GitHub - valivalivali/x-os

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.

What It Is 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.

Vision This is not a retro hobby OS. The goal is a forward-looking system where the boundary between user and developer disappears. App Bundles with Source 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. Controlled User Customization 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. Live Programming 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. Architecture Overview

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

Requirements (macOS) Tested on macOS with Apple Silicon. You need:

Xcode Command Line Tools (provides clang, make, git) xcode-select --install

Homebrew — https://brew.sh

lld (LLVM linker) brew install lld

xorriso (for building the bootable ISO) brew install xorriso

QEMU — install via Homebrew or build from source. The Makefile auto-detects the path. Option A — Homebrew (quickest): brew install qemu

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 install

The Makefile checks /opt/qemu-head first, then the Homebrew prefix, then falls back to qemu-system-x86_64 in your PATH.

Build One-time setup (downloads the Limine bootloader): make setup

Build the bootable ISO: make

This produces x-os.iso in the project root.

Run BIOS mode (SeaBIOS): make run

UEFI mode (OVMF): make run-uefi

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

Project Layout 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)

Cleaning Up make clean # remove build artifacts and ISO make distclean # also remove the fetched Limine directory

License 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.