Microsoft Corp. on Tuesday announced it was acquiring privately owned Winternals Software, an Austin, Texas developer of recovery and data protection tools, and the host of the well-known Sysinternals free toolset.

Winternals co-founder Mark Russinovich will join Microsoft's Platforms and Services group as a technical fellow, the Redmond, Wash. giant said in a press release. Bryce Cogswell, the company's other co-founder, will head to Microsoft's Core Operating Systems division as a software architect.

"I've had my eye on Mark for some time," said Jim Allchin, co-president of the Windows team, in a statement. "The work he and Bryce have completed in system recovery and data protection illustrates the depth of thinking and skill they will bring to future versions of Windows."

Although the Winternals commercial software -- including Protection Manager and Recovery Manager -- and the free-of-charge Sysinternals tools are well-known, Russinovich is most famous as the discoverer of a rootkit tucked inside Sony BMG audio CDs. His 2005 find raised a firestorm of protest against Sony BMG, led to several court cases, and was pegged as a reason for a slowdown in CD sales.

In a Tuesday blog entry, Russinovich admitted he didn't yet know how the Winternals and Sysinternals software and technologies would be integrated into Windows.

"Microsoft is still evaluating the best way to leverage the many different technologies that have been developed by Winternals," he wrote. "Some will find their ways into existing Microsoft products or Windows itself and others will continue on as Microsoft-branded products."

The Sysinternals Web site will remain as is for the time being, Russinovich said, and when Microsoft eventually decides how to integrate it with existing online content, the tools will continue to be free to download.

Financial terms of the deal were not disclosed.