IBM has fired back at The SCO Group with a lawsuit filed late asserting that SCO is in violation of the license that governs contributions to the Linux operating system, and that SCO has infringed upon IBM patents, an IBM spokesman said.
In the lawsuit, filed in Utah, IBM claims that SCO has violated the GPL (general public license) 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.
"These counterclaims arise from SCO's efforts to wrongly assert proprietary rights over important, widely used technology 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 destruction of the competing operating systems known as AIX and Linux, and to extract windfall profits for its unjust enrichment," IBM said in the complaint.
SCO planned to release a statement, and had expected IBM to file its counter suit, a SCO spokesman said.
The Utah-based company initially filed a suit against IBM in March claiming that IBM had tried to undermine the Unix operating system, the rights to which were owned by SCO, with its Linux development efforts.
SCO had falsely asserted that it has the right to revoke IBM's Unix license, the complaint said.
SCO announced in June that it was terminating IBM's AIX license 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 licenses, 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 license, which was described as "perpetual and irrevocable" in the complaint, according to Novell and IBM.
IBM attached letters from Novell to SCO from June of this year to support its claims in the complaint.
SCO announced this week that it would attempt 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 that SCO agreed not to seek such fees on any software distributed under the GPL when it distributed its own Linux products under that license using source code developed by IBM.
The patent-infringement charges centred around 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 claims.
The patents that are being infringed, according to IBM include: a patent called Data Compression Method; another called "Method of Navigating among Program Menus Using a Graphical Menu Tree; one called Self-Verifying Receipt and Acceptance System for Electronically Delivered Data Objects; and Method for Monitoring and Recovery of Subsystems in a Distributed/Clustered System.