Search
Engines
In
addition to typing in a URL, users can find information on the
Web by using a search
engine. A search engine is a large collection
(or a full-text database) of Web-based documents and other types
of Internet files collected by a computer program. These programs,
called spiders or crawlers (hence the name Web Crawlers), scan
the Web for pages that are publicly accessible. As they scan,
they store (log) the words on each page in their database, following
the links on each page to access other Web pages. Other software
programs allow users to search these Web sites. When users do
a search, the search engine scans the database to find any pages
which contain the search term(s) and brings them up in a results
list. Search engines can have over a billion documents, and for
this reason the results list is usually quite lengthy.
Google,
which can be accessed at http://www.google.com,
is currently the search engine with the largest database
and has the best record for keeping pages current.
