Red Hat and Ubuntu, both important distributors of Linux, have refused to discuss with Microsoft a technology licensing deal similar to those the software maker has signed with other open-source organizations.

Rumors had been floating around the Web that Ubuntu was in discussions with Microsoft. Red Hat, on the other hand, decided to issue a statement after seeing some of the terms of deals Microsoft had reached with other open source vendors.

"Based on what we have seen, the deal was not interesting to us," Red Hat spokeswoman Leigh Day said in an e-mail Tuesday. "We continue to believe that open source and the innovation it represents should not be subject to an unsubstantiated tax that lacks transparency."

Ubuntu took issue with signing an agreement in which patent infringements were not specified. Microsoft has claimed that open source software such as Linux violate 235 of its patents, but has not provided a list of the infringements, despite requests by the open-source community.

"We have declined to discuss any agreement with Microsoft under the threat of unspecified patent infringements," said Mark Shuttleworth, a South African entrepreneur who provides commercial support to Ubuntu through his company Canonical Ltd. Shuttleworth posted the statement in his blog over the weekend.

Earlier this month, Linspire, which also distributes a desktop version of Linux, became the latest open-source software distributor to sign a pact with Microsoft. The agreement, similar to those Microsoft reached with Novell, JBoss, Xandros, XenSource, and Zend Technologies, provides Linspire users with assurance that they won't be violating Microsoft intellectual property and patents.

In rejecting talks with Microsoft, Ubuntu saw no need to protect users. "Allegations of infringement of unspecified patents carry no weight whatsoever," Shuttleworth said. "We don't think they have any legal merit, and they are (sic) no incentive for us to work with Microsoft on any of the wonderful things we could do together."

Shuttleworth went on to say that paying Microsoft would not guarantee protection for users. "People who pay protection money for that promise are likely living in a false sense of security," he said.

Shuttleworth, however, did not rule out future collaboration with Microsoft, if the software maker changed its position. "I have no objections to working with Microsoft in ways that further the cause of free software, and I don't rule out any collaboration with them, in the event that they adopt a position of constructive engagement with the free software community," he said.

In May, Dell started offering Ubuntu pre-installed in two consumer desktops and a notebook. Before the release, Dell only offered Linux on workstations and servers.

The long-awaited release was a landmark for Linux in the consumer market. Until then, no computer maker with the market strength of Dell has made a similar commitment to supporting the free software.