Open source activists such as the free software foundation may not regard Microsoft Corp.'s shared source license as "open", but shared source manager Jason Matusow makes it plain that the company has been inspired and influenced by the free software movement.
Matusow acknowledges that shared source software is not "open" in the sense that Linux, Apache or the BSDs are considered open, but says Redmond recognizes the "technical and trust benefits" of open source.
"This is not open source and that's why we call it shared source," he says. "But we're certainly learning from open source." Microsoft "very firmly" believes in the value of its proprietary software, Matusow says. "We're going to directly sell software at the same time as we potentially offer the source code, so we need to think about the balance of these two elements."
The shared source initiative has four main targets, he says: existing customers, such as governments, OEMs and corporates; new development, such as CE.Net and ASP.Net applications; teaching and research; and business opportunities for Microsoft partners.
Although some source code is released with few restrictions, other code is very limited in its circulation. The Windows source is available only to some large corporates, about 125 universities, and 15 "sovereign entities" including NATO, the EU, and the governments of New Zealand, Australia, China, Taiwan, Russia and the U.S..
Code access for governments is through the government security program, or GSP. Governments are particularly interested in security and privacy audits, but Matusow says licensees also use the shared source program to assist with debugging or to improve their own internal support.
Developers are mainly interested in source access to assist with debugging, Matusow says. "You don't need the Windows source code to write good Windows apps," he says. "But sometimes just being able to debug, and separate 'Is it a Microsoft scenario, or ours?' can save hundreds of hours of work."
Other source releases, such as the CE.Net codebase and ASP.Net starter kit, are more liberal. The license for the ASP.Net starter kit allows reselling.
"Not only can you look at the code and modify and redistribute, but you can sell this stuff if you choose and you don't owe us a licensing fee."
Matusow says the kit has been downloaded 450,000 times.
"It has been very interesting to watch how projects have sprung off."
Much of the CE.Net source code is also available.
"We took 45 percent of the OS and put it under a very simple license ... that says you can look at this code, you can modify this code, you can redistribute this code but you cannot commercialize it."
The Rotor license is more restrictive; although it is free to download, commercial use is forbidden, limiting its use outside universities.
"Absolutely," Matusow agrees. "That is definitely a research endeavor." Asked whether the more liberal license are used as a tool to catch up in markets where Microsoft does not have a clear lead, Matusow says "Sure. Certainly. That's why we separate these ideas.
"We're trying to be very direct about this, in that Microsoft is a commercial software provider. Our business model is built around the idea that we will invest in innovation in software and then we'll turn around and we'll sell that software. Now some of it we'll indirectly commercialize, and some of it we'll directly commercialize."
However, there's no corporate directive on when source should be released.
"It's really up to the development team," Matusow says. "My job at Microsoft is to understand the benefits of open source, understand the benefits of the various business models and how people are applying those, and then to bring those back to (the product groups).
"Our executive staff is very interested in seeing us expand our shared source program, yet we're not going by fiat to each and every group and saying 'You will share source code'."
The government security program includes access to the Windows 2000, XP and 2003 source, documentation, and a visit to Redmond, Matusow says.
"What's turned out to be critical about that is that we thought source code was going to be the central part of the GSP. It turns out governments are far more interested in the documentation, and in coming to Redmond and meeting the individual development teams and the program managers."
In any case, the Windows source is too large for a casual browse. It is hosted on a server in Redmond and made available to licensees through MSDN Code Centre Premium subscriptions. The 700 engineers who have MSDN access are authorized through the use of smartcards and smartcard readers.
"There's such a significant amount of source code that it becomes somewhat troublesome to find the code that they need to find," Matusow says. "So we have indexed that entire Windows source code, which turned out to be more of a job than we originally thought it would be." Uptake has been limited, he says.
"All over the world there are about 2,000 enterprises which are able to receive Windows source code. There are about 50 which have taken it up.
"Linux is the same way. If you talk to Linux users you'll find that many are happy that the Linux source is available to them were they to need it -- but it's 10 million lines of code, easy."
So how far can Microsoft take its newfound interest in source release? Matusow says the company will do whatever makes business sense. "We have no intention of eviscerating our business model around source code access; at the same time, if there's a clear customer benefit to be had, we will definitely go down that path."