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JrowanITEC2110-FinalWrapUp2

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JrowanITEC2110-FinalWrapUp2 Powered By Docstoc
					Digital Media

 Dr. Jim Rowan
  ITEC 2110
                                      webpages
                                          and
      your browser                     other stuff
      (Safari)(client)               yahoo.com
                         DHCP:         (server)
your computer                       235.01.30.564


                                     walmart.com
                                       (server)
                                    100.43.153.07
                    The Internet

           Data Name System (DNS)
                                     webpages
                                         and
     your browser                     other stuff
     (Safari)(client)               yahoo.com
        DHCP: 135.10.34.443           (server)
your computer                      235.01.30.564
             ISP
                                    walmart.com
                                      (server)
                                   100.43.153.07
                   The Internet

          Data Name System (DNS)
                                                webpages
                                                    and
      your browser                               other stuff
      (Safari)(client) http://www.yahoo.com    yahoo.com
         DHCP: 135.10.34.443                     (server)
your computer                                 235.01.30.564


                                               walmart.com
                                                 (server)
                                              100.43.153.07
                  The Internet

          Data Name System (DNS)
          http://www.yahoo.com =
          235.01.30.564
                                                webpages
                                                    and
      your browser /index.html                   other stuff
      (Safari)(client) http://www.yahoo.com    yahoo.com
         DHCP: 135.10.34.443                     (server)
your computer                                 235.01.30.564


                                               walmart.com
                                                 (server)
                                              100.43.153.07
                  The Internet

          Data Name System (DNS)
          http://www.yahoo.com =
          235.01.30.564
      How to start a website
• You have to buy a Domain Name
  – register.com
  – godaddy.com
• The Domain Name supplier
  – pay by the year
  – may provide some storage space for your web
    pages using their IP
  – probably get email accounts with it
  – will allow you to configure your site
     • set up domain-name-to-IP mapping
          Let’s look at LINKS
                           notice that the links are
                           distinguished from
                           regular text (underlined
                           and color)
                           also... once used, they
                           turn a different color



here the nodes connected by links are only 1 level deep...
4-5 is usually the deepest that is recommended
                more LINKS...




                     into pages

                                  within pages
between pages
                  Disorientation..
• Where am I?
  – URL is SOMETIMES useful... Example:
       • http://www.pondliner.com/
       • http://www.pondliner.com/index.html
       • http://www.pondliner.com/PontecKits.htm
  – Why just sometimes?
       • dynamically generated content like PHP, Perl, CGI
       • webpage can be different each time you visit it
• Where was I?
  –   browsers have “back” buttons
  –   pages can have embedded links that take you back
  –   browser history works without user interaction
  –   browser bookmarks work with user interaction
  –   use search engine and remember search strings
   Finding your way around...
• Bookmarks User-built
  – indices and links can be built by hand
  – people search the web and keep useful indexes
    making them part of the site
  – may rely on the user to search and rate sites
• Indices Machine-built
  – indices and links are built using spiders, robots or
    WebCrawlers
  – these are programs that search the web looking
    for content
              WebCrawlers
• Once looked and collected email addresses to
  sell to spammers
• Simple to do
  – request a page
  – look through the text of the page for something @
    something.something
• Can be defeated by using unfriendly-to-robot-
  code like: jrowan (at) GGC (dot) USG (dot) EDU
  – humans can read this just fine!
            Search Engines
• Search web pages looking for keywords
• Then they build a catalog of keywords
   – You enter a keyword in the engine
   – It looks at its table
   – It sends you the URLs associated with the
     keyword
• GOOGLE extends this by including the
  number of links that point to that particular
  page
               Web Protocols
• Protocols define the rules to be followed in a
  conversation
  –   who talks first
  –   what is acceptable to request
  –   what are acceptable responses to a request
  –   syntax is the actual form of each interaction
• HTTP - Hyper Text Transfer Protocol
  – identifies it as a web page request
• FTP - File Transfer Protocol
  – identifies it as a file that needs to be downloaded
• SMTP - Simple Mail Transport Protocol
  – identifies it as pertaining to email
           Parts of the URL
• Has three parts:
  – Specifies the protocol to use
     • HTTP
     • FTP
     • SMTP
  – The Domain Name
     • www.ggc.usg.edu
  – Other defining stuff
     • directory info and pages
     • data to be handed to a program
                    Other defining stuff...
                   directory info and pages
HTTP://www.jimrowan.com

www.jimrowan.com/about/
-can have two responses
-assumes index.html yielding web page
-assumes you want a directory list yielding a list
of the contents of the directory:
        CV.html
        index.html
        publications.html

www.jimrowan.com/about/index.html
www.jimrowan.com/about/research.html

www.jimrowan.com/about/before1990/index.html
www.jimrowan.com/about/after1990/index.html
       Other defining stuff...
       data to be handed to a program

http://www.google.com/
search?hl=en&q=tim+berners-lee&btnG=Google+Search

http://cgi.ebay.com/
ebaymotors/ws/eBayISAPI.dll
?ViewItem&item=260182066605&
ssPageName=ADME:X:AAQ:MOTORS:1123

http://www.almanac.com/weatherhistory/oneday.php?number
=747808&wban=99999&day=31&month=3&year=2008&sear
chtype=zip
And now for a little history...
              A brief history
• Tim Berners-Lee (not al gore)
  – invented the internet
  – 1980 built the first web server
  – mid 1980s worked with hypertext
  – 1988- “I just had to take the hypertext idea and connect
    it to the TCP and DNS ideas and ta-da! the World Wide
    Web!”
  – wrote the first web browser (the client)
• Command driven computer interface
• GUI
  – Alan Kay
• GUI
  – Alan Kay XEROX PARC 1970’s
• GUI
  – Alan Kay XEROX PARC 1970’s
  – Steven Jobs Macintosh 1984
                   Outside Reading

•   http://en.wikipedia.org/wiki/Web_crawlers
•   http://en.wikipedia.org/wiki/GUI
•   http://en.wikipedia.org/wiki/PHP
•   http://en.wikipedia.org/wiki/Cgi_script
•   http://en.wikipedia.org/wiki/Perl
•   http://en.wikipedia.org/wiki/Tim_Berners-Lee
•   http://en.wikipedia.org/wiki/Alan_Kay
•   http://en.wikiquote.org/wiki/Alan_Kay
•   http://en.wikipedia.org/wiki/Copyright
•   http://en.wikipedia.org/wiki/Fair_use
•   http://en.wikipedia.org/wiki/Digital_Millennium_Copyright_Act

				
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