1Copyright © Prentice Hall 2000 The Internet Chapter 7 A Resource for All of Us.

1Copyright © Prentice Hall 2000

The Internet

Chapter 7Chapter 7

A Resource for All of UsA Resource for All of Us


The Internet as a Phenomenon

• The Internet is a loosely The Internet is a loosely configured, rapidly configured, rapidly growing labyrinth of growing labyrinth of networks,networks,

• composed of computers composed of computers from around the world, from around the world,

• owned by multiple owned by multiple corporations, corporations, organizations, and organizations, and individuals. individuals.


Don’t Know Much about History

The history of the The history of the Internet is Internet is mercifully short, mercifully short, and is covered and is covered briefly in the next briefly in the next sections.sections.


First Stirrings at the Department of Defense

• In the Cold War era of the In the Cold War era of the 1950s, paranoid atmosphere in 1950s, paranoid atmosphere in the United States prompted the the United States prompted the U.S. DoD to design a survivable U.S. DoD to design a survivable computer network. computer network.

• This result was the This result was the Advanced Advanced Research Projects Agency Research Projects Agency Network (ARPANet)Network (ARPANet)..



The packets, or message parts, The packets, or message parts, conveyed through ARPANet were conveyed through ARPANet were taken care of by the taken care of by the Transmission Control Transmission Control Protocol/Internet Protocol Protocol/Internet Protocol software (TCP/IP)software (TCP/IP)..

Length Data1 DataNType Checksum



Computers from research universities and Computers from research universities and defense contractors joined the network,defense contractors joined the network,

but the technology’s popularity was still but the technology’s popularity was still restricted largely to professionals and restricted largely to professionals and those with technical expertise.those with technical expertise.


Tim Berners-Lee

In 1990, In 1990, Dr. Tim Berners-Dr. Tim Berners-LeeLee, a physicist at , a physicist at CERNCERN, , knew his work would be knew his work would be easier if he linked his and easier if he linked his and his colleagues’ his colleagues’ computers together on a computers together on a network.network.

He saw the linked machines He saw the linked machines as a spider’s web, hence as a spider’s web, hence the term “the term “WebWeb”.”.

CERN Lab, Switzerland


Link Terminology

LinksLinks on a web site are easy to see. on a web site are easy to see. They appear as eitherThey appear as either– HypertextHypertext, colored text that shows , colored text that shows

the web site to which it links. Or a link the web site to which it links. Or a link can be:can be:

– A A hyperregionhyperregion, an icon or image , an icon or image with a link or links to web sites.with a link or links to web sites.


Marc Andreessen

Marc Andreessen Marc Andreessen was a student was a student when, in 1993, he when, in 1993, he led a team that led a team that invented the invented the browserbrowser, software , software used to explore used to explore the Internet.the Internet.


Marc Andreessen

The browser, Mosaic, featured a The browser, Mosaic, featured a graphical interface, so that users graphical interface, so that users could see and click on pictures as could see and click on pictures as well as text.well as text.

Today, several competitive browsers Today, several competitive browsers exist, such as Netscape and exist, such as Netscape and Internet Explorer.Internet Explorer.


The Internet Surges Ahead

TCP/IP software was, and still is, in the TCP/IP software was, and still is, in the public domain, and the Internet grew public domain, and the Internet grew by leaps and bounds as more and by leaps and bounds as more and more people joined in and linked up.more people joined in and linked up.

As the As the InternetInternet, a name taken from , a name taken from the TCP/IP protocol, began to the TCP/IP protocol, began to dominate, the original ARPANet dominate, the original ARPANet began to disappear altogether.began to disappear altogether.


The Internet Success Factors

The emergence of the Internet is due to The emergence of the Internet is due to four factors:four factors:– The universal TCP/IP standardThe universal TCP/IP standard– The web-like ability to link from site to The web-like ability to link from site to

sitesite– The ease of use provided by the The ease of use provided by the

browser’s graphical interfacebrowser’s graphical interface– The growth of personal computers and The growth of personal computers and

their LANs connected to the Internettheir LANs connected to the Internet


Getting Started

The following The following sections sections briefly cover briefly cover the process of the process of accessing and accessing and using the using the Internet and Internet and its resources.its resources.


