Microsoft Corp. reached a rapprochement with a major seller of the Linux operating system, a deal that makes a kind of peace between two opposing camps in the software industry.

The deal with Novell Inc. is designed to make it easier for customers to use both Linux and Microsoft's Windows software. It puts new pressure on Red Hat Inc., a Linux seller whose shares were recently roiled when Oracle Corp. announced plans to offer its own technical support for Red Hat's products.