Internet - Searching

One of the advantages of the Internet is that anyone can put content onto it. This means that there are millions of web resources, none of which are catalogued or indexed. Finding the correct resource requires the use of a search engine.

Searching the Internet means finding Internet resources.

A search engine uses ‘spiders’ (specialised software) that visit every website, indexing the content of each web page. It does this by scanning the metadata in every web page header, as well as by using keywords registered by web authors.

There are two types of search:

• natural language
• Boolean.

Natural language search

A natural-language search usually takes the form of a question. The Internet user enters a question, using his or her natural language, which in our case is English.

For example, ‘What is the highest mountain in the World?’

Search engines such as www.ask.co.uk allow the Internet user to use natural language.

Boolean search

Boolean search uses logical, or Boolean, operators (such as AND, OR) together with keywords. These operators are used to filter out unwanted resources and leave a concise list of possible resources.

Basic, or simple, searches produce thousands of hits. Many of these hits are totally unwanted, relating to topics that the Internet user does not want.

Advanced searches allow the Internet user to fine tune their search, reducing the number of unwanted responses. Advanced searches require the use of operators that act on the keywords selected.

Standard Boolean operators

Different Search Engines will use different operators, but they all use the standard Boolean operators shown in the following table.

[Remember that, if you simply enter a list of keywords to search, the result will list not only those pages that mention all of the keywords, but also any instance of each of the keywords.]

Operator	Description
" "	A phrase search requires the Internet user to use quotation marks to enclose a keyword phrase: “Donald Duck” This search will return a list of pages containing the phrase ‘Donald Duck’.
+	If a keyword is essential, you can include it by putting a “+” sign in front of it. Donald +Duck This search will return a list of pages containing the words ‘Donald’ and ‘Duck’.
-	A keyword can be excluded from the search by placing a minus sign in front of it. Windows +95 +XP –Glass This search will return a list of pages containing the words ‘Windows’ and ‘95’ and ‘XP’ but not the word ‘glass’, so it will not return information about glass windows.
AND	This is synonymous with “+”.
OR	To search optional key words, use this operator. Travel Glasgow OR Edinburgh Travel information will be returned about either Glasgow or Edinburgh, but not both together.
NOT	This is synonymous with “–”.

(Boolean operators must printed be in UPPER CASE or capital letters.)

There are a number of very good search engines, all offering advanced search facilities. Google is one of the more commonly used and offers a number of advanced search facilities.

Apart from the Boolean logical operators, search engines can accomplish other types of advanced searches.

Operator

Description

domain: domain name

The domain: operator locates web pages that have a

specific domain. domain:uk will return all the web pages that

use .uk.

host:host name

The host: operator locates web pages that have a specific host name.

host:www.google.co.uk will return all Google web pages.

text:text

The text: operator locates web pages that contain the specified text. text:windows will return the web pages that contain the word 'windows'.

Domain search

Google domain search allows the Internet user to find links to web domain names. For example, you can find links that contain .org.uk or .sch.uk domain names.

Download and complete Worksheet 12.