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
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.
We need to install two more tools for building our OS. The first is
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.
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.
With that, we're done! Let's actually get some code going!