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Theseus is a modern OS written from scratch in Rust that explores ๐ข๐ง๐ญ๐ซ๐š๐ฅ๐ข๐ง๐ ๐ฎ๐š๐ฅ ๐๐ž๐ฌ๐ข๐ ๐ง, novel OS structure, and state management. It strives to close the semantic gap between compiler and hardware in order to maximally leverage the power of language safety, and thus shift OS responsibilities (resource management) into the compiler.

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Theseus OS

Documentation Action Documentation Book

Theseus is a new OS written from scratch in Rust to experiment with novel OS structure, better state management, and how to leverage intralingual design principles to shift OS responsibilities like resource management into the compiler.

For more info, check out Theseus's documentation or our published academic papers, which describe Theseus's design and implementation.

Theseus is under active development, and although it is not yet mature, we envision that Theseus will be useful in high-end embedded systems or edge datacenter environments. We are continually working to improve the OS, including its fault recovery abilities for higher system availability without redundancy, as well as easier and more arbitrary live evolution and runtime flexbility.

Quick start

On Linux (Debian-like distros), do the following:

  1. Obtain the Theseus repository (with all submodules):
    git clone --recurse-submodules
  2. Install Rust:
    curl -sSf | sh
  3. Install dependencies:
    sudo apt-get install make gcc nasm pkg-config grub-pc-bin mtools xorriso qemu qemu-kvm
  4. Build and run (in QEMU):
    cd Theseus
    make run
    To exit QEMU, press Ctrl + A, then X.

See below for more detailed instructions.

Building and Running Theseus

Note: when you first check out the project, be sure to get all the submodule repositories too:

git submodule update --init --recursive

Currently, we support building Theseus on the following platforms:

  • Linux, 64-bit Debian-based distributions like Ubuntu, tested on Ubuntu 16.04, 18.04, 20.04.
    • Arch Linux has also been reported to work correctly.
  • Windows, using the Windows Subsystem for Linux (WSL), tested on the Ubuntu version of WSL and WSL2.
  • MacOS, tested on versions High Sierra (10.13) and Catalina (10.15.2).
  • Docker, atop any host OS that can run a Docker container.

Setting up the build environment

First, install Rust by following the setup instructions here. On Linux, just run:

curl -sSf | sh

Building on Linux or WSL (Windows Subsystem for Linux)

Install the following dependencies using your package manager:

sudo apt-get install make gcc nasm pkg-config grub-pc-bin mtools xorriso qemu qemu-kvm
  • Or on Arch Linux:
    sudo pacman -S make gcc nasm pkg-config grub mtools xorriso qemu

If you're on WSL, also do the following steps:

  • Install an X Server for Windows; we suggest using Xming.

  • Setup an X display as follows:

    • on original WSL (version 1), run:
      export DISPLAY=:0
    • on WSL2 (version 2), run:
      export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0

    You'll need to do this each time you open up a new WSL terminal, so it's best to add it to the end of your .bashrc or .profile file in your $HOME directory.

  • If you get an error like Could not initialize SDL (No available video device) ..., then make sure that your X Server is running and that you have set the DISPLAY environment variable above.

  • NOTE: WSL and WSL2 do not currently support using KVM.

Building on MacOS

  • Install MacPorts and HomeBrew, then run the MacOS build setup script:

    sh ./scripts/

    If things go wrong, remove the following build directories and try to run the script again.

    rm -rf $HOME/theseus_tools_src $HOME/theseus_tools_opt /opt/local/bin/make
  • If you're building Theseus on an M1-based Mac, you may need to use x86 emulation

    arch -x86_64 bash   # or another shell of your choice

    and possibly adjust your system PATH if both x86 and ARM homebrew binaries are installed:

    export PATH=/usr/local/Homebrew/bin:$PATH

Building using Docker

Note: building and running Theseus within a Docker container may be slower than on a native host OS.

  1. Ensure docker scripts are executable:

    chmod +x docker/*.sh
  2. (Skip if docker is already installed.) Install Docker Engine. We provide a convenience script for this on Ubuntu:

    • After docker installs, enable your user account to run docker without root privileges:
      sudo groupadd docker; sudo usermod -aG docker $USER
      Then, log out and log back in (or restart your computer) for the user/group changes to take effet.
  3. Build the docker image:


    This does not build Theseus, but rather only creates a docker image that contains all the necessary dependencies to build and run Theseus.

  4. Run the new docker image locally as a container:


    Now you can run make run or other Theseus-specific build/run commands from within the docker container's shell.

Notes on Docker usage:

  • The docker-based workflow should only require you to re-run the script multiple times when re-building or running Theseus after modifying its code. You shouldn't need to re-run multiple times, though it won't hurt.
  • KVM doesn't currently work in docker. To run Theseus in QEMU using KVM, you can build Theseus within docker, exit the container (via Ctrl+D), and then run make orun host=yes on your host machine.

Building and Running

To build and run Theseus in QEMU, simply run:

make run

Run make help to see other make targets and the various command-line options.

