Intro to .NET Core

.NET is a general purpose development platform. It has several key features that are attractive to many developers, including automatic memory management and modern programming languages, that make it easier to efficiently build high-quality apps. Multiple implementations of .NET are available, based on open .NET Standards that specify the fundamentals of the platform.

.NET Implementations

There are various implementations of .NET, some coming from Microsoft, some coming from other companies and groups:

  • The .NET Framework is the premier implementation of the .NET Platform available for Windows server and client developers.

    There are additional stacks built on top the .NET Framework, for example Windows Forms and Windows Presentation Foundation (WPF) for UI, Windows Communication Foundation (WCF) for middleware services and ASP.NET as a web framework.

  • Mono is an open source implementation of Microsoft’s .NET Framework based on the ECMA standards for C# and the Common Language Runtime.
  • .NET Native is the set of tools used to build .NET Universal Windows Platform (UWP) applications. .NET Native compiles C# to native machine code that performs like C++.

I’ll explain a little bit more on what is .NET Core below. But first, let’s take a look at the .NET Ecosystem.

.NET Ecosystem

The NET Ecosystem is undergoing a major shift and restructuring in 2015. There are a lot of “moving pieces” that need to be tied together in order for this new ecosystem and all of the recommended scenarios to work. As you can see, this is a very vibrant and diverse ecosystem.

You might not know but most of these projects are currently open sourced and fostered by the .NET Foundation (independent) organization. Yes! These projects are open source!



A wild .NET implementation appeared!

.NET Core is a cross-platform implementation of .NET that is primarily being driven by ASP.NET 5 workloads, but also by the need and desire to have a modern runtime that is modular and whose features and libraries can be cherry picked based on the application’s needs.

It includes a small runtime that is built from the same codebase as the .NET Framework CLR. The .NET Core runtime includes the same GC and JIT (RyuJIT), but doesn’t include features like Application Domains or Code Access Security.

There are several characteristics of .NET Core:

  • Cross-platform support is the first important feature. For applications, it is important to use those platforms that will provide the best environment for their execution. Thus, having an application platform that can enable the app to be ran on different operating systems with minimal or no changes provides a significant boon.
  • Open Source because it is proven to be a great way to enable a larger set of platforms, supported by community contribution.
  • Better packaging story – the framework is distributed as a set of packages that developers can pick and choose from, rather than a single, monolithic platform. .NET Core is the first implementation of .NET Platform that is distributed via NuGet package manager.
  • Better application isolation as one of the scenarios for .NET Core is to enable applications to “take” the needed runtime for their execution and deploy it with the application, not depending on shared components on the targeted machine. This plays well with the current trends of developing software and using container technologies like Docker for consolidation.
  • Modular – .NET Core is a set of runtime, library and compiler components. Microsoft uses these components in various configurations for device and cloud workloads.

NuGet as a 1st class delivery vehicle

In contrast to the .NET Framework, the .NET Core platform will be delivered as a set of NuGet packages.

Using NuGet allows for much more agile usage of the individual libraries that comprise .NET Core. It also means that an application can list a collection of NuGet packages (and associated version information) and this will comprise both system/framework as well as third-party dependencies required. Further, third-party dependencies can now also express their specific dependencies on framework features, making it much easier to ensure the proper packages and versions are pulled together during the development and build process.

If, for example, you need to use immutable collections, you can install the System.Collections.Immutable package via NuGet. The NuGet version will also align with the assembly version, and will use semantic versioning.



Open Source and Cross-Platform

Last year, the .NET Core main repositories were made open source: CoreFX (Framework libraries) and CoreCLR (Runtime) are public in GitHub. The main reasons for this is to leverage a stronger ecosystem and lay the foundation for a cross platform .NET and it is a natural progression on current .NET Foundation’s open source efforts:

However, as of only a few months ago (April) you can install .NET Core on Windows, Linux and OSX. This makes code written for it is also portable across application stacks, such as Mono, and platforms making it feasible to move applications across different environments with ease.


Further reading

.NET Core: Cross Platform – Windows

.NET Core: Cross Platform – OS X

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