Comp 101
Exploring the Internet
Dr. John G. Del Greco
Spring Semester 1996

Overview of the Internet

The Internet

Here are some basic facts about the Internet...
The Internet is a loosely coupled network of networks of computers located around the world. There are currently about three million computers connected to the Internet.

The Internet is like a library. Each book in the library is structured differently from all the other books (e.g., different subjects, organization, publishers, etc.). Despite these internal differences, each book can be found in a specific location in the library determined by its call number. So, if you are reading a book that refers to another book, you can look up that book's call number and find it on the shelves. Similarly, each network (in fact, each computer) on the Internet can be accessed by a unique address.

There are many different types of computers on the Internet! Technically speaking, computers on the Internet run different types of operating systems like DOS, Windows (NT, 3.11, '95), Unix, Macintosh, etc. So that all these different computers can communicate, they all use the same networking language called TCP/IP (Transfer Control Protocol/Internet Protocol). TCP/IP ensures that when two computers converse over the Internet, their conversation is complete, accurate and unaffected by hardware failures. In a sense, TCP/IP is the software that makes the Internet 'hang together'.

The Internet provides users with a variety of data processing services based on the client/server model. Internet users (like us) run programs on our local machines called client programs. These client programs send out requests for service. Computers on the Internet that are willing to process our requests run other programs called server programs. Server programs send back the desired answers to our requests over the Internet. As an example, one of the most popular Internet services is called the World Wide Web (WWW). The client programs for this service are called web browers. Popular browers include Netscape Navigator, Mosaic, WinWeb, Cello, etc. There are usually many different clients for a particular Internet service.

No one owns the Internet! The individual networks on the Internet are owned and maintained by government, educational and commercial institutions, but no entity owns the entire network.

Although no one owns the Internet, there are a number of oversight organizations like the ISOC (Internet Society) and the IETF (Internet Engineering Task Force). The ISOC is the main coordinating agency for other groups interested in the management of the Internet while the IETF sets the technical guidelines for how the Internet operates.

The Internet is not complete! It is continually evolving. The way it looks today may not (and probably won't) be the way it looks five years from now. Stay connected...

Internet Services

A wide variety of useful services are provided on the Internet. Some of them are described below...
Email (Electronic mail)
Email provides a method for the sending and receiving of electronic mail. Email is the most popular Internet service. Users can subscribe to specialized mailing lists on numerous subjects.

This service enables users log onto a remote computer (i.e., a computer geographically distant from the user) and work on it as though they were directly connected to the system on site. To log onto another computer, the user must have an account on that computer.

FTP (File Transfer Protocol)
FTP allows users to transfer files from one machine to another over the Internet. To download a file means to transfer a file from a remote machine to your local machine. To upload a file means the opposite. That is, to send a file on your machine to a remote machine. FTP is among the most useful Internet services.

Archie allows users to search computers on the Internet for files that they are interested in. After Archie helps you find a particular file, FTP can be used to transfer the file to your local machine (assuming that the file is not proprietary to that machine).

Usenet is a widely used Internet service that organizes users' comments by topic. These topics, called newsgroups, have their own structure with people commenting on previous comments and starting new discussions, called threads. Flame wars, heated (often vulgar) discussions between people, sometimes break out in newsgroups. In addition, this is were pornography exists on the Internet in various forms. Recently, there has been a lot of discussion about how to restrict access to this material by minors.

Gopher is a service that allows users to search for information using menus. Gopher displays all informataion as either a directory or file. Gopher also allows users to find specific data. Once a very popular service, Gopher has been overshadowed somewhat by another Internet service called the World Wide Web. The reason for the name Gopher is because the service was developed at the University of Minnesota.

Veronica (Very easy rodent oriented network-wide index to computerized achives)
Veronica is a service that perfoms keyword searches for files in 'GopherSpace' (all the information available through Gopher). Veronica outputs only the titles of files and directories that match the keyword. Veronica is a friend of Archie, of course!

WAIS (Wide Area Information Servers)
WAIS provides a method for creating and searching databases of information on the Internet. WAIS searches are keyword oriented. Databases are of varied types including email messages, text and electronic books, computer code, Usenet articles, email addresses, graphic images, etc.

World Wide Web (also known as WWW, W3, W3, the Web, etc.)
The World Wide Web is not the Internet! WWW is a service that is provided on the Internet. It is becoming increasingly important as time passes. WWW includes many of the services listed above such as Email, FTP, Telnet, etc. WWW is so popular because it enables the distribution of hypertext documents using a protocol called http (hypertext transfer protocol). Hypertext documents are called pages and contain links to other hypertext documents which permits a user to move easily from one (related) document to another. Hypertext is written is a special language, called HTML (HyperText Markup Language). Using HTML, web pages can be created. Users can establish a presence on the web by writing a page called a home page.

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