Move could speed resolution of SCO Group's hot-button Linux-related suit against Big Blue.
The move is a piece of good news for SCO, whose suit so far has been met with skepticism by the federal judge overseeing the case.
In a court filing Thursday, IBM said it dropped the claims to speed the case and to try to curtail the number of depositions SCO seeks, and added the potential monetary rewards are slim.
"While IBM continues to believe SCO infringed IBM's valid patents, IBM agreed to withdraw its patent counterclaims to simplify and focus the issues in this case and to expedite their resolution," IBM said in the filing. "Since SCO's sales have been, and are, limited, a finding of infringement would yield only the most modest royalty or award of damages and would not justify the expense of continuing prosecution of these claims."
When IBM countersued a few months after SCO's initial legal volley, it included four claims of patent infringement, but it dropped one claim in 2004.
Patent infringement suits are very expensive to defend, often costing about $3 million per claim, intellectual-property lawyers say.
Not everything went SCO's way, though. In a ruling Friday, Magistrate Judge Brooke Wells, who is overseeing the discovery phase of the trial, denied SCO's motion to compel IBM to release more information about its Linux work.
Dan Frye, director of IBM's Linux Technology Center, had argued in a deposition that it would be impractical to retrieve the information SCO wants, generating hundreds of thousands of documents and more than a million pages of information.
"In order to collect all the development history documentation sought by SCO, it would be necessary to search the individual offices and workstations of each of the more than 300 IBM developers throughout the world who have made Linux contributions," he said, adding that interviews of managers, support staff and others also would be required.