INTRODUCTION TO COMPUTERS
LECTURE 2 : WEEK 2
Credit : (03) / Week
TEXT AND REF. BOOKS
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Text Book:
Peter Norton (2011), Introduction to Computers, 7 /e, McGraw-Hill
Reference Book:
Gary B (2012), Discovering Computers, 1/e, South Western
Deborah (2013), Understanding Computers, 14/e, Cengage Learning
June P & Dan O (2014), New Perspective on Computer, 16/e
MOBILE ALERT
Kindly Switch Off your Mobile/Cell Phone
OR
Switch it to Silent Mode Please
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GOOGLE SITE ADDRESS
FOR LECTURE NOTES AND STUDY MATERIAL PLEASE VISIT :
https://sites.google.com/site/visualprog2016/itc
For Book Download:
https://drive.google.com/file/d/0B-7LjIntmmEHUlVjUG5selpPaEE/view
FOR TYPING PRACTICE :
http://www.sense-lang.org/typing/tutor/keyboarding.php
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Assistant Professor CS Dept
Presented by: Asma Khan
THE INTERNET AND THE WORLD WIDE WEB
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Learning Outcome
Internet
The Internet’s History
The Internet’s Major Services
The World Wide Web
Understanding the World Wide Web
Understanding the HTTP
Understanding the URL
Using your browser and the World Wide Web
Searching the Web
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What Is Internet
A global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols.
The vast collection of computer networks which form and act as a single huge network for transport of data and messages across distances which can be anywhere from the same office to anywhere in the world.
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Why use the Internet?
Apply for jobs or schools
Fill out government forms
Check bank accounts
Communicate with family, friends and co-workers
Do research
Learn new skills
Read news
Watch videos
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What is an Internet Service Provider?
A company that provides Internet access for customers
(examples: Comsat, Wi-tribe, Supernet, AOL)
Your computer connects to the Internet Service Provider (ISP), then to the Internet
Your computer ISP Internet
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How to connect to the Internet
Three main ways to connect to the Internet
Dial-Up (Old/outdated)
High Speed/DSL
Wireless Connection (Wi-Fi)
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Dial-Up Internet Connection
Dial-Up
All you need is a computer, phone-line and Internet Service Provider! (ISP)
Not as fast as other Internet connections, but often more affordable
ISP Internet
Your computer Landline
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High Speed (Cable/DSL) Connection
Travels through fiber-optic cables underground
Needs to be connected by a Modem to your computer
Modem: A hub that connects the computer to the Internet
Much Faster than Dial-up
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Wireless Internet Connection (Wi- Fi)
Your computer must be a
“Wireless enabled” device
Your computer can pick up signals from different
wireless networks
Some networks require passwords or a
subscription, others are free
This is what the wireless symbol would look like if your computer was connected
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History
J.C.R. Licklider of MIT, first proposed a global network of computers in 1962
Moved over to the Defense Advanced Research Projects Agency (DARPA) in late 1962 to head the work to develop it
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History
Internet was designed to provide a communications network that would work even if some of the sites were destroyed by nuclear attack
The early Internet was used by computer experts, engineers, scientists, and librarians
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E-mail & Telnet
E-mail was adapted for ARPANET by Ray Tomlinson of BBN in 1972
He picked the @ symbol from the available symbols on his teletype to link the username and address
The telnet protocol, enabling logging on to a remote computer on the same network, was published in 1972
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The TCP/IP suite
In 70's TCP/IP architecture first proposed by Bob Kahn at BBN and further developed by Kahn and Vint Cerf at Stanford and others throughout the decade
Adopted by the Defense Department in 1980
Replace the earlier Network Control Protocol (NCP) and universally adopted by 1983
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Gopher
Gopher was an Internet application in which hierarchically-organized text files could be brought from servers to a viewer on your computer
In 1991, the first really friendly interface to the Internet was
developed at the University of Minnesota
They wanted to develop a simple menu system to access files and information on campus through their local network
Named after Univ. of Minnesota mascot -- the golden gopher
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Gopher
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World Wide Web (WWW)
Tim Berners-Lee and others at the
European Laboratory for Particle Physics, more popularly known as CERN, proposed a new protocol for information distribution
in 1991 based on hypertext
Hypertext is a system of embedding links in text to link to other text
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Now
Internet backbone bandwidth is getting bigger – reaching 12 gigabits per second versus 56K, 16 years ago
Subscribers have the option to connect at 56K, 128K, 256K, and now even 100 Mbps & more
E-mail and web are now multimedia-rich
The Net has become an entertainment center
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Today and the Future
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100,000 new web sites per month
More than 75% of U.S. households online
Access is available world wide
Concepts of E-economy, E-world
Massive impact on social lives
Internet Growth
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The Internet’s Major Services
The World Wide Web (WWW)
Developed in 1993 by Tim- Berners Lee
Allowed connection of documents
Required a browser to read documents
Electronic mail (e-mail)
Instantaneous transmission of documents
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The Internet’s Major Services
News
Often called newsgroups
Electronic discussions on several topics
File Transfer Protocol (FTP)
Sends and receives files
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The Internet’s Major Services
Chat
Public real time conversation
Instant messaging
Private real time conversation
Peer-to-peer services
Allows sharing of files among users
Illegal to share copyrighted material
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World Wide Web (WWW)
The World Wide Web is system of Internet servers that support specially formatted documents.
