He urged the Commission, Europe's top antitrust regulator, to take action. "Regulatory intervention against IBM is needed," he said in a blog post on Tuesday.
The Commission is examining several complaints about IBM's behavior in the market for mainframe computers. One of the central concerns is about the way IBM uses patents to protect its core technologies from being cloned by others.
The most recent antitrust complaint was filed last month by TurboHercules, a small open-source software vendor in France.
Mueller published a letter from IBM CTO Mark Anzani to TurboHercules President Roger Bowler dated March 11, warning that IBM would defend its patents if TurboHercules used them without permission.
"Your product emulates significant portions of IBM's proprietary instruction set architecture and IBM has many patents that would, therefore, be infringed," Anzani letter said.
Anzani listed 106 patents that could be breached by TuerboHercules. According to Mueller, two on the list were included in IBM's patent pledge made five years ago, when the company promised open-source developers that it would not assert its intellectual property rights over a wide range of its patents.
In his blog posting Mueller said that the "betrayal of the promise is unbelievable, but I never believed that IBM was sincere about that pledge in the first place."
IBM was unavailable to say whether it had terminated its pledge on the two patents concerned. A spokesman said the company is "looking into" the accusation.
People close to the company dismissed Mueller's blog posting as a stunt to try and relaunch himself on the European Union lobbying scene, after his failure at the end of last year to persuade the Commission to block the Oracle-Sun deal.
They also accused him of trying to drive a wedge between IBM and the open-source software community, and they questioned whether Mueller is in a position to speak for free and open source software developers.
Mueller's blog appeared to give credence to this claim. "IBM's threat letter will make major waves in the open source community because the one thing everyone in open source always feared the most was that a large player like this could use patents against an open source project," Mueller wrote.
Thomas Vinje, the founder of the European Committee for Interoperable Systems (ECIS), which ranks IBM among its members, said that "Microsoft lies behind the antitrust complaints against IBM." Mueller can in turn be linked to Microsoft, he said, because he joined forces with Microsoft to oppose the Oracle-Sun deal, which was approved after an in-depth investigation by the Commission that ended in December. Vinje acted for Oracle in that case.
"They have learned how to play the game in Europe," Vinje said of Microsoft, which itself has been the target of antitrust regulators there. Microsoft has invested huge amounts in attacking its rivals, including Oracle and Google as well as IBM, in Brussels in recent years, he said.
