Sunday, August 12, 2007

Features of messenger

A messenger is installed on the user's computer and its facilities sending and receiving instant messages , graphical symbols , audio and visual information .The features of messenger that make is a favourite among Internet users include :
  • Chatting : With a messenger , one can char using a web cam or microphone and web cam or microphone and send textual messages . In addition , users can find and meet people instantly.
  • Audibles : Audibles are faces used to say something or express the attitude of the user in the form of greetings , games and fun. These audibles are used for sending verbal animations directly from the instant messaging application.
  • Emotions /Smileys :The emotions or smileys are used to express the feelings in the form of little symbols and smiling faces.
  • Games : When connected online , users can play multi-player games such as chess ,checkers , and many more . Users can see how they stack up against their friends by comparing their scores.
  • Address Book : Messengers also provide address books so that users can easily find and manage their friend's contact details.

Instant Messaging

Instant messaging is a web-based service to exchange messages in real time between two or more people over the Internet .It is a combination of e-mail and chat room . For sending instant messages , users create a list of users with whom they wish to communicate .The messages sent through this service take less time and the delivery of messages is instantaneous. However , to send and receive instant messages , Internet connections along with instant messaging software (known as instant messengers) , such as Yahoo Messenger or MSN Messenger , are required .Instant messenger is one of the most popular Internet tools , which allows the users to communicate over the Internet through voice , live pictures , or text. It is free and faster than e-mail because instant messages can be sent to friends whether they are online or offline.It allows the users to carry multiple conversations at a time.

Usually , users send their messages in text format . However , while sending instant messages , a user can also communicate through web cam (video chatting) as well as through speakers and microphone(chatting) . In addition , one send audio or video files along with instant messages . the recipient can view the received files at that particular time or late as desired by him.

Refining the search

The search engines allow the user to choose whether to search for the exact typed phrase , all the words in the phrase , any of the words in a phrase , and so on. However , the search engines do not provide such options . In this case , the user can define the search by adding one or more words or symbols to the search topic.
  • AND : It is used to search for two or more terms on the same page . Type the word AND between the terms ( for example , poverty AND crime ) or put a plus sign right before the second term (example : poverty+crime).
  • OR : It is used to search for either of two (or more) terms on the same page.Type the word OR between the terms (for example , college OR university).
  • NOT : It is used to search for pages that include the first term but not the second. Type the words NOT between the terms (for example , cats NOT dogs ) or put a minus sign right before the second term (for example,cat-dogs).
  • "" : Double quotes are used to search for an exact phrase.For example , "desktop wallpapers ".
  • () : Parenthesis are used to group parts of the search phrase.For example , type desktop AND (themes OR wallpapers ). This returns pages with the words desktop and themes or both the words themes and wallpapers.
  • * : Asterisk is used to search for various forms of a word . For example , prior * returns pages with the words prior , prioritise , priority and so on.

Searching the Internet

With most search engines , you fill out a form with your search terms and then ask the search engine to find web pages relevant to the search terms.Some of the well known search engines are www.google.com,www.hotbot.com , www.lycos.com, and www.altavista.com.www.ask.com , www.yahoo.com , www.wikipedia.com , www. pagebull.com.



The engine searches its index and generates a page with links to those resources containing some or all of the search terms.Clicking on any link opens a website or web page in which the searched keyword appears.

Saturday, August 11, 2007

Search Engine

The Internet provides access to a wealth of information on countless topics contributed by people throughout the world .However, the internet is not a library in which all its available items are identified and can be retrieved by a single catalogue . In fact , no one knows how many individual files (could be billions ) reside on the Internet. Hence , to conduct a search on the Internet , a special search tool , known as ' search engines ' are used.A search engine is a searchable database of internet files collected by a computer program called a wanderer , crawler , or spider . It allows the user to enter keywords relating to particular topics and retrieve information about Internet sited containing those keywords . As such , a search engine consists of four components :

1.Spider : Program that traverses the web from link to link , identifying and reading pages.
2.Indexing Software : Program that analyses web a pages that are downloaded by spiders.
3.Database : Warehouse of the web pages downloaded and processed.
4.Search Engine Mechanism : Software that enables users to query the index and that usually returns results in term relevancy ranked order.

A search engine doesn't really search the web directly.To find the information on the millions of web pages , a search engine employs special software , called spiders. After spiders find pages , they pass them on to another computer program for indexing . This program identifies the text , links , and other content in the page and stores if in the search engine database's files so that the database can be searched by keyword. Note that creating index and updating search database is a never-ending process because of the constantly changing nature of the web . As a result , the spiders are always 'crawling'.




One of the famous search engine is GOOGLE search engine

When users search the web using a search engine , they are provided with the links of all the searched web pages. On clicking on the links provided in a search engine's search results , the correct versions of the web pages are retrieved form the server.