After a series of preliminary filings between the two companies, IBM has now gone for the jugular, asking for a summary judgment on Lindon, Utah-based SCO’s core claims that IBM breached its Unix Systems V contract by contributing code from its AIX and Dynix versions of Unix to Linux.

It is SCO’s opinion that according to IBM’s original Unix System V license with AT&T Corp., the Unix server business which SCO acquired via Novell Inc. and Santa Cruz Operation Inc., SCO has rights over derivative works, such as AIX and Dynix.

IBM denies that this is the case, and in its filing states that it has testimonial evidence from the AT&T and IBM executives that drafted the original agreements and that there is no dispute among them that the IBM Software Agreement and the Sequent Software Agreement were not intended to, and do not, restrict in any manner the use or disclosure of any original code written by, or for, IBM and Sequent.

IBM further states in its declaration that even if it had breached contract, Novell – which claims to have retained copyright over Unix System V when it sold its Unix server business and is also in litigation with SCO – waived in October 2003 any purported right of SCO to assert a breach of contract claim against IBM or to terminate IBM’s right to distribute AIX and Dynix.

Finally IBM maintains that SCO has knowingly distributed the code it now claims should not have been contributed to Linux within its OpenLinux and SCO Linux distributions, and that as recently as August 4, 2004, continued to make available for download from its website version 2.4 of the Linux kernel, containing the code.

SCO has previously stated it unknowingly distributed the code in question under the General Public License that covers Linux, and as such had not lost the right to claim breach of contract. According to IBM, the fact that SCO continued to distribute the code after commencing its lawsuit against IBM means that it has waived any right to claim breach of contract.