Microsoft and Novell have settled a long-running dispute - enabling Novell's version of the Linux operating system to work better with Windows.
Windows and Linux have been battling over compatibility.
Many businesses prefer Linux as it can be tailored to a company's needs - but Microsoft has been reluctant to allow its products to work alongside it.
Engineers will now work together to enable software from both companies to work better with each other.
Microsoft will also offer packages including Linux support.
Non-business users may also benefit from the deal - with plans to have a more seamless operation between Microsoft Office and its open source rival, OpenOffice.
Linux is open-source software and Novell relies largely on fees from offering support and servicing for its version, SUSE.
"This agreement gives customers interoperability and peace of mind all in one," said Novell chief executive Ron Hovsepian.
He added Microsoft had committed "a significant amount of money" to the partnership.
Microsoft chief executive Steve Ballmer said customers would find the deal "compelling" because it delivered "practical value by bringing two of their most important platform investments closer together".