"The principles outlined by the ALI interfere with the natural operation of open source licenses and commercial licenses as well by creating implied warranties that could result in a tremendous amount of unnecessary litigation, which would undermine the sharing of technology," Jim Zemlin, executive director of the Linux Foundation, wrote in a about the letter.

Microsoft and the Linux Foundation are writing and publishing the letter because it is essentially the only way for them to express their opinions about the ALI document. Only ALI members can participate in the process of drafting such documents and there is no public review prior to publication, Zemlin said.

The draft of the document is for download for US$45.

Microsoft and the Linux Foundation are asking the ALI to delay adoption of the principles to allow more time for input from interested parties.

They both recognize how unusual it is to be on the same side of such a debate. "The mere fact that the Linux Foundation and Microsoft are joining forces may be viewed by some as remarkable," wrote Horacio Gutierrez, deputy general counsel for Microsoft in a . "But there is a wide range of issues that affect all software developers alike."