All enterprise Linux users will have to pay SCO's new licensing fees to use Linux, or they could find themselves in a copyright infringement lawsuit.
That was the ultimatum laid out by SCO chief executive officer and president Darl McBride, who said that the $3bn (£1.9bn) lawsuit against IBM in March was apparently just the start of his company's march to defend itself from what it sees as rampant theft of its Unix System V intellectual property (IP).
"We agree on the point that this case started out as a contracts case against IBM. As of today, it's a different game," McBride said.
"SCO's Unix IP has been misappropriated into Linux," he said. "SCO is giving customers [of any Linux distribution] the opportunity to run Linux legally."
Back in May, SCO warned all commercial Linux users that they could be using its code illegally and recommended that they seek legal advice to help decide what to do about the issue.
Last month, McBride said, some corporate Linux users contacted SCO and said they wanted to find a "way to work it out" so they could continue to use Linux.
SCO also announced that it had received copyrights for its System V code.
The company had never before officially filed for the copyrights, which it needed to do as a procedural step while it pursues its legal case against IBM, McBride said.
In that case, SCO alleges that IBM misappropriated trade secrets related to SCO's Unix products to benefit IBM's Linux strategy.
The specially tailored SCO UnixWare 7.1.3 licences will support runtime, binary use of Linux for all commercial users of Linux based on kernel version 2.4.x and later.
Buying a licence would allow users to comply with SCO's copyrights, the company said, adding that if enterprise Linux users do so, SCO would not pursue legal challenges against them related to the code.
Pricing has not yet been announced but will be comparable to existing UnixWare licences, McBride said.
Analyst Gordon Haff at Illuminata, said he sees SCO "going after users because if they go after [Linux vendors such as] Red Hat, those guys are going to have to fight them" to defend their businesses. "They can't roll over" and pay the demands like corporate users could, he said.
George Weiss, an analyst at Gartner said that if SCO is successful in squeezing licensing fees out of users, it would essentially create a new tax on Linux, perhaps upsetting the often-favourable total cost of ownership arguments for using it.
"SCO is really applying pressure. It's gotten very nervous" among users, he said. "They don't know what to do."
One part of SCO's argument, though, is that much of the alleged code infringement is related to the latest symmetric multiprocessor (SMP) capabilities in Linux kernel 2.4 and later, Weiss said. If that's the case, then SCO's claims may not affect most enterprise users, who are using Linux more for infrastructure services than SMP.
"SMP is where the impact could be more in the future. [The SCO threats] could slow the advance of Linux" for higher power uses for now, he said. "It could put on hold a lot of planned purchases."
Todd R Weiss writes for Computerworld