IBM has fired back at The SCO Group with a lawsuit asserting that SCO is in violation of the licence that governs contributions to the Linux operating system, and that SCO has infringed IBM patents.
In the lawsuit, IBM claims that SCO has violated the General Public Licence (GPL) that regulates how the Linux operating system can be used. IBM also alleges that SCO is violating four IBM patents with some of its products, the spokesman said.
"These counterclaims arise from SCO's efforts to wrongly assert proprietary rights over important, widely used technology," said IBM in the complaint, "and to impede the use of that technology by the open-source community.
"SCO has misused, and is misusing, its purported rights to the Unix operating system developed initially by Bell Laboratories, then a research and development arm of AT&T, to threaten the destruction of the competing operating systems known as AIX and Linux, and to extract windfall profits for its unjust enrichment," the complaint said.
A SCO spokesman said his company had expected IBM to file a countersuit.
SCO initially filed a suit against IBM in March claiming that IBM in developing Linux had tried to undermine the Unix operating system, the rights to which are owned by SCO.
The IBM complaint said SCO has falsely asserted that it has the right to revoke IBM's Unix licence. SCO announced in June that it was terminating IBM's AIX licence and would seek compensation from IBM's AIX business. AIX is a version of Unix developed by IBM.
Novell sold certain Unix System V rights that it had acquired from AT&T to The Santa Cruz Operation in 1995, but it did not grant that company the right to revoke Unix licences, IBM said in the complaint.
SCO, formerly known as Caldera, bought the Unix rights in question in 2001 when it acquired some assets of The Santa Cruz Operation.
Those Unix rights did not include the right to revoke IBM's licence, which is described as "perpetual and irrevocable" in the complaint, according to Novell and IBM. IBM attached letters from Novell to SCO sent in June of this year to support its claims in the complaint.
SCO announced this week that it will try to collect licensing fees from Linux users.
By attempting to claim licensing fees on Linux, SCO is in violation of the GPL, IBM said. It also said SCO agreed not to seek such fees on any software distributed under the GPL when it distributed its own Linux products under that licence using source code developed by IBM.
The patent-infringement charges centre on four SCO products, UnixWare, Open Server, SCO Manager and Reliant HA, IBM said. SCO infringed four separate IBM patents with those products, and should be enjoined from developing or selling those products, IBM claimed.
The patents that are being infringed, according to IBM include: the "Data compression method", "Method of navigating among program menus using a graphical menu tree", "Self-verifying receipt and acceptance system for electronically delivered data objects" and "Method for monitoring and recovery of subsystems in a distributed/clustered system" patents.
Tom Krazit and Robert McMillan write for IDG News Service