The concession is meant to address the concerns of many corporate users who have been reluctant to use Linux because they feared Microsoft might retaliate with patent-infringement claims.

The new partners have a stormy history.

In 2004, Novell reached a $536 million settlement with Microsoft over antitrust complaints in Europe and then sued its rival again in the United States. The U.S. suit alleged the Microsoft withheld technical information about Windows that Novell needed for word processing and spreadsheet programs. Novel has since sold those WordPerfect and Quattro Pro programs.

Microsoft's decision to work with Novell reflects the increasingly important role of Linux's open-source software in corporate computing systems.

Because it's available for free, Linux software long has been has been a source of consternation for Microsoft, which makes most of its money from the sale of its proprietary software.

But Microsoft has been under increasing pressure to loosen up, and not just from customers who want to be able to run Linux with Windows.

Online search leader Google Inc. also is giving away more online software, including word processing and spreadsheet programs, and last year promised to work with Sun Microsystems Inc. to help distribute OpenOffice.

Just last week, Oracle Corp. provided the Linux system with another major lift by offering steep discounts on product support of the Linux platform provided by Red Hat Inc.

Microsoft's backing of Novell's Linux platform may raise even more worries for Raleigh, N.C.-based Red Hat, whose stock price has dropped by 17 percent since Oracle launched its assault.

1

2