Microsoft and Novell have announced an incremental investment in their partnership to promote interoperability between the SUSE Linux platform and Windows, with Microsoft pledging to purchase up to $100 million in certificates that customers can redeem for support.

The goal of the Microsoft/Novell partnership, initiated in November of 2006, is to build a bridge between open source and proprietary software to deliver interoperability and intellectual property (IP) peace of mind for organizations operating mixed-source IT environments, said Susan Heystee, vice president and general manager of global strategic alliances at Novell.

To complement the technology investments the companies have made in the partnership, “We’re expanding our business and sales collaboration,” Heystee said, noting that the investment features enhanced programs from Novell to provide tools, support, training and resources for customers seeking an enterprise-class Linux platform and interoperability solution between Microsoft Windows Server and SUSE Linux Enterprise Server from Novell.

“This incremental investment is motivated by strong customer demand for integration of SUSE Linux and Windows,” said Susan Hauser, general manager of strategic partnerships and licensing at Microsoft.

Although the companies announced the incremental investment on August 20, Hauser said the investments will not take effect until Nov. 1, 2008, and between now and then Microsoft and Novell will solicit customer input on various aspects of the effort.

Heystee noted that as part of the two companies’ five-year partnership agreement, Microsoft purchased $240 million of Novell certificates to sell to customers, and within 18 months, Novell “sold $157 million of the first $240 million” in certificate revenues, or 65 percent of the original allotment. Indeed, the list of customers that are running both Windows Server and SUSE Linux Enterprise Server include Wal-Mart Stores Inc., HSBC Holdings, Renault, Southwest Airlines Co., and BMW among others, Microsoft and Novell officials said.

“Cross-platform interoperability is something that we all want and need to achieve. But it’s difficult to accomplish this,” said Ulrich Koch, Head of License Management T-Systems Enterprise Services in a statement. “The pragmatic approach Microsoft and Novell are taking to address this complex challenge, including IP assurance, through engineering as well as offering tangible support and training programs, will make it easier for us to develop a path forward.”

Meanwhile, Microsoft and Novell will continue to collaborate on technical interoperability initiatives, both at their joint interoperability lab in Cambridge, Mass., and in other initiatives to focus on a number of areas including virtualization, systems management, directory and identity federation, document format compatibility, accessibility technology, and the Moonlight multimedia framework that is based on Microsoft’s Silverlight technology.