As part of the deal, signed in early November, Microsoft and Novell have promised to improve interoperability between the two platforms. Microsoft has additionally pulled back from threats to prosecute Suse users or developers for patent infringement. The company has also pledged to spend $240m on subscription coupons for Suse Linux and $94m promoting Windows/Linux over five years.

Credit Suisse, Deutsche, and AIG are among the earliest beneficiaries of this largesse, each taking delivery of Suse Linux Enterprise 'subscription certificates' from Microsoft.

Tom Sanzone, chief information officer at Credit Suisse, says interoperability is the key. "We see both Windows and Suse Linux as strategic platforms going forward, and we’re very pleased to see Microsoft and Novell, who support these platforms, step up and work on interoperability," he says. "This is a great model because it provides a bridge to connect the open source and proprietary software to benefit customers. We commend the two companies for taking this step."

Clemens Jochum, chief technology officer of Deutsche Bank - which operates a substantial mixed Linux/Windows shop - agrees. "Employing both Windows and Linux in our company always seemed the right thing to do, but making the systems work together would require a significant amount of time and resources," he says. "Microsoft and Novell’s agreement gives us the benefit of choice of platforms and tremendous flexibility."