libJIT has also seen some use in other open source projects, including GNU Emacs,[2][3] ILDJIT[4] and HornetsEye.[5]
Framework architecture
Simplified Mono architecture
The Portable .NET class library seeks to provide facilities for application development. These are primarily written in C#, but because of the Common Language Specification they can be used by any .NET language. Like .NET, the class library is structured into Namespaces and Assemblies.[6] It has additional top-level namespaces including Accessibility and DotGNU. In a typical operation, the Portable .NET compiler generates a Common Language Specification (CLS) image, as specified in chapter 6 of ECMA-335, and the Portable .NET runtime takes this image and runs it.
Free software
DotGNU points out that it is Free Software, and it sets out to ensure that all aspects of DotGNU minimize dependence on proprietary components, such as calls to Microsoft Windows' GUI code. DotGNU was one of the High Priority Free Software Projects from July 31, 2007[7] till October 2, 2008.[8][clarification needed]
DotGNU's implementation of those components of the .NET stack not submitted to the ECMA for standardization has been the source of patent violation concerns for much of the life of the project. In particular, discussion has taken place about whether Microsoft could destroy the DotGNU project through patent suits.
The base technologies submitted to the ECMA may be non-problematic. The concerns primarily relate to technologies developed by Microsoft on top of the .NET Framework, such as ASP.NET, ADO.NET, and Windows Forms (see Non standardized namespaces), i.e. parts composing DotGNU's Windows compatibility stack. These technologies are today not fully implemented in DotGNU and are not required for developing DotGNU-applications.
In 2009, Microsoft released .NET Micro Framework under Apache License, Version 2.0, which includes a patent grant. However, the .NET Micro Framework is a reimplementation of the CLR and limited subset of the base class libraries meant for use on embedded devices. Additionally, the patent grant in the Apache License would have protected only contributors and users of the .NET Micro Framework—not users and developers of alternative implementations such as DotGNU or Mono.
In 2014, Microsoft released Roslyn, the next generation official Microsoft C# compiler, under the Apache License. Later that year, Microsoft announced a "reboot" of the official .NET Framework. The framework would be based on .NET Core, including the official runtime and standard libraries released under the MIT License and a patent grant explicitly protecting recipients from Microsoft-owned patents regarding .NET Core.
^"DotGNU Project". As of December 2012, the DotGNU project has been decommissioned, until and unless a substantial new volunteer effort arises. The exception is the libjit component, which is now a separate libjit package.
