rosh

A teaching operating system kernel written in Rust, developed by following the Writing an OS in Rust tutorial. The repository demonstrates how to use a custom target specification, integrate the bootloader crate, and run the built image in QEMU through bootimage.

The repository includes a custom osconfig.json target file and augments .cargo/config.toml to make the compiler use it, while enabling build-std support and configuring the runner:

[build]
target = "osconfig.json"

[unstable]
build-std = ["core", "compiler_builtins"]
build-std-features = ["compiler-builtins-mem"]

[target.'cfg(target_os = "none")']
runner = "bootimage runner"

Toolchain Installation

rustup component add rust-src llvm-tools-preview --toolchain nightly-x86_64-pc-windows-msvc
rustup override set nightly

Bootloader Support

Install the required tooling and declare the dependency:

cargo install bootimage
rustup component add llvm-tools-preview

[dependencies]
bootloader = "0.9"

Build

Compile with the nightly toolchain using the custom target:

cargo +nightly build --target osconfig.json

The compiled binary is placed at target/osconfig/debug/hello.

Create a bootable disk image:

cargo bootimage

Run in QEMU

With QEMU installed, start the kernel with the default runner:

cargo run

cargo run invokes the bootimage runner, which launches QEMU with the generated image.

Reference

• Writing an OS in Rust — https://os.phil-opp.com/