IBM's effort to promote Linux as a viable alternative on the company's 350,000 corporate desktops took a step forward last month, when the company's IT organization began supporting the open-source Firefox browser. However, while the move to support a browser that runs on Linux may provide a boost for both Firefox and IBM's internal Linux effort, Big Blue hasn't been nearly so eager to promote a lesser-known piece of software, called Wine, that it has used to advance Linux on the desktop.

Like Firefox, Wine is open-source software that provides an important piece of the Linux desktop puzzle. IBM's reluctance to promote Wine underscores some of the complex legal and technical issues surrounding Linux adoption.

The Wine software essentially masquerades as the Windows operating system, letting software that was written for Windows run on a Linux desktop. IBM employees have used it internally as a way of running the Lotus Notes desktop client, according to sources familiar with IBM's efforts, who say that Wine and the Notes client are part of the Linux version of IBM's standard desktop client, called the Client for eBusiness. IBM's goal is to have all their internal users running Linux, but they have not publicly said how many users currently run the operating system.

But trying to get IBM to talk about Wine is another thing entirely. IBM executives declined to comment on the company's use of Wine for this article, and while the software is mentioned occasionally on IBM's Web site, it is generally not endorsed as a tool for moving Windows desktops to Linux. Last year, IBM raised eyebrows in the Wine community by pulling an article describing the use of Wine from its DeveloperWorks Web site.

An IBM "Redbook" guide to Linux desktop migration, published in late 2004 contains one of the company's few public statements on the software. But even there, Wine is mentioned only in passing, in a section entitled "What to do if all else fails," and it is called a "temporary workaround" to get an application running on the Linux client. "This is not a solution for the long run," the guide states.

This unwillingness to publicly support Wine has frustrated Jeremy White, whose company CodeWeavers Inc. sells a commercial version of Wine.

"What they're doing is they're chilling the high-end migration opportunities for me," White said. "What I find galling is that they use it. I have tons of friends at IBM who use Wine every day to run Lotus Notes."

Part of the problem for White is that IBM has been reluctant to say what, if any, problems it has with the software. "I suspect it's legal issues or an OS/2 allergy," said White, referring to IBM's desktop operating system, which the company has stopped supporting. "Maybe they've got a deal with Bill Gates."

IBM's answer is more simple than that, according to Scott Handy, vice president of worldwide Linux strategy with IBM. IBM wants to promote open standards, like the Web-based protocols used in its Lotus Workplace suite of collaboration software, rather than the Microsoft APIs (application programming interfaces) used by Wine, he said.

"Our whole strategy revolves around Workplace, and we think one of the critical elements to Linux being successful is that we provide an open programming model," he said.

But Workplace uses new technologies like J2EE (Java 2 Enterprise Edition) that are unfamiliar to many long-time Notes developers, and it may be years before IBM's open-standards vision is embraced by the majority of Notes developers.

Until then, many Notes users will need either open-source software like Wine, or proprietary tools like the Citrix Systems Inc. MetaFrame server or VMware's virtual machine software, in order to run Notes on their desktops.

The "legal issue" that White mentions may play a part as well. After all, IBM is already engaged in protracted litigation with The SCO Group over intellectual property claims relating to Linux.

Because Wine's purpose is to interoperate with Microsoft's Windows platform, the project is in a special situation, said Eben Moglen, a law professor at Columbia University and the chairman of the Software Freedom Law Center, an organization dedicated to providing free legal services to open source developers.

Observers fear that Wine, by emulating the Windows operating system, could somehow find itself running afoul of Microsoft's thousands of software patents.

"People have reason to expect that there may be fear for uncertainty and doubt in connection with that interoperability layer," Moglen said.

Last month, the Wine project became a client of the Software Freedom Law Center, which is providing legal analysis and counsel to the open-source project. One of the most important effects of this relationship, Moglen believes, is that companies like IBM will view Wine as a less risky option.

"I believe that improved legal assurance will improve acceptance of and help acceleration of the use of Wine," Moglen said. "You are not likely to see a SCO-type lawsuit connected with any software connected with any client of mine... unless I have fallen down on the job completely."