Microsoft .NET framework

The Microsoft .NET framework is a software framework for developing applications for Microsoft Windows although it was engineered in such a way so that other parties can develop the same framework for other operating systems.

The Common Language Runtime (CLR) is the executing engine of the .NET framework, it’s basically its core and the implementation of the Common Language Infrastructure (CLI). CLI is an open specification developed by Microsoft that defines how these core engines should be built, engines that among other things define common types, memory management and security. That way if an application is developed for one CLI (in the case of Microsoft, CLR) it can be run on any other OS running a version of the CLI.

Besides the core engine, the .NET framework includes many other class libraries that help developers create Windows applications and web applications. In order to develop applications the developer must choose a language. Two of the most popular .NET languages are VB.NET and C#. Both are object oriented (OO) although there are some aspects of OO not available to each language. Deciding which language to develop with depends on many variables, not least of which is your knowledge and comfort level with the language.

When you compile and build a .NET solution, whether it’s developed with VB.NET or C#, it’s converted to something called the Common Intermediate Language (CIL) also defined in the CLI.

The CIL is a lower level readable language that the CLR can execute but isn’t platform or processor specific. When executed by the CLR it converts the CLI code to the native code (machine code) for that processor. This means that you can develop one set of code and distribute across different systems that implement a version of the CLI.