The Internet Service Provider and the Browser

An Internet user needs:An Internet user needs:– A computer with a A computer with a modemmodem,,– An An Internet service provider (ISP)Internet service provider (ISP)

that provides the server computer and that provides the server computer and software to connect to the Internet.software to connect to the Internet.

– A A browserbrowser to explore the Internet and to explore the Internet and access links.access links.

You can also sign up for an You can also sign up for an online serviceonline service to access the Internetto access the Internet



Approximately two thirds of Internet users Approximately two thirds of Internet users connect via online services.connect via online services.

The other third use ISPs.The other third use ISPs.

To use an ISP, you must first decide which To use an ISP, you must first decide which one. one.

Once you have arranged to pay the fees Once you have arranged to pay the fees (installation, monthly), you’ll set up (installation, monthly), you’ll set up your ISP as the provider’s instructions your ISP as the provider’s instructions direct.direct.



The next step is to install The next step is to install the browser software. the browser software.

• You can purchase a You can purchase a browser in your local browser in your local software retail outlet.software retail outlet.

• You could download a You could download a browser for free.browser for free.

• Once set up, you invoke Once set up, you invoke the browser like any the browser like any other program.other program.


The Browser in Action

Two popular browsers are Marc Two popular browsers are Marc Andreesen’s Andreesen’s Netscape CommunicatorNetscape Communicator and Microsoft’s and Microsoft’s Internet ExplorerInternet Explorer..

When you start the browser, it will dial up When you start the browser, it will dial up the ISP and, once connected, the ISP and, once connected,

• display either the home page of the display either the home page of the Web site that created your browser or Web site that created your browser or

• some other site designated by the ISP.some other site designated by the ISP.


The Parts of a Browser

Browser control panelBrowser control panel - shows the web - shows the web address currently displayed, buttons to go address currently displayed, buttons to go to the previous/successive pages visited.to the previous/successive pages visited.

Browser display windowBrowser display window - the largest - the largest part of the display. Shows the content of part of the display. Shows the content of the current web page.the current web page.

Browser status lineBrowser status line - shows the status of - shows the status of data being loaded or the destination of data being loaded or the destination of selected linksselected links


The Parts of a Browser

ControlPanel

StatusLine

DisplayWindow


Browser Functions and Features

The following The following sections sections cover the cover the functions functions and and workings of workings of the browser the browser control control panel.panel.


Menus and Buttons

Using a mouse you issue Using a mouse you issue commands through a series commands through a series of of menusmenus, a set of choices , a set of choices typically selectable from typically selectable from the top of the screen.the top of the screen.

Most menus are Most menus are pull-down pull-down menusmenus, at the very top of , at the very top of the display.the display.


Menus and Buttons

ButtonsButtons also invoke commands. also invoke commands. •Back and Forward traverse site Back and Forward traverse site history, history, •Print prints a web site, Print prints a web site, •Home goes to the home page.Home goes to the home page.


URL

The location slot contains a rather The location slot contains a rather messy bit of text called the messy bit of text called the Uniform Resource Locator Uniform Resource Locator (URL)(URL). .

First, the First, the HyperText Transfer HyperText Transfer Protocol (http://)Protocol (http://)

http://http://www.intel.com/pressroom/index.htm


URL

Second, the Second, the domain namedomain name, the , the address of the ISP contacted. address of the ISP contacted.

(If it is a commercial site, it ends (If it is a commercial site, it ends in in .com.com, , .org.org means nonprofit means nonprofit organization). organization). (http://www.kevinmitnick.com)(http://www.kevinmitnick.com)

http://www.intel.comwww.intel.com/pressroom/index.htm


URL

Third, the Third, the paths, directories, paths, directories, and file namesand file names of sites and of sites and their content loaded by the their content loaded by the browser. browser.

http://www.intel.com/pressroom/index.htmpressroom/index.htm


Frames

Each section Each section can operate can operate independentlindependentlyy

Most Most browsers browsers support support a a concept concept called called framesframes

Frames let you divide pages into rectangular sections


Competition

Not just functional buttons, but buttons Not just functional buttons, but buttons that illuminate when the cursor passes that illuminate when the cursor passes over them.over them.

