Developers of open-source Samba software will find their work a little easier thanks to an agreement with Microsoft, signed Thursday, that will give them access to previously secret data on how the Windows operating system works.

Microsoft was compelled to make this information available following a March 24, 2004, European Commission antitrust ruling against the company. In July 2006, the EU fined Microsoft €280.5 million ($338.6 million at that time) for failing to provide documentation on Windows protocols to its rivals. Microsoft lost an appeal of that decision in September, setting the stage for the deal.

The deal was signed with a nonprofit group called the Protocol Freedom Information Foundation, (PFIF) which negotiated on behalf of the Samba team because Samba is not represented by a corporate entity. PFIF will pay a one-time fee of €10,000 and, in return, will be able to allow open-source developers, including the Samba team, to access the documents.

Developers will have to sign nondisclosure agreements and will not be allowed to redistribute Microsoft's documentation, but they will be able to write open-source software that implements the Windows protocols. The deal will also clarify which patents Microsoft believes are related to this technology, making it easier for open-source developers to avoid patent violations.

Antitrust rulings forced Microsoft to set up protocol-licensing programs in the past, including the MCPP (Microsoft Communications Protocol Program) and the WSPP (Work Group Server Protocol Program), but these efforts were not compatible with open-source software licenses.

To reach an agreement with the Samba team, Microsoft created a new type of WSPP licensing agreement, which gives developers access to the Windows protocols as well as a clear list of the patents that Microsoft has declared relative to its technology.

"They're giving us all the documentation to make everything work," said Jeremy Allison, co-author of Samba. "We will have no more excuses to suck ... if we don't have something, we won't be able to say it's not our fault we don't know how to do it."

Samba and Microsoft executives had been meeting since March in hopes of hammering out a deal, said Sam Ramji, director of Microsoft's Open Source Software Lab, in a blog post entitled "If you're surprised, you're not paying attention."

"I expect that this will significantly improve the process of Samba development and produce better quality interoperation between Windows and Linux/UNIX environments," he wrote.

Samba is an open-source version of the file-and-print software used by Windows. It is a standard component of the Linux and Unix operating systems, allowing these systems to share data and work alongside Windows clients.

But development of Samba has traditionally been back-breaking work. Developers would analyze network traffic to try and glean how Windows was working and then build their software based on that knowledge -- a process called reverse-engineering.

With the new agreement, developers will have access to Microsoft's own protocol specifications and will be able to build their software based on those documents, Allison said. That, in turn, will accelerate the team's development of its next generation of software, which will implement the new Sever Message Block 2.0 protocol, used by Windows Vista.

Though the deal was reached on Thursday, developers were still waiting for the final technical aspects of the document hand-over to be settled, Allison said. He expects to get his hands on the technical specifications fairly soon. "I'm guessing that for my Christmas vacation I'll have some enjoyable things to read," he said.

This story was updated on December 20, 2007