After reviewing Unix source code provided by IBM, The SCO Group appears to be experiencing difficulties in identifying the specific lines of code that it alleges IBM improperly contributed to the Linux operating system, according to court documents filed in a federal court last week.After reviewing Unix source code provided by\u00a0IBM,\u00a0The SCO Group\u00a0appears to be experiencing difficulties in identifying the specific lines of code that it alleges IBM improperly contributed to the Linux operating system, according to court documents filed in a federal court last week.In the filings, SCO asks the court to order IBM to produce more materials documenting the development of its AIX and Dynix operating systems, and argue that the files that IBM has produced to date are "incomplete."In March, the United States District Court for the District of Utah ordered IBM to provide SCO with source code to the two operating systems. SCO now claims that "the files previously produced by IBM pursuant to this Court's March Order show that IBM improperly contributed code to Linux," according to court filings dated May 28.SCO's filings provide few details on the nature of these "improper" contributions, however.When contacted Thursday, SCO spokesman Blake Stowell declined to say where, specifically, they had occurred.Since launching its multibillion dollar lawsuit against IBM in March of 2003, SCO has publicly provided some examples of alleged intellectual property (IP) violations within the Linux source code, all of which have been strongly disputed by the open source community. In fact, the question of whether or not SCO even owns the copyright to the Unix System V source code is unanswered, and SCO and Linux vendor Novell Inc. are engaged in a legal dispute over the matter.In the March ruling, the court also ordered SCO to respond to IBM's discovery demand that it identify the specific lines of code that it says IBM contributed to Linux.SCO has apparently had difficulty accomplishing this task. The May 28 filings list a number of steps SCO has taken to identify the IP violations, but adds, "these efforts have not, however, yielded much of the information required for SCO to further respond to IBM's discovery demands.""SCO has attempted to follow IBM's scattered path through the winding history of countless alterations, derivations, and revisions, but the task is nearly impossible without a map, a map so easily accessible to IBM," the filings say.More documentation of IBM's source code and developer contributions is needed for SCO to respond to IBM, the filings say.The May 28 filings raise questions about how much evidence SCO actually has about any IBM wrongdoing with respect to Linux, given that SCO already has access to the open-source Linux source code, said Jeff Norman, an intellectual property partner with the Chicago law firm Kirkland & Ellis."We're talking about open source code. The code is out there," he said. "For them to say that they can't respond to IBM's request to identify specific items of code they are infringing, I just don't understand that. I don't think the judge is going to understand that.""Either they know that there's code that's infringing or they're just fishing," he said.