outline

The Changing Role of Computers

• How are they used?
  -powerful calculators
  -word processors
  -game platform
  -communication tool
  -etc.

Computer

• Prior to World War II, it was a human being who undertook complex mathematical calculations
• Early machines were used to calculate artillery firing tables and code breaking
• Today, computers still are used to do calculations, but the more frequent use if for communication

Computer Communication Evolution

• In 1943, Thomas Watson, then chairman of IBM, is reported to have said: "In the whole world there is a market for maybe 5 computers."
• During Mr. Watson's time, this might have been true - computers filled large rooms
  -they were expensive to build and maintain
  -they were difficult to program

Mainframe Computer

• A massive computer that could be used by many people at the same time
• Each person had their own keyboard and monitor
• The advantage of this was the computer was used as a communication medium

The Personal Computer

• The microprocessor was developed in the 1970's which initiated the personal computer
• Image changed from a huge room full of a computer to what you see on your desktop
• "Paperless office" was touted a potential benefit of computers - but paper remained the method of communication

Enter the LAN

• Local Area Network - combination of programs and hardware that connected a series of personal computers so the computers could communicate electronically
• LAN's were useful within an organization, but made transferring information outside the LAN a problem
• Not all computers store information the same way

The Internet

• Got its start at the heart of the Cold War (1960's)
• Research in computing was funded by the US military
• The military wanted a communications network that could tie several geographical locations together, but one that would not be affected if one location was blown up by the opposing side

TCP/IP
(Transfer Control Protocol/Internet Protocol)

• This took messages, broke them into packets and sent each packet separately to its destination
• If the path was blocked, the packets could find another route
• When the packets reached the destination, the packets were automatically re-joined

ARPANET
(Advanced Research Projects Agency Network)

• The network using TCP/IP to tie together the military computers
• Was later modified to include scientific and educational capabilities

NSF
(National Science Foundation)

• Control of ARPANET was absorbed by NSF which changed the name to NSFNET
• Commerce was strictly forbidden on the NSFNET

"Internet"

• Became popular during the 1992 US Presidential campaign
• The charter of NSFNET was changed to encourage personal and commercial use
• NSFNET (which is a US institution) joined forces with other large networks to for the Internet
• InterNIC - a consortium of private entities has what little control there is of the Internet

The Internet

• Global in scope
• Is not owned or controlled by anybody
• IAB - Internet Architecture Board helps to establish mutually agreed standards for Internet protocols

The Internet is NOT

• Centrally owned
• A single entity
• "Den of Iniquity"
• A hive of viruses waiting to attach your computer
• Not just for teenagers

What IS the Internet?

• A vast information source
• Relatively universal
• Dynamic - ever changing

The Problem

• How do we take advantage of the vast resource?
• How can we find the specific information we want?
• What types of problems can we solve by using the World Wide Web?

Tools

• World Wide Web
  - formats for storing, retrieving and transferring information on the Internet are called PROTOCOLS
• Each major protocol could be considered a tool, but we will concentrate on the World Wide Web
• The WWW protocol is different from other protocols

WWW Protocols

• Uses a model based on pages
• Designed to use hypertext
• Allows exploration without the user having to worry about which computer he will be accessing
• Is easy to use
• Very easy to create pages
• Designed to share information

Browsers as Tools

• Browsers use similar features that make navigation easier:
  -Location box
  -Navigation buttons
  -Menus
  -On-line help
• Commands within browsers are tools (previous page, home page, search, directory, etc.)

Protocols

• Are a series of agreements about how information will be shared and communicated between machines and networks
• Protocols are NOT the same as programs

TCP/IP

• Transfer Control Protocol/Internet Protocol is the underlying protocol of the Internet today

Telnet

• One of the earliest protocols
• Allows the user to access a remote computer
• Is an inexpensive protocol to implement and utilize, but uses plain text, no graphics

FTP (File Transfer Protocol)

• Designed to aid in copying information between computers through the Internet

Mail and News Protocols

• Protocols designed to transfer text from computer to computer
• SMNP
• POP

HTTP (HyperText Transfer Protocol)

• The World Wide Web is based on this protocol
• Integrates many of the other protocols
• Is designed with Hypertext in mind
• Encourages hypertext multimedia

DNS (Domain Name Server) System

• IP numbers - addresses
• Domain names - the "Name" for the IP numbers
  
• 
  

Subdomains

• Large Organizations
• Organizations apply to InterNIC for a particular subdomain name

UserIDs

• Often called login or userid
  -usually based on the user's name, often abbreviated and lower case letters

Passwords

• An important consideration of the Internet is security
• Passwords are a way to "lock" your computer
• Protect your password
  -change it regularly
  -consider combining words and numbers
  -don't use something simple that some can guess
  -don't use words in English, people can hook up spell checkers

How does this all work?

• Consider the tree structure
  -the smallest unit on the Internet is the individual user
  -LAN (Local Area Network) a network of computers within a department or floor of an organization connected together for ease of communication
  -WAN (Wide Area Network) LANs tied together within an organization

LANs and Routers

• Routers are designed to direct traffic between the LAN and the Internet
• Routers take the information you give it and uses TCP/IP to send the packet to other routers
• The packets are "routed" to the 'Information Super-highway' to the Internet Backbone
• Packets are transferred to other routers via the IP addresses until they find the correct destination

The Client-Server Approach

• Drive-thru restaurant example
  -You are the client ordering from the server (restaurant)
• The restaurant (server) waits for requests from clients (you at the drive-thru window), processes them and gives the results to the clients

Levels of Connectivity

• Direct connection
• Dial-in connection
• Slip-PPP connection
• Commercial service providers
• Proprietary Networks
  -Compuserve, Prodigy, America Online
• ISP (Internet Service Providers)

Email

• Uses the mail/news protocol
• Communication tool
• Email etiquette

Talk and Chat

• Allows a connected person to interact directly with another connected person by typing simultaneously and seeing the message

Mailing Lists

• Mailing lists are simple - contains an email address
  -Listserv
  -Majordomo
• Sign up using email to join the list
  -when sending a message to the list, all members of the list receive the message