Microsoft has embraced Novell's open-source software platform, forming a technological truce between two longtime antagonists who want to make it easier for the still-dominant Windows operating system and the increasingly popular Linux system to work together.

The agreement between the world's largest seller of patent-protected software and a leader in the open-source software movement has potentially important business, technical and legal implications.

''This builds a very important intellectual-property bridge between the open source and proprietary sides of software,'' Brad Smith, Microsoft's general counsel, said shortly before the companies formally announced their alliance in San Francisco.

Financial terms of the arrangement weren't disclosed.

The alliance is primarily aimed at the growing number of major companies and government agencies that rely on elements of Redmond, Wash.-based Microsoft's Windows and Linux to run their computers. The partnership's impact on consumers appears to be inconsequential except for a commitment to improve the interaction between Microsoft's top-selling suite of Office software and a free alternative known as OpenOffice.

Microsoft's stamp of approval, extracted after six months of negotiations, represents a coup for Waltham, Mass-based Novell as it touts the advantage of its version of Linux over other varieties made by competitors such as Red Hat.

Under the partnership, Microsoft's sales team will offer its corporate customers a chance to license its Windows operating system as part of a package offering maintenance and support for Novell's Suse Linux platform.

Novell primarily relies on the fees for customer support to make money off the Linux software, which is developed by a global community of programmers who aren't tied to any single company and freely share improvements to the code.

Ballmer stressed that Microsoft will first try to convince corporate customers to use Windows exclusively before relenting to the notion of a hybrid system using Suse Linux.

To encourage more companies to embrace Novell's open-source platform, Microsoft has pledged not to assert its patent rights over any of its technology that may be blended with Suse Linux. The concession is meant to address the concerns of many corporate users who have been reluctant to use Linux because they feared Microsoft might retaliate with patent-infringement claims.

''This is a big day for Microsoft customers,'' said Stuart Cohen, chief executive officer of the Open Source Development Labs, a Beaverton, Ore. group trying to expand corporate America's reliance on Linux. ''They are being told by Microsoft that they can use Linux and not worry about it. That's a big statement.''

Microsoft's patent waiver only applies to users of the Suse Linux platform.