1.2 What exactly is .NET?

.NET is a general term which encompasses a variety of technologies and products. ^[4] .NET also contains technologies to reach out to the Internet via web services “ a very hot topic today with a very bright future in distributed computing.

^[4] For the general 'official definition' (which includes lots of marketing), check out www.microsoft.com/net/defined.

In Microsoft's own words, Microsoft .NET is "Microsoft's XML Web services platform." Using this definition for .NET is as good as calling J2EE "Sun's web application platform."

.NET is much more than that and, depending on your role in your software organization, your view of .NET may not be the same. To a system administrator, .NET means rolling out and deploying the new range of Windows .NET Server and the .NET Enterprise Servers. To an end user , .NET means a convenient single sign-in on the Internet via .NET My Passport, and .NET My Services.

So, what is .NET about for the developer?

To a developer (who this book is for), .NET signifies a new programming paradigm, new programming languages to master, and a new runtime engine. A web application developer will concentrate on ASP.NET and XML web services, while a desktop application developer will be writing Windows forms. A pocket PC developer will be mastering the .NET Compact Framework and the VS .NET extensions for writing constrained applications.

Picture a runtime platform which sits on top of the Windows operating system. This runtime platform supports the execution of applications by providing a basic infrastructure such as automatic memory management, security checking, and type checking. This runtime platform includes a wide selection of BCLs which the applications running within can invoke. One nice thing about these applications is that they can be written in any language. Another nice thing is that the applications can be of any type, not just common desktop applications which show a spreadsheet or word processor, but also web applications, servers providing web services, database clients “ in fact almost anything that a program can do. That's the picture of the .NET world for the developer.

In essence, .NET encompasses two major components as far as the developer is concerned :

• A new runtime environment for new .NET applications to run within. Some use the term 'framework' to describe this runtime environment.

• A set of BCLs which .NET applications use. A BCL not only enables .NET applications to reach out to the Windows API, but is also a rich set of classes with lots of useful functionality.

I shall briefly describe each aspect of .NET.