IBM has filed court documents seeking a dismissal of a second major component of the lawsuit filed against it last year by Unix supplier SCO.
The documents argue that SCO's breach of contract allegations should be dismissed from the lawsuit.
"Although SCO for months perpetuated the illusion that it had evidence that IBM took confidential source code from Unix System V and 'dumped' it into Linux, it has become clear that SCO has no such evidence," the filings state.
SCO has accused IBM of breaching a Unix System V licensing contract between AT&T and IBM, saying that it acquired the rights to enforce this contract when it purchased the Unix System V operating system in 2002.
The filings address this allegation, arguing that Novell, which at one point owned the rights to Unix System V, retained the right to waive any alleged breaches of IBM's agreement - something that IBM Novell has now done, according to IBM.
IBM also provided two more reasons why the breach of contract claims should be dismissed.
The filings argue that because SCO itself, a former Linux supplier, had distributed "public" versions of the code IBM is alleged to have revealed, SCO's breach of contract case against IBM should be dismissed.
They also argue that IBM's original AT&T contract does not preclude IBM from "using and disclosing source code that is written by IBM and does not include the Unix System V code".
In March 2003, SCO filed a multibillion-dollar lawsuit against IBM, accusing it of violating SCO's Unix intellectual property. SCO accused IBM of unfair competition, breach of contract and violation of SCO's trade secrets.
In late February, it dropped the trade secret allegations in the case, but added a claim that IBM had violated SCO's Unix copyright - a component of the case that IBM asked the judge to dismiss last May.
Robert McMillan writes for IDG News Service