A search engine is an information retrieval system designed to help find information stored on a computer system. The search results are usually presented in a list and are commonly called hits.
Search engines help to minimize the time required to find information and the amount of information which must be consulted, akin to other techniques for managing information overload.
There are three pieces of software that together make up a search engine: the spider software, the index software and the query software and it will make your foundation for getting your website to the top of the search engines.
The Spider Software
The spider software crawls the web looking for new pages to collect and add to the search engine indices’ and it harvests web links from page to page.
The difference is that the spider doesn’t collect images or formatting it is only interested in text and links and the URL, (for example, http://www.Unique-Resource-Locator.html) from which they come. it doesn’t display anything and it gets as much information as it can in the shortest time possible.
Since the spider doesn’t collect images, it doesn’t take notice of Flash intros or colorful pictures. So, make sure your images, logo or videos are identified by a text ‘alt tag,’ or the spider will ignore them and they will not have value in the search engines.
The Index Software
Index software is a database that is organized and search able of the Spider’s harvested results.
The index makes sense of the mass of text, links and URLs using what is called an algorithm a complex mathematical formula that indexes the words, pairs of words, phrases, and so on.
Essentially, an algorithm analyzes the pages and links for word combinations to figure out what the web pages are all about in other words, what topics are being covered. Then, scores are assigned that allow the search engine to measure how relevant or important the web pages (and URLs) might be to the person who is searching.
And of course the index software records all of this information and makes it available.
The spider takes the information it has gathered about a web page and sends it to the index software where it is analyzed and stored.
When someone types apple into the query box on a search engine page (such as Google), then it’s time for the query software to go to work. See image on the following page.
The Query Software
A search engine query is a request for information that is made using a search engine. Every time a user puts a string of characters in a search engine and presses “Enter”, a search engine query is made.
The query software is what you see when you go to a search engine – it is the front end of what everybody thinks of as a search engine. It may look simple but the query software presents the results of all the quite remarkable spider and index software that works away invisibly on our behalf.
So, when you type in your search words and hit search, then the search engine will try to match your words with the best, most relevant web pages it can find by ‘searching the web’.
The query software doesn’t actually search the web – instead, it checks through all the records that have been created by its own index software. And those records are made possible by the text, links and URL material the spider software collects.