The word “internet” is short for INTERCONNECTED NETWORK.  The Internet is a specific worldwide collection of networks. A large collection of computers all over the world - connected together.  Using e-mail on the Internet, you can communicate with people throughout the world.  “E-mail” is short for “ELECTRONIC MAIL


WORLD WIDE WEB is the part of the Internet where the computers are connected in a specific way that makes those computers and their contents accessible to all the other connected computers.


COMPUTER NETWORKS – The computers in the computer lab are connected to each other by inserting a network interface card into each computer and then connecting cables from each card to the lab’s SERVER. The Server accepts requests from other computers connected to it and shares resources such as printers, files and programs. This is called a CLIENT/SERVER NETWORK. The special software is called a NETWORK OPERATING SYSTEM.





During the 1960s, the Department of Defense became concerned about the possible effects of nuclear attack. It realized that the weapons of the future would require powerful computers for coordination and control.


The DOD created a network of networks. It is designed to look like a spider so that if any node on the network was destroyed, data could be routed through a different channel.


Because the computers during the 1960s were all large mainframe, the task was enormous. The DOD had to examine various ways to connect these computers to each other  - and to all the weapons installations around the world.


The agency in the Department charged with this task was the ADVANCED RESEARCH PROJECTS AGENCY.  Referred to as both ARPA and DARPA. The agency hired the best communications technology researchers and funded research at leading universities.


Initially, the networked computers were linked over telephone lines. Once the connection was established, the data traveled along that single path and the telephone company’s central switching system selected specific telephone lines (circuits) that would create the single path. This centrally controlled, single-connection method is called CIRCUIT SWITCHING.


DARPA used PACKET SWITCHING. In a packet switching network, files and messages are broken down into packets that are labeled electronically with codes indicating their origin and destination. The packets travel from computer to computer until they reach their destination. The destination computer reassembles the data. Each computer that a packet encounters on its trip through the network determines the best way to move the packet forward to its destination. The computers along the way are called ROUTERS.


In 1969, DARPA connected the first computer switches at the University of California at Los Angeles, SRI International, the University of California at Santa Barbara, and the University of Utah. The connection was called ARPANET, and grew over the next three years to include over 20 computers and used the NETWORK CONTROL PROTOCOL (NCP).



PROTOCOL is a collection of rules for formatting, ordering, and error-checking data in a network.



INTERNET PROTOCOL (IP) ensures that all computers on the network will be able to communicate with each other – regardless of their brand name or operating system. (Transparency)



TRANSMISSION CONTROL PROTOCOL (TCP) converts messages into streams of packets and reassembles them. This is similar to sending a letter that gets cut up into little pieces when you mail it, each piece traveling a different route, and yet arriving at its address whole.


In 1972 a program was written that could send and receive messages over the network. E-MAIL was born and grew quickly.



FILE TRANSFER PROTOCOL (FTP) allowed users to transfer files between computers, and TELNET let users log in to their computer accounts from remote sites. The first e-mail mailing lists also appeared on these networks. This was not e-mail as we know it today... (A MAILING LIST is an e-mail address that takes any message it receives and forwards it to any user who has subscribed to the list.)


In 1979, a group of students and programmers at Duke University and the University of North Carolina started USENET (User’s News Network). Usenet allows anyone that connects with the network to read and post articles on a variety of subjects – the forerunner of CHAT rooms.


Researchers at the University of Essex wrote a program that allowed users to assume character roles and play an adventure game. This game let multiple users play at the same time and interact with each other. Today, these games are called MUDs (originally this stood for multiuser dungeon.)





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