Microsoft made a minority investment Monday in Unix/Linux management vendor Vintela.

Neither Microsoft nor Lindon, Utah-based Vintela would comment on the size of the investment. But sources said the amount was less than $10 million.

Vintela has acted as a key participant in Microsoft’s Unix/Linux interoperability strategy. Nonetheless, Vintela is an unlikely Microsoft partner.

Vintela is a spinoff of Caldera, the company that sued Microsoft for antitrust violations and settled for an undisclosed amount in 2000. Vintela also has deep roots in the Unix/Java worlds.

In spite of these two factors, Vintela has been working with Microsoft on a number of current and future initiatives, ranging from systems management to security.

Microsoft and Vintela are working together on Microsoft’s ADFS (Active Directory Federation Services), the technology formerly code-named “TrustBridge,” which is slated to be incorporated into the Windows Server “R2” release. R2 is expected to ship in late 2005.

Read more here about the Windows Server “R2” release.

“We are working to figure out how people really want to federate across platforms,” Vintela president Dave Wilson told Microsoft Watch in August. “We’re building a genuine roadmap with them for the Longhorn time frame and beyond, vis-a-vis what’s happening in the Unix/Java world on the federated identity front.”

Vintela also is working with Microsoft to extend Microsoft’s Group Policy Management Console to manage Unix objects via Active Directory. Vintela’s plug-in for handling this function will ship in September, Wilson said.

At the same time, Vintela is working to develop a Unix/Linux plug-in for Microsoft Operations Manager 2005, he added, that should be ready to ship in the first half of 2005. Vintela is slated to show off the new plug-in this week at the Microsoft IT Forum conference in Copenhagen.

One of Vintela’s core products, VAS (Vintela Authentication Services), allows Unix/Linux users to authenticate against Active Directory. A number of vendors, including SCO, build on top of VAS.

In late July, Vintela released a new product, VMX (Vintela Management Extensions). VMS is a plug-in for Microsoft’s SMS (Systems Management Server) 2003 that allows SMS to manage Solaris, HP-UX, AIX, Mac OS X and various Linux systems. Vintela “jointly engineered” VMX with Microsoft, according to Wilson.

Read the full story on Microsoft Watch: Vintela: Microsoft’s Secret Unix/Linux Weapon?