Saturday, September 10, 2011

...........about Internet.

In order for information to travel on the Internet, a computer has to break down a single message into smaller chunks of data called packets and send those packets through modem and down the telephone lines.  These packets move independently from one line to another, one network to another, until they reach their final target destination, where another computer gathers them all together and reassembles them into the original message.  The beauty of the way the Internet works as a communication tool is that even if one or more phone lines become unavailable, or a number of individual networks go down, data  packets can always find another route through different lines, networks, and computers - to their final destination.  Consequently, it would be very hard to shutdown the entire Internet
   That's why the Internet came into existence in the first place.  In 1969, the US Department of Defence decided to try connecting several major computing centre together in a network.  The Defence department reasoned that this would permit communications to continue across the United States, even if a natural disaster or armed conflict destroyed parts of the network.  From theses humble beginnings, the 'Net' was born.

What is a Modem?
The term modem comes from the word Modulator Demodulator, which actually describes how this essential piece of hardware acts as your computer's link to the rest of the world.  Connected to your computer either internally or externally, a modem transforms (modulates) THE DIGITAL Signals that can travel across regular phone lines and into the modems of other computers.  When a modem receives a signal, it must reverse the original process and transform the original signal back (demodulate) into a digital one the computer can use.

One of the most important attributes of a modem is speed at which it can transmit and receive signals.  A fast modem lets you jet across the Internet and its famous offspring  the World Wide Web in no time.  You can move from site to site more quickly and download more efficiently, and more cost effectively, by staying online for less time.  (Downloading is when you transfer a file from a site on the Internet to your computer's hard drive.)  We measure a modem's speed in bits per second (bps).  Bits are tiny pieces of data.  Most of the modemns sold these days have a speed of 28,800 bps.  However, this number is usually expressed as 28.8 kilobits per second, or 28.8 Kbps.

What is the World Wide Web?

The Internet contains different parts, with the most famous being the World Wide Web.  Users with a Web browser can enjoy the graphical interfaces on the Web that are considerably more user-friendly than the text-only sites found throughout much of the Internet.  By pointing the cursor and clicking the mouse, users can visit individual Web sites that contain everything from text and images to sound, animation, and video.

It seems everybody has their own Web sites these days.  From universities to movie studios, advertising agencies to potato chips manufacturers, scientists to the average Joe-they are all on there.  If you want information, useful or not, presented in a visually pleasing way, you want the Web.

In web also gives users the ability to jump from site to site by simply clicking highlighted sections of text, called hyperlinks, that appear in most sites.  For  example, if you are reading an online magazine's review of current movie, you might notice the director's name highlighted in blue within the body of the text.  That means the person who created this page has created a link for you.  If you click the name, you'll jump to a related story about the film's director.

What is a Web browser?

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