问题
I see that Node.js has added i/o to its capabilities, does that mean that it's more async now, or it is using the same concurrency model as before?
Also, I thought Node was on v8, why have they rolled back to v4?
回答1:
io.js was a fork of the node.js codebase that was advancing differently than the core node.js. io.js was its name and is not directly related to some large set of I/O capabilities.
The version 4.0 nomenclature is derived from the versioning scheme that io.js was using and this is essentially the next major version of that fork. You can read more details in this article: 4.0 is the new 1.0. And, you can read about the merger of the io.js and node.js code bases into the Node Foundation in this article: Node.js and io.js Merge Under the Node Foundation.
All versions of node.js and io.js use the V8 Javascript engine from Google. Those the phrase "V8" implies "version 8", that is not how it is used. "V8" is the name of the Google JS engine and does not change. There is a separate version number for the V8 engine. The 4.0 version number is a node.js version and has nothing to do with which specific version of the V8 JS engine is included.
In this article All you need to know about Node.js 4.0.0, there is this passage which addresses the version number question:
Why “4.0.0”?
The io.js project uses semantic versioning (semver) with its first major release being a 1.0. The current main line of io.js is 3.x. To avoid collisions with the 0.x scheme of Node.js it was decided that the converged version should be a 4.0.0 and will also be following the semver scheme .. from now on.
来源：https://stackoverflow.com/questions/32468832/now-that-node-js-has-added-io-js-is-it-more-async-than-it-was-before-whats-wi