. Net Frame Work

 The .NET framework has two major components-- The Common Runtime (CLR) and the Class Library

The CLR is the foundation upon which the .NET Framework has been built. The runtime manages code at execution time and provides all the core services such as memory management, thread management and remoting. It also enforces strict type safety and ensures code accuracy in order to provide security and robustness to the applications. This capability to manage code at runtime is the distinguishing feature of the CLR. All code that is managed by the CLR is known as managed code while other codes are known as unmanaged code.

The Class Library is an object oriented collection of reusable types. It is comprehensive and the types can be used to develop command line applications or GUI applications such as Web forms or XML Web services. Unmanaged components that load CLR into their processes can be hosted by the .NET Framework to initiate the execution of managed code. This creates a software environment that exploits both the managed and unmanaged codes. The.NET Framework also provides a number of runtime hosts and supports third party runtime hosts

CLR Features

1. CLR manages memory, thread execution, code execution, compilation code safety verification and other system services.

2. For security reasons, managed code is assigned varying degrees of trust based on origin. This prevents or allows the managed component from performing file access operations, registry access operations or other sensitive functions even within the same active application.

3. The Runtime enforces code robustness by implementing strict type and code verification infrastructure called Common type System (CTS). The CTS ensures that all managed code is self describing and all Microsoft or third party language compiler generated codes conform to CTS. This enables the managed code to consume other managed types and enforce strict type fidelity and type safety.

4. CLR eliminates many common software issues like handling of object layout, references to objects and garbage clearance. This type of memory management prevents memory leaks and invalid memory references.