Search engines are the programs that are needed to extract information from the internet. They play a very important role in our daily routine, like today for each and every information we are dependent on the internet.
Web search engines work with the help of two programs, Spider which fetches as many documents as possible. Another program, called an indexer, reads the documents and creates an index based on the words contained in each document. Each search engine uses an algorithm to create its indices such that, only related results for specified keywords are stored and returns a list of the documents where the keywords were found.
A search engine works in the following order:
- Web crawling: Web search engines work by storing information about many web pages. These pages are retrieved by the program known as Web crawler – which follows every link on the site. Web crawler may also be called a Web spider.
- Indexing: Indexing also known as web indexing, it stores data to facilitate fast and accurate information retrieval.
- Searching: A web search query fetches the result from the web search engine entered by the user to meet his information needs.
Few search engines available are as follows: Google, Sogou, Baidu, Bing, Gigablast, Mojeek, DuckDuckGo and Yandex.