IBM snubbed a request from the British founder of TurboHercules SAS to let it offer a disaster recovery product for IBM mainframe users and instead accused the French open source startup of violating its intellectual property.

According to a letter published today by NosoftwarePatents founder Florian Mueller, Big Blue has abandoned its commitment to the open source community by attacking the Hercules project, which was founded by Roger Bowler more than a decade ago.

The mainframe emulator code was written to enable users to run IBM's z/OS on x64 or Itanium iron instead of System z hardware from Big Blue.

"A reliable source close to the Hercules project has provided me with this letter that Mark Anzani, IBM's mainframe CTO, recently sent to TurboHercules SAS," wrote Mueller.

"The letter comes with a 'non-exhaustive' list including 106 IBM patents plus 67 pending patent applications."

He claimed that the list includes two of the US patents (5613086 and 5220669) which were among the 500 patents IBM pledged not to use against the open source community.

"This is so appalling that I felt compelled to show to the FOSS community what IBM is doing: IBM is using patent warfare in order to protect its highly lucrative mainframe monopoly against Free and Open Source Software."

Mueller is demanding regulatory action against IBM, which already faces an anti-trust probe after TurboHercules filed a complaint with the European Commission last month.

"In an area in which IBM generates massive revenues (an estimated $25bn annually just on mainframe software sales!), any weapon will be brought into position against open source," griped Mueller.

"Even patents, which represent to open source what nuclear arms are in the physical world."

We asked Big Blue to comment on this story, but at time of writing it hadn't gotten back to us. ®