The Internet:
A Resource for All of Us
Chapter 8
Objectives
• Briefly describe the history of the Internet
• Explain what is needed to get on the Internet
• Describe gener...
Contents
• History of the Internet
• URL
• Getting Started
• Internet Service Provider
• Browser
• Browser Support
• Movin...
History of the Internet
• Government and Universities over 30 years
• Who’s connected today?
– Individuals
– Educational i...
ARPANet
Advanced Research Projects Agency Network
• 1969 – US Department of Defense and Rand
Corporation
• Origins
– Cold ...
ARPANet
Transmitting the Message
• Messages divided into packets
• TCP/IP protocol
– TCP – does the packeting and
reassemb...
ARPANet
Expands Beyond the Military
• Research computers from universities
• Defense contractors
• Needed technical expert...
Tim Berners-Lee
• 1990
• Perceived a spider’s web of computers with
links from computer to computer
• CERN site
– Dr. Bern...
Marc Andreessen
• 1993
• Created browser software
• Mosaic – first browser
• Provided attractive images and a graphical
in...
ARPANet to Internet
• TCP/IP software is public domain
• Network became more valuable as it
embraced other networks
• ARPA...
Internet Explosion
• Mid 1990s
• Estimate over 333 million users worldwide
• Part of our daily lives
• Four factors
– TCP/...
URL
Uniform Resource Locator
• Unique address of a web page or file on the
Internet
• Case-sensitive
http://domain-name.to...
http
hypertext transfer protocol
• Protocol – rules
• Communication using links
http://domain-name.top-level-domain/last-s...
Domain name
• Address of the ISP
• Domain names are registered
• Ongoing fee is paid for each domain name
http://domain-na...
Top-level Domain
Represent the purpose of the organization of entity
.com
.gov
.edu
.org
.net
May be a two-letter country ...
Last section
Directories and file names that specify a
particular web page
http://domain-name.top-level-domain/last-section
Getting Started
• Computer with a modem or NIC
• Internet service provider (ISP)
• Browser
• Related software
Internet Service Provider
• Vehicle to access the Internet
• Provides
– Server computer
– Software to connect
Online service
• ISP
• Members-only services and information
• Simple interface with clickable topics
• Parent controls
Wireless Internet Access
• Supports mobile handheld devices
– Text pagers
– PDAs
– Pocket computers
– Web-enabled cellular...
Wireless Internet Access
• Need
– Account with wireless access provider
– Cellular modem card or adapter
• Wireless Applic...
Browser
Netscape Communicator
Microsoft Internet Explorer
Browser
• Used to explore the Internet
• Dials the ISP
• Display web pages
Browser
Parts of the screen
Browser
Functions and Features
• Browser display window
– Displays contents of web page from each Internet
site visited
– ...
Browser
Functions and Features
• Welcome banner on title bar
• Browser logo – animation indicates you are in
the process o...
Browser
Menus and Buttons
• Pull-down menu
• Buttons
– Convenient shortcuts for commonly used
functions
– Click button rat...
Browser Support
Frames
• Divides page into rectangular sections
• Each section displays web pages independently
• Several ...
Plug-ins
• Software that increases the functionality of a
browser
– Audio-video
– Image viewing
• Download from web sites
...
Programming
Java
• Write software that is machine independent
• Programming language
– Dancing icons
– Sound clips
– Flash...
Programming
ActiveX Controls
Capabilities similar to Java
Browser must be enabled to support
applets / ActiveX Controls
Se...
Moving Between Sites
• Clickable categories in the browser
– Sports
– Weather
– News
– Technology
– Comic strips
• Enter t...
Processing Requests
URL
• User enters a URL
• User computer sends request to the ISP
server
• ISP server sends request acr...
Searching the Internet
Search engine
• User specifies a search request
• Browser links to Search Engine
• Request returns ...
Processing Requests
Search Engine Database
• Search Engine builds database
– Searchable terms
– Related web sites
• Spider...
• Request same search using different engines
yields different results
• Databases built independently
– Size
– Content
– ...
Processing Requests
Directory vs. Search Engine
• Directory
– Human involvement
– Sites organized by content category
– Ma...
Processing Requests
Search Engine Limitations
• Index only a fraction of the Web
• Approximately 20% to 33% of sites
• Mor...
Search Tools
Directories
• Yahoo!
• NetGuide
Metasearch Sites
• MetaCrawler
• Dogpile
Search Engines
• AltaVista
• Excite
...
Refine the Search
• Add words
• Enclose words in “quotes”
• Use Boolean logic
• Examples
– “World Trade Center”
– Jordan A...
Other Uses of the Internet
• Newsgroups
• FTP
• Telnet
• E-mail
• Internet Relay Chat (IRC)
Newsgroups / Usenet
• Large bulletin board divided by category
• Posting and reading of messages that focus
on specific to...
Newsgroup Operations
• Lurking
• Posting material
– Inappropriate material
• Flame
• Flame war
– Moderated newsgroup
FTP
File Transfer Protocol
• Download files to your local computer
• Upload files to another computer
• Requirements to do...
Public Archives
Free files provided by educational
institution or the government
Telnet
• Use your PC as a terminal providing remote
access to another computer
• Permits
– Log on to a host
– Use as if yo...
e-mail
• Send/receive written messages
• Most used feature of the Internet
• Mail server – Collects and stores e-mail
• Ma...
e-mail
Client Software Functions
Retrieve
Create
Send
Store
Print
Delete
Address book
Attach files
Filters
IRC
Internet Relay Chat
Not Quite Perfect Yet
• Unregulated
• Useless web sites
• Misinformation and misstatements on web
sites
• Concern over gov...
Not Quite Perfect Yet
Social Issues
• Behavior problems
– Who is out there?
– What are they doing?
• Netiquette
– Suggesti...
英文投影片
Upcoming SlideShare
Loading in...5
×

