1. 1 LBSC 690: Week 2 HTML, The Internet Jen Golbeck College of Information Studies University of Maryland

2. 2 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

3. 3 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

4. 4 Packet Routing (TCP/IP) 128.0.1.5 4.8.15.2 192.28.2.5 63.6.9.12 52.55.64.2 18.1.1.4 DestinationNext Hop 52.55.*.*63.6.9.12 18.1.*.*192.28.2.5/63.6.9.12 4.*.*.*225.2.55.1 … (Much simplified) Routing table for 4.8.15.2

5. 5 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

6. 6 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, …

7. 7 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

8. 8 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 http://tinyurl.com/dw6qd You register for a domain name and point it to the host –Cost is about $35/year (less if you buy for multiple years)

9. 9 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

10. 10 Foundations of the Web TCP/IP DNS HTTP

11. 11 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

12. 12 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

13. 13 Today’s Tutorial Your first HTML page Uploading your page to the Web server via FTP

14. 14 “Hello World” HTML Hello World! Hello world! This is my first webpage! This is the header This is the actual content of the HTML document

15. 15 Uploading Your Page Connect to “wam.umd.edu” Change directory to “/pub/USERID” Upload files

16. 16 Tips Edit files on your own machine, upload when you’re happy Save early, save often, just save! Reload browser