Avoiding Confusion – the Role of the .NET Enterprise Servers - Page 3

Microsoft has already released several products, which they describe as part of the .NET Enterprise Server family. More of these are coming, and most will be released by the time this book is published. Some of the marketing literature for these products emphasizes that they are part of Microsoft's .NET strategy.

However, it is important that you understand the difference between these products and the .NET Framework, which is the major focus of this book. The .NET Enterprise Servers are not built on the .NET Framework. Most of them are successors to previous server-based products, and they use the same COM/COM+ technologies their predecessors did.

Chapter 12 in this book summarizes these products and explains their purposes. These .NET Enterprise Servers still have a major role to play in future software development projects. When actual .NET Framework projects are developed, most will depend on the technologies in the .NET Enterprise Servers for functions like data storage and messaging.

When this book refers to .NET, it should be understood that this is generally intended to mean the technologies in the Microsoft.NET Framework.

What's Wrong With What We Have Now?

Starting in late 1995, Microsoft made a dramatic shift towards the Internet. The company was refocused on marrying their Windows platform to the Internet, and they have certainly succeeded in making Windows a serious Internet platform as well as a solid platform for all the business-oriented software developed with the Windows DNA programming model.

However, Microsoft had to make some serious compromises to quickly produce Internet-based tools and technologies. In particular, Active Server Pages (ASP) has always been viewed as a bit clumsy. After all, writing reams of interpreted script is a real step backwards from structured and object-oriented development. Designing, debugging and maintaining such unstructured code is also a headache.

Other languages such as Visual Basic have been used successfully in Internet applications on Microsoft platforms, but mostly as components that worked through Active Server Pages. Presently, Microsoft's tools lack the level of integration and ease-of-use for web development that would be ideal. A few attempts were made to place a web interface on traditional languages, such as WebClasses in VB, but none of these gained wide acceptance.

Microsoft has attempted to bring some order to the chaos with their concept of Windows DNA applications. DNA paints a broad picture of standard three-tier development based on COM, with Active Server Pages in the presentation layer, business objects in a middle layer, and a relational data store and engine in the bottom layer. The concept behind DNA is reasonably sound, but actually making it work has many challenges. Developing COM components requires a level of development expertise that takes a lot of time to reach, though some languages, such as Visual Basic, make it easier than others. Also, the deployment of DNA applications can be nightmarish, with many problems that can arise from the versioning and installation of components, and the components that they rely on.

Microsoft realized that, while it was possible to write good Internet applications with Windows-based technologies, it was highly desirable to find ways to develop applications faster and make it far easier to deploy them. Other platforms (such as Unix) and other development environments (such as ColdFusion) were continuing to raise the bar for developing Internet applications, making it essential that Microsoft address the limitations of the DNA programming model.

The Origins of .NET

In the beginning 1998, a team of developers at Microsoft had just finished work on a new version of Internet Information Server (version 4.0), including several new features in Active Server Pages. While developers were pleased to see new capabilities for Internet development on Windows NT, the development team at Microsoft had many ideas for its improvement. That team began to work on a new architecture implementing those ideas. This project eventually came to be known as Next Generation Windows Services (NGWS).

After Visual Studio 6 was released in late 1998, work on the next version of Visual Studio (then called Visual Studio 7) was folded into NGWS. The COM+/MTS team brought in their work on a universal runtime for all the languages in Visual Studio, which they intended to make available for third party languages as well.

The subsequent development was kept very much under wraps at Microsoft. Only key Microsoft partners realized the true importance of NGWS until it was re-christened as .NET and introduced to the public at the PDC. At that point, development had been underway for over two years, and most attendees were pleasantly surprised to see the enormous strides Microsoft had made.

The concepts in .NET draw inspiration from many sources. Previous architectures, from p-code in UCSD Pascal up through the Java Virtual Machine, have similar elements. Microsoft has taken many of the best ideas in the industry, combined with some ideas of their own, and brought them all into one coherent package.

The .NET Framework – an Overview

First and foremost, .NET is a framework that covers all the layers of software development from the operating system up. It provides the richest level of integration among presentation technologies, component technologies, and data technologies ever seen on a Microsoft platform. Secondly, the entire architecture has been created to make it as easy to develop Internet applications as it is to develop for the desktop environment.

.NET actually "wraps" the operating system, insulating software developed with .NET from most operating system specifics such as file handling and memory allocation. This prepares for a possible future in which the software developed for .NET is portable to a wide variety of hardware and operating system foundations. (Beta one of Visual Studio.NET supports all versions of Windows 2000 plus Windows NT4, Windows 9x, and Windows Millennium Edition.)

.NET Overview - Page 2
Introducing .NET
A Common Substrate for all Development - Page 4