Tuesday, August 30, 2011

How Google Search Engine Works?

Before we start anything, we must know who is the founder of Google. It was Larry Page and Sergey Brin who founded the Google in the year 1996. I am writing this blog because of huge popularity of Google and any way learning about the search engine is not at all waste of time, at least next time if any one asks "How Google Engine Works?" you will have the answer. In this blog i won't be explaining any programming part, its just a overview of how Google works.
The three tools which Google use is Web Crawler, Indexer and Searching Algorithm.


Web Crawler or Web Spider is a tool which travels the Internet and downloads and saves the web pages across world wide web. A web Crawler is fed with the URL of the website and it will download all pages and images related to the website. WebRipper and BlackWidow are the free Internet scanner and downloader(web crawler), which download massive amounts of images, videos, audio, executables or documents from any website in just a moment. They use spider-technology to follow the links in all directions from the start address. It filters out the interesting files on the way, and adds them to the download-queue for fast downloading by the multi channel download-engine.

Name of Google web crawler is Googlebot which travels world wide web and Download and saves pages and indexes them. It is not always necessary that Googlebot crawls every website and index the page. Sometimes it is possible that we don't want some of our page to be indexed in Google i.e. we don't want Google search engine find this page and show in search result. For this purpose you can use meta robots tag or robots.txt file, to learn more Click Here.


Now the saved pages is submit to indexer, which will index the pages in Index Database. Here Indexing means extracting the words from title, heading, keyword meta tag, description meta tag etc and storing in database. No doubt it will help search engine to refine the results.


Now the last thing we should know about is searching, here we are given a search box where we can enter our query or keyword, now the basic algorithm is match the keyword with pages indexed in database, but wait, there may be more than thousands of pages with such keyword, so, which one to show and by which priority. One of the parameter of priority finding can be, showing the indexed page which matches best with the keyword/query specified. And Google uses its own pagerank algorithm to rank and prioritize  the pages for a  query.

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