Microsoft Corp., which in years past has been accused of hawking vaporware, is reaching into its past to placate corporate audiences anxious to know how the software giant plans to respond the challenge posed by the Linux operating system. Company president Steve Ballmer, who earlier this year raised the possibility of embracing the so-called open source approach to software development, returned to that same theme on Thursday during a presentation in San Francisco. Speaking at a conference sponsored by Tibco Finance Technology in the U.S., Ballmer said Microsoft was still grappling with whether it made sense to open some of its software protocols for general development. "We're trying to learn from the things that represent clear upside and where a change in our approach will benefit you," Ballmer said to the audience of IT professionals. But company insiders and analysts said Ballmer's tease did not indicate an immediate shift in the company's thinking. One Microsoft official who tracks the evolving Linux market said the company was unlikely to go "full-hog" toward embracing the open source approach. "Don't hold your breath," the official said, asking to remain unidentified. "Tell me again why it would make sense to slay our cash cow?" Indeed, just last month, a senior executive responsible for shepherding Windows 2000 openly poured cold water on the suggestion that Microsoft might give up sole authorship of its software. Yet Ballmer seemed to signal that Microsoft was indeed doing more than a simple tech tease. He said there "are parts of our source codes" that Microsoft is considering opening up. "We see that fairly clearly as a requirement being expressed out of people's interest in Linux," he said. "And we're trying to figure out what that means. ... There are parts of the system where if you had the source code, people would feel they could be more effective." Take me to the Linux Lounge