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?
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Apply for jobs or schools
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Fill out government forms
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Check bank accounts
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Communicate with family, friends and co-workers
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Do research
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Learn new skills
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Read news
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Watch videos
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What is an Internet Service Provider?
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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
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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
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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
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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
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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
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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
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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
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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
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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 links to 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 !
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Art Rein
◻
Tim Niser
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Rae Mang
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Roy Tenat
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Brock Kortes
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Janis Roult
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Chet Incani
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Anna Stoccut
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Ron Sturcti
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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
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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
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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
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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
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Sponsored links
Sites pay for better search results
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Search Techniques
◻
Quote the exact phrase
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Use the keyword AND
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Use the keyword NEAR
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Avoid common words
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Use the site’s advanced tools
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