At the Hadoop Summit in California Wednesday Yahoo released the source code to its version of Hadoop, its Google-inspired distributed file system and parallel execution environment for sifting through Brobdingnagian-size data sets, for anyone to use.

It's not, however, commercializing it or supporting it. It's leaving that to the likes of Cloudera and Amazon.

Yahoo says it's releasing it because it's been asked so often; and the wider Hadoop's adoption the more it's asked. Anyway, it figures to get added development out of the exercise.

In a statement Yahoo's senior VP of cloud computing Shelton Shugar said, "By making the Yahoo Distribution of Hadoop generally available, we are contributing back to the Apache Hadoop community so that the ecosystem can benefit from Yahoo's quality and scale investments."

Its stuff runs the largest Hadoop clusters in the world and is extensively tested. Yahoo has also employed Hadoop founder Doug Cutting since 2006 when it began pouring money into the widgetry.

Hadoop now underpins Yahoo properties such as Yahoo Search, which is the world's largest Hadoop application, as well as Yahoo Mail and various content and advertising services. It runs on more than 25,000 Yahoo servers and, by Yahoo's count, analyzes tens of billions of web pages, multiple petabytes of storage and billions of new records a day.

The Yahoo Distribution of Hadoop is based entirely on code available from Apache Hadoop, the open source project at the Apache Software Foundation.

Yahoo pioneered much of the Apache Hadoop technology and is now the primary contributor to Apache Hadoop.

Cloudera figures incorporating Yahoo's refinements into its commercial Hadoop distribution will make it more robust.

The first release is Hadoop v20 in alpha test at Yahoo. See http://developer.yahoo.com/.