01 Linux distribution · x86_64
A minimal Linux system, built from scratch to boot to a shell in 16 MiB of memory.
QEMU verified · BIOS + UEFI
For x86_64 PCs: boot from USB or optical media, then install to a local disk.
02 Overview
Small by construction.
L2 is a compact Linux distribution assembled around a single supervisor and a static userspace. It boots from read-only media, pivots into a 107 KB initramfs, and keeps in memory only what the running system needs.
One supervisor
rcl2 runs as PID 1 and stays resident. There is no service manager layered above it and no second init to replace it.
Static by default
The shell, utilities, package manager and system tooling are static musl binaries. gcompat covers prebuilt glibc programs.
Measured, not assumed
Every figure on this page comes from the project's measured specification, collected on QEMU TCG with standard virtual hardware.
03 Specification
Measured specification
Boot and memory figures were collected under QEMU TCG with E