Raymond, who's been known to don an Obi-Wan costume during public events, said a Microsoft research and development scientist invited him to give a talk to some R&D folks there. He said he doesn't expect to meet with anyone outside of R&D. Surprised, he said, is not strong enough a word to describe his reaction to the invitation. "Astonished and utterly weirded out would be closer to the mark," Raymond said during an interview via e-mail. Raymond has been a vocal opponent of Microsoft's software plans. In February, he rallied outside the company's Foster City, Calif., offices, one of 100 Windows Refund Day protesters demanding that Microsoft repay people if they chose software other than the Windows program that comes on their machines. The open-source evangelist said he'd give his standard open-source talk at Microsoft and try to convince the company that it's closed-source strategy "is a sure recipe for failure." A spokeswoman for Microsoft said the visit was "not a big deal," that Raymond is one of several guest lecturers coming to the campus to address researchers as part of a regular series of speakers. Microsoft maintains tight control over the source code of its software. In contrast, developers can tinker with source code that's part of the open-source movement as long as, in most cases, they share their changes. Shipments of Linux, the highest-profile driver of the open-source movement, have skyrocketed in the past year, and International Data Corp. analysts expect its growth rate to outpace all other operating systems combined, including those created by Microsoft, over the next five years. Raymond is best known for his paper, "The Cathedral and the Bazaar," which explains the benefits of the open-source movement and inspired Netscape Communications Corp. to release its browser code last year. Most recently, Raymond helped Apple Computer Inc. (Nasdaq:AAPL) iron out its open-source plans. In March, Apple became the first mainstream company to open up parts of its OS core, and Raymond joined Apple CEO Steve Jobs on stage to bless the plan. However, Raymond came under fire from several members of the open-source community, who said Apple's license was too restrictive didn't provide developers enough freedom. The dispute was evidence of a growing schism between two camps involved in open source: those who want to pursue a more commercial path for open software and those who want software to be free. For its part, Microsoft has been ambivalent about its open-source plans, taking whatever stance suits its needs at the time. In April, Gates pooh-poohed Linux, saying it will have only limited impact on the industry, primarily for simple applications such as word processing. On the other hand, during the company's landmark antitrust trial in Washington, D.C., Microsoft lawyers have cited Linux as a major competitor in their effort to combat antitrust charges. Microsoft already has indicated an interest in open source, striking a recent deal to optimize open-source language Perl for Windows. But the company also has tapped an internal team to track Linux's progress.