CLR is .NET equivalent of Java Virtual Machine (JVM). It is the runtime that converts a MSIL code into the host machine language code, which is then executed appropriately.

The CLR is the execution engine for .NET Framework applications. It provides a number of services, including:

·          Code management (loading and execution)

·          Application memory isolation

·          Verification of type safety

·          Conversion of IL to native code.

·          Access to metadata (enhanced type information)

·          Managing memory for managed objects

·          Enforcement of code access security

·          Exception handling, including cross-language exceptions

·          Interoperation between managed code, COM objects, and pre-existing DLL's (unmanaged code and data)

·          Automation of object layout

·          Support for developer services (profiling, debugging, and so on).