GNU is operating system software developed by the FSF that is included with the Linux kernel, which is why Linux is sometimes referred to as GNU/Linux. Many have used the GNU/Linux operating system to create myriad versions of Linux, tailored to a wide range of user needs. Popular commercial versions include those from Red Hat Inc. and SuSE Linux AG. The FSF is confident it has done its due diligence to ensure that its GNU software doesn't infringe on any copyrights, Kuhn said.
The deal appears to be a normal Microsoft attempt to make sure it is honoring properly SCO's intellectual property rights, IDC analyst Dan Kusnetzky said. Those advancing a conspiracy theory to explain the timing of the deal will have a hard time proving it, he said.
"I'm not sure there's a way to support a quid pro quo notion. It is certainly an interesting theory, but it's one that would be almost impossible to prove or disprove," he said.
Moreover, using SCO as its "henchman" against Linux and IBM would be a bad move for Microsoft, said Ted Schadler, a Forrester Research Inc. analyst.
"I discount the notion that Microsoft is secretly funding SCO's lawsuit," he said.
The announcement's timing might raise eyebrows, but the most likely motivation behind the deal is Microsoft's desire to make sure it isn't infringing on any of SCO's Unix intellectual property, Schadler said Tuesday.
Asked to comment on the news of the licensing deal at a press conference Monday, Oracle Chairman and Chief Executive Officer Larry Ellison seemed to have no compunction about drawing a link between the agreement and SCO's litigation. "Bill [Gates] is innovating. Microsoft has always had incredible innovation. You've had advanced bundling and what you see now is extreme litigation. They have a lot of experience with extreme litigation, actually," he said.
The SCO-Microsoft announcement comes little over two months after SCO filed suit against IBM and days after SCO said it will suspend its Linux business.
Microsoft once licensed Unix source code from AT&T Corp., Unix's creator, but that license ran out after Microsoft abandoned the Unix-related project that had prompted the licensing, Sontag said.
The licensing agreement announced Monday is one of two SCO signed in its second fiscal quarter, ended in April, worth a combined total of over $10 million, Sontag said. He declined to be more specific on how much the Microsoft deal was worth.
SCO and Microsoft both have grievances against Linux. SCO, which owns Unix, claims Unix code has been illegally copied into Linux. Meanwhile, Microsoft sees Linux as a rising threat to its desktop and server operating systems.
The kernel of the Linux operating system is developed by a team of volunteers led by Linux creator Linus Torvalds. The Linux kernel is available to anyone who wants it free of charge. Moreover, it is distributed under the FSF's General Public License (GPL) that gives users access to the Linux source code, and permission to modify, copy, share and redistribute it. A GPL condition is that if users redistribute the software, they must share their changes and improvements. Linux is the best-known example of open-source software.
By contrast, most commercial software vendors, such as Microsoft, rarely, if ever, disclose the source code of their programs, and normally forbid users from freely modifying, copying or distributing them, an approach sometimes called "proprietary."
SCO has become increasingly reviled in Linux circles in the past two months with its allegations that Unix code has been copied illegally into the Linux operating system's kernel, allegedly violating SCO's intellectual property rights.
SCO's actions over this matter so far include a formal lawsuit against IBM and stern warnings against Linux users and vendors, such as Red Hat and SuSE, that they also might be in violation of SCO's intellectual property. IBM has denied the allegations, while Red Hat and SuSE have brushed off SCO's warnings, saying they are baseless.
-- Joris Evers in San Francisco contributed to this story.