title: Node.js server with multiple concurrent requests, how does it work?
body: <p>I know node.js is a single threaded, asynchronous, non blocking i/o. I've read a lot about that. e.g PHP uses one thread per request but node uses only one thread for all, like that.</p>
  
  <p>Suppose there are three requests a, b, c arriving at same time at node.js server. Three of these requests require large blocking operation e.g they all want to read same big file.</p>
  
  <p>Then how are the requests queued, in what sequence will the blocking operation be carried out and in what sequences are the responses dispatched? Of course using how many threads?</p>
  
  <p>Please tell me the sequences from request to response for three requests.</p>