it is delivered right to the person. When a message is composed, an E-Mail client software package will send the message from one server to the next server until it reaches its final destination. This means that the sending machine and the receiving machine do not have to be directly connected. The E-Mail address determines whether or not an E-Mail reaches its final destination. For an E-Mail to reach its destination, the address entered in the TO: portion of an E-Mail must precisely match the receiver's address.

FTP stands for File Transfer Protocol and this protocol is used when a person wants to download a file from a remote computer to his/her own computer, regardless of where the two computers are located, how they are connected, or whether they are using the same operating system. FTP was designed originally to let persons access files on computers where they maintained accounts. Anonymous FTP provided a mechanism for persons wanting to access the broad range of public access databases and services.

Gopher is a tool used for browsing enormous amounts of information. It can be likened to a huge menu system for the Internet. Organizations and individuals from all over the world have set up Gopher servers with menus that can be accessed. While using Gopher client software, a person can search many databases using one or two keywords to quickly obtain the needed information. This information can be text, binary executable, graphic, or sound files.

Usenet was started as an experimental bulletin board system at the University of North Carolina in 1979. Usenet Newsgroups now number in excess of 16,000. These Newsgroups are a large collection of discussion groups about specific topics which involve millions of people from all over the world. Chances are, if you have a topic that you are interested in, there is a Usenet Newsgroup discussing that particular subject.

Connecting to the Internet can be accomplished in one of two ways. First, the large commercial on-line providers, such as America Online and CompuServe, allow persons easy access to the Internet. This is accomplished using their software and having your computer dial into one of their many local servers located throughout the country. These commercial providers offer many other services in addition to furnishing an on-line ramp to the Internet. These services typically have a free trial period of ten to fifteen hours of use, after which a monthly fee is charged. A set amount of free access time per month is available through these commercial providers, but once this time is used, an hourly charge is then assessed. The second way to access the Internet is by securing an account with a local Internet Access Provider (IAP) and using one of the many client software packages available. Examples of popular client software include Netscape Navigator, NCSA Mosaic and Eudora E-Mail. An IAP typically charges a monthly fee, which is usually somewhat more expensive then America Online or CompuServe, but it generally allows unlimited access time on the Internet.

The Internet is the network of networks connecting millions of people from all over the globe. It can be major corporations conducting business, it can be universities performing vital research, or it can be a person searching for a new recipe or looking for a new computer game to play. Gaining access to the Internet can be a challenging undertaking. If you need any information about gaining access to the Internet or just have questions regarding the Internet, contact your local ATRC.