"The World Wide Web (W3) is the universe of network-accessible information, an embodiment of human knowledge. It is an initiative started at CERN, now with many participants.
It has a body of software, and a set of protocols and conventions. W3 uses hypertext and multimedia techniques to make the web easy for anyone to roam, browse, and contribute to." -- Tim Berners-Lee URL: http://www.w3.org/pub/WWW/WWW/
A tour of a few sites.
How the WWW Works
The WWW project was started to give a single means of access to the services and resources on the Internet.
You access the WWW by using a program called a web browser.
You use a broswer to contact or access a site on the WWW. The
item you retrieve is called a Web page. The
starting point for a particular site or person is called a home
page.
Some common Web browsers are
service://internet-name-of-server/full-path-name-of-resource
There are essentially two ways of going about it: Directories and Search Tools (search engines).
Two popular directories are
In addition to browsing through a list of topics, many directories allow keyword searches.
With these: You type in a keyword or phrase
Then: The program searches a database of resources on the WWW (or other portions of the Internet)
Finally: The results are presented as a list of hyperlinks, ranked in order of relevance.
Two popular sites for searching are
The Internet is used by millions of people throughout the world. Its used for communication, person to person or in groups. It's used to share information either in a passive way with archives or libraries of information, brochures, documents, or in an active way by making programs available for others to access. It's also used to share computational resources by giving users on one system on the Internet access to programs and databases. Its used to search for and retrieve information on all sorts of topics in a wide variety of areas including the arts, business, government, humanities, news, politics, recreation, and all areas of the sciences. It's used to disseminate news and other information. It's used for commercial transactions. This is no surprise since the Internet was crated as a means to share information. It is, after all, a network.
We can apply these same methods of interaction, distributing information and communication to any activity: training, learning, recreation, or business.
The World Wide Web (WWW) is a part of the Internet, but it's not a collection of networks. Rather, it is information that's connected or linked together, like a web. You access services and resources, basically, through one interface or tool called a Web browser.
There are over 20 million users of the WWW and more than half the information that's transferred across the Internet is accessed through the WWW. Through a computer to terminal connected to a network which itself is connected to the Internet, and through the use of a program to browse and retrieve information that's part of the World Wide Web users have access to a wide variety of services, tools, information, and opportunities.
All this activity is possible because tens of thousands of networks are connected to the Internet and exchange information in the same basic ways.
What is the Internet? We'll look at it from three points of view.
The Internet is a network of tens of thousands computer networks. These computers and networks communicate with each other by exchanging data according to the same rules or protocols, even though the networks and computer systems individually use different technologies.
How It Works
The Internet is a network connecting thousands of computer networks.
Each network on the Internet has a unique address, and the computer systems making up a network have an address based on the network's address. At a basic level the addresses are numeric, a sequence of four numbers separated by periods. An example is 192.65.245.76. You don't need to memorize numeric addresses, they can also be specified as names such as www.mwc.edu.
The Internet is a packet-switched network. Networks on the Internet agree to communicate by the Internet protocol (IP).
The networks on the Internet use hardware or a device called a router to communicate with other networks.
Information is broken into packets and each packet contains the address of the destination and the address of the sender. The packets are passed from one network to another until they all arrive and are reassembled into a message. As a packet is passed form one network to another network, a device called a router decides whether to accept packet or pass it on to another. Once it's accepted within a networks, it's the network's job to get it to a specific computer system.
Note that a packet is examined by several routers before it gets to its destination. This is a potential security problem. Also, packets can be forged, another problem.
The Internet is designed so the computer systems within one network can exchange information with computers on other networks. The rules that govern this form of communication are called protocols. Using the same protocols allows different types of networks and computer systems to communicate with each other.
This means a computer system or network has to be able to transform information from its own form into the form(s) designated by the protocols, transform information from the protocol's form to its own form, and it has to be able to send and receive information in that form. Two protocols used are Internet Protocol (IP) and Transmission Control Protocol (TCP). You'll often see these mentioned together as TCP/IP when dealing with the software needed to make an Internet connection.