Using QEMU

QEMU allows us to run Theseus quickly and easily in its own virtual machine. To release, press Ctrl + Alt + G (or just Ctrl + Alt on some systems), which releases your keyboard and mouse focus from the QEMU window. To exit QEMU, in the terminal window that you originally ran make run, press Ctrl + A then X, or you can also click the GUI โ“ง button on the title bar if running QEMU in graphical mode.

To investigate the hardware/machine state of the running QEMU VM, you can switch to the QEMU console by pressing Ctrl + Alt + 2. Switch back to the main window with Ctrl + Alt + 1. On Mac, manually select VGA or compact_monitor0 under View from the QEMU menu bar.

To access/expose a PCI device in QEMU using PCI passthrough via VFIO, see these instructions.

KVM Support

While not strictly required, KVM will speed up the execution of QEMU. To install KVM, run the following command:

sudo apt-get install kvm

To enable KVM support, add host=yes to your make command, e.g.,

make run host=yes


Theseus includes two forms of documentation:

  1. The source-level documentation, generated from code and inline comments (via rustdoc).
    • Intended for Theseus developers and contributors, or those who want low-level details.
  2. The book-style documentation, written in Markdown.
    • Useful for high-level descriptions of design concepts and key components.

To build the documentation yourself, set up your local build environment and then run the following:

make view-doc   ## for the source-level docs
make view-book  ## for the Theseus book


Booting on Real Hardware

We have tested Theseus on a variety of real machines, including Intel NUC devices, various Thinkpad laptops, and Supermicro servers. Currently, the only limiting factor is that the device support booting via USB or PXE using traditional BIOS rather than UEFI; support for UEFI is a work-in-progress.

To boot over USB, simply run make boot usb=sdc, in which sdc is the device node for the USB disk itself (not a partition like sdc2) to which you want to write the OS image. On WSL or other host environments where /dev device nodes don't exist, you can simply run make iso and burn the .iso file in the build/ directory to a USB, e.g., using Rufus on Windows.

To boot Theseus over PXE (network boot), see this set of separate instructions.

Debugging Theseus on QEMU

GDB has built-in support for QEMU, but it doesn't play nicely with OSes that run in 64-bit long mode. In order to get it working properly with our OS in Rust, we need to patch it and build it locally. The hard part has already been done for us (details here), so we can just quickly set it up with the following commands.

  1. Install the following packages:

    sudo apt-get install texinfo flex bison python-dev ncurses-dev
  2. From the base Theseus directory, run this script to download and build GDB from an existing patched repo:

    curl -sf | sh

    After that, you should have a rust-os-gdb directory that contains the gdb executables and scripts.

  3. Run Theseus in QEMU using make run (or make run_pause to pause QEMU until we attach GDB).

  4. In another terminal window, run the following to start GDB and attach it to the running QEMU instance:

    make gdb 

    QEMU will be paused until we move the debugger forward, with standard GDB commands like n to step through the next instruction or c to continue execution. Any standard GDB commands will now work.

IDE Setup

Our personal preference is to use VS Code, which has excellent cross-platform support for Rust. Other options are available here.

For VS Code, recommended plugins are:

  • rust-analyzer, by matklad
  • Better TOML, by bungcip
  • x86 and x86_64 Assembly, by 13xforever

Fixing Rustup, Rust Toolchain, or RLS Problems

Sometimes things just don't want to behave, especially if there were issues with the currently-chosen Rust nightly version. In that case, try the following steps to fix it:

  • Set your default Rust toolchain to the one version in the rust-toolchain file, for example:
    rustup default $(cat rust-toolchain)
  • With your newly-set default toolchain, add the necessary components:
    rustup component add rust-src
  • In VS Code (or whatever IDE you're using), uninstall and reinstall the Rust-related extension(s), restarting the IDE each time.
  • Check your IDE's settings to make sure that no weird Rust settings have been selected; building Theseus doesn't require any special settings.
  • If you're still having issues, remove all other Rust toolchain versions besides the default one and try again. You can see other installed toolchains with rustup toolchain list.


We would like to express our thanks to the OS Dev wiki and its community and to Philipp Oppermann's blog_os for serving as excellent starting points for Theseus. The early days of Theseus's development progress are indebted to these resources.


Theseus's source code is licensed under the MIT License. See the LICENSE-MIT file for more.


We adhere to similar development and code style guidelines as the core Rust language project. See more here.

PRs and issues are welcome from anyone; because Theseus is an experimental OS, certain features may be deprioritized or excluded from the main branch. Don't hesitate to ask or mention something though! ๐Ÿ˜„


Theseus is a modern OS written from scratch in Rust that explores ๐ข๐ง๐ญ๐ซ๐š๐ฅ๐ข๐ง๐ ๐ฎ๐š๐ฅ ๐๐ž๐ฌ๐ข๐ ๐ง, novel OS structure, and state management. It strives to close the semantic gap between compiler and hardware in order to maximally leverage the power of language safety, and thus shift OS responsibilities (resource management) into the compiler.




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