"For all of its logic, however, this is a move that would have been inconceivable a few years ago, meaning that the glasnost of Microsoft vis a vis open source continues," O'Grady said.
Future open source moves being pondered by Microsoft include better support for the Python language on Windows and continuing its support for Java on Windows, Ramji said. Frameworks like Hibernate or Spring also could be embraced by Windows technologies, including offering tooling support, he said. Microsoft also will continue to work with the Eclipse Foundation to enable development of rich Internet applications based on Microsoft's Silverlight platform. Silverlight, though, has not been open-sourced although Novell offers an open source implementation of it called Moonlight.
Ramji said he could not comment now on whether Microsoft might join the foundation.
Microsoft's selection of the GPL drew strong reactions.
"I think MS's embrace of a viral license like GPL shows just how far they've come since they considered it a 'cancer' a few years ago," said analyst Jeffrey Hammond, of Forrester.
"They've been making steady progress, and the attitude I see developing now seems to reflect the ultimate in pragmatism. They've conceded that since [open source software] isn't going away, they might as well profit from it, in this case making their server virtualization product more appealing," Hammond said.
Even an ardent opponent of Microsoft, Roy Schestowitz, editor of the Boycott Novell Web site, gave a nod to the company while also criticizing the arrangement.
"While it is commendable that Microsoft is no longer entirely allergic to the GPL2, it ought to be strongly emphasized that this is the latest example (among others) where Microsoft submits an open source patch from which Microsoft Windows or another part of the proprietary Microsoft stack is to gain," Schestowitz said.
Microsoft on Monday also is highlighting its ongoing investment in optimizing PHP on Windows Server and the Microsoft SQL Server database. The company has had work ongoing on a SQL Server driver available for PHP to support more native features in SQL Server 2008. Microsoft also has partnered with PHP tools vendor Zend Technologies to boost PHP.