Not just English, but French, German, and Not just English, but French, German, and Italian.Italian.

Not just frames, but borderless frames.Not just frames, but borderless frames.

Today’s browsers are a whole suite of Today’s browsers are a whole suite of programs for communicating, sharing programs for communicating, sharing information, mail and security support.information, mail and security support.


Plug-ins

In addition to the browsers themselves, In addition to the browsers themselves, many vendors offer many vendors offer plug-insplug-ins, software , software that enhances the value of a browser by that enhances the value of a browser by increasing its functionality or features.increasing its functionality or features.

Typical plug-ins enhance audio-visual Typical plug-ins enhance audio-visual experience or image viewing capability.experience or image viewing capability.

Most plug-ins can be downloaded from Most plug-ins can be downloaded from their own web sites.their own web sites.


Java

JavaJava is a programming language developed is a programming language developed by Sun Microsystems, used to write by Sun Microsystems, used to write software that can run on any machine.software that can run on any machine.

Java makes possible the dancing icons, Java makes possible the dancing icons, sound clips, flashing messages, and sound clips, flashing messages, and scrolling banners that you see on the scrolling banners that you see on the Internet today.Internet today.

The Java programs that provide multimedia The Java programs that provide multimedia effects are called effects are called appletsapplets..


Moving from Site to Site

Most browsers provide lists of clickable Most browsers provide lists of clickable categories.categories.

Many home sites provide “cool” links to Many home sites provide “cool” links to selected pages.selected pages.

If you want to be specific, you can If you want to be specific, you can delete the URL listed in the location delete the URL listed in the location bar and enter a desired URL to bar and enter a desired URL to “transport” you to an intended site. “transport” you to an intended site.


Searching the Internet

A A search engine search engine is software, usually is software, usually located at its own web site, that lets a located at its own web site, that lets a user specify terms; the search engine user specify terms; the search engine then finds sites that fit those terms.then finds sites that fit those terms.

A search engine finds sites by building a A search engine finds sites by building a database, following links across the database, following links across the Web and keeping data on some or all of Web and keeping data on some or all of the words on a Web site.the words on a Web site.


Hot Search Engines

The various search engines of the The various search engines of the Internet vary widely in size, Internet vary widely in size, content, and search methodology.content, and search methodology.


Hot Search Engines

A brief comparison:A brief comparison:– AltaVista AltaVista - Very fast; indexes every - Very fast; indexes every

word on every page of every site; word on every page of every site; searches Usenet too; excellent for searches Usenet too; excellent for custom searches.custom searches.

– HotBotHotBot - Fast; unique search options - Fast; unique search options let you restrict searches; very let you restrict searches; very comprehensive; excels at finding comprehensive; excels at finding current news.current news.


Hot Search Engines cont.

– LycosLycos - Numerous search - Numerous search options, a comprehensive options, a comprehensive directory, and good returns on directory, and good returns on simple searches.simple searches.

– InfoseekInfoseek - Searches not only - Searches not only the Web but also newsgroups, the Web but also newsgroups, FAQs, and E-mail addresses; FAQs, and E-mail addresses; extras such as foreign language extras such as foreign language searching and searching by searching and searching by geographical region.geographical region.


Hot Search Engines

– ExciteExcite - Good returns for simple - Good returns for simple searches; related hints and an array searches; related hints and an array of extra content.of extra content.

– WebCrawlerWebCrawler - Good for simple - Good for simple searches; returns clickable links searches; returns clickable links related to the search topic.related to the search topic.

– Yahoo!Yahoo! - Well-organized categories - Well-organized categories let you switch from browsing to let you switch from browsing to searching in a certain area; but searching in a certain area; but finds only keywords, not any word finds only keywords, not any word on a site.on a site.


