CMPF 124:Basic Skills for Knowledge Workers The Internet
Jan 02, 2016
CMPF 124:Basic Skills for Knowledge Workers
The Internet
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Chapter Overview
Welcome to Cyberspace:
The Internet And World Wide Web
Gaini Search Engines:
Finding Information On The Web
Welcome to Cyberspace:
The Internet And World Wide Web
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The Internet
• Internet is a network of networks that connects computers across the country and around the world.
• Created by ARPAnet– DOD(Department of Defense), used by the military
during world war.– ARPA(Advanced Research Projects Agency Network)
• 1994 Act of Congress opened Internet to commercial use
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• Each computer/node is independent of others• Message/data travels different path each time it
is sent
• Data is transmitted from one computer to another across the internet through a series of protocols known as TCP/IP (Transmission Control Protocol/Internet Protocol)
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Capabilities of the Internet
• Internet provides 2 basic capabilities :-– World-wide information retrieval– World-wide communication
• Interactive
• User-determined
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What’s On the Internet?
• Documents• Graphics• Weather• TV/Movie Listings• Music and Art• Chat Rooms• Businesses
• Mailings Lists• E-mail• Hotel/airline
reservations• Auctions• Shopping
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The World Wide Web
• The original language of the internet was difficult to use.
• You had to use a variety of programs (telnet, ftp, archie, gopher etc) to locate and download data.
• The programs were based on the Unix OS and you had to know the precise syntax of the commands within each program.
• No graphics and sound were available• 1991 WWW - uses both hypertext (links) and
Hypermedia (text, graphics, sound &video)
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World Wide Web
• Subset of the total Internet• Hypertext and/or hypermedia documents
– Hypertext is a document that contains a hyperlink to another hypertext document.
– Hypermedia provides links to graphic,sound and video files in addition to text files.
• Hyperlinks allow instant access to next site or document
• Client requests documents from Web server using hyperlinks
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HyperText Transfer Protocol
• Data travels from client to server using the HTTP standards
• A browser allows you to access Web documents– Internet Explorer – Mozilla Firefox
• Start at site’s home page; click hyperlinks to jump to other Web pages
• Many sites include advertising
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Hyperlinks
• Provide text, graphics, sound or video links
• Blue underlined fonts are unexplored
• Magenta links have been previously accessed
www.microsoft.com
www.yahoo.com
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Web Browsing Example
• Start at www.yahoo.com and click Sports
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Uniform Resource Locator (URL)
• Address bar shows URL (location) of the document
http://www.microsoft.com/windows/ie/Features.default.asp
DocumentPath (directory or folder)
Web site (address of Web server)
Means of access (HTTP)
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Connecting to the Internet
• 2 basic ways to connect to the Internet.
• Connect through a LAN– Typical of college or business access– Faster than dial-up access– System configuration created and maintained
for you
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Connecting to the Internet (cont.)
• Dial up– Requires Internet Service Provider (ISP) and modem
• Modem is the hardware interface between your computer and the telephone.
Subscriberdials ISP
Internet Backbone
ISP creates connection to Internet
backbone
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Connecting to the Internet
• Wireless technology– Allows user to have mobile connection.– Accomplished via public Wi-Fi networks.– A computer with wifi network cards connect
wirelessly to a wireless router.
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Internet Service Providers (ISP)
• ISP is a company that maintains a computer with permanent access to the Internet.
• Jaring
• Tmnet
• Maxis Broadband
• Yes 4G with Voice
• You need to pay certain amount of fee
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How the Internet Works
• The backbone is operated by commercial providers such as TM.
• When you click a hyperlink, your request goes to your ISP, through a router to the backbone.– Router is a special-purpose computer that
ensures each request(message) is sent to its correct destination.
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TCP/IP
• Messages broken into packets
• TCP/IP sends packets by best available route and reassembles at destination
Message reassembled by recipient’s client
Message broken into packets and sent on multiple paths
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Internet Architecture Layers
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How Big is the Internet?
• No one knows!• It’s expanding
geometrically
Search Engines:
Finding Information On The Web
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Search Engines
• A program that systematically searches the Web for documents on a specific topic.
• You enter a query (a key word or phrase) into a search form, and the search engine scans its database to see which documents are related to the key word you requested.
• It will list the titles together with a link to each document.
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Search Engines
• Many search engines available• Each uses its own database of Web documents.• Each database stores information about each
document it contains, typically the document’s URL, key words that describe the document and selected information from the document.
• Use spiders to crawl the Web and find new sites and pages to add to search engine database
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• Enter a key-word query into search form
• Hits displayed on search results page
• Go from Web search to site search at relevant home page
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Popular Web Search Engines
URL Site
http://www.altavista.digital.com
http://www.infoseek.com
http://www.lycos.com
http://webcrawler.com
http://www.yahoo.com
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Logical Boolean Operators
• And, Or, Not– And ->includes all findings of both key word(s)– Or -> looks for only one of the specified key
word (s)– Not -> allows you to exclude certain key word
(s)
• Each search engine has its own syntax• Use “advance search” function in search
engine to enter Boolean operators
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The Find and Save Commands
• Use the Find command to locate key word on current Web page
• Use Save Picture As command to save picture locally for later use in other documents
• Cite the site!
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Find Command
• Edit Menu
• Find Command
• Searches within the document
• Faster
• Convenient
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Pictures & Thumbnail Images
• Small Version
• Save Picture As
• Insert Picture– Insert menu– From File– Find Picture– Click Insert
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File Compression
• Files are often compressed to reduce the file size, when sending a file from one location to another.– Such as when you are downloading software
from the internet to your PC.
• Advantages :– Reduces the time for downloading.– Multiple files can be placed inside a single
compressed file (also called an archive)
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Compress (Zip) Files
xxx.doc yyy.doc zzz.doc
File Decompression Utility
ProjectDocs.zip
xxx.doc yyy.doc zzz.doc
File Decompression Utility
ProjectDocs.zip
Sender creates zip file to store on Internet
Receiver downloads zip file and unzips archive onto local drive
Internet Server
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Issues in Cyberspace
• Copyright Protection– Everything on the Internet is copyright
protected unless in the public domain– You may use material from the Web in papers
and presentations under the fair use doctrine– Cite your sources!
• Viruses– Use antivirus program and update it often for
best protection
The End
CMPF 124:
Basic Skills for Knowledge Workers