Introduction to Computers

1
The Internet

• E-mail, search engines, phishing, netiquette, etc.

2
Overview

• How the Internet works
• Choosing your access provider
• Email
• World Wide Web
• Smart surfing
• Other Internet resources

3
What Is the Internet

• Originated in 1969
• Defense Advanced Research Projects Agency
• Intended for war time military communications
• Commercial use began in mid 1980s
• World Wide Web invented in early 1990s
• Does the government control the Internet?
• How?

4
What Is the Internet

• A collection of interconnected networks
• A world wide network of networks
• Some are small while others are very large
• The Internet has no one owner or controller
• Membership and participation is voluntary
• Central clearing house exists for names
• Why do companies join the Internet?
• What are their costs?
• Why did you join the Internet?

5
Internet Resources
6
Internet Resources
7
The Internet
8
Cyberspace

• The virtual space occupied by the internet
• An intellectual model that simplifies reality
• Hides all of the complexity of networking
• Physical location of machines is irrelevant
• Everything in cyberspace has a unique name
• What happens when two companies want the same
  name?

9
Domains

• Cyberspace is arranged into domains
• Domains are groups of similar entities
• All schools, all commercial, all government
• Domains are not geographic
• Each member of domain has unique name
• A naming agency enforces uniqueness
• Registering a name costs 25-50 per year

10
Domains
11
Organizations

• Organization names subdivide each domain
• Usually a company name
• Name must be unique within the domain
• Names are not associated with locations
• whitehouse.gov could be located anyplace
• French embassy is in Washington but part of .fr

12
Servers

• Servers subdivide a company
• Machines that provide a particular service
• Web, email, etc. are different internet services
• Servers naming belong to company
• Name must be unique within company domain
• Most web servers are named www

13
Domain Name Service - DNS

• Translates domain name to internet address
• Internet uses addresses like 204.84.192.18
• Every ISP provides DNS service
• Coordinated by central naming authority
• Successful translations are invisible
• Failures generate DNS lookup failed message
• Can you think of a similar service outside of the
  Internet?

14
Cyberspace
15
Connection Methods
16
Modems

• Which of these connection methods uses a modem?
• Does your computer have a modem in it?

17
Bandwidth

• Bandwidth - the amount of data a communications
  channel can carry
• Also called speed
• Broadband
• very high speed connection
• Narrowband
• a slow speed connection dialup
• Do you need broadband connection?

18
Choosing your ISP

• Internet Service Provider
• Provides you with a connection to its servers,
  which then connect you to the Internet
• How will you pick from the many available?

19
What is E-mail?

• Electronic equivalent of the Post Office
• messages delivered to your mailbox at ISP
• they wait for you to pick them up
• messages move to computer that checks mail
• Delivery time is unpredictable
• from a few minutes to a few days
• usually less than an hour

20
E-mail Addresses

• Email address format -- name_at_location
• name is name of persons account
• Capitalization is important
• No spaces and limited punctuation allowed
• _at_location is where the persons account is
• _at_ is required
• No spaces allowed, capitalization is ignored
• Can you access your email from anyplace? How?

21
Netiquette

• Netiquette is proper online behavior
• Use upper and lower case appropriately
• Use emoticons to mark humor -) -(
• Avoid sloppiness
• Avoid criticizing others sloppiness
• Send attachments only if requested
• When replying, quote only relevant portion
• Why do we need netiquette rules?

22
Spam - Unwanted Junk E-Mail

• Delete without opening the message
• Never reply to a spam message
• Spammers guess at email addresses
• answering proves yours was a real address
• SPAM may have phony reply address
• Your ISP may offer spam filters
• How much spam do you get? Why do you get it? How
  can you stop it?

23
Email Lists

• List-serves automatically manage Email lists
• Members send email to list-serve engine
• Engine forwards mail to everyone on list
• Members might get 100-200 messages a day
• Each list addresses a single topic
• there are over 80,000 lists
• What could you use a list-serve for?

24
World Wide Web

• A graphically oriented section of the internet
• Every page has a unique name
• Web documents are linked via hyperlinks
• Click blue underlined words to visit new pages

25
Uniform Resource Locator - URL

• Unique address of page
• Capitalization punctuation is significant

• Protocol
• End protocol
• Begin server
• Server name
• Begin folder
• Folders
• Begin page
• Page name

• http
• //
• www.disney.com
• /
• Parks/today
• /
• Epcot.html

26
Browser

• Program used to display web pages
• Also known as a client
• Which browser do you prefer? Why?
• Web pages are copied to your machine before they
  are displayed
• Cache directory holds these temporary files
• Speeds up second access to a page
• When would this feature hurt you?