英文投影片

342

Published on

Published in: Technology, Design
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
342
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

英文投影片

  1. 1. The Internet: A Resource for All of Us Chapter 8
  2. 2. Objectives • Briefly describe the history of the Internet • Explain what is needed to get on the Internet • Describe generally what an Internet service provider does • Describe the rudimentary functions of a browser • Describe how to search the Internet • List and describe the non-Web parts of the Internet • Explain some of the ongoing problems associated with the Internet
  3. 3. Contents • History of the Internet • URL • Getting Started • Internet Service Provider • Browser • Browser Support • Moving Between Sites • Searching the Internet • Other Uses of the Internet • Internet Issues
  4. 4. History of the Internet • Government and Universities over 30 years • Who’s connected today? – Individuals – Educational institutions – Government – Research – Medical – Businesses – Everyone!
  5. 5. ARPANet Advanced Research Projects Agency Network • 1969 – US Department of Defense and Rand Corporation • Origins – Cold War – fear that a bomb could demolish computing capabilities – Several computers, geographically dispersed, networked together – Plan – if one computer was disabled, others could carry on using alternative communication routes
  6. 6. ARPANet Transmitting the Message • Messages divided into packets • TCP/IP protocol – TCP – does the packeting and reassembling of the message – IP – handles the addressing
  7. 7. ARPANet Expands Beyond the Military • Research computers from universities • Defense contractors • Needed technical expertise to work on Internet
  8. 8. Tim Berners-Lee • 1990 • Perceived a spider’s web of computers with links from computer to computer • CERN site – Dr. Berners-Lee’s physics laboratory – Birthplace of the World Wide Web • Easy movement due to links – Hypertext – Hyper-region
  9. 9. Marc Andreessen • 1993 • Created browser software • Mosaic – first browser • Provided attractive images and a graphical interface permitting users to click on pictures as well as text
  10. 10. ARPANet to Internet • TCP/IP software is public domain • Network became more valuable as it embraced other networks • ARPANet disappears
  11. 11. Internet Explosion • Mid 1990s • Estimate over 333 million users worldwide • Part of our daily lives • Four factors – TCP/IP standard – Ability to link from site to site – Ease of use of browser – Growth of PC and LANs that can connect
  12. 12. URL Uniform Resource Locator • Unique address of a web page or file on the Internet • Case-sensitive http://domain-name.top-level-domain/last-section
  13. 13. http hypertext transfer protocol • Protocol – rules • Communication using links http://domain-name.top-level-domain/last-section
  14. 14. Domain name • Address of the ISP • Domain names are registered • Ongoing fee is paid for each domain name http://domain-name.top-level-domain/last-section
  15. 15. Top-level Domain Represent the purpose of the organization of entity .com .gov .edu .org .net May be a two-letter country code
  16. 16. Last section Directories and file names that specify a particular web page http://domain-name.top-level-domain/last-section
  17. 17. Getting Started • Computer with a modem or NIC • Internet service provider (ISP) • Browser • Related software
  18. 18. Internet Service Provider • Vehicle to access the Internet • Provides – Server computer – Software to connect
  19. 19. Online service • ISP • Members-only services and information • Simple interface with clickable topics • Parent controls
  20. 20. Wireless Internet Access • Supports mobile handheld devices – Text pagers – PDAs – Pocket computers – Web-enabled cellular phones • Applications – E-mail – Checking weather – Making airline reservations
  21. 21. Wireless Internet Access • Need – Account with wireless access provider – Cellular modem card or adapter • Wireless Application Protocol (WAP) – Convert web pages into format for mobile devices – Resized for limited display area – Fewer graphics transmitted • Slow download speeds
  22. 22. Browser Netscape Communicator Microsoft Internet Explorer
  23. 23. Browser • Used to explore the Internet • Dials the ISP • Display web pages
  24. 24. Browser Parts of the screen
  25. 25. Browser Functions and Features • Browser display window – Displays contents of web page from each Internet site visited – Screen limits how much of the site you can view at a time. The page can be scrolled using the scroll bar to see its entire contents • Status line – progress of data being transferred and other messages
  26. 26. Browser Functions and Features • Welcome banner on title bar • Browser logo – animation indicates you are in the process of moving to a new site • Hot list – Bookmark – Favorites – Store your favorite URLs • Browser control panel – menus and buttons