Narrowing the Search

Boolean logicBoolean logic - a system of - a system of mathematics based on three mathematics based on three key operations - AND, OR, and key operations - AND, OR, and NOT. NOT. – AND - in Boolean, include both AND - in Boolean, include both

terms (life AND insurance)terms (life AND insurance)– OR - in Boolean, include either or OR - in Boolean, include either or

both terms (university OR college)both terms (university OR college)– NOT - in Boolean, exclude any site NOT - in Boolean, exclude any site

with terms preceded by NOT with terms preceded by NOT (browsers AND NOT Microsoft) (browsers AND NOT Microsoft)


Search Engine Limitations

Search engines are known for Search engines are known for turning up turning up too muchtoo much information. information.

But even with the pages they turn But even with the pages they turn up, search engines only search up, search engines only search about about one thirdone third of the entire Web. of the entire Web.

For now, the best way to turn up For now, the best way to turn up Web pages with content you want Web pages with content you want is to use multiple search engines.is to use multiple search engines.


Branching Out

Although the WWW is usually the Although the WWW is usually the focus of any Internet discussion, focus of any Internet discussion, there are other parts of the there are other parts of the Internet that deserve attention.Internet that deserve attention.

One way to identify such sites is the One way to identify such sites is the protocol. Instead of protocol. Instead of httphttp, you may , you may see see newsnews or or ftpftp..


Newsgroups

UsenetUsenet is an informal network of is an informal network of computers that allows the posting and computers that allows the posting and reading of messages in newsgroups that reading of messages in newsgroups that focus on specific topics.focus on specific topics.

A more informal name is simply A more informal name is simply newsgroupsnewsgroups..

Think of a newsgroup as one large bulletin Think of a newsgroup as one large bulletin board marked off by category.board marked off by category.


FTP: Downloading Files

Whether or not a file is available for Whether or not a file is available for downloading depends on two things:downloading depends on two things:– (1) whether you are allowed to download (1) whether you are allowed to download

files to the hard disk of the computer you files to the hard disk of the computer you are usingare using

– (2) whether the file you want is available (2) whether the file you want is available for copyingfor copying

All kinds of files - programs, text, graphics, All kinds of files - programs, text, graphics, images, even sounds - are available to be images, even sounds - are available to be copied without restriction.copied without restriction.


FTP: Downloading Files

Computers on the Internet have a Computers on the Internet have a standard way to transfer copies of standard way to transfer copies of files, a program called FTP, for files, a program called FTP, for file file transfer protocoltransfer protocol..

Most downloading is done by a Most downloading is done by a method called method called anonymous FTPanonymous FTP..


Not Quite Perfect Yet

The Internet has been heaped with The Internet has been heaped with well-deserved praise. But still there well-deserved praise. But still there are concerns. are concerns.

The last two sections cover the The last two sections cover the shortcomings of the Internet.shortcomings of the Internet.


Behavior Problems

• There really are some behavior There really are some behavior problems on the Internet. problems on the Internet.

• Those who abuse the Internet are, Those who abuse the Internet are, relatively speaking, few in number. relatively speaking, few in number.

• Meanwhile, the community of Meanwhile, the community of Internet users has made serious Internet users has made serious effort to monitor behavior on the effort to monitor behavior on the Internet. Internet.

• One consistent effort is One consistent effort is netiquettenetiquette, , which refers to appropriate which refers to appropriate behavior online.behavior online.


Useless, Overburdened, and Misinformed

Some people consider home pages Some people consider home pages useless. Still, many people are useless. Still, many people are willing to pay for the connection to willing to pay for the connection to a Web server primarily to promote a Web server primarily to promote their own web pages. their own web pages.


Useless, Overburdened, and Misinformed, cont.

The “coolest” sites of the Internet, and The “coolest” sites of the Internet, and the sites which list popular URLs are the sites which list popular URLs are often crowded with thousands of often crowded with thousands of visitors.visitors.

The Internet can be full of misinformation The Internet can be full of misinformation as well, from news hoaxes to conspiracy as well, from news hoaxes to conspiracy buffs to tall tales of popular culture and buffs to tall tales of popular culture and far-fetched remedies. far-fetched remedies.

1Copyright © Prentice Hall 2000 The Internet Chapter 7 A Resource for All of Us.

Documents

copyright prentice hall

switzerland slide

internet surges

internet chapter

internet explorer

survivable computer

spiders web

term web