The Microsoft .NET Framework is a runtime for CLR based executables. It's included with Windows from 2003/Vista on but can be installed on earlier versions. It consists of several parts including:
- a large type system, including types for database access
- GUI development
- web application development
- network communications
- a garbage collector for memory management
- extensive code security support.
It makes use of a JIT to convert the byte code into executable code for the platform it's used on, requiring no changes in the compiled code, only converting byte code to native code when it's ran.
The .NET runtime is language independent and the framework SDK includes a C# and VB.NET compiler. Oxygene is our own compiler for .NET. An alternative implementation called Mono exists to run .NET executables on Linux and other platforms.