In a major turnaround for Microsoft, the company Thursday promised "greater transparency" in its development and business practices, outlining a new strategy to provide more access to APIs and previously proprietary protocols for some of its major software products, including Windows and Office.

The move, inspired by the ongoing antitrust case against Microsoft in the European Union, shows the company finally acknowledging the significant impact open source and open standards have had on the industry and the company's own business. It also should mean the end of Microsoft's patent threats against Linux and interoperability concerns surrounding Office 2007 file formats.

[ More coverage: E.U. has guarded reaction to Microsoft's open-source move | Open APIs may help Microsoft repair its image ]

During a news conference with top executives Thursday, Microsoft said it is implementing four new interoperability principles and actions across its business products to ensure open connections, promote data portability, enhance support for industry standards, and foster more open engagement with customers and the industry, including open-source communities.

These steps are "important" and represent "significant change in how we share information about our products and technologies," Microsoft CEO Steve Ballmer said in a statement. "For the past 33 years, we have shared a lot of information with hundreds of thousands of partners around the world and helped build the industry, but today's announcement represents a significant expansion toward even greater transparency."

Under increased global pressure, Microsoft has limped toward a more open development policy for some time with strategies like the Open Specification Promise, which it published in September 2006 as a pledge that it would not take any patent-enforcement action against those who use certain technology APIs (application programming interfaces). The company launched an open-source Web site last year, a move that was notable for one of the first official uses of the term "open source" by the company. Microsoft previously would release APIs and code to developers and other companies through something it called the Shared Source Initiative rather than specifically calling its policy open source.

However, at the same time as it appeared to be more open, Microsoft continued to make bold claims and threats against technologies like Linux that it said violated many patents the company holds. While the open-source community mostly scoffed at Microsoft's claims, some companies -- including Novell -- signed specific deals with the vendor to protect customers from indemnification and promote interoperability with Microsoft software.

Microsoft also continued to promote proprietary file formats it designed as the default for Office 2007 -- Office Open XML (OOXML) -- in favor of another file format, ODF (Open Document Format for XML), which already has been approved as a global technology standard by the International Organization for Standardization (ISO).

Microsoft submitted the OOXML specification to another standards body, Ecma International, in November 2005 in an effort to have it fast-tracked through the ISO. However, approval by the ISO has been stalled and the process riddled with complaints that Microsoft is not acting in the transparent way typical of an international standards process.

The announcements on Thursday don't affect the company's continued efforts to standardize OOXML, Ballmer said during the press conference.

Thursday's news includes broad, royalty-free publishing of APIs and the establishment of an Open Source Interoperability Initiative to provide ongoing resources and documentation to the community, and marks more commitment than the notoriously proprietary software maker has ever shown toward embracing open standards and open source.

Microsoft plans to publish on its Web site documentation for APIs and communications protocols that are used by what it calls its "high-volume products." Microsoft includes Windows Vista (including the .NET Framework), Windows Server 2008, SQL Server 2008, Office 2007, Exchange Server 2007 and Office SharePoint Server 2007 -- as well as their future versions -- under this umbrella. Microsoft will not require developers to license or pay royalties for this information, the company said.