Hi, thanks for your interest.
Actually, both node.js and node.native are based on libuv (https://
github.com/joyent/libuv).
And, libuv is based upon other 'non-blocking asynchronous I/O'
libraries on different platforms.
Under the hood, these non-blocking things are also using threads
internally.
But, on top of these, end users are given an environment that
everything is event-driven and callbacks are deferred.
So, when you're working with node.js or node.native, you can just
simplify things as every code is executed in a single thread.
If you want to know more about the detail, please visit:
http://nodejs.org/about/
Hope this help you.
- Daniel