The war of words between groups that promote the sharing of source code and Microsoft, which is infamous for its closed, proprietary approach, reached a new level today. Even before a high-ranking Microsoft official gave a speech -- which leaked reports suggested would rubbish the open source and free software communities -- the open source community hit back. Senior vice president of Microsoft, Craig Mundie, is expected to launch the anti-open source campaign in a speech to be given at the Stern School of Business at New York University today. It is thought that the speech will defend Microsoft's own business model in the face of anti-competitive criticism by turning attention to the dangers of open source. Open source software -- meaning software released under a license that promotes the sharing of source code -- has made significant inroads into the corporate business arena. The best known of these licences is the General Public License (GPL), created by Free Software Foundation founder Richard Stallman, which allows anyone to view and reuse code so long as it is republished under the same licence agreement. Mundie is expected to attack in particular the GPL by claiming that it poses a threat to company's intellectual property. He will suggest that Microsoft already shares as much code as is prudent with hardware manufacturers, researchers and government. Self-styled open source evangelist Eric Raymond was the first to respond to Microsoft's challenge in an article published in LinuxToday. He accuses Microsoft of spreading fear, uncertainty and doubt -- often referred to as FUD -- about open source software among software vendors and their customers. Raymond says he expects Mundie to blur the distinction between the GPL and controversial information sharing tools such as Napster as well as straightforward copyright violation. He says that, while open source programmers support sharing code, so that it can be reviewed, fixed and be as compatible as possible, they also support intellectual-property rights and copyright. Prominent UK programmer Alan Cox, one of the key developers of the Linux kernel, which is released under the GPL and is the most celebrated success of the open source movement, also attacked Mundie's move to criticise open source software. "The GPL creates a pool that anyone can dip into but what they improve they must return," said Cox. "This allows people to rapidly develop software at low cost, to offer their end users great value and to avoid being tied to a monopoly vendor. There are I suspect very few customers who would consider that a problem." Mundie's criticism builds on remarks made by Microsoft software designed Jim Allchin in an interview in February. Allchin suggested that freely distributed code might stifle innovation. According to Raymond, Microsoft's keenness to rubbish open source is in fact evidence that the software company is rattled and believes that the movement poses a threat to the dominance of its proprietary software. "What he'll hope you don't notice is that the 'assets' he's mainly interested in protecting are Microsoft's -- and not just the $26bn it has in the bank, but the far more important asset of over 90 percent desktop market share and tight control of its customer base through proprietary lock-ins." In today's speech, Mundie will also say that Microsoft is concerned about the in-roads that open source software is making into other countries, an position that Cox challenges. "The fact that governments want to be free of a US monopolist should not be a suprise. Many smaller nations simply do not have the financial resources to burn on proprietary software," he says. However, Cox also thinks that most people will not be fooled by Microsoft's smokescreen. "Fear Uncertainty and Doubt have been the cornerstone of Microsoft marketing for far too long," he said. "I doubt people are going to take them too seriously any more. Especially with large companies like IBM embracing free software." Find out how the open-source movement is revolutionising the high-tech world at the Linux Lounge. In this industry we often come across what can only be called a "Big Lie", this year's is the assertion that Apple is to embrace open source software. At Apple, free software goes in but it doesn't come out. Evan Leibovitch asks -- Since Apple plans to leverage open source more than many mainstream computer companies, shouldn't it be giving back too? Go to AnchorDesk UK for the news comment. For complete business coverage, see ZDNet UK's Enterprise Channel. Take me to ZDNet's Small Business Special. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read other letters.