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Digital Media. Dr. Jim Rowan ITEC 2110. webpages and other stuff. DHCP:. your browser (Safari)(client). yahoo.com (server) 235.01.30.564. your computer. The Internet. walmart.com (server) 100.43.153.07. Domain Name System (DNS). webpages and other stuff. DHCP: 135.10.34.443.
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Digital Media Dr. Jim Rowan ITEC 2110
webpages and other stuff DHCP: your browser (Safari)(client) yahoo.com (server) 235.01.30.564 your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS)
webpages and other stuff DHCP: 135.10.34.443 your browser (Safari)(client) yahoo.com (server) 235.01.30.564 your computer ISP The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS)
webpages and other stuff DHCP: 135.10.34.443 your browser (Safari)(client) yahoo.com (server) 235.01.30.564 http://www.yahoo.com your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS) http://www.yahoo.com = 235.01.30.564
webpages and other stuff /index.html DHCP: 135.10.34.443 your browser (Safari)(client) yahoo.com (server) 235.01.30.564 http://www.yahoo.com your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS) http://www.yahoo.com = 235.01.30.564
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 Uniform Resource Locator URL • 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
How to start your own website • You have to buy a Domain Name from a Domain Name supplier • register.com • godaddy.com • The Domain Name supplier • pay by the year • set up domain-name-to-IP mapping • may provide some storage space for your web pages using their IP
…or to start a website • You could have your own server • Macs come with servers built in • You must have a FIXED IP from your ISP • not really but it makes life MUCH simpler • You still need a Domain Name from a Domain Name Supplier • pay by the year • set up domain-name-to-IP mapping
Locating stuff on a server http://www.jimrowan.com/about/before1990/research.html http://www.jimrowan.com/about/after1990/hobbies.html 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&searchtype=zip
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 • Web crawlers look through the web 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
A brief history • Ward Cunningham • invented the WikiWikiWeb • www pages quickly editable by its users • Wiki is Hawaiian for “fast”
A brief history • Tim Berners-Lee • invented the World Wide Web • 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)
Before Alan Kay • Command driven computer interface
Alan Kay’s 1968 vision of how computing COULD be: The Dynabook
Alan Kay’s 1970’s XEROX PARC work • The Graphical User Interface GUI • But Xerox corporate didn’t think it was important
which opens the door for Steven Jobs • Macintosh 1984 • …and personal computing as we know it is born