A Google engineer who recently left says that the company uses "obsolete" software to run its search engine and other services.

Dhanji Prasanna was on the Google Wave team and quit earlier this year after receiving his bonus check for 2010. On a blog post he explains why Google's software is out of date:

Here is something you've may have heard but never quite believed before: Google's vaunted scalable software infrastructure is obsolete. Don't get me wrong, their hardware and datacenters are the best in the world, and as far as I know, nobody is close to matching it. But the software stack on top of it is 10 years old, aging and designed for building search engines and crawlers. And it is well and truly obsolete.

Protocol Buffers, BigTable and MapReduce are ancient, creaking dinosaurs compared to MessagePack, JSON, and Hadoop. And new projects like GWT, Closure and MegaStore are sluggish, overengineered Leviathans compared to fast, elegant tools like jQuery and mongoDB.

Notably, Facebook is a big user of Hadoop, which is open-source software for massive parallel processing.

Facebook just opened its first data center after years of leasing space from third-party providers, and released detailed specs about it under an open-source license -- a sharp contrast with Google's secrecy.