Microsoft shares source code

Microsoft published the code for one of its products on an open-source software development website late Monday, departing from its hard-line stance against making the underlying components of its technology available to the general public.

Microsoft revealed the code for its Windows Installer XML (WiX) software, a set of tools used to build installation packages for the company's Windows products from XML source code. According to the information posted on the SourceForge site, a resource for open-source collaboration projects, the actual code Microsoft published supports an environment that software developers can use for creating Windows setup packages.

Jason Matusow, Shared Source Initiative manager at Microsoft, said the code was posted in public because the company felt that developers could build more effective applications for Windows products with the actual elements of the WiX package to work with, rather than using shareware that was already available. He said Microsoft chose to reach people using SourceForge, because more than 25 per cent of the projects being worked on via the site are related to Windows.

"WiX was a project that got picked up and used widely throughout Microsoft and we felt that making the code available would improve people's ability to build their own setup packages," Matusow said. "We will continue to be a lot more conservative with how we share code from products such as Windows, but this kind of software calls for a different kind of business approach."

The software giant made the code available under the Open Source Initiative's Common Public Licence, which allows an application and source code to be used and modified freely, as long as the resulting code is distributed under the same terms. Representative of the founding tenets of the open-source movement, the idea of the CPL is to give the public a set of software that it can freely use, improve and share.

The CPL is considered somewhat more flexible than the GNU General Public License, which Microsoft Chairman Bill Gates has criticized in the past for its inability to jibe with proprietary software development.

Matusow said his company views the CPL as more favorable to vendors that want to release some code while also keeping their proprietary business interests in mind. IBM authored CPL, and licenses offer the software development community the right mix of availability and commercial rights, he said.

To say that Microsoft has traditionally avoided such public displays of its source code is an understatement. Despite previous initiatives that have allowed various pieces of code to be distributed under what the company calls shared-source licenses, the WiX release marks the first time Microsoft has attempted an unadulterated effort at open source. The company said earlier this year that it was considering a number of products for potential code releases under its Shared Source Initiative, which has been under way for roughly three years.

The company fervently defends the source code of the various versions of its Windows operating system, sharing it only with universities and government agencies that sign agreements not to release the code. While working versions of Microsoft's operating system have occasionally made it onto the internet, actual source-code leaks have been rare.

One of the company's concerns around the airing of its proprietary code is the possibility of increased security breaches in its products, an issue that already troubles Microsoft.

Matusow would not say whether Microsoft has specific plans to offer more source code through SourceForge or CPL licences. However, he said, Microsoft does say it plans to continue expanding the Shared Source Initiative and future releases where possible.

Matt Hines writes for CNET News.com