QSOE 0.1 Ships an OS That Lets You Swap Kernels at Boot

An operating system that lets you choose between two radically different kernels — at boot, from a menu — and gives you the exact same userspace on both. That's QSOE 0.1, released June 2026, and it's the first public drop of a project that takes the QNX Neutrino design philosophy and grafts it onto 64-bit RISC-V hardware.

Why a Two-Kernel OS Exists

QSOE ships in two variants: QSOE/N runs on Skimmer, a new SMP-capable microkernel written from scratch for this project; QSOE/L runs on seL4, the formally verified microkernel. Both share one build system, one userspace toolchain, and one set of drivers. The kernel and initrd from either variant can be loaded directly by U-Boot or the project's own EFI bootloader, mr-bml.

The Shared Userspace Trick

The userspace is 100% identical between variants. The only per-kernel artifacts are taskman (the task manager) and libc.so. Even the C library is 85% shared at the source level — only the thin layer that touches the kernel API diverges. That means a program compiled for QSOE/N runs unmodified on QSOE/L, and vice versa. You get the formal assurance of seL4 when you need it, and the speed of Skimmer (which is built for convenience) for the rest.

Boot It on QEMU or a HiFive Unmatched

Both variants boot on real hardware — the SiFive HiFive Unmatched (FU740) — and in QEMU. The fastest way to see it in action: grab nvme.img.gz, point QEMU 11.0.1 or newer at it, and boot to the mr-bml menu. Log in as root with password QSOE. The project provides ready-made disk images, so you don't need to wrestle with -kernel flags.

On real hardware, install mr-bml into the EFI System Partition, drop the kernel images and a simple config file into /boot/, and pick your kernel from the boot menu. Both variants drive the NVMe disk directly — no virtio split like QEMU.

Building from source is a single make after a make prepare with a riscv64-linux-gnu toolchain. The umbrella repo at gitlab.com/qsoe/os pulls in all components. The binary releases live at github.com/qsoe-dev/dl, all under Apache-2.0.

QSOE 0.1 isn't a preview — it's a bootable, installable, dual-kernel OS that proves the QNX resource-manager model can live on open-source RISC-V hardware with a choice of kernel underneath."

Source: A QNX-inspired operating system with selectable kernels
Domain: qsoe.net