1. Multimedia and The World Wide Web
HCI 201
Multimedia and The World Wide Web

2. The Internet

3. History of Internet Started 1960s - Packet Switching
Research project by U.S. Department of Defense
ARPAnet (Advanced Research Projects Agency)
Really took off in 1993

4. History of the World Wide Web
CERN (Tim Berners-Lee) developed authoring language and distribution system for creating and sharing multimedia-enabled, integrated electronic documents over the Internet
World Wide Web and HTML was born
Allows relationships between documents and elements
NCSA developed Mosaic to view these documents

5. Overview The Internet The WWW How does it all work? Hardware Software
Networking
Protocols

6. Internet and World Wide Web What’s the difference between the two terms?

7. The Internet and the WWW
The Internet (late 60s): “It’s a worldwide collection of computer networks – a network of networks – sharing digital information via a common set of networking and software protocols.”
HTML & XHTML – The Definitive Guide
The World Wide Web (early 90s): the monster application that runs on the Internet infrastructure (over 2 billion pages).
With the invention of GUI -> color, voice and video were added to the Internet.

8. History of the Internet
Started 1960s - Packet Switching
Research project by U.S. Department of Defense
ARPAnet (Advanced Research Projects Agency)
Really took off in 1993, why?
URL

9. History of the World Wide Web
CERN (Tim Berners-Lee) developed authoring language and distribution system for creating and sharing multimedia-enabled, integrated electronic documents over the Internet
World Wide Web and HTML was born.
Allows relationships between documents and elements.
NCSA developed Mosaic to view these docs.
URL

10. Overview The Internet The WWW How does it all work? Hardware Software
Networking
Protocols

11. Hardware
The difference between hardware and software is you can touch hardware.
The hardware you need to be connected to the Internet is
A computer
A networking device, e.g. a modem or network card
A connection, e.g.
At home, an Internet Service Provider
At school, a LAN connection

12. Most modems today have a maximum speed of 56 Kbps.
Telephone (Dial-Up) Modem: Low Speed but Inexpensive & Widely Available
Modem - device that sends and receives data over telephone lines to and from computers
Most modems today have a maximum speed of 56 Kbps.
Using a modem and phone line to establish a connection to the Internet is called making a dial-up connection.
FACTOID: Just 20 years ago, most modems operated at a speed of only 300 bps. What a difference!

13. Internet Service Provider (ISP)
ISP - a company that connects you through your communications line to its servers, or central computer, which connect you to the Internet via another company’s network access points
Well-known ISPs:
AOL (America Online)
Earthlink
Microsoft Network (MSN)
AT&T WorldNet
Prodigy
POP (Point of Presence) - your ISP’s local access number for your area.
Log on - make connection to the remote computer of your ISP.

14. Software
Software is a term used to describe programs that allow the hardware to do things for you.
You need a few pieces of software to connect to the Internet
An operating system, e.g. Windows XP
A browser, e.g. Internet Explorer, Firefox, Opera
If you want to develop web sites or pages, you need a few more
Authoring tool, e.g. Notepad, Dreamweaver or Frontpage
FTP program, to transfer files from your client machine (in front of you) to the server (your students account), e.g. SSH

15. Protocols
Because networks use a wide variety of hardware and software, protocols are needed to coordinate communication and data transmission.
A protocol is a set of rules for the exchange of data across communication lines.
Protocols make the whole thing work!

16. Standards Organizations
World Wide Web Consortium (W3C)
Internet Engineering Task Force (IETF)
URL

17. What protocols do
Identify the different devices in the communication path.
Establish the speed and method for transmission of data.
Alert the receiving device to the incoming data.
Determine the method of error checking and correction.

18. HyperText Transfer Protocol
HTTP is the protocol responsible for transferring and displaying web pages.
HTTP uses the client/server model of computing.
The client is the user’s web browser: a software program that retrieves the page and displays it. (I.E, Netscape).
A Web browser can either be text-based, or graphical.
A Web page is stored on a Web server, which makes the page available to users of the Web.
The server is the web server where the page resides. (Ex:

19. TCP/IP protocol TCP – Transmission Control Processing
IP – Internet Protocol
TCP: Rules to control on how messages are broken down into packets, and then reassembled at the final destination.
IP: Rules to label packets for delivery and to control the packet’s path from sender to recipient.
TCP/IP software processes data transmission through the Internet.

20. Internet protocols
Simple Mail Transfer Protocol (SMTP): transferring messages from one machine to another
File Transfer Protocol (FTP): transferring files between local and remote machines.
Telnet: a terminal emulation protocol used to remote login.
Others?
TCP/IP
HTTP
POP

21. IP addresses: dotted quads
Each node in the IP world is identified by a unique 32-bit number called an IP address.
IP addresses appear as a series of four 8-bit numbers separated by dots (dotted quads). Each number ranges from 0 to 255.
students.cs.depaul.edu
IP addresses are usually assigned human-readable names (domain names).

22. IP Address

23. Domain Name Server (DNS)
IP addresses are hard to remember.
(Domain Name)
(IP Address)

24. Domain news.com amazon.com cnn.com chicago.com yahoo.com depaul.edu
microsoft.com
depaul.edu
chicago.com
news.com
cnn.com

25. Domain Name Amazon. COM yahoo.com microsoft.com depaul.edu chicago.com
news.com
cnn.com

26. Domain Name Server
A Domain Name Server is responsible for the mapping between domain names and IP addresses.
bach.cs.depaul.edu
Org. type (top level domain)
Organization name
Host name
.com
.org
.gov
.mil
.net
.fr
.museum
.biz
How to convert a domain name into an IP address or IP address into domain name : Use MS/DOS command prompt on WINDOWS:
Type: nslookup <domain name> or <IP address>
depaul.edu is domain name, i.e. depaul is a subdomain of .edu
cs.depaul.edu is considered a subdomain of depaul.edu
a root server looking for an ip address for cs.depaul.edu would probably query the depaul.edu domain for an ip address
IP address:

27. A Typical HTTP Exchange
Client: Please open a connection
to ‘ and send me
the default file. I am located at
IP Address
Netscape’s URL
Window
NY Times
Web Server
Server: Let me check…. Okay, the default file at this site is of type HTML. It is 1749 bytes in size. The
date is Tue, May 2nd at 15:33:33.
NY Times Web Page

28. Web Pages and Web Browsers
A Web page is stored on a Web server, which makes the page available to users of the Web.
To view a Web page, the user runs a Web browser, a software program that retrieves the page and displays it.
A Web browser can either be text-based, or graphical.

29. URL: Uniform Resource Locator
People on the Web use a naming convention
called the uniform resource locator (URL).
A URL consists of at least two and as many as four parts.
A simple two part URL contains the protocol used to access the resource followed by the location of the resource.
Example:
A more complex URL may have a file name and a path where the file can be found.

30. A Web URL deconstructed
The user is a directory in the system
The protocol used
path that indicates
the location of the
document in the
host’s file system
domain
document
name

31. Anatomy of an e-mail address
cs . depaul . edu
Handle
Top level domain
Host/Server
Domain
Others:
students
hawk
condor
Others:
com, net, org,
mil, gov
fr, uk, dz
info, biz, name,
pro, museum, coop