27
Web Portals

• The starting point for finding information
• Provide popular features such as
• search tools
• e-mail
• electronic commerce
• discussion groups
• Examples
• Yahoo, AOL, and MSN any others?

28
Search Engines

• Search engines catalog contents of the web
• Like library catalog but not as well organized
• Thousands of specialized search engines
• Three basic types keyword, subject meta
• All searches are pre-built databases not live
• Too slow to search the web directly
• Changes take a while to reach the database

29
Keyword Search Engines

• Keyword search engines
• Continuously updated by robots called spiders
• Index every word on every page they reach
• You enter several topic keywords
• Displays list of several million possible sites
• Many dubious matches
• Refine search by adding or removing words
• Google is a keyword search engine

30
Subject Search Engines

• Subject search engines
• Updated by people
• Index includes only sites that request listing
• You select from lists of subjects and subtopics
• After selecting final subtopic you get a few
  sites
• No dubious entries, but not every possible site
• Yahoo is a subject search engine

31
Meta Search Engines

• Meta search engines
• Send your query to several other search engines
• Compile results from all into single list
• Can be Slower must wait for answers to return
• Broader list of matching sites
• Dogpile is a meta search engine
• Which search engine is your personal favorite?
  Why?

32
Definitions

• Plug-in
• program that adds a specific feature to a
  browser, allowing it to play or view certain
  files
• installs itself on your computer automatically
• Streaming (audio or video)
• a way of sending files so that you can begin
  viewing a file before the end of the file is sent
• Internet telephony
• using the Net to make phone calls

33
Your Personal Cyberspace

• How do you use the Internet?
• What was your last E-commerce transaction? Why
  did you use the internet for it?

34
Download / Upload

• What is Downloading?
• What is Uploading?

35
Discussion

• Using the web for research

36
Concept Check

• What is the term for using the Net to make phone
  calls, either one-to-one or for audioconferencing?

• Internet telephony

37
Concept Check

• Which program allows you to connect to remote
  computers on the Internet using a username and a
  password?

• Telnet

38
Concept Check

• Which type of search site sends your query to
  several other different search tools and compiles
  the results?

• Metasearch site

39
Concept Check

• What is the method whereby you can connect to a
  remote computer and transfer files from it to
  your own microcomputers hard disk?

• FTP (File Transfer Protocol)

40
Concept Check

• Which language consists of tags, and is used to
  create web pages?

• Hypertext Markup Language (HTML)

41
Concept Check

• What are the four components of a URL?

• The web protocol
• The name of the web server
• The directory on that server
• The file within that directory

42
Concept Check

• What is the name given to online education
  programs?

• Distance learning

43
Concept Check

• What is the term for writing an online message
  that uses derogatory, obscene, or inappropriate
  language?

• Flaming

44
Concept Check

• What is the term for keyboard-produced pictorial
  representations of expressions?

• Emoticons

45
Concept Check

• What is meant by Gbps?

• One gigabit per second--one billion bits per
  second.

46
Concept Check

• What is netiquette?

• Network etiquette--guides to appropriate online
  behavior

47
Concept Check

• What is the term for an independently
  controllable section of a Web page?

• A frame

48
Concept Check

• What is the term for a Website such as Yahoo!
  that groups together popular features such as
  search tools, e-mail, electronic commerce, and
  discussion groups?

• Portal

49
Concept Check

• What is broadband?

• Very high speed connection

50
Concept Check

• What is the term for the transmission of data
  from a remote computer to a local computer?

• Download

51
Concept Check

• What is the first component of a URL?

• The protocol (for example, http)

52
Concept Check

• What method of interaction with a Web page
  consists of little circles in front of
  user-selectable options?

• Radio buttons

53
Concept Check

• What type of program adds a specific feature to a
  browser, allowing it to play or view certain
  files?

• Plug-in

54
Concept Check

• What is the term for unsolicited e-mail in the
  form of advertising or chain letters?

• Spam

55
Concept Check

• What does RTC stand for?

• Real-time chat, a typed discussion among online
  users