Transcript The Internet

The Internet
October 30, 2007
The Internet
• URL’s
• Search Engines
• Boolean Operators
• Internet Searches
• Scavenger Hunt
URL’s
• The address of a web page
• URL =
• = Uniform Resource Identifiers
– Universal Resource Identifiers
– Uniform Resource Locators
• 31 billion web pages with URL names!!!
URL’s
• 6 Examples
http://www.whitehouse.gov
https://www.nbnzco.nz/login.asp
http://forums.about.com/ab-guitar/messages/?msg=61981
ftp://ftp.download.com/public
telnet.//freenet.ecn.ca
gopher://205.17.0.108
URL’s
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Some general rules:
Never has any spaces in it
For the most part it is all lower case
Not the same as an email address
Always starts with protocol prefix
• Eg. http:// - most browsers will type that for you
• Other internet protocols
• Eg. ftp:// gopher:// telnet:// irc://
ANATOMY of a URL
ANATOMY of a URL
ANATOMY of a URL
Search Engines
3 kinds of search engines
1. Crawler Based
2. Human Powered Directories
3. Hybrids
Crawler Based Search Engines
• Eg. Google
• Create listings automatically
• Crawl or spider web produce list that we go
through
• These engines will eventually find any
changes you make to your site and will
update the index accordingly
Human Powered Directories
• Eg. Open Directory
• You submit a short description to the
directory for your entire site
• Editors can also write a summary for a site
they view as well
• When you search a directory you are only
searching the descriptions, NOT the sites
Hybrid Search Engines
• Combine the best of both worlds!
• Eg. MSN search
• Usually these favour Crawler or Human,
they’re never ½ and ½.
• MSN favours human powered over crawler
How do Search Engines Work?
• 3 Elements
1. Spider (aka crawler)
Visits web page, reads it and goes to other
pages that are linked on the site
Site was “spidered”
Returns every month or two to check for any
changes
How do Search Engines Work?
1. Spider to Index
Spider  Index or Catalog
A site will not turn up in a search until it has
been indexed or catalogued.
How do Search Engines Work?
1. Search engine software
Sifts through the index to find any matches to
a search
Takes any matches and ranks them in order of
relevance for you
Searching the Net
• What do you type into the Search bar so you
will find what you’re looking for???
Searching the Net
Boolean Operators
Searching the Net
• The use of words to show the relationship
between two items
AND
OR
NOT
Searching the Net
• Can also use “” (Quotes – not smiley)
• Quotes will _______ your search because
the words need to show up side by side
• Quotes also make your search more direct
and you tend to get better results!
Searching the Net
• Using + and – signs also helps your search!
• + tells the search engine which keyword
you think is most important
• + must have a space in front of it and must
be attached to the word it relates to
• - removes words that you do not want
included in your search results