Install gatOS

gatOS and purrTTY are companion KSA mods. purrTTY supplies the terminal window. gatOS supplies the small Linux computer behind its gatOS shell entry. Install both through your usual KSA mod workflow, using matching current releases.

Choose the right archive

• Windows: install gatOS-windows-*.zip. It includes the Alpine guest and a trimmed Windows QEMU bundle. No separate Linux install is needed.
• Linux: install gatOS-linux-*.zip. It includes the guest but deliberately uses your system qemu-system-x86_64.
• macOS: useful for development, not a supported player release target.

On Linux, install QEMU before launching KSA:

# Debian / Ubuntu
sudo apt install qemu-system-x86

# Fedora
sudo dnf install qemu-system-x86

# Arch
sudo pacman -S qemu-system-x86_64

KVM is used automatically when your account can access /dev/kvm; otherwise gatOS falls back to software emulation. On Windows, the Windows Hypervisor Platform makes boot much quicker, but the software fallback works too. The project README has the full WHPX setup and troubleshooting notes.

First launch

1. Start KSA.
2. Open purrTTY’s New Tab or New Window menu.
3. Choose gatOS.
4. Wait for the first boot, then try ls /sim.

The VM remains running after you close a terminal tab and stops when the game exits. If you use ModMenu, gatOS also offers a status window for VM state, accelerator, bound ports, and the data folder.

Configuration

On first launch, gatOS copies its shipped gatos.default.toml to gatos.toml in the mod folder. That live file survives mod updates. Delete it to reseed the defaults. Settings are flat TOML keys, not nested [sections].

Next: your first five minutes.