Exploring the Internet
Dr. John G. Del Greco
Spring Semester 1996
Overview of 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...
A wide variety of useful services are provided on the Internet.
Some of them are described below...
- 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
- 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
- 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
- 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.