• A runtime system is used to support the execution of programs
• .NET Framework provides a runtime system that is used by all .NET languages
• Microsoft are providing .NET compilers for:
  • Managed C++
  • JScript
  • Visual Basic.NET
  • C#
• Others are providing .NET compilers for:
  • COBOL
  • Eiffel
  • Fortran
  • Haskell
  • Perl
  • Python
  • ...

A .NET compiler writer can rely on the CLR:

• to create new types;
• to create and initialize objects;
• to track references to objects and provide garbage collection;
• to handle the calling of methods;
• to manage the access to array elements;
• to provide support for exceptions;
• ...

• A .NET compiler generates code in an intermediate language called MSIL.
• A platform needs a CLR engine in order to run a file containing MSIL instructions.
• There are CLR engines for most Windows platforms.
• A project called Mono is building an open-source implementation of the .NET Framework.