A clean-slate x86_64 microkernel operating system built from scratch. No POSIX baggage, no legacy Unix assumptions. The kernel stays minimal: scheduling, memory management, IPC ports, and hardware abstraction. Everything else (display server, filesystem, shell) lives in ring-3 userspace and communicates over message passing.
X OS is a microkernel designed for the AI era. No decades of compatibility debt, no legacy Unix assumptions, no POSIX baggage. The goal is an operating system that feels native to intelligent agents and human users alike: beautiful, consistent, and fully open to modification.
- Microkernel architecture — the kernel provides ~33 syscalls. Filesystem access, GPU rendering, and input handling are delegated to ring-3 services that talk over IPC ports.
- No POSIX / no Unix ABI — this is not Linux, BSD, or anything derived from them. The syscall surface is deliberately minimal.
- Embedded userspace — the init process and display server (composer) are compiled as ELF binaries, then embedded directly into the kernel image as byte arrays. The kernel spawns them at boot.
- Display server in userspace — a hardware-accelerated composer runs in ring 3, receiving surface commands from applications via IPC and flushing to a virtio-gpu framebuffer.
This is not a retro hobby OS. The goal is a forward-looking system where the boundary between user and developer disappears.
Applications ship as bundles. In many cases the source code is included directly in the bundle. Open any app, read how it works, modify it, and run your version immediately. Software on X OS is meant to be read, understood, and changed.
Users have absolute control over the look and feel of the system, but within guardrails that preserve beauty and consistency. A user-space xui.plist file lets you tune animations, transitions, spacing, and behavior. You can make it yours without turning the desktop into a Frankenstein. The system enforces visual coherence — customization, not chaos.
Eventually, X OS will host a real-time programming environment. You edit code and see the result immediately, with no compile-wait-run loop. Changes propagate live into running processes. This is the natural endpoint of a microkernel built on IPC and dynamic surface composition: the entire system is designed to be modified while it runs.
| Component | Ring | Responsibility |
|---|---|---|
| Kernel | 0 | Scheduling, memory alloc/map, IPC ports, timer, interrupts, NVMe/virtio drivers |
| Init (PID 1) | 3 | First userspace process; spawns services and registers well-known nameserver ports |
| Composer | 3 | Display server — surfaces, dirty rectangles, cursor, desktop background |
| Future: Terminal, Shell, FS service | 3 | Will run as normal ring-3 processes using IPC |
Tested on macOS with Apple Silicon. You need:
-
Xcode Command Line Tools (provides
clang,make,git) -
Homebrew — https://brew.sh
-
lld (LLVM linker)
-
xorriso (for building the bootable ISO)
-
QEMU — install via Homebrew or build from source. The Makefile auto-detects the path.
Option A — Homebrew (quickest):
Option B — build latest from source into
/opt/qemu-head:git clone https://gitlab.com/qemu-project/qemu.git cd qemu mkdir build && cd build ../configure --prefix=/opt/qemu-head --target-list=x86_64-softmmu \ --enable-virtiofsd --enable-spice --enable-cocoa make -j$(sysctl -n hw.ncpu) sudo make installThe Makefile checks
/opt/qemu-headfirst, then the Homebrew prefix, then falls back toqemu-system-x86_64in your PATH.
One-time setup (downloads the Limine bootloader):
Build the bootable ISO:
This produces x-os.iso in the project root.
BIOS mode (SeaBIOS):
UEFI mode (OVMF):
QEMU is launched with:
- Machine:
q35 - 512 MB RAM, 1 SMP
- virtio-gpu-pci at 2560x1600, Cocoa display
- NVMe disk (
disk.img, created automatically if missing) - Serial output forwarded to stdio
x/
├── boot/ # Limine bootloader config and handoff structures
├── kernel/ # Microkernel source
│ ├── arch/x86_64/ # GDT, IDT, syscall entry, context switch
│ ├── memory/ # Physical page allocator, VMM, heap
│ ├── sched/ # Round-robin scheduler
│ ├── ipc/ # Port-based message passing
│ ├── proc/ # ELF loader; init and composer blobs
│ ├── hal/ # NVMe, virtio GPU, PS/2 input, PCI, timers
│ ├── fs/ # Custom XFS filesystem
│ └── entry/ # kmain() boot sequence
├── userspace/ # Ring-3 code
│ ├── init/ # PID 1
│ ├── runtime/ # Syscall wrappers (shared C library)
│ └── services/
│ └── composer/ # Display server
├── Makefile
└── disk.img # Raw 4 MiB block device image (auto-created)
make clean # remove build artifacts and ISO
make distclean # also remove the fetched Limine directory
Business Source License 1.1
X OS is source-available under the BSL. This means:
- Free for contributors — you can fork, modify, build, and send pull requests.
- Free for personal, educational, and research use.
- Commercial use requires a paid license — if you want to sell it, offer it as a service, or embed it in a product, contact the copyright holder.
- All commercial rights reserved — the copyright holder controls all commercial licensing and may grant or deny commercial use at their sole discretion.
This model lets the community grow the project while keeping all commercial and acquisition paths fully controlled by the copyright holder. See LICENSE for full terms.
For commercial licensing, partnership, or acquisition inquiries, contact the copyright holder.