Communications, Networks, the Internet, and the World Wide Web

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COMPUTERS IN THE CLASSROOM CT 243
Emery Roth eroth_at_hartford.edu http//uhaweb.hartfo
rd.edu/eroth/
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CHAPTER 2Communications, Networks, the Internet,
and the World Wide Web
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http//www.scsite.com/tdc2/
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QA
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What are the two main categories of software
and how are they different? (1.13-1.14)
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What are the National Educational Technology
Standards for Teachers (NETS-T), and where do
they come from? (1.19-1.20)
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What is a motherboard, and what are its two
main components? (1.08)
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What are 5 components of a computer? and give
examples of each. (1.07-1.10)
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What is, the Internet, and what are several
ways it is useful for teachers? (1.17-1.18)
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http//www.scsite.com/tdc2/ Click on Chapter
1 From the menu on the left, select Integration
Corner, then chapter 1 Scroll to any level of
personal interest explore one resource
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PROCESSING YOUR CLASSMATE SKETCHES

• Gather by teams to regroup
• Read at least 3 sketches.
• Select group recorder (WP).
• Process
• I really liked
• I learned to
• How do I?
• Publish???

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To publish or not to publish
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(No Transcript)
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Drawing Tablet

• pressure-sensitive
• designed to work with software applications that
  simulate real artists media

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spreadsheet
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ASSIGNMENT posted on blackboard web site
Web site http//uhaweb.hartford.edu/eroth/
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CHAPTER 2Communications, Networks, the Internet,
and the World Wide Web
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Objectives

• Define communications
• Identify the basic components of a communications
  system
• Describe how and why network computers are used
  in schools and school districts
• Explain how the Internet works
• Describe the World Wide Web portion of the
  Internet
• Specify how Web documents are linked to one
  another
• Explain the use of Web browser software
• Explain how to use a Web search tool to find
  information
• Identify several types of multimedia products
  available on the Web
• Explain how Internet services such as e-mail,
  newsgroups, chat rooms, and instant messaging
  work
• Describe how to connect to the Internet and the
  WWW

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Communications Networks

• Communications - refers to the transmission of
  data and information between two or more
  computers using a communications channel such as
  standard telephone lines
• Communications network - is a collection of
  computers and other equipment organized to share
  data, information, hardware, and software
• Communications software - programs that manage
  the transmissions of data between computers
• Communications channel - is the path the data
  follows as the data is transmitted from the
  sending equipment to the receiving equipment in a
  communications system.

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Communications Networks Continued

• Transmission media - is the physical materials or
  other means used to establish a communications
  channel
• Twisted-pair cable - consists of pairs of
  plastic-coated copper wire twisted together
• Other examples (coaxial cable, fiber-optic cable,
  microwave transmission, communications
  satellites, and wireless transmissions

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Communications Networks Continued

• Digital signals - are individual electric pulses
  that a computer uses to represent data
• Analog signals - continuous electrical wave used
  for telephone transmission and other devices
• Modem - converts analog signals into digital
  signals
• Network interface card (NIC) - connects computers
  directly to a school or business network without
  using a modem

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Types of Networks

• Local area networks (LAN) - is a communications
  network that covers a limited geographical area
  such as a school, an office, a building, or a
  group of buildings
• Wireless LAN (WLAN) - uses no wires, instead it
  uses wireless media, such as radio waves.
• Wide area networks - covers a large geographical
  region and used regular telephone cables, digital
  lines, microwaves, wireless systems, satellites,
  or other combinations of communications channels.
• Home networks - if you have multiple computers in
  your home or home office you can create your own
  network

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History of the Internet

• ARPANET - Advanced Research Projects Agency
  Network
• allow scientists to share information
• parts could function even if some of it went down
• Established 1969 and by 1984 it had 1,000 hosts
• In 1986 NSFnet joined together with ARPANET to
  serve as the backbone of the Internet
• In 1995 NSF turned over responsibilities to major
  corporations
• Internet2 - extremely high speed network that
  will develop and test advanced Internet
  technologies for research, teaching, and learning.

