Microsoft is making available to any and all interested testers on October 24 public preview test builds of the Hadoop big-data framework for Windows Server and Windows Azure.
The two products -- which as of today have new and official names (Windows Azure HDInsight Service and Microsoft HDInsight Server for Windows) -- are the fruits of the Hortonworks-Microsoft partnership announced last fall. The previews can be obtained via Microsoft's Big Data site (at some point today).
Microsoft already has released two previews of Hadoop for Azure. Today's is the third. The company has been privately testing Hadoop for Windows Server with select Technology Adoption Program (TAP) participants. But today's Windows Server preview is the first publicly available build.
Microsoft officials are not disclosing the latest timetable for delivery of the final version of either Hadoop product. They also are not discussing any new features that have been added to either product between the last test builds and the current ones. (If any testers discover anything noteworthy, please chime in below in the comments.)
In the fall of 2011, Microsoft announced it was partnering with Hortonworks to create both a Windows Azure and Windows Server implementations of the Hadoop big data framework. At that time, Microsoft officials committed to providing a Community Technology Preview (CTP) test build of the Hadoop-based service for Windows Azure before the end of calendar 2011 and a CTP of the Hadoop-based distribution for Windows Server some time in 2012. A month after announcing the Hortonworks partnership, Microsoft dropped plans to make its own big data alternative, codenamed Dryad.
In late December 2011, Microsoft posted a video on its Channel 9 site that provided updated information about the company's Hadoop plans. According to that video, which Microsoft subsequently pulled from Channel 9, the company planned to make Hadoop on Windows Azure generally available in March 2012, and Hadoop for Windows Server generally available in June 2012.