As an example suppose we want to transfer a file or e-mail message from your home site to a computer in Hong Kong. The software at your site takes the file and puts in into packets with the address of the destination as part of the packet. Each packet is transmitted form your network on to another, and that network may pass it on to another, and so on until a packet reaches the destination network. The router at that network accepts the packet and delivers it to the final destination. Not all packets need take the same route and they may not arrive in order. it's up to the Internet software at the destination to make sure all the packets have arrived and to put them in order. The Internet protocol (IP) specifies the rules for moving packets form one site to another and another protocol, Transmission Control Protocol or TCP makes sure the packets have arrived and the message is complete.
Each computer system with a direct connection to the Internet has to have the hardware and/or software to allow it to work with packets. This usually means either a network card with TCP/IP software is in the computer you use or get a direct connection by using PPP (Point to Point Protocol) or SLIP (Serial Line Internet Protocol) software and a modem. If you're using a modem, but not using PPP or SLIP then you probably don't have a direct connection to the Internet, but you're contacting one which does.) It's up to the individual computer systems to take care of sending and receiving packets.
Domain Names and Addresses
Each node on the Internet has a numeric address called its IP address. Additionally most sites also have a name called the fully qualified domain name. These names are usually 3 or 4 strings separated by dots (periods). The names are associated with numerical IP (Internet Protocol) addresses
Domain Name IP Address oregano.mwc.edu 192.65.245.77 nssdca.gfsc.nasa.gov 128.183.10.4 askhp.ask.uni-karlsruhe.de 192.67.194.33
These domain names are part of an e-mail address and also used to access Internet services and resources.
To send electronic mail to someone you need to know their Internet address. For nodes that are directly connected to the Internet this address is usually
login-name@domain-name
To access an Internet service or resource you usually start a program, for example, a Web browser such as Netscape Navigator, and give the address of a remote site or service that will interact with the program you start.
Access to Internet services and resources is specified as a URL or Uniform Resource Locator. Some examples are
gopher://twinbrook.cis.uab.edu
http://www.mwc.edu/ernie/lrn-net.html
http://www.newslink.org/newspapers
http://update.wsj.com/update/edit/frontpg.html
http://yoda.unl.edu/Network.html
http://www.sec.gov/rulemake.htm
Be careful that the names you type are correct in terms of upper or lower case of letters, spelling, and punctuation.
The most general form of a URL is
service://doman-name-of-site-supplying-service/full-path-name-of-item
Client-Server
Many of the services and resources available on the Internet operate according to a client-server model. You run a program on your computer to access information on a remote system. The program on your computer, such as a Web browser acts as a client, accepting your input and then passing it on to the other system which is running a program that acts as a server. That is, it accepts requests form clients, acts on the request, and then send a response. The response then goes to the client which processes the response and presents it to the user.
When you start a Web browser the browser often presents in formation in a window. That information may be on your computer or may come from a remote site. The information comes to it in a specific format and the client displays it. You select an item or type in a URL and your program then uses the information in the URL to contact the appropriate server. The server receives the request and passes some information back to he client which then displays it for you in its window. For Web browsers this is done through one of several protocols, the most common one being HyperText Transfer Protocol or HTTP.
HTTP is what's used to allow access to the World Wide Web (WWW). You have a hypertext, hypermedia interface to all the services and resources on the Internet. This is done through a graphical interface where you select items with a mouse, click the mouse button, and access the resource.
Other client-server applications or protocols you're likely to see are
FTP
File Transfer Protocol, allows for transfer of file form one site to another (regardless of the format of the file.
Telnet
A remote login facility. The Telnet protocol allows a user at one computer to login to another on the Internet, and use resources on the remote system as if he were hard-wired or directly connected to that system. But, it's not a direct connection; a virtual terminal session is created. Remember, everything is passed as packets.
Gopher
A menu based document delivery system. Users can access various types of information such as files, documents, address books, and images. Also allows access to FTP, Telnet, and searchable data bases.
WAIS
Wide area Information System. A user form one location can search databases dispersed on the Internet.
Several client programs may exits and be used on a one computer and each can contact and interact with server programs throughout the Internet.
Getting Connected
In order to access the Internet you need hardware and software to become connected to a network as an Internet site-called an IP connection.
