What is .NET?

To explain what Microsoft .NET is, let us begin by discussing what Microsoft .NET is not. First, it is not a new language for which you need to learn a whole bunch of new syntax and the like. Second, .NET it is not a new operating system or anything like that (some people have gotten this impression). Finally, .NET is not the end-all for web development solutions, but it sure is a good start. .NET is a run-time that is an add-on or plug-in to Microsoft IIS, but that is just what makes the stuff work. .NET is really a framework, a model for developing web-based applications called "Web Services." .NET is about making web sites and applications into services a consumer can use. For instance, one goal Microsoft has with .NET is for the next version of Office to be a web service. In an article I read a while back, Office.NET was slated to be a web-based service offering that would facilitate subscription based pricing (which can be good or bad depending on how you look at it) in an entirely web based environment. Rather then buying a CD and installing hundreds of megabytes worth of software, just connect to "Office.NET" and begin working. Of course, this type of ideal cannot be fully realized yet (and we will probably see a hybrid version) with our current bandwidth constraints, but with .NET, Microsoft is planting the seed and taking major strides towards this type of computing.

So if Microsoft .NET is more of a framework then anything else, what does it frame? Good question! To be honest, .NET is not exactly a unique concept, if any of you are familiar with Enterprise Java Beans, then you have an early form of what .NET is intended to be. Basically the .NET framework is a three-tiered architecture for developing web-based applications. The .NET "stuff" itself sits in the middle tier, where all the application logic is developed. For those of you who do not know what a three tiered architecture is, it is pretty easy. The first tier or "Front-end" is exactly that, the front-end or the client, what the user gets. The middle tier is the where all the application logic sits; it includes business rules and anything necessary to take data from the backend and communicate it to the front-end. The final tier is also the "Back-end" wherein the database resides and all that other fun stuff. The advantages of a three-tiered system are many, but a few in particular are that the backend is modular, or it does not really matter what DBMS sits back there, if you switch it to something else and have an appropriate driver for it, your set, the application works the same. Furthermore, the separation of logic and data processing from presentation means you can change the processing and application logic without having to touch the front-end. Below is a picture of Microsoft's vision for this three-tier system. It is a little more detailed then the above explanation, but you will get the idea.


Image from the September Issue of MSDN Online Magazine

As I mentioned before, Enterprise Java Beans (EJB) have been doing this sort of thing for a while now. In a three-tiered architecture using EJB, you have a bunch of EJB's which are JAVA programs used for various data processing tasks. Then, you write pages that will talk to these EJB's and present the desired output. Very neat, but limited because you have to use JAVA and not everyone is a JAVA fan (I for one am not). .NET builds off this and does it better, in fact if Microsoft delivers as promised, .NET does it right. Rather then being forced to program in JAVA for all your application logic, Microsoft has given the .NET runtime the brains to read just about any language. That is right, I said any language. That means you can develop some logic in C++, Perl, Visual Basic, JAVA, Pascal or even Microsoft's new C# (a language that combines the power of C++ with the ease of use of Visual Basic) and .NET will compile it into it's own Intermediate Language (IL) that is understood by the server. In fact, you should be able to program a function in one language and pass variables and their values to functions programmed in a different language!

Now, not all those languages are de facto supported initially, but Microsoft has given developer's the rights and ability to create .NET support for just about any language you want, so expect to see a lot of them available as .NET becomes more popular after its release. Modern Microsoft languages will be supported natively, while Perl, Cobol, Java and other .NET compilers are already in the works by third parties.

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