Run .Net Core on the Raspberry Pi

The .NET framework acts as an intermediate execution environment; with the right runtime a .Net executable that was made on one platform can run on another. With .NET Core the focus on the APIs that are supported on a variety of platforms allows it to be supported on even more platforms. Windows, Linux, and macOS  are operating systems on which the .NET Core framework will run.

The .NET Core Framework also runs on ARM systems. It can be install on the Raspberry Pi. I’ve successfully installed the .NET CORE framework on the Raspberry Pi 3 and 4. Unfortunately it isn’t supported on the Raspberry Pi Zero; ARM7 is the minimum ARM version supported. The Pi Zero uses an ARM6 processor. Provided you have a supported system you can install the framework in a moderate amount of time. The instructions I use here assume that the Pi is accessed over SSH. To begin you must find the URL to the version of the framework that works on your device.

Visit https://dotnet.microsoft.com to find the downloads. The current version of the .NET Core framework is 3.1. The 3.1 downloads can be found here. For running and compiling applications the installation to use is for the .NET Core SDK. (I’ll visit the ASP.NET Core framework in the future). For the ARM processors there is a 32-bit and 64-bit download. If you are running Raspbian use the 32-bit version even if the target is the 64-bit Raspberry Pi; Raspbian is a 32-bit operating system. Since there is no 64-bit version yet the 32-bit .NET Core SDK installation is necessary. Clicking on the link will take you to a page where it will automatically download. Since I’m doing the installation over SSH I cancel the download and grab the direct download link. Once you have the link SSH into the Raspberry Pi.

You’ll need to download the framework. Using the wget command followed by the URL will result in the file being saved to storage.

wget https://download.visualstudio.microsoft.com/download/pr/ccbcbf70-9911-40b1-a8cf-e018a13e720e/03c0621c6510f9c6f4cca6951f2cc1a4/dotnet-sdk-3.1.201-linux-arm.tar.gz

After the download is completed it must be unpacked. The file location that I’ve chosen is based on the default location that some .NET Core related tools will look by default for the .NET Core framework. I am using the path /usr/share/dotnet. Create this folder and unpack the framework to this location.

sudo mkdir /usr/share/dornet
tar zxf dotnet-sdk-3.1.201-linux-arm.tar.gz -C /usr/share/dotnet

As a quick check to make sure it works go into the folder and try to run the executable named “dotnet.”

cd /usr/share/dotnet
./dotnet

The utility should print some usage information if the installation was successful.  The folder should also be added to the PATH environment variable so that the utility is available regardless of the current folder. Another environment variable named DOTNET_ROOT will also be created to let other utilities know where the framework installation can be found.  Open ~/.profiles for editing.

sudo nano ~/.profiles

Scroll to the bottom of the file and add the following two lines.

PATH=$PATH:/usr/share/dotnet
DOTNET_ROOT=/usr/share/dotnet

Save the file and reboot. SSH back into the Pi and try running the command dotnet. You should get a response even if you are not in the /usr/share/dotnet folder.

With the framework installed new projects can be created and compiled on the Pi. To test the installation try making and compiling a “Hellow World!” program. Make a new folder in your home directory for the project.

mkdir ~/helloworld
cd ~/helloworld

Create a new console project with the dotnet command.

dotnet new console

A few new elements are added to the folder. If you view the file Program.cs the code has default to a hello world program. Compile the program with the dotnet command

dotnet build

After a few moments the compilation completes. The compiled file will be in ~/helloworld/Debug/netcoreapp31. A file name  helloworld is in this folder. Type it’s name to see it run.

My interest in the .NET Core framework is on using the Pi as a low powered ASP.NET Web server. In the next post about the .NET Core Framework I’ll setup ASP.NET Core and will host a simple website.

 

To see my other post related to the Raspberry Pi click here.

What is .Net

.NetFramework

I have some .Net related content that I plan to post and thought that I would revisit this question.

It’s a question I find interesting in that the answer has changed slightly over the year. In the earliest years it was a branding for technologies that were not necessarily related to each other; Windows .NET Server and Windows .NET Messenger are two products that had the branding at one point. But let’s not walk down memory lane and jump straight into the answer.

.NET is still a branding but the technologies with the branding are related to each other. Microsoft uses the branding on their Common Language Runtime (CLR) products. That answer only has kicked the can down the road. What is the CLR?

The CLR is a virtual machine component. Executables targeting the CLR don’t necessarily contain any code that is native to the processor on which they are running (though it may contain native code, but let’s ignore that for a moment). CLR binaries can be distributed with no processor dependent executable code within them. At runtime when the code is being executed it is converted to machine code as needed. Because of this the same program can be run on machines that have different processor architectures. The computer on which a program is running needs to have the runtime that is specific to it’s architecture and operating system.

This system might sound familiar as modern Java does something similar. There was a time when Microsoft was invested in Java virtual machines and made the first Java runtime that compiled the Java binary to machine language. The entity that owned Java at the time (Sun) wasn’t happy about this and they took Microsoft to court for deviating from the standard of how Java virtual machines worked and for using the Internet as a method of distribution among other reasons. This disagreement might sound petty, and in part it was. But there were good reasons for their position that I’ll present in another post. But this interaction added weight to the argument that Microsoft should have their own virtual machine. They also made their own programming languages (C# and Visual Basic .NET) and a few CLRs for x86, x64, and for their mobile devices.

The CLR, also known as the .Net Framework has seen several updates over the years. Microsoft eventually decided to make the CLR open source. This contributed to another CLR implementation being created named Mono which allowed .Net Framework applications to run on Linux and Mac.

If you look up .Net now you’ll find a few .NET systems listed.

  • .Net Standard
  • .Net Core (2016)
  • .Net Framework (2002)
  • ASP.Net / ASP.Net Core

What are these?

.Net Standard is a specification of the set of APIs that are expected to be in all implementations of the .Net Framework. Think of this as analogous to an interface; .NET standard itself isn’t an implementation. If you make an application that sticks with these APIs then it will have a wide range of compatible targets.

For the .Net Framework only one version of the framework can be installed at a time. Microsoft generally kept backwards compatibility, but it wasn’t perfect. Since a system could only have one version of the Framework installed in corporations updating the Framework had to be a company level decision.

.Net Core was made to contain the most common features of the .Net Framework, but has a few new features installed. It was made with multiple operating systems in mind and multiple versions in mind.  A system can have multiple versions of .Net core installed and they can run side-by-side.  From hereon Microsoft will be putting efforts on improving .Net Core. The .Net Framework will continue to support the .Net Framework but don’t expect to see new features in it; the new features will be coming to .Net core. There are a lot of legacy functionality from the .Net Framework that did not get ported over to .Net core in the interest of performance and compatibility.

ASP (Active Server Pages) is the name for Microsoft’s Web development system. Some of the earlier versions used a language that was similar to Visual Basic (yuck). The first version of ASP that supported .NET was called ASP.NET. ASP.NET used the .Net runtime and the more recent version supports the .NET Core runtime.  Traditionally ASP pages were hosted within IIS (Internet Information Services), a Windows component for hosting web pages. Wit the modern versions while this is still an option ASP.NET pages can be hosted outside of IIS too.

If you are starting a new desktop .Net project and don’t know what version to use the safe choice will generally be .Net Core. In my opinion the best feature is its ability to run on multiple systems (Mac, Linux, Windows, and varios IoT devices including the Raspberry Pi).

 

Trying to learn C# and .Net Core? This is a book I would recomend.