In an unexpected move, Microsoft announced today that it will license the UNIX source code from SCO Group, the company that owns patents on the technology and is involved in a controversial lawsuit alleging that Linux has illegally stolen source code from UNIX. Why Microsoft really wants to license the technology is unclear; analysts say the company made the decision to license UNIX source code and technologies to encourage other companies to strike similar deals with SCO and improve interoperability. But darker reasons could exist. In March, SCO sued IBM for $1 billion, charging the company with transferring SCO trade secrets to Linux. The Linux community reacted with outrage, voicing fears that other Linux makers would soon be sued. Obviously, the Microsoft decision could cause further fury from the Linux world, and given the software giant's attitude toward Linux, causing an uproar could have been the plan all along.

AT&T created UNIX--once considered the penultimate OS--and the C programming language in the 1960s. (Microsoft licensed the technology from AT&T in the 1980s for its Xenix OS, a UNIX version that ran on IBM and compatible PCs.) In 1992, Novell bought UNIX, then sold the technology to SCO in 1995. Because most major companies that develop UNIX products, such as Sun Microsystems, license the technology, it's still a fairly lucrative business. But UNIX has been running out of steam in recent years because of the success of Windows NT (and more recent versions of Windows) and a UNIX clone called Linux. Created as an open-source project, Linux source code is available to anyone.

And that's the problem, SCO says. The company believes that Linux contains significant portions of patented UNIX source code. If so, any companies that sell or create Linux projects could be at legal risk; SCO recently threatened to revoke IBM's UNIX license as early as next month. Microsoft says it's taking the high road and licensing the technology specifically so that the company can improve interoperability between Windows and UNIX and, in the process, preserve SCO's intellectual property rights. SCO notes that Microsoft isn't the only major vendor to acquire a UNIX license in recent days, although the company isn't naming names yet.