Files produced by IBM back up SCO's claims Big Blue "improperly contributed code to Linux," the Unix seller said in a memorandum to a US court last week.
In a strongly worded discovery submission to the US District Court in Utah, SCO said the files provided by Big Blue to date, though "only partial responses to SCO's requests for information and materials," revealed the Dynix/ptx enterprise-class operating system "contains material and significant Unix system V code".
SCO claims AIX and Dynix, "considered as whole programs," are derivative works of Unix System V.
SCO said that while it only had the partial responses to work with, the fact Dynix code "contains some historical commentary" meant it could trace some sources of contributions to the code.
"AIX almost certainly has a similar history, but because AIX's code does not contain any historical comments, or at least the AIX code provided did not, SCO has had difficulty determining all the portions of AIX that were taken from Unix System V," the SCO filing said.
SCO said IBM had to date only produced selected pieces of AIX and Dynix, while consistently refusing to produce all requested versions of AIX or Dynix or revision control systems for either program.
The filing is the latest move in the legal brawl between Utah-based SCO and Big Blue over the controversial Unix seller's claims the tech heavyweight breached SCO's intellectual property rights by copying some of the source code from Unix into Linux.
Operating without the items it was seeking through the discovery process, SCO said it had spent "countless hours -- and sometimes fruitless effort -- trying to track the improper use of Unix System V code in Linux through AIX and Dynix".
SCO said it had been forced to rely on alternative methods to try to establish proof, including: identification of all publicly available code patches contributed by IBM/Sequent engineers to Linux, to the extent identified on IBM's Web site and in Linux forums; tracing of code in available code patches to versions of AIX and Dynix; and identification of IBM's public statements regarding its roadmap for building Linux and its technology contributions to Linux.
The company said: "To trace the foundations of AIX source code and to have a complete understanding of Dynix' source code origins, SCO must have
- access to all interim and final versions of AIX, Dynix and ptx;
- access to programmer notes and design documents that reveal the work behind the revisions to the programs;
- and most importantly, access to all revision control systems that track changes to AIX and Dynix, thus exposing the sources of IBM's current AIX and Dynix code and revealing what portions of Unix System V made their way from AIX and Dynix into Unix.
IBM last month filed a motion for summary judgment in the case, claiming SCO had produced no evidence to back up its copyright claims and was unlikely to do so. Big Blue said the claims should be dropped.
"Despite the fact that SCO has been claiming for months that IBM's Linux activities infringe SCO copyrights," the filing reads, "SCO still fails to adduce the basic evidence necessary to support its copyright assertions".
However, SCO hit back in its filing, dated 28 May, stating: "IBM is apparently taking the position that in order for SCO to succeed in its contract claims, SCO must prove copyright infringement.
"This position -- if taken as a description of the sole basis for IBM's liability for breach -- confuses contract with copyright and thereby essentially eliminates the protections of the contract for SCO.
"Nevertheless, SCO recognises that the rules of discovery obligate it to respond, to the best of its ability, to IBM's discovery requests.
"And in any event, SCO, like any plaintiff, is entitled to proceed under alternate theories of liability and to obtain the discovery needed to allow it to do so".
The filing added that [SCO had] "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, so clearly relevant to this case and so absolutely essential to SCO that IBM's withholding of it and subsequent filing of a summary judgement motion is unconscionable".