RostOS

RostOS is an operating system written in Rust, a relatively new systems programming language. Phillip Oppermanns excellent tutorial series "Writing an OS in Rust" helped me grasp the fundamentals of low-level programming and served as a perfect starting point for the Project. From there on many features were added to reach its current state.

Right now the Kernel's features include the following:

• It boots on many systems running the x86_64 architecture.
• It can display text using the legacy VGA buffer.
• It reads PS/2 keyboard input.
• It can start userspace applications from ELF-files on a ramdisk.
• The ramdisk has its own format RostFS to save files.
• Multiple processes can be run at the same time using a simple scheduler.

To make use of these features, there are system calls which are abstracted away in a small library. Some example programs have been written, including a simple shell and pong.

Installation and Testing

DISCLAIMER: Only works reliably on Linux.

To begin, you first need to download the language itself. Because an OS requires certain unstable features, a nightly version of the Rust toolchain has to be installed. This can be done using rustup, the official rust toolchain installation program. Make sure that the ~/.cargo/bin is added to $PATH. The exact toolchain and its components (rust-src, llvm-tools) are pinned in rust-toolchain.toml; to install them up front, run this in the repository:

rustup toolchain install

To run the OS you need some sort of virtual machine. The qemu-system-x86_64 binary has to be present in $PATH, which can be downloaded from www.qemu.org or preferably installed with your distribution's package manager.

To build RostOS and start it in QEMU, run this from the repository root:

cargo run                # builds everything, assembles bin/RostOS.bin and starts QEMU
cargo run -- --virt      # the same with KVM
cargo run -- --no-run    # only assemble bin/RostOS.bin

The top-level crate builds the programs workspace and packs the binaries into the ramdisk's bin directory (bin/disk.img), builds the kernel, which embeds that image, and the bootloader, and then assembles the boot image.

To write your own programs you can take a look at the pong program. If you copy it, delete its logic, change its name in Cargo.toml and add it to the members of programs/Cargo.toml, you'll have a nice template.