title: I/O completion port's advantages and disadvantages
body: <p>Why do many people say I/O completion port is a fast and nice model?<br />
  What are the I/O completion port's advantages and disadvantages?</p>
  <p>I want to know some points which make the I/O completion port faster than other approaches.</p>
  <p>If you can explain it comparing to other models (select, epoll, traditional multithread/multiprocess), it would be better.</p>