7 April 2004 Microsoft has broken from its own strict policy of not disclosing the source code of its software by posting code from its Windows Installer XML (WiX) on an open source development website.

By sharing the code, the world’s biggest software company hopes that developers will be able to build better applications for its Windows operating system. Microsoft will also benefit from the open source community’s practice of making improvements to the software and testing them under peer review.

“We felt that making the code available online would improve people’s ability to build their own set-up packages,” said Jason Matusow, manager of Microsoft’s Shared Source Initiative. “We will continue to be a lot more conservative with how we share code from products such as Window, but this kind of software calls for a different kind of business approach.”

This is the first time that Microsoft has distributed its code under the Open Source Initiative’s Common Public Licence (CPL), which is a vendor-friendly version of the GNU General Public Licence under which Linux is distributed. The CPL allows developers to use and improve the code freely as long as the modified product is distributed under the same terms, but maintains the original developer’s commercial rights.

Microsoft has historically been vehemently opposed to sharing its source code, although it has shown some elements to preferred partners, including government agencies and universities.

WiX is used internally by Microsoft to create installers for its own programmes. The toolset includes a compiler, linker, library tools and decompiler. The WiX code is available from SourceForge.net, which claims to be the world’s largest open source development and resource website.