XAIOS

An experimental freestanding Unix-like operating system, written in C99, built towards an SSH-administered distributed CPU inference server. It boots to a login with durable storage, dual-stack networking and SSH. Real-model inference is not implemented.

Everything about what XAIOS does lives in the XAIOS Wiki, mirrored under wiki/ so every claim can be checked against source. Everything about what remains lives in one place, the Project Tracker.

Get a build

Released builds are on the releases page; the current one is build 4. You do not need to compile anything to try XAIOS.

Six downloads, and five of them contain the same image — what differs is what is packaged around it:

To run XAIOS	Take
in QEMU	xaios_b4-qemu.zip — image plus a launch script per architecture
in VMware Fusion	xaios_b4-vmware-fusion.zip — image plus a .vmx
in Apple Virtualization.framework	xaios_b4-virtualization-framework.zip — image plus a harness you build and sign
on a real machine, from a USB stick	xaios_b4-usb.zip — image plus a writer that names the target disk back before it writes
on a real machine with no disk, over the network	xaios_b4-netboot.zip — two boot binaries plus a DHCP/TFTP server script
with your own tooling	xaios_b4.iso.zip — the image, and nothing else

Unzip before use. The image is one file that is an ISO 9660 filesystem, a GPT-partitioned disk and a bootable USB image at once, which is why one download covers CD-ROM, hard disk and stick. On first boot there is no account and no default password; the machine asks how to set itself up.

Each release note records exactly which hypervisors and firmware that build was booted on, and what was not tested — see the build 4 note. To build from source instead, see Getting Started.

Where it runs

Hypervisor	Qualification profile	Gate	Evidence class
QEMU ARM64	macOS QEMU ARM64	full CI	correctness and ABI only
QEMU x86_64	Intel VPS QEMU x86_64	full CI	correctness and ABI only
VMware Fusion	macOS VMware Fusion ARM64	make vmware-fusion-smoke	Fusion 26H1 four-vCPU lifecycle
Apple Virtualization.framework	none; development target	make vz-gate, make vz-stress-gate	not qualification evidence

XAIOS behaves the same on all of them. Firmware supplies capabilities, never identity and never behaviour, and make platform-neutrality-check enforces it. Where a capability is absent the system degrades the same way everywhere. The per-environment feature matrix is in the Project Tracker; no ARM result stands in for Intel evidence, and each profile records its own firmware hashes, device inventory and gates — see Firmware Platform Profiles.

No result here is physical-hardware evidence. Emulators prove correctness, not performance or firmware behaviour.

Boundaries worth knowing before you read further

Unix compatibility. FreeBSD is the behavioural reference for commands, SSH/SFTP and network interoperability. XAIOS is not FreeBSD-derived and offers no FreeBSD or Linux binary ABI — guest programs use native syscalls, so passing host-client tests proves wire behaviour only. See Unix compatibility.

Architectures. AArch64, x86_64 and RISC-V (rv64gc). AArch64 and x86_64 run on real machines and hypervisors; RISC-V runs the same shared kernel on the QEMU virt board, booting to 100% across four harts with a login prompt, a working SSH server and the hosted C99 library, either from a kernel handed to QEMU or from its own disk through UEFI firmware. What it does not have is hardware qualification: no RISC-V machine or hypervisor is in the test set, so its evidence is one board. See RISC-V.

C99 libc. A statically linked hosted ISO C99 library for AArch64 and x86_64, with no public POSIX API and no new syscall identifiers. See C99 libc.

Model support status. Neither the deterministic model-v1 path nor the model-v2 format foundation executes a transformer. Qwen 3.8 is the next correctness target, Kimi K3 and DeepSeek V4 later; nothing is production supported. XAIOS is built around official architecture adapters rather than a hard-coded graph. See Model support.

Updates. The native xapt updater installs signed applications without rebooting and stages OS images into the inactive A/B slot. Its trust root is for development use; production key custody and rotation remain open gates.

License

Source-available under the PolyForm Noncommercial License 1.0.0: private, personal, educational and noncommercial research use, including by universities and public research organisations. It does not grant commercial use, which requires a separate written licence obtained beforehand — see COMMERCIAL-LICENSE.md.