JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.
Background
Released in 2009
Nearly a commit a day
Created by Ryan Dahl, for interactive web app with maximum throughput and efficiency
Sponsored by Joyent, specialized in high-performance cloud computing
Used by LinkedIn, eBay & PayPal
The Architecture
NodeJS is ..
Very Fast in code execution
Asynchronous & Event-driven
Single-threaded, Non-blocking I/O calls
High scalability
Single-threaded?
Isn't multi-threaded faster?
Not exactly!
Single vs Multi threaded
Clients
Threads
I/O operations
Assuming that each thread potentially has an accompanying 2 MB of memory with it, running on a system with 8 GB of RAM puts us at a theoretical maximum of 4000 concurrent connections, plus the cost of context-switching between threads.
By avoiding all that, Node.js achieves scalability levels of over 1M concurrent connections.
