Microsoft lawyers have joined the company's campaign against open-source software, restricting how developers may use what it terms "viral software" in connection with Microsoft programming tools.
The license of the second beta version of Microsoft's Mobile Internet Toolkit--software used so programmers can create server software to connect with handheld computers over the Internet--prohibits customers from using the Microsoft software in conjunction with "potentially viral software."
In describing this category of software, Microsoft includes the most common licenses used for publishing open-source software, such as the Linux operating system. Licenses specifically excluded by Microsoft include the General Public License, the Lesser General Public License, the Mozilla Public License and the Sun Industry Standards License.
While the provision in Microsoft's license isn't surprising, Fenwick & West intellectual property attorney Dana Hayter said the company could have picked a more neutral term, such as "open software."
"The choice of the term says more about Microsoft's view than the rest of it," Hayter said. "I think it's a pejorative and misleading term. To suggest that open-source software is somehow 'viral' is to confuse harm to your customers' machines and data with harm to Microsoft's profits."
Microsoft representatives weren't immediately available for comment.
The license provision, posted Thursday at Linux Today, is the latest step in an increasingly vocal campaign by Microsoft Chairman Bill Gates, Senior Vice President Craig Mundie and Chief Executive Steve Ballmer to disparage open-source software.
The campaign, in which the executives have compared open-source software to viruses and cancer, comes at a time when some observers believe Microsoft is worried that Linux--the best-known open-source project--will undermine the Microsoft.Net strategy for joining desktop computer users with sophisticated Internet services.
Some open-source fans weren't happy with Microsoft's view of the software world and its use of the term "viral software."
"The GPL is not a virus, it is a vaccine, an inoculation against later abuse of your code by having someone, such as Microsoft, take your hard work, incorporate it into a proprietary product which is then extended and kept closed, marginalizing your project in the process," said one comment at discussion site Slashdot.
The Microsoft license seeks to prevent the possibility that a program that links both to Microsoft and open-source software components could force Microsoft to expose the now-secret source code of its software, Hayter said.
"They're saying you cannot use (Microsoft) software in a way that would create in Microsoft any obligations to do anything with (Microsoft's) code, for example to make the source public," Hayter said.
One example of a forbidden move would be to create software that used prepackaged components called libraries from Microsoft as well as a library covered by the GPL, Hayter said. Under the terms of the GPL, software covered by it may be directly incorporated only into other GPL software.
But a legally grayer area is creating software that merely calls upon such libraries rather than incorporating the library code directly. The Free Software Foundation created the LGPL license for precisely such occasions; this license allows links to proprietary software.
One example is the use of a library called "readline" that lets people use arrow keys and perform some other tasks when typing information into a computer, said PostgreSQL database developer Bruce Momjian. Because PostgreSQL is released under a BSD-style license that has different terms than the GPL, GPL code may not be freely mixed within PostgreSQL.
"If we required the readline library, then the entire PostgreSQL software would have to be GPL'd," Momjian said, noting that programs such as the BSD-licensed libedit software offer an alternative. "If you use (readline) in any application, your entire application is GPL."
Regardless of the legalities involved, the provision in the license is significant, Hatyer said. "This demonstrates they're taking open source seriously."