title: How node.js works?
body: <p>I don't understand several things about nodejs. Every information source says that node.js is more scalable than standard threaded web servers due to the lack of threads locking and context switching, but I wonder, if node.js doesn't use threads how does it handle concurrent requests in parallel? What does event I/O model means? </p>
  
  <p>Your help is much appreciated. 
  Thanks</p>