IBM says that they are within their rights to protect their investment in mainframe technology and have not broken their 2005 pledge. IBM had sent a letter to TurboHercules SAS listing patents that believed the open source mainframe emulator could possibly infringe. IBM say they were not claiming the patents were infringed but that the letter was an illustration of the company's patent portfolio related to mainframe technology.

Florian Meuller, founder of NoSoftwarePatents, discovered that two of the one hundred patents listed was included in a 2005 patent pledge by IBM and had questioned the sincerity of that pledge. In an addendum to a response given to eWeek, IBM said that it stood by its 2005 pledge but added

In 2005, when IBM announced open access to 500 patents that we own, we said the pledge is applicable to qualified open-source individuals or companies. We have serious questions about whether TurboHercules qualifies. TurboHercules is a member of organizations founded and funded by IBM competitors such as Microsoft to attack the mainframe. We have doubts about TurboHercules' motivations.

The Hercules project is licensed under the QPL, an OSI listed open source licence. The original pledge says that the promise to not assert the patents applies to Open Source Software, defining it as "any computer software program whose source code is published and available for inspection and use by anyone, and is made available under a license agreement that permits recipients to copy, modify and distribute the program’s source code without payment of fees or royalties".

IBM further qualifies the pledge saying "All licenses certified by opensource.org and listed on their website as of 01/11/2005 are Open Source Software licenses for the purpose of this pledge". IBM's new statement appears to add the term "qualified" to "open source" and that they believe that the pledge is limited to companies who do not commercially compete with IBM.

IBM may be using a further clause from the original pledge which says that they reserve the right to terminate the pledge if any company "files a lawsuit asserting patents or other intellectual property rights against open source software". TurboHercules filed an antitrust complaint with the European Commission last month, and IBM may be considering that as a move that qualifies for revocation of the pledge in this case.

(djwm)