A bitter legal row over who owns key parts of the Linux operating system has entered a new phase.
SCO has been paid cash to use its code
US company EV1 Servers has bought a licence to use Linux from SCO, which claims that some its intellectual property has been illegally included in the open source software.
EV1 bought the licence even though SCO's claim to own some of the code inside Linux has yet to be tested by the US courts.
SCO said other companies had bought licences for Linux but, so far, EV1 was the only one willing to go public.
Linux and open source software is winning fans because it is cheap, robust, gives people the freedom to tinker and is generally less plagued by the security problems that dog Microsoft Windows.
In March 2003 SCO filed a lawsuit against IBM alleging that the computer giant had illegally put some of its Unix computer code into Linux.
IBM has disputed the claim and is countersuing.
SCO's claim to own Unix is also being decided by the courts.
Soon after launching the legal action SCO urged Linux users to buy licences to use its intellectual property contained in the software and said those without a licence might face lawsuits later on.
However, SCO's actions have enraged many in the Linux and open source movement who dispute the claims of ownership.
The fact that SCO has yet to publicly disclose which bits of the venerable Unix operating system it believes are being illegally used in Linux have only fuelled doubts about its claims.
Leading lights of the open source movement have said they would happily remove disputed code if SCO told them what it owned. So far SCO has not responded to this offer.
The legal wrangle is being exhaustively documented by the Groklaw website which reproduces legal documents from all sides in the case.
SCO's main website was knocked out by the Mydoom web worm which subjected it to a denial-of-service attack.
Some thought the worm might have been written by a Linux fan angered by SCO's actions. However, others thought the tactic was a ruse to conceal the worm's real intent.
Despite the disputes, some weight has been lent to SCO's opinion by the announcement by EV1 Servers that it has bought a licence to use some of SCO's intellectual property on the 11,000 servers it uses to host websites.
The amount it paid to SCO has not been disclosed.
In a letter to customers Robert Marsh, head surfer at EV1, said the licence was bought to ensure its customers would not face legal action from SCO later on.
He added: "We make no endorsement of SCO nor do we make any admission as to their claims."
Following the announcement many open source advocates called for a boycott of EV1 Servers.
In related news SCO has announced the first copyright infringement lawsuit against an end user of Linux.
Car parts retailer AutoZone was named in the first lawsuit and SCO is seeking damages for unauthorised use of its intellectual property.