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LBSC 690: Week 2 HTML, The Internet. Jen Golbeck College of Information Studies University of Maryland. A Short History of the Internet. 1969: Origins in government research Advanced Research Projects Agency (ARPAnet) 1983: Design adopted by other agencies
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LBSC 690: Week 2HTML, The Internet Jen Golbeck College of Information Studies University of Maryland
A Short History of the Internet • 1969: Origins in government research • Advanced Research Projects Agency (ARPAnet) • 1983: Design adopted by other agencies • Expansion from educational institutions to corporations • 1991: World Wide Web added point-and-click capabilities
The Internet • Global collection of public networks • Private networks are often called “intranets” • Each organization maintains its own network • Use of shared protocols • TCP/IP (Transmission Control Protocol/Internet Protocol): basis for communication • DNS (Domain Name Service): basis for naming hosts • HTTP (HyperText Transfer Protocol): World Wide Web
Packet Routing (TCP/IP) 128.0.1.5 63.6.9.12 4.8.15.2 52.55.64.2 18.1.1.4 192.28.2.5 (Much simplified) Routing table for 4.8.15.2
Addresses and Domain Names • Every computer has an IP address • E.g. 128.135.20.100 • Hard to remember, and hard wired • Domain names are short cuts to IP addresses • umd.edu, facebook.com, etc
Domain Name Service (DNS) • “Domain names” improve usability • Easier to remember than numeric IP addresses • DNS coverts between names and numbers • Written like a postal address: specific-to-general • Each name server knows one level of names • “Top level” name server knows .edu, .com, .mil, … • .edu name server knows umd, umbc, stanford, … • .umd.edu name server knows wam, glue, ttclass, … • .wam.umd.edu name server knows rac1, rac2, …
Domain Names • Unsponsored • .biz .com .edu .gov .info .int .mil .name .net .org • Sponsored • .aero .asia .cat .coop .jobs .mobi .museum .pro .tel .travel • Infrastructure: .arpa .root • Proposed • .berlin .bzh .cym .gal .geo .kid .kids .lat .mail .nyc .post .sco .web .xxx • Deleted/retired: .nato • Reserved • .example .invalid .localhost .test
If you want one… • You need a web host • Company to host your web pages • Alternatively, you can do it yourself, but it requires a lot of infrastructure (and permissions) you don’t have • Cost ranges from $5/month (e.g. http://tinyurl.com/dw6qd ) and up depending on services • You register for a domain name and point it to the host • Cost is about $35/year (less if you buy for multiple years)
The Web • Not the same thing as the Internet • Internet is the network of computers that sends information around (email, web pages, chat, skype, file transfers, etc) • The web is a layer on top of the internet that sends files in a certain way (using HTTP) • 1991 - now
Foundations of the Web • TCP/IP • DNS • HTTP
Standards • No one owns the web or the internet • Platform and software independent - it should work the same everywhere • W3C - World Wide Web Consortium • A group of people (universities, businesses, governments, etc) who decide by committee what the web will be and how it changes • Some people modify standards • BAD! • E.g. a web page that only works in Internet Explorer
Why Code HTML by Hand? • The only way to learn is by doing • WSIWYG editors… • Often generate unreadable code • Ties you down to that particular editor • Cannot help you connect to backend databases • Hand coding HTML allows you to have finer-grained control • HTML is merely demonstrative of other important concepts: • Structured documents • Metadata
Today’s Tutorial • Your first HTML page • Uploading your page to the Web server via FTP
This is the header This is the actual content of the HTML document “Hello World” HTML <html> <head> <title>Hello World!</title> </head> <body> <p>Hello world! This is my first webpage!</p> </body> </html>
Uploading Your Page • Connect to “wam.umd.edu” • Change directory to “/pub/USERID” • Upload files
Tips • Edit files on your own machine, upload when you’re happy • Save early, save often, just save! • Reload browser