Page 12 - TCS ICT Book 8

The City School 2021-2022

1.1. What is a Search Engine?

A search engine is designed to search for information on the World Wide Web by using
specified keywords. The search results are usually presented in a list commonly called

hits. The information may consist of web pages, images, information and other types
of files. Below are some of the most common search engines:

Search Engine Purpose

google.com For generally searching anything

images.google.com For image searching
scholar.google.com For educational and research searches

books.google.com For searching books online

yahoo.com For generally searching anything

duckduckgo.com For organic searching

1.2. How do Search Engines Work?

Internet search engines are special sites on the web that are designed to help people
find information stored in other sites. There are differences in the ways various search

engines work, but they all perform three basic tasks:

They search the They keep an index They allow users to
internet or select of the words they look for words or
pieces of the internet find, and where they combinations of words
based on important find them. found in the index of
words. words.

Early search engines held an index of a few hundred thousand pages and documents

and received maybe one or two thousand inquiries each day. Today, a top search
engine will index hundreds of millions of pages, and respond to tens of millions of

queries per day.

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