cmpf 124:basic skills for knowledge workers the internet

CMPF 124:Basic Skills for Knowledge Workers

The Internet

CMPF124: Basic Skills for Knowledge Workers

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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

cmpf 124:basic skills for knowledge workers the internet

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