Microsoft is going to pump up to $100 million more into Novell for additional certificates that it will sell or give to customers to redeem for SUSE Linux support. Novell should get the money on November 1 right before the second anniversary of the widely loathed Microsoft-Novell pact that indemnifies SUSE users against infringing Microsoft patents under a so-called covenant not to sue and got the open source community’s knickers in a twist.

Microsoft initially bought $240 million worth of certificates under the five-year arrangement. Within 18 months, Novell invoiced upwards of $157 million in certificate revenues, or 65% of the original allotment, money that's been a life saver for the company.

Novell has also gotten cross-platform interoperability out of the deal in areas such as virtualization and Active Directory - as well as Linux client version of Microsoft's Silverlight technology called Moonlight - along with an argument against other Linux distribution

Microsoft says certificates have gone to Wal-Mart, Renault, Southwest Airlines and BMW.

Microsoft said "the investment focuses on enhanced programs from Novell to provide tools, support, training and resources for customers seeking an enterprise-class Linux platform and specifically, the optimal interoperability solution between Microsoft Windows Server and SUSE Linux Enterprise Server from Novell."

Between now and November Microsoft and Novell are supposed to "solicit customer input and identify aspects of the support programs that will be most useful to organizations running mixed-source environments."