Ever since the .NET initiative launched in January 2000 and the Visual Studio .NET beta subsequently launched in October 2000, the .NET train has been gaining speed; it now is the number-one development platform for the Windows operating system. However, you may have noticed a key point in that statement: for the Windows operating system! Yes, you guessed it: Microsoft targeted the .NET technology suite at the Windows operating system only; therefore, at the time of its launch, .NET was not available on other platforms such as Unix, Mac OS X, or Linux. This is not surprising, as Microsoft develops the Windows operating system and doesn't want to invest time in creating versions for competing operating systems; however, in the corporate world, other operating systems exist and for good reasons.

In this chapter, you'll learn exactly what .NET is and what it consists of; it's important to note that Microsoft made a key decision that acted as the catalyst for the Mono project and ultimately enabled .NET to run on operating systems other than Windows. This decision was to submit the specification for a core component of the common language runtime (CLR) and the Common Language Infrastructure (CLI) to the international standards body ECMA International, an industry association "dedicated to the standardization of information and communication systems." What does this mean? It means that anybody can obtain the specification for core .NET components and in doing so develop their own implementation of that specification, effectively writing their own .NET Framework components.

In addition, this chapter will introduce Mono and its associated elements including its tools and configuration. You'll also take a brief look at integrated development environments (IDEs), which are graphical applications that make developing your application as little easier. Finally, this chapter will cover what you need to know about the sample application you'll develop throughout this book, which is a fully functional RSS aggregator.

Microsoft Introduces .NET

In 2000, use of the Microsoft Windows operating system was widespread on desktop and laptop PCs, both at home and at work. In addition to the numerous other desktop products (such as Microsoft Office) and server products (such as SQL Server, Exchange, and so on) Microsoft produces, it had achieved success with development technologies such as C++, Visual Basic, Active Server Pages (ASP), the Common Object Model (COM), and so on. However, Java was starting to gain steam, and Microsoft needed to evolve its technology stack to help combat this threat and others in the open-source community (such as Python and PHP). After hiring the lead designer of Borland Delphi, Microsoft announced .NET 1.0 in the summer of 2000 for a 2001 launch (see http://www.pcworld.com/news/article/0,aid,17397,00.asp). Thereafter, Microsoft launched version 1.1 of the .NET Framework in April 2003, and more recently, it announced version 2.0, which is to be launched late in 2005.

What Is .NET?

Microsoft .NET is, according to Microsoft, "a strategy for connecting systems, information, and devices through Web Services." This is true; however, it doesn't do justice to the power of the .NET Framework, so I'll describe it in a slightly different way.

.NET is a software platform that provides several technologies that benefit corporate organizations, individuals, and the development community. Its aim is to provide a set of technologies that will offer ubiquitous interoperability through the standards it embraces and defines. At a high level, .NET consists of several elements, such as the .NET Framework and class library. I'll introduce each of these in the following sections.

The .NET Framework

As its name implies, the .NET Framework is an all-encompassing framework or environment for constructing, deploying, and running applications that leverage the features of .NET, including Extensible Markup Language (XML), Web Services, Windows Forms, ADO.NET, and so on. In addition, the .NET Framework also encompasses a companion framework, called the .NET Compact Framework, that is targeted at mobile devices or indeed any device that can run the CLR, including set-top boxes.