Preface

Developing large distributed software systems is a complex and interesting challenge. A number of architectures have emerged to simplify this task and to relieve developers of the burden of dealing with the many interoperability issues associated with creating such systems. This book focuses on one of those architectures, Microsoft's .NET Framework.

An often-asked question is, "So what is new in the .NET Framework?" On one level, the answer is simple: "Not much." To put this answer into context, however, the same may be said of most recent software advancements. For example, C++ represented a significant step forward ”but it was actually an amalgamation taking advantage of the object-oriented concepts of Simula 67 and the efficiency of C. Likewise, Java contained very little new science, with the concepts of virtual machines and class libraries having been commonplace for many years . So how, then, do these advancements contribute to the computing body of knowledge? Often they exploit synergy ”that is, the combination of known technologies in a new and different manner that allows developers to bring together two powerful concepts in a single architecture. So it is with the .NET Framework. Although significant benefits can be gained by using the framework, many readers will be relieved to see that the environment includes many familiar concepts, although their implementation may have changed.

For example, a major concept pervading the .NET Framework is object orientation. Recently, this paradigm has won enormous acceptance in many areas, ranging from graphic user interface (GUI) development to network programming. The .NET Framework supports all of the object-oriented concepts, including classification, information hiding, inheritance, and polymorphism. What is new in the .NET Framework is the elimination of language boundaries that have hampered object orientation in the past. The framework also extends these concepts in concert with other concepts. For example, inheritance can be subject to security constraints; just because you can use a type, it may not follow that you can subtype from that type.