Dell Inc will soon offer more personal computers that use the Linux operating system instead of Microsoft Corp's Windows, said the founder of a company that offers Linux support services.

Mark Shuttleworth, who created a version of Linux software named Ubuntu, said Dell is happy with the demand it has seen for Linux PCs that were introduced in May.

Dell, the world's second-largest PC maker after Hewlett-Packard Co., now offers three consumer PCs that run Ubuntu Linux.

What's been announced to date is not the full extent of what we will see over the next couple of weeks and months, Shuttleworth said an interview late on Wednesday.

There are additional offerings in the pipeline, he said. Shuttleworth founded Canonical Inc to provide support for Ubuntu Linux.

A Dell spokeswoman, Anne Camden, declined comment, saying the company does not discuss products in the pipeline.

She added that Dell was pleased with customer response to its Linux PCs. She said Dell believed the bulk of the machines were sold to open-source software enthusiasts, while some first-time Linux users have purchased them as well.

Open-source software refers to computer programs, generally available over the Internet at no cost, that users can download, modify and redistribute.

The Linux operating system is seen as the biggest threat to Microsoft's Windows operating system.

Shuttleworth said sales of the three Dell Ubuntu PC models were on track to meet the sales projections of Dell and Canonical. He declined to elaborate.

Companies like his privately held Canonical Inc, Red Hat Inc and Novell Inc make money by selling standardized versions of Linux programs and support contracts to service them.

There are dozens of versions of Linux, available for all sorts of computers from PCs to mainframes and tiny mobile devices.

Shuttleworth said his company was not in discussions with Hewlett-Packard or the other top five PC makers to introduce machines equipped with Ubuntu.

The other three top PC makers are Lenovo Group Ltd, Acer Inc and Toshiba Corp.

(Reporting by Jim Finkle)