"SCO is taking this important step because there are intellectual property issues with Linux," said Chris Sontag, a senior vice president at SCO Group.
He argued:
"When SCO's own UNIX software code is being illegally copied into Linux, we believe we have an obligation to educate commercial users of the potential liability that could rest with them for using such software to run their business. We feel so strongly about this issue that we are suspending sales and distribution of SCO Linux until these issues are resolved."
UNIX originated at Bell Labs in 1969. It evolved with many versions being provided by various companies, universities, and individuals, becoming the first open operating system that could be amended or improved by anyone.
The operating system is widely used in workstations. Linux is a UNIX derivative that was designed to give PC users a free or very low-cost operating system comparable to the more expensive UNIX systems, although its use in the business environment is growing.
There are intellectual property rights in UNIX – and SCO purchased significant parts of them in 1995, including source code, source documentation, software development contracts, licenses and other intellectual property that pertained to UNIX-related business.
IBM originally entered into a UNIX license agreement with AT&T in February 1985 in order to produce the AIX operating system. SCO subsequently acquired its rights in UNIX. The agreements required that IBM hold the UNIX software code in confidence, and prohibited unauthorised distribution or transfer.
But SCO alleges that IBM gave the rights away to Linux and in March this year launched a $1 billion lawsuit against IBM.
In the course of preparing for the trial the SCO Group has apparently uncovered many instances of illegally copied code in the Linux kernel source. Hence the warning and the letter sent out to commercial users of Linux.
The letter states that:
“Linux has been built from contributions by numerous unrelated and unknown software developers, each contributing a small section of code.
"Many Linux contributors were originally UNIX developers who had access to UNIX source code distributed by AT&T and were subject to confidentiality agreements, including confidentiality of the methods and concepts involved in software design. We have evidence that portions of UNIX System V software code have been copied into Linux and that additional other portions of UNIX System V software code have been modified and copied into Linux, seemingly for the purposes of obfuscating their original source.
"As a consequence of Linux’s unrestricted authoring process, it is not surprising that Linux distributors do not warrant the legal integrity of the Linux code provided to customers. Therefore legal liability that may arise from the Linux development process may also rest with the end user.
“Similar to analogous efforts underway in the music industry, we are prepared to take all actions necessary to stop the ongoing violation of our intellectual property or other rights.”
As yet SCO has not laid out the evidence for these claims. According to the Linux Journal, an independent panel will be invited to inspect the evidence in a few weeks time, subject to a non-disclosure agreement.