If you are a committer on any Apache project (not just Hadoop), then you have access to a free MSDN license. The details are described here.
https://svn.apache.org/repos/private/committers/donated-licenses/msdn-licen se-grants.txt You'll need to authenticate with your Apache credentials. This means that all Hadoop committers, and a large number of contributors who are also committers on other Apache projects, are empowered to review and test patches on Windows. After getting the free MSDN license, you can download the installation iso for Windows Server 2008 or 2010 and run it in a VirtualBox VM (or your hypervisor of choice). Instructions for setting up a Windows development environment have been in BUILDING.txt for a few years. This would prevent situations where patches are blocked from getting committed while waiting for me or any other individual to test. --Chris Nauroth