You need the software/hardware to be able to exchange packets with the systems on the Internet. This gives you a connection that allows you to work with the Internet in both a text and graphical mode. This is done in essentially two ways: a direct connection to a network from your computer which has a device installed called a network card with TCP/IP software, or a dial-up connection where your computer has a modem and software for SLIP or PPP. With either of these you've got access to all the services and resources on the Internet.
With either of these types you're able to take advantage of the graphical interfaces tot he Internet and World Wide Web (WWW).
The Internet is a vast collection of information that can be searched an retrieved electronically. This includes advice on all sorts of topics, data, electronic texts, government information and data, images, museum exhibits, scholarly papers, software, and access to commercial activities.
There is a staggering amount of information on a wide variety of topics on the Internet. Some of it is very practical; it can be used for business, research, study, technical purposes, and access to the services and information provided by professional organizations. This includes documents, government information, data, on-line bibliographic searches, articles, publications, and software.
There is an increase in the use of the Internet for commercial applications. This includes researching and using financial and economic data, business applications such as marketing and buying items of all types, and making services available for a fee.
Other types of information include travel recommendations and news, medical and health information, weather reports, entertainment listings, library holdings, museum exhibits, and sports news. You're able to tap into university and other libraries throughout the world, museums, commercial publications, archives of software for many different types of computer systems and databases of information.
Almost all of this information is shared free of any charges except what you pay to access the Internet. Sharing information and resources is at the basis of the Internet.
Carrying on secure business transactions on the Internet, is becoming more commonplace. One of the fastest growing sectors of work on the Internet is in the area of commercial applications. As Internet use becomes more available and common, it's being viewed as a viable means of doing business and marketing.
Through the WWW you can find information about all sorts of products, information about health and environmental issues, government documents, and tips and advice on recreational activities such as camping, cooking, food, gardening, and travel. A little bit of exploring will show you the wide range of information and types of information available.
A few starting points.
From a social point of view:
The Internet is millions of people communicating, sharing ideas and information. They communicate electronically on a on-to-one basis or in groups.
Folks communicate with each other through e-mail. To do this you need a program that can send and receive e-mail. The mail is sent and received using Internet e-mail addresses.
An individual's address has the form
local-address@domain-name
Where local-address is often a user's login name.
For example:
ernie@oregano.mwc.edu
hostmaster@internic.net
postmaster@any-domain-name
Sometimes you'll see addresses of the form
coco%jojovm.bitnet@brownvm.brown.edu
coco%jojo.ffolo.edu@vm.tcs.tulane.edu
In these cases the local address is handled by a gateway through the domain name to the right of the @. A gateway is a system that provides information transfer between the Internet and another type of network.
There are lots of folks who make their presence known, tell something about themselves by creating personal Web pages. These are documents that can be displayed on the world wide web and tell about the individual. Some examples:
http://www.mwc.edu/ernie/index.html My Web or Home page
http://www.mwc.edu/dmang5fe/index.html A student's Home page
http://www.atg.apple.com/personal/Tom_Erickson/default.html Researcher's Home page. Look for the hyperlink "The World Wide Web as Social Hypertext"
With so many people having access to e-mail it's reasonable that groups are formed to discuss certain topics. There are over 6,000 such groups on all sorts of topics. Individuals exchange information with a group through electronic mail. To find interest groups take a look at
Usenet stands for "User's Network". This was started independent of the Internet. The information is called news, a collection of "articles" arranged into newsgroups. Information is exchanged between computer systems, with individuals selecting the newsgroups and articles to read or post. Very little control on topics or content. Individuals use software called a news reader to read and contribute to the information available through Usenet. TO take advantage of these you need access to a server called a news server. To see the variety of newsgroups available use the URL
To use a public newsserver look at
Yahoo News:Usenet:Public Access Usenet Sites
Materials prepared by
Ernest Ackermann, Mary Washington College.
Professor of Computer Science.
E-mail Address: ernie@mwc.edu
Home Page: http://www.mwc.edu/ernie/index.html
Phone: 540-654-1320
Author of Learning to Use the Internet, ISBN 0-938661-92-2. Published by Franklin Beedle & Associates (1-800-FBA-BOOK),
8536 SW St. Helens Drive, Suite D, Wilsonville, Oregon 97070.