Write short notes on FCL ( Framework Class Library )

This is also called as Base Class Library and it is common for all types of applications i.e. the way you access the Library Classes and Methods in VB.NET will be the same in C#, and it is common for all other languages in .NET.
The term .NET framework refers to the group of technologies that form the development foundation for the Microsoft .NET platform. The key technologies in this group are the run time and the class libraries.

The Unified Classes (Base Class Library) is a set of classes that provide useful functionality to CLR programmers. The .NET Framework class library exposes features of the runtime and simplifies the development of .NET-based applications. In addition, developers can extend classes by creating their own libraries of classes. All applications (Web, Windows, and XML Web services) access the same .NET Framework class libraries, which are held in namespaces. All .NET-based languages also access the same libraries.

The run time is responsible for managing your code and providing services to it while it executes, playing a role similar to that of the Visual Basic 6.0 run time.

The .NET programming languages including Visual Basic .NET, Microsoft Visual C# and C++ managed extensions and many other programming languages from various vendors utilize .NET services and features through a common set of unified classes.

The .NET unified classes provide foundation of which you build your applications, regardless of the language you use. Whether you simply concating a string, or building a windows Services or a multiple-tier web-based applications, you will be using these unified classes.

The unified classes provide a consistent method of accessing the platforms functionality. Once you learn to use the class library, you'll find that all tasks follow the same uniform architecture, you no longer need to learn and master different API architecture to write your applications.

By building your applications on a unified, integrated framework, you maximize your return on the time you spend learning this framework, and you end up with more robust applications that are easy to deploy and maintain.

Class Libraries

The .NET Framework has an extensive set of class libraries. This includes classes for:

• Data Access: High Performance data· access classes for connecting to SQL Server or any other OLEDB provider.

• XML Supports: Next generation XML support that goes far beyond the functionality of MSXML.

• Directory Services: Support for accessing Active directory/LDPA using ADSI.

• Regular Expression: Support for above and beyond that found in Perl 5.

• Queuing Supports: Provides a clean object-oriented set of classes for working with MSMQ.

These class libraries use the CLR base class libraries