The documents are formatted in a markup language called HTML (HyperText
Markup Language) that supports linksto other documents, as well as graphics, audio, and video files.
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World Wide Web : Major Parts
The World Web is based on these technologies:
HTML - Hypertext Markup Language
HTTP - Hypertext Transfer Protocol
Web servers and Web browsers
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WWW
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HTML (HyperText Markup Language)
Hypertext Markup Language, a standardized system for tagging text files to achieve font, colour, graphic, and hyperlink effects on World Wide Web pages.
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HTML (Hypertext MarkUP Language)
HTML is the lingua franca for publishing hypertext on the World Wide Web
Define tags <html><body> <head>….etc
Allow to embed other scripting languages to manipulate design layout, text and graphics
Platform independent
Not case sensitive
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HTML (Hypertext Markup Language)
Example HTML code:
<html>
<body>
<h1>Hello World</H1>
</body>
</HTML>
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HTML (Hypertext Markup Language)
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HyperText Transfer Protocol (HTTP)
HTTP is the underlying protocol used by the World Wide Web
HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in
response to various commands
HTTP is called a stateless protocol because each command
is executed independently
The three main HTTP message types are GET, POST, and HEAD
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HyperText Transfer Protocol
For example,
when you enter a URL in your browser,
this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.
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Uniform Resource Locator (URL)
URL is the global address of documents and other resources on the World Wide Web
The first part of the URL is called a protocol identifier, and the second part is called Resource name and it specifies the IP address or the domain name where the resource is located.
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URL Explained
http://www.google.com/index.html
Protocol Sub domain
Domain Name Resource Name
Top level domain File Path/Name
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Name of People : Find Profession !
Art Rein
Tim Niser
Rae Mang
Roy Tenat
Brock Kortes
Janis Roult
Chet Incani
Anna Stoccut
Ron Sturcti
Cheing Fiener
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Accessing The Internet
Internet Service Provider (ISP)
Company that provides Internet access
Dialup
Connects to Internet through phone line
Modem connects to the phone line
Slow connection
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Accessing The Internet
High-speed access
Connect through a special line
2 – 25 times faster than dialup
DSL, Cable, T1 are common
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Understanding the Internet
The Internet allows accessing resources
The Web simplifies the Internet
The Web connects documents
Hypertext creates links between documents
Documents are stored on a web server
HTTP delivers documents
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Understanding the Internet
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Web site is a collection of documents
Document is a web page
Pages are published to the web
Hypertext Markup Language
Creates web pages
Describes how pages should look
Content enclosed in tags
<tag>content</tag>
Understanding The Internet
A web browser is a software application for retrieving and presenting information resources on the World Wide Web
OR
Browser is a software application used to locate,
retrieve and display content on the World Wide Web, including Web pages, images, video and other files.
Read and translate the HTML
Display web content
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Famous Browsers
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Understanding The Internet
Helper applications
Plug-ins
Enhance a browser’s functionality
Streaming audio and video
Sends the file in small chunks
Chunks downloaded while others play
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Streaming Audio
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Using a Browser And The WWW
Browser starts on the home page
Navigating the web
Enter a URL in the browser
Click a link
Links are typically blue underlined words
Image maps are picture links
When finished, close the browser
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Browser window explained
Browser’s Market Share : 2014
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Searching the Web
The Web is unorganized
Directories
Categorize the Internet
Search engines
Find sites by keyword
The search engine www.google.com has become one of the hottest search engines on the planet.
It is so popular, it’s name has become a verb. For example, “I googled the answer last night”
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Searching the Web
Site searches
Large sites have an internal search
MetaSearch sites
Search several web sites at once
http://www.excite.com,
http://www.metacrawler.com
Sponsored links
Sites pay for better search results
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Search Techniques
Quote the exact phrase
Use the keyword AND
Use the keyword NEAR
Avoid common words
Use the site’s advanced tools
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Any Questions !!!
END OF LECTURE 2
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