  27. 27. Browser Menus and Buttons • Pull-down menu • Buttons – Convenient shortcuts for commonly used functions – Click button rather than locate command from pull-down menu
  28. 28. Browser Support Frames • Divides page into rectangular sections • Each section displays web pages independently • Several small pages on one screen – Can be scrolled independently – Can be replaced with other pages independently
  29. 29. Plug-ins • Software that increases the functionality of a browser – Audio-video – Image viewing • Download from web sites • Install • Example – Adobe Acrobat Reader – Shockwave
  30. 30. Programming Java • Write software that is machine independent • Programming language – Dancing icons – Sound clips – Flashing messages – Banners that scroll • Applets – Permits dynamic web pages – Display animations – Receive input – Perform calculations
  31. 31. Programming ActiveX Controls Capabilities similar to Java Browser must be enabled to support applets / ActiveX Controls Security issues
  32. 32. Moving Between Sites • Clickable categories in the browser – Sports – Weather – News – Technology – Comic strips • Enter the URL in the address text box and press <Enter>
  33. 33. Processing Requests URL • User enters a URL • User computer sends request to the ISP server • ISP server sends request across networks of TCP/IP computers • Destination site is reached • Content is transmitted back to your computer (process in reverse)
  34. 34. Searching the Internet Search engine • User specifies a search request • Browser links to Search Engine • Request returns matching pages based upon the Search Engine’s database • Results presented
  35. 35. Processing Requests Search Engine Database • Search Engine builds database – Searchable terms – Related web sites • Spider, robot, bot – Follows links across the web – Automatically indexes pages to a database • One word • All words • Pages may be submitted by the owner
  36. 36. • Request same search using different engines yields different results • Databases built independently – Size – Content – Search methodology • Metasearch – atomically puts the same request to several search engines Processing Requests Search Engine Database
  37. 37. Processing Requests Directory vs. Search Engine • Directory – Human involvement – Sites organized by content category – May concentrate on specific content areas – Subjective decisions regarding inclusion and importance • Search Engine – Spider, robot, or bot automatically builds database – Index on a few keywords – Index on all words on web page
  38. 38. Processing Requests Search Engine Limitations • Index only a fraction of the Web • Approximately 20% to 33% of sites • More web pages added daily • Solution – Same request to several search engines – Metasearch
  39. 39. Search Tools Directories • Yahoo! • NetGuide Metasearch Sites • MetaCrawler • Dogpile Search Engines • AltaVista • Excite • Google • HotBot • Infoseek • Lycos • Northern Light
  40. 40. Refine the Search • Add words • Enclose words in “quotes” • Use Boolean logic • Examples – “World Trade Center” – Jordan AND NOT Michael
  41. 41. Other Uses of the Internet • Newsgroups • FTP • Telnet • E-mail • Internet Relay Chat (IRC)
  42. 42. Newsgroups / Usenet • Large bulletin board divided by category • Posting and reading of messages that focus on specific topics • Over 20,000 newsgroups • Functions – Conversation – File download • Newsreader software required (included with most browsers)
  43. 43. Newsgroup Operations • Lurking • Posting material – Inappropriate material • Flame • Flame war – Moderated newsgroup
  44. 44. FTP File Transfer Protocol • Download files to your local computer • Upload files to another computer • Requirements to download file – Permission to download from a site – File is available for copying • Anonymous FTP – do not need to identify yourself to the remote computer
  45. 45. Public Archives Free files provided by educational institution or the government
  46. 46. Telnet • Use your PC as a terminal providing remote access to another computer • Permits – Log on to a host – Use as if you are sitting at a local terminal • Need account on the host system • Telnet software required (provided with most browsers)
  47. 47. e-mail • Send/receive written messages • Most used feature of the Internet • Mail server – Collects and stores e-mail • Mailbox – Assigned to each user • E-mail address – User name – @ – Domain of the mail server
  48. 48. e-mail Client Software Functions Retrieve Create Send Store Print Delete Address book Attach files Filters
  49. 49. IRC Internet Relay Chat
  50. 50. Not Quite Perfect Yet • Unregulated • Useless web sites • Misinformation and misstatements on web sites • Concern over government censorship
  51. 51. Not Quite Perfect Yet Social Issues • Behavior problems – Who is out there? – What are they doing? • Netiquette – Suggestions for appropriate behavior – Example: TYPING IN CAPS is shouting
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×