Some of the world's biggest companies could shortly face lawsuits over their use of the Linux computer operating system, the executive at the center of the growing legal storm over the software has warned.
The potential lawsuits would escalate the legal wrangle around Linux, dragging non-US companies into a battle that has threatened to derail one of the technology industry's biggest recent success stories.
BP, Siemens and Fujitsu are among a large number of big companies whose use of the operating system has come under scrutiny, said Darl McBride, chief executive of SCO, the small US company that has mounted the challenge.
He said the company had not yet decided whether to sue. But he added: "That clearly is an option we are looking into very closely."
An open-source system developed and maintained by volunteers, the free Linux software has become a mainstay in corporate computing departments. SCO began a legal campaign early last year, claiming some of its own software code had been illicitly included in Linux.
The prospect of legal action depends on the precise use each company makes of Linux, said Mr. McBride. Commenting on the use of the software by BP, he said: "There are clearly some concerns with those guys." But he added that SCO is "trying to work through these things without going to court". The threat of legal action overseas extends a mounting campaign in the US.
The company has a list of a dozen US companies it is considering suing. Opponents claim the threats are little more than blackmail to persuade companies to buy licenses from SCO.
The SCO chief would not confirm Google was on the list but he did little to dispel the prospect of legal action that could hamper the search engine company's listing plans. "Google is using a lot of Linux; they've benefited from that," said Mr. McBride.
Extending the legal challenge overseas would open a new front in the battle. Mr. McBride said SCO "started a dialogue" with a number of international companies last month over the use of Linux and planned to decide on action by the end of January.
It is using an unusual breach-of-contract claim to try to draw the international companies into the fray. Many companies around the world using the Unix computer operating system - which has long been a fixture of corporate computing - bought licenses from AT&T, which first developed the software.
SCO assumed the rights to Unix in the 1990s and now claims some of the Unix code has found its way into Linux.
As a result, companies with Unix licenses could be in breach of contract if they now use Linux, said Mr. McBride.