title: difference between http and www
body: <p>pardon me for asking a very basic doubt.</p>
  
  <p>I have hosted a page in the site <pre>collinfo.annauniv.edu</pre></p>
  
  <p>The page opens fine when i enter the address as <pre>http://collinfo.annauniv.edu</pre></p>
  
  <p>But when i gave <pre>www.collinfo.annauniv.edu</pre> my browser shows 404 error.</p>
  
  <p>What is the difference that http causes here in place of www.</p>