Digital Media Dr. Jim Rowan ITEC 2110

The Internet your computer DHCP: your browser (Safari)(client) webpages and other stuff yahoo.com (server) walmart.com (server) Domain Name System (DNS)

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

yahoo.com (server) The Internet walmart.com (server) DHCP: your computer your browser (Safari)(client) Domain Name System (DNS) = webpages and other stuff

yahoo.com (server) The Internet walmart.com (server) /index.html DHCP: your computer your browser (Safari)(client) Domain Name System (DNS) = webpages and other stuff

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

Parts of the Uniform Resource Locator URL Three parts: –Specifies the protocol to use HTTP FTP SMTP –The Domain Name –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

…suppose on your Server:

ebaymotors/ws/eBayISAPI.dll ?ViewItem&item= & ssPageName=ADME:X:AAQ:MOTORS: =747808&wban=99999&day=31&month=3&year=2008&sear chtype=zip search?hl=en&q=tim+berners-lee&btnG=Google+Search Locating stuff on a server

WebCrawlers Once looked and collected addresses to sell to spammers Simple to do –request a page –look through the text of the page for 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

And now for a little history...

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!”TCPDNS –wrote the first web browser (the client)

And now… Alan Kay

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