Computers, The Internet
& The Web
M. Jacie Yang
Texas State University
Computers
Computers
• Hardware
– Motherboard
– CPU (Central Processing Unit)
– RAM (Random Access Memory)
– Hard drive
– CD/DVD drive
– Power
• Operating Systems
• Software
Operating Systems
• Windows (PC)
– Windows XP
– Windows Vista
– Windows 7
• Mac OS
– Classic Mac OS
– Mac OS X
• Linux
• OS Market Share
Display
• Pixel
– Smallest addressable screen element
– Also a unit for image dimensions
• Screen display
– Lower than 1024x768
– 1024x768
– Higher than 1024x768
– Screen display market share
Files
• File size
– 1 bit= 0 or 1
– 1 byte= 8 bits
– 1KB= 1024 bytes (1024=210)
– 1MB= 1024KM
– 1GB= 1024MB
– 1TB= 1024GB
• So, do you need a 32G ($299) iPod or a 64G
($399) iPod?
Internet=Web?
The Internet
Defining the Internet
• The Internet is a global system of
interconnected computer networks that use
the standard Internet Protocol Suite (TCP/IP)
to serve billions of users worldwide
(Wikipedia).
• An electronic communications network that
connects computer networks and
organizational computer facilities around the
world (Merriam-Webster).
History of the Internet
• History of the Internet
• In the 1960s (the Cold War)
• US government created Defense of Advanced
Research Projects Agency (DARPA)
• US Military was concerned about survivability
of their centralized communication networks
• First two nodes of the ARPANET
– UCLA, School of Engineering & Applied Science
– SRI International in Menlo Park CA
What Can You Do on the Internet?
• E-Mail (electronic mail)
• Instant Message (AOL, MSN Messenger, etc)
• BBS (Bulletin Board System)
• VOIP (Voice-over Internet Protocol)
• WebCam
• File sharing (FTP)
• Media Streaming (webcasts, podcasting)
• The Web
The Web
Defining the Web
• The Web: World Wide Web, or WWW.
• A system of interlinked hypertext documents
accessed via the Internet (Wikipedia).
• A part of the Internet accessed through a
graphical user interface and containing
documents often connected by hyperlinks —
called also Web (Merriam-Webster).
History of the Web
• 1989-1990
• Tim Berners-Lee
• Built “Hypertext project”
called WorldWideWeb.
• Creator of HTML
(Hypertext Markup
Language).
Mosaic: First Web Browser
• 1992-1993
• Made the Web
popular and
accessible to the
public.
• Later become
Netscape (1994).
Web Browsers
• Internet Explorer (Microsoft, 1995)
• Opera (Opera Software,1996)
• Firefox (Mozilla Corporation, 2004)
• Safari (Apple, 2005)
• Chrome (Google, 2008)
• Browsers Market Share
How to Locate Web Sites?
• URL: Uniform Resource Locator
– i.e. http://www.txstate.edu
• http://
– Hypertext Transfer Protocol
• www
– World Wide Web
• www.txstat.edu
– Domain name
Example of URLs
• URL:
– http://www.txstate.edu
– ftp://admin@ftp.jacieyang.com
– http://en.wikipedia.org/wiki/Uniform_Resource_Locator
• Domains:
– www.txstat.edu
– www.jacieyang.com
• Subdomains:
– www.masscomm.txstate.edu/
– www.library.txstate.edu/
– www.wcms.jacieyang.com
How does the Web work?
• How does the Web work?
• WWW in Plain English
Multimedia on the Web
• Text
• Images
• Audio
• Video
• Let’s take a look at those elements on the
Web.
Images on the Web
• JPG/JPEG (Joint Photographic Experts Group)
– Supports true color
– Is usually the file format of digital cameras
• GIF (Graphic Interchange Format)
– 256 colors
– Good for graphics with limited colors
• PNG (Portable Network Graphics)
– Best when you have combination of photos and
text
Audio and Video on the Web
• Popular audio formats:
– MP3, ACC, WMA
• Popular video formats:
– AIFF, WAV, MOV (QuickTime), MP4, RM
• Supports both audio and video:
– ogg
Search Engines
Defining Search Engines
• A web search engine is designed to search for
information on the World Wide Web
(Wikipedia).
• Computer software used to search data (as
text or a database) for specified information;
also : a site on the World Wide Web that uses
such software to locate key words in other
sites (Merriam-Webster).
How Do Search Engines Work?
• How Search Engines Work
Popular Search Engines
• Search Engines
– Google
– Bing
– Yahoo
– Ask.com
• Meta-search engines
– Ixquick
– Clusty
Building a Web Site
Static & Dynamic Web Pages
• Static Web pages:
– HTML documents stored on Web servers.
– The content of the page does not change in
response to users input.
• Dynamic Web pages:
– A page that is generated by a server-side program
or script.
– The page changes accordingly to the information
that is submitted by the browser to the server.
Server-side Languages
• PHP
• JSP
• ASP.NET
• Perl
• Python