CLR Common Language Runtime

The CLR(Common Language Runtime) is the heart of .NET framework and it does primary important things:

           ·         Garbage Collection

           ·         CAS (Code Access Security)

           ·         CV (Code Verification)

           ·         IL to Native translation

           ·         memory management

           ·         type safety

           ·         exception handling

           ·         garbage collection

           ·         security and thread management

The Common Language Runtime (CLR), the virtual machine component of Microsoft's .NET framework, manages the execution of .NET programs.

Just-In-Time (JIT) is the process which converts compiled MSIL code to machine understandable format. JIT will send the instructions to the CPU for the execution process.

As part of the Microsoft  .NET Framework, the Common Language Runtime (CLR) is the programming (Virtual Machine component) that manages the execution of programs written in any language that uses the .NET Framework, for example C#, VB.Net, F# and so on.

Code written in any language, including VB.Net, C# and F# when they compile their programs into an intermediate form of code called CLI in a portable execution file (PE) that can be managed and used by the CLR and then the CLR & JIT converts  it into machine code to be will executed by the processor.

The runtime provides the following benefits:

·         Memory management (Garbage collection).

·         Convert code into CLI.

·         Performance improvements.

·         Support for structured exception handling.

·         The ability to easily use components developed in other languages.

·         Extensible types provided by a class library.

·         Support for explicit free threading that allows creation of multithreaded, scalable applications.

·         Language features such as inheritance, interfaces, and overloading for object-oriented programming.

·         Use of delegates instead of function pointers for increased type safety and security. For more information about delegates, see Common Type System.

Managed and Unmanaged

Managed is defined as, the code which executes under CLR environment is called managed code.

Unmanaged is defined as, the code which does not executes under CLR environment is called managed code.