1. Internet and World Wide Web: Amazing Developments Internet- A large collection of computers all over the world that are connected to one another in various ways

2. The Internet can be used to: e-mail (electronic mail)- Communicate with other people throughout the world access articles (e-zines)- Read magazines, newspapers, and books online join discussion groups- Discuss virtually any topic online participate in games and simulations obtain free software (downloads)

3. World Wide Web- A subset of computers connected to the each other on the Internet that allow users easily access other computers in that subset.

4. Computer Networks Computers can be linked together to form an network by inserting a network interface card into each computer and connecting them to the server with a cable. Network Interface Card (NIC)- A device used to connect a computer to a network.

5. Server- Any computer that accepts requests from other computers (called clients) that are connected to it. The server runs software that allows the computers to communicate with each other. This software is called a Network Operating System.

6. Server (Cont.) This network is called a Client/server network and is used to connect computers located very close together. This type of connection is also called a local area network (LAN) because the direct connection from one computer to another only works over short distances. Computers in a network can share printers, files, software and other equipment.

7. Different cable types are used to connect networks. Twisted-pair- The oldest type of cable which telephone companies have used and is the slowest and least expensive cable (has been improved to b e faster than coaxial cable). Coaxial cable- Carries signals 20 times faster than traditional twisted-pair cable and is the cable most cable television connections use. Fiber-optic cable- Transmits information using beams of light through small strands o f glass (fastest and most expensive connection).

8. Wireless Networks Wireless Networks use wireless transmitters and receivers that plug into NICs. These networks are especially useful in older buildings which lack appropriate wiring.

9. Wide Area Network Wide Area Network (WAN)- An interconnected network of networks (internet). This WAN may also be connected to the Internet (a collection of interconnected networks whose owners have agreed to share resources.

10. How the Internet Began In the 1960's the Department of Defense (DOD) began examining ways to connect computers around the world to each other. Advanced Research Projects Agency (ARPA) was set up to accomplish this task. Early models for networked computers were the telephone companies with a single connection between sender and receiver called Circuit switching

11. Packet switching With Packet switching network files are broken down into packets that are labeled electronically with codes for their origin and destination. The packets travel from c omputer to computer along the network until they reach their destination. Routers are computers that determine the best way to move the packet forward to its destination.

12. Open architecture philosophy Open architecture philosophy- each network could continue using its own protocols an d data-transmission methods internally.

13. Protocols Vincent Cerf and Robert Kahn developed the Transmission Control Protocol and the Internet Protocol (TCP/IP). In the early 70s Ray Tomlinson wrote a program that could send and receive messages over the network and e-mail was born. TCP/IP protocols included Rile Transfer Protocol (FTP) and Telnet

14. History (cont.) In the 1980s the ARPANET and other networks continued to grow and in 1984 ARPANET was split into ARPANET (would continue its advanced research activities) and MILNET (would be reserved for military uses). As PCs became more powerful and affordable, firms increasingly used them to construct LANs. Today we use the term intranet to describe LANs or WANs that use the TCP/IP protocol.

15. Growth of the Internet A formal definition of Internet was adopted in 1995: In 1991, the NSF began implementing plans to privatize much of the Internet. The estimate of Internet users is probably underestimated because:

16. Popularity of the Internet There are over 20 million connected computers and between 50 and 150 million users on the Internet today. Opening the internet to businesses help motivate its growth. Additional motivations were Hypertext and Graphical User Interfaces.

17. World Wide Web Hypertext is a method of allowing text in one document to point to other text in that or another document. T im Berners-Lee developed the code for this hypertext server program and made it available on the Internet. Most people use a Web Browser (Microsoft Internet Explorer or Netscape) which is software that lets users read documents and move from one document to another.

18. Browsers Created In 1994, Andreessen joined Silicon Graphics to found Netscape. Microsoft created its Internet Explorer Web browser soon after.

19. Connection Options Organizations and businesses provide Internet access to other businesses and individuals. These firms who provide access are called Internet Service Providers (ISPs). ISPs usually provide: – Software needed to connect to the ISP – Web browsing and e-mail software – Other functions such as file transfer, remote login, consulting, and web design

20. Connecting Through Your School or Employer One of the easiest ways to connect to the Internet is through your school or employer. Most colleges are connected and may offer Internet access to their students, faculty, and other employees.

21. Connecting Through and Internet Service Provider When you shop for an ISP inquire about the following: – Monthly fee and number of hours included – Hourly rate for time over the included time – Is the telephone access number local or long distance – What Internet services are included – Are user-support services available

22. Connecting Through Your Cable Television Company Cable television connections have a very high bandwidth (up to 170 times faster than a telephone line connection) but may cost more than twice that of an ISP. The greatest disadvantage is that cable connections are not available everywhere.

23. Connecting Via Satellite Connections can now be established via satellite (downlink only). Satellite connections are 5 to 10 times faster than telephone connections. May be the only option for those in remote areas