FAQ Question 131:
Could patents be used to completely disable Mono (either submarine patents filed now, or changes made by Microsoft specifically to create patent problems)?
First some background information.
The .NET Framework is divided in two parts: the ECMA/ISO covered technologies and the other technologies developed on top of it like ADO.NET, ASP.NET and Windows.Forms.
Mono implements the ECMA/ISO covered parts, as well as being a project that aims to implement the higher level blocks like ASP.NET, ADO.NET and Windows.Forms.
The Mono project has gone beyond both of those components and has developed and integrated third party class libraries, the most important being: Debugging APIs, integration with the Gnome platform (Accessibility, Pango rendering, Gdk/Gtk, Glade, GnomeUI), Mozilla, OpenGL, extensive database support (Microsoft only supports a couple of providers out of the box, while Mono has support for 11 different providers), our POSIX integration libraries and finally the embedded API (used to add scripting to applications and host the CLI, or for example as an embedded runtime in Apache).
The core of the .NET Framework, and what has been patented by Microsoft falls under the ECMA/ISO submission. Jim Miller at Microsoft has made a statement on the patents covering ISO/ECMA, (he is one of the inventors listed in the patent): here.
Basically a grant is given to anyone who wants to implement those components for free and for any purpose.
The controversial elements are the ASP.NET, ADO.NET and Windows.Forms subsets. Those are convenient for people who need full compatibility with the Windows platform, but are not required for the open source Mono platform, nor integration with today's Mono's rich support of Linux.
The Mono strategy for dealing with these technologies is as follows: (1) work around the patent by using a different implementation technique that retains the API, but changes the mechanism; if that is not possible, we would (2) remove the pieces of code that were covered by those patents, and also (3) find prior art that would render the patent useless. Not providing a patented capability would weaken the interoperability, but it would still provide the free software / open source software community with good development tools, which is the primary reason for developing Mono.
The patents do not apply in countries where software patents are not allowed.
For Linux server and desktop development, we only need the ECMA components, and things that we have developed (like Gtk#) or Apache integration.