Thu Jan 10 02:02:44 PST 2019

Imagine the World Wide Web as a network of stops in a big city subway
system

Each stop is its own unique document (usually a web page, but sometimes a PDF, JPG or other
calculating relevancy & rankings and serving results

1
Crawling and Indexing
Crawling and indexing the billions of
documents, pages, files, news,
videos and media on the world wide
web

2
Providing Answers
Providing answers to user queries,
most frequently through lists of
relevant pages through retrieval and
rankings


Once the engines find these pages, their next job is to parse the code from them and store selected
pieces of the pages in massive hard drives, to be recalled when needed in a query
To accomplish
the monumental task of holding billions of pages that can be accessed in a fraction of a second, the
search engines have constructed massive datacenters in cities all over the world

These monstrous storage facilities hold thousands of machines processing unimaginably large
quantities of information
After all, when a person performs a search at any of the major engines,
engines work hard to provide answers as fast as possible