Active Server Pages was first made available on Microsoft's IIS web server in the mid-1990s. Fast-forward about 20 years, and ASP.NET Core (that is, ASP.NET 5 while in development) is now open source and runs on Windows, Linux, and OS X. Moreover, Visual Studio is now available as a cross-platform lightweight code editor in addition to the full-featured IDE on Windows.
As a .NET developer, you can take advantage of all the recent improvements, while building on the experience that you already have. The .NET Framework has evolved beyond the full framework and is now available as a cross-platform runtime called .NET Core.
In this chapter, we will discuss the following principles and concepts to get you started with ASP.NET Core:
.NET architecture
ASP.NET unified programming model
New Visual Studio IDEs
Cross-platform runtime