Microsoft and Novell have announced that Wal-Mart is buying into the agreement between the two software vendors to collaborate on improving interoperability between Windows and Linux.

The agreement was concluded last November, and resulted in a wailing and gnashing of teeth by Linux devotees, who saw Novell's move as not so much supping with the devil as getting into bed with him with a hot water bottle.

Under the Wal-Mart deal, Microsoft will deliver SuSE Linux Enterprise Server subscription certificates to Wal-Mart for use in the retailer's data centres. No terms of the agreement have been disclosed, although Wal-Mart said it can now move to lower-cost commodity server hardware managed by Microsoft's Systems Management Server, Active Directory and Microsoft Operations Manager.

The deal opens up other potential opportunities for both Microsoft and Novell to provide Wal-Mart with additional software resources and support.

The impetus behind the Wal-Mart deal becomes more apparent when you know that Microsoft's chief operating officer Kevin Turner used to be Wal-Mart's chief information officer. Wal-Mart, already a Microsoft user, said it was pleased at the possibility of improved inter-operability between systems. The company's chief technology officer Nancy Stewart said: "We have wanted information technology vendors to deliver true inter-operability and IP assurance between multiple platforms for some time now, and we are pleased that Microsoft and Novell are committed to fulfilling that need."

"Customers tell us every day that they need to operate a cost-effective IT organisation and leverage the most they can out of their investments," said Ron Hovsepian, president and CEO of Novell. "Through our relationship with Microsoft, we've created new opportunities for enterprise inter-operability and virtualisation that ultimately result in real savings for our customers."

Novell and Microsoft's five-year deal will see them work together to improve deliver powerful new virtualisation capabilities, make Microsoft and Novell products work better together, and reassure their customers that both companies stand behind the products they deliver. Under the agreement, Microsoft agreed to use, resell or distribute certificates that customers redeem to receive SuSE Linux Enterprise Server subscriptions for upgrades, updates and technical support from Novell.

Since the announcement, more than 35,000 new certificates for three-year priority support subscriptions to SuSE Linux Enterprise Server have been activated under the Microsoft and Novell collaboration agreement.