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How the Internet works

• Step 1. Data is divided into small pieces, called
  packets.
• Step 2. Packets travel over the Internet via
  routers.
• Step 3. At the destination, the packets are
  reassembled into the original message.
• Packet switching
• TCP/IP - transmission control protocol/Internet
  protocol - protocol used to define packet
  switching

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ISP vs. OSP vs. WSP

• Internet service provider (ISP) - allows you to
  connect to the internet for a fee. (ex. Netzero,
  ATT)
• Online service provider (OSP) - allows you to
  connect to the internet and also provides other
  personalized options for a higher fee than an ISP
• Wireless service provider (WSP) - allows users to
  connect to the internet without any wires. (ex.
  Palm)

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Ways to Connect to the Internet

• Dial-up access - you use your computer and a
  modem to dial in to the internet. (56k)
• Cable modem - you use your existing tv cable and
  a cable modem (20-50 x faster)
• Digital subscriber line - you use digital phone
  lines and dsl card. (25-150 x faster)

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Internet Backbone

• Step 1 Request a web page from your home
  computer
• Step 2 Modem converts digital to analog
• Step 3 Data travels through telephone lines to
  local ISP
• Step 4 Data may travel through 1 or more routers
• Step 5 Regional ISP uses lines, leased from a
  telephone company, to send data to a national ISP
• Step 6 A national ISP routes data across the
  country to another national ISP
• Step 7 Data moves from a national ISP to a local
  ISP to a server that contains the requested site
• Step 8 The server requests the data and sends it
  back through the internet.

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Internet Addresses

• The Internet uses addresses the same way the post
  office does. Each computer has a specific
  numeric address.
• I.e. 137.49.1.150
• Domain name - the text version of a computer
  address
• Domain abbreviations - .com, .edu, .gov, .mil,
  .net, .org, .k12
• Country abbreviations
• Au - Australia CA - Canada UK - United Kingdom

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World Wide Web

• The Web - consists of electronic documents that
  have built in hyperlinks to other related
  documents
• Hyperlinks - allow users to navigate quickly from
  one page to another
• Web page - electronic document viewed on the Web
  that can contain audio, video, text, etc.
• Web site - a collection of related web pages
• Home page - starting point of a web site
• URL - uniform resource locator
• HTTP - hypertext transfer protocol

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How a Web Page Works

• Three types of hyperlinks exist
• Target hyperlinks - links within the same page
• Relative hyperlinks - link to another document on
  the same Internet computer (server)
• Absolute hyperlinks - link to another document
  that could be located on a computer across the
  country
• HTML - hypertext mark-up language - the code that
  defines what a website will look like

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Web Browser Software

• A web browser is a program that interprets HTML
  and displays Web pages and allows links to other
  pages
• Mosaic - developed in 1993 by Marc Andreesen, a
  student at the University of Illinois
• Netscape, Internet Explorer, AOL, Safari

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Searching for Info. on the Web

• Search tools - enable users to locate information
  found at Web sites all over the world
• Search engine - a type of search tool that uses
  keywords
• Subject directory - a type of tool that allows
  the user to navigate the directories and
  subdirectories

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Multimedia on the Web

• Multimedia is the combination of graphics,
  animation, audio, video, and virtual reality
• Graphics - were the first media used to enhance
  text only sites
• Animation - is the appearance of motions created
  by displaying a series of still images in rapid
  sequence
• Audio - you can listen to prerecorded audio clips
  and live audio
• Video - consists of full motion images that are
  played back at various speeds
• Virtual reality - is the simulation of a real or
  imagined environment

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E-mail

• E-mail (electronic mail) - is the transmission of
  messages and files via a computer network
• E-mail program - allows you to compose, view,
  send, and receive email
• E-mail address - is a combination of a user name
  and a domain name

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File Transfer Protocol

• FTP - is an Internet standard that allows you to
  exchange files with other computers on the
  Internet.
• Anonymous FTP - anyone can transfer files on this
  type of site.

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Information Sharing via the Web

• Newsgroup - is an online area in which users
  conduct written discussions about a particular
  subject
• Mailing list - is a group of email addresses
  given a single name
• Chat rooms - is a real-time typed conversation
• Instant messaging - is real-time Internet
  communications service that notifies you when one
  or more people are online.
• Netiquette - is the code of acceptable behavior
  while on the Internet

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Interesting Sites

• http//www.epals.com