Objectives
You should be able to:- Define a URL
- Describe the parts of a URL
- Describe the World Wide Web
- including the software
- the terms
- Discuss the size of the web.
- Identify and describe a web index
- Discuss when to use a web index.
- Know the location of one web index.
- Identifiy and describe a search engine
- Discuss when to use a search engine.
- Know the location of one search engine.
The URL
- Universal Resource Locator
- http://www.edinboro.edu/~bennett
- http://www.edinboro.edu/~bennett
- Specifies the protocol
- http is the most common, some others
- file: - load a file
- mailto: - send a mail message
- ftp: - transfer a file
- There are others.
- Try the following url
mailto:dbennett@edinboro.edu
- http://www.edinboro.edu/~bennett
- This is the name of a machine on the net (Domain Name.
- The name works like our names left to right
- Dan Bennett - Dan is my first name, ...
- www.edinboro.edu, www is the machine name, edinboro is the organization ...
- Take a look at this site
- Remember, the machine name does not have to be www.
- http://www.edinboro.edu/~bennett
- This is the name of a user
- Or the name of a file
- try http://douc54.cs.edinboro.edu/hello.html
- Or the name of a program
- try http://douc54.cs.edinboro.edu/cgi-bin/foo
- Or ...
- The definition is open, so more things can, and have been added.
Hyper____
- Text - hypertex is text with a link to another text somewhere else.
- Link - a hyperlink is that pointer.
- Hyper Text Markup Language (html) - the language of web pages.
- Hyper Text Transport Protocol - (http) - the way they are sent over the network.
- Browser - the thing you use to look at web pages.
- Web Server - the thing that sends the pages to your browser.
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How Big is the Web?
- How many pages are there on the web?
- What is the count at google? Is this complete?
- How about this Press Release
- How about this one?
- So, can you expect to:
- Know "All about the web"?
- Find anything at all?
- Two things that help
- A Web Index
- A Search Engines
- Remember, this is a dynamic system
- Pages are changed daily
- Some pages are generated for you based on current information
- New pages are added
- Old pages are deleted.
- Attempting to "Know the Web"
- Is impossible in the sense of "Knowing the ___" insert holy book here.
- Is possible in the sense of a river. (Or any other dynamic object)
Web Index
- First attempt to classify information on the web.
- Some of them are
- yahoo http://www.yahoo.com
- google http://directory.google.com
- dmoz http://dmoz.org
- The Directory category at dmoz.org
- Find Erie County PA at
- dmoz.org
- google.com
- How do these sites make money? Search for Saturn
- How are these useful?
- Where do they fail?
Search Engines
- An attempt to automatically classify the web.
- A crawler is a program that travels the web looking for pages and ranking them somehow.
- The search engine looks for phrases in pages the crawler has found, and rates them on how they match the search.
- There are many search engines
- google.com
- altavista
- Take a look at this report on search engines.
- You should select one.
- Try some out, find one that you have success with
- Learn how to search better with that one.
- For Example: Google
- Look at the the GOOGLE General Faq
- Look at Basics of a Google Search
- Look at Advanced Search
- Take a look at this report
- Note there is a difference between searching a site and searching the internet.
- An AND operation requires both words (Dogs AND Cats means both are present)
- An OR operation allows one or the other. (Dogs OR Cats means one, or both)
- How do these sites make money? Search for Saturn
- How are these useful?
- Where do they fail?