Setting up a development environment

Traditionally, getting a development environment set up for working on an operating system is really hard. However, we have it pretty easy! We'll be using the Rust programming language to develop our kernel, and thanks to some awesome work by the language developers, as well as the homebrew Rust operating system community, getting our environment set up is really easy.

To get going, you'll need a few tools:

• An editor or IDE to write the source code
• A compiler and other tools to turn that source code into binary code
• A virtual machine to try our OS out without installing it on our computer
• A project directory to do develop in

You can get all of these tools working on Windows, macOS, and Linux. Other operating systems may work, but we've only tried this on these systems. This section is the only one with OS-specific instructions; from here on out, everything will be identical.

An editor or IDE

This is needed, but is also largely a personal choice. You can use whatever you'd like here, and that's 100% fine.

If you're not sure what to use, I do have two recommendations though. If you prefer text editiors, give Visual Studio: Code a try. It's fairly light-weight, but also has some nice features, and a great Rust plugin provided by the Rust team.

If you prefer IDEs, I'd suggest Clion with the Rust plugin. JetBrains makes a suite of IDEs for a ton of languages, and their Rust support is solid!

Really, anything works though: I use both of the above, and also vim at times. It's just not a huge deal.

The compiler and other tools

Next, we need to get the Rust compiler installed. To do that, head to Rust's install page and follow the instructions. You can also install Rust another way if you'd prefer, such as from your system's package manager, but through the website is generally easiest.

This will give you a tool called rustup, used to manage versions of rustc, the Rust compiler, and Cargo, the package manager and build tool. To check that this was installed properly, run these three commands and check that you get some output:

$ rustup --version
$ rustc --version
$ cargo --version

If you do, everything's good!

Stable vs. Nightly Rust

One of the reasons that it's easiest is that you can't use any version of Rust to develop OSes; you need "nightly" Rust. Basically, Rust comes in different flavors, and in order to develop operating systems, we need to use some experimental, cutting-edge features. As such, we can't use the stable Rust distribution, we need the nightly one.

To install nightly, do this:

$ rustup update nightly

This will download and install the nightly toolchain. We'll configure the use of this toolchain automatically in the next section.

Other tools

We need to install two more tools for building our OS. The first is called bootimage, and its job is to take our kernel and produce a file that our virtual machine (discussed in the next section) knows how to run. To install it:

$ cargo install bootimage

To check that it installed correctly, run this:

$ bootimage --help

And you should see a help message printed to the screen.

The second tool is called cargo-xbuild. It extends Cargo, allowing us to build Rust's core libraries for other OSes than the ones provided by the Rust team. To install it:

$ cargo install cargo-xbuild

And to check that it was installed correctly, run this:

$ cargo xbuild --version

And make sure that you get some version output.

Additionally, to do its job, cargo-xbuild needs the source code for these core libraries; to get those, run this:

$ rustup component add rust-src --toolchain=nightly

With that, we're all set up!

A virtual machine

In order to see that your code runs, you could install it on a real computer, but that is way too complex for regular development. Instead, we can use a virtual machine to give our OS a try locally.

There's a few options, but for this, we'll use Qemu. Qemu works on all of our platforms, and has enough features for us too. Qemu's downloads page should help you get it installed.

To check that it's working, try this:

$  qemu-system-x86_64 --version

And make sure it spits out a version number.

A project directory

Finally, we need to put our source code somewhere. This can be wherever you'd like, but for this book, we'll call ours ~/src/. You'll see examples have this path in the output, just to have something, but you can do this anywhere you'd like. We'll call this "your project directory" a few times in the book, and we mean wherever you decided to put stuff.

That's it!

With that, we're done! Let's actually get some code going!