The Internet and the World Wide Web Chapter 2A The Internet and the World Wide Web

The Internet’s History 1969 – ARPANET Developed by the Department of Defense Connected universities and defense bases 1973 – ARPANET connects to Europe

ARPANET 1973

The Internet’s History Mid-1980s – NSFNet Network between supercomputers Internet was the link to ARPANET No commercial traffic allowed 1990s ARPANET shut down NSFNet abandoned Commercial networks take over Discussion point Have students discuss the pros and cons of no central control for the Internet. Some discussion points can include copyright issues, free speech, advertisements and information access to all.

Today and the Future 100,000 new web sites per month More than 50% of U.S. households online Access is available throughout the U.S. Eventually access will be global

U.S. Internet Growth

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

The Internet’s Major Services News Often called newsgroups Electronic discussions on several topics File Transfer Protocol (FTP) Sends and receives files Teaching tip Show a typical news group to the students in class. Be sure that you have connected and downloaded all posts before trying the demonstration. Demonstrate the use of ftp to change a web site.

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 Napster and Kazaa are examples Illegal to share copyrighted material Discussion point Recently the pop artist Madonna posted several copies of her songs on Kazaa and other file sharing services. Instead of music, she talked at length about copyright infringement through music sharing. In retaliation, hackers hit her website and temporarily made her songs free to purchase. Who is right?

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

Accessing The Internet High-speed access Connect through a special line 2 – 25 times faster than dialup DSL, Cable, T1 are common

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 Teaching tip Find out who has a web presence. If the site is appropriate, display it in class. Have the student discuss what is needed to establish and maintain a web presence.

Understanding the Internet 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> Teaching tip Show your students how to access the HTML of an appropriate web site.

Understanding The Internet Browsers Read and translate the HTML Display web content Uniform Resource Locator (URL) Address of a web page Teaching Tip Dissect the URL provided.

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 Teaching point Direct the students to several different streaming video sites. Www.launch.com and www.apple.com/QuickTime are two excellent examples. Be sure your classroom browsers have the appropriate plug-ins.

Streaming Audio

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

Searching the Web The Web is unorganized Directories Search engines Categorize the Internet Search engines Find sites by keyword Insider information 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” is a phrase uttered on college campuses the world over.

Searching the Web Site searches Metasearch sites Sponsored links Large sites have an internal search Metasearch sites Search several web sites at once Sponsored links Sites pay for better search results

Search Techniques Quote the exact phrase Use the keyword AND Use the keyword NEAR Avoid common words Use the site’s advanced tools

MONITOR A monitor or a display is an electronic visual display for computers.

History Early electronic computers were fitted with a panel of light bulbs where the state of each particular bulb would indicate the on/off state of a particular register bit inside the computer. This allowed the engineers operating the computer to monitor the internal state of the machine, so this panel of lights came to be known as the 'monitor'. As early monitors were only capable of displaying a very limited amount of information, and were very transient, they were rarely considered for programme output. Instead, a line printer was the primary output device, while the monitor was limited to keeping track of the programme's operation.

Cont’d………. Originally, computer monitors were used for data processing while television receivers were used for entertainment. From the 1980s onwards, computers (and their monitors) have been used for both data processing and entertainment, while televisions have implemented some computer functionality. The first CRT monitor was created in 1987 by a German physicist named Karl Ferdinand. The first time it was used by regular consumers, though, was not as a computer screen, but rather as a 5' desktop calculator screen! Technology really has gotten smaller and smaller since those days!

Types of Monitor The first type that comes with most desktop computers ;it look like a television screen and works in much the same way . This type of monitor uses a large vacuum tube ,called a cathode ray tube (CRT). The second type ,known as flat –panel display ,was used primarily with portable computer in past .Today, flat penal monitors are popular features with desktop computers .

Categorized All the Monitors can be categorized by the way they display colors……… Monochrome monitor display only one color (such as green ,amber, or white ) against a contrasting back-ground ,which is usually black. These monitors are used for text –only displays , where the user does not need to see color graphics.

Grayscale Monitors Grayscale monitors display varying intensities of gray against a white or off-white background and are essentially a type of monochrome monitor .Grayscale flat – panel display are used in low –end portable system –especially handheld computers to cost down.

Colors Monitors Colors monitors can display 16 colors and million colors . Today ,most new monitors display in colors. Many color monitors can be set to work in monochrome or grayscale mode.

Printing Devices

Printer Its types, working and usefulness

What is a printer? An external hardware device responsible for taking computer data and generating a hard copy of that data. They print text and still images on the paper.

“Print Quality” (1) Near typeset quality: A Lower quality print similar to the output of a type-writer. (2) Letter quality: Print made up by fully formed (solid line) characters. (3) Near letter quality: A print of high quality formed by multiple passes of print head over the same letter. (4) Standard quality: A high quality print formed by a single pass of the print head. (5) Draft quality: A print formed with minimum number of dots or lines and are smaller than the standard quality characters.

“Factors affecting print quality” (1) DPI: It is a measurement of printer’s resolution indicating how many ink dots can be placed by the printer in one square inch. The higher the DPI, the sharper is image. (2) Type of printer: Each type of printer has its own capabilities of printing. Some types of printers produce high quality print while other produce low quality print. (3) Print Mode: The printing mode may also affect the quality. For example the draft mode increases the print rate but quality is reduced. (4) Toner: The quality and amount of toner also affects print quality.

“Dot Matrix Printer” The term dot matrix refers to the process of placing dots to form an image. Its speed is usually 30 to 550 characters per second (cps). This is the cheapest and the most noisy printer and has a low print quality. Dot Matrix were 1st introduced by Centronics in 1970.

How Dot-Matrix works? The dot matrix forms images one character at a time as the print head moves across the paper. Uses tiny pins to hit an ink ribbon and the paper much as a typewriter does. This printer arranges dots to form characters and all kinds of images. 9 to 24 vertical column pins are contained in a rectangular print head. When print head moves across the paper, pins are activated to form a dotted character image. These printers can produce carbon copies along with the originals.

Printers

“Advantages/Dis-advatages of Dot-Matrix” (1) In-expensive. (2) Low per page cost. (3) Energy efficient. Dis-advantages: (1) Noisy (2) Low resolution (3) Limited fonts flexibility (4) Poor quality graphics output.

“Printers for different users” To choose a printer from a printer’s family following considerations are to be made. (1) What’s the budget? (2) Is color needed or just black& white? (3) What is the Volume of the output? (4) How important is the quality of the output? (5) What special features are needed? (6) Is the printer is to be used by a single user or a whole network?

“Printers for banks, large business organizations and companies” In banks, large size business environments and companies printers with networking capabilities should be preferred which can increase productivity and reduce the cost without compromising on the quality. Of course laser printer is quite suitable choice but multi-functional printer and inkjet printer can also play vital role.

“Conclusion” In fact computer world is incomplete without printers in the modern age of technology. A printer is one of the basic needs of every computer user and one can not utilize computer resources properly in the absence of a quality printer.