One year after sealing their surprise alliance, Novell and Microsoft have announced an expansion of their technical collaboration to "link together the existing Windows and Linux frameworks".

The firms will extend their existing collaboration to focus on virtualisation, standards-based management, directory and identity federation and document format compatibility.

As part of this process, Microsoft said that both companies are "now working closely" at the Microsoft and Novell Interoperability Lab in Massachusetts.

Technicians are running automated tests to ensure the interoperability of SuSE Linux Enterprise Server 10 with Windows Server virtualisation and Windows Server 2008 with Xen.

The firms are also helping software companies and developers to create and deliver accessible products for the Windows and Linux platforms, providing better computer access for people with disabilities, especially the partially sighted.

Microsoft will make available its User Interface Automation specification, an accessibility framework designed to simplify the development of technology products for people with one or more disabilities.

The Redmond giant added that it will not assert any patents necessary to implement the specification against anyone, regardless of platform, in the open source and proprietary software communities.

Jeff Jaffe, executive vice president and chief technology officer at Novell, said: "Customers told us they wanted Linux and Windows to work better together so they could focus on their businesses."

Bob Muglia, senior vice president of the Server and Tools Business Group at Microsoft, added: "As we mark the first anniversary of our relationship, we are very pleased with the customer support we have received for a solution that provides cross-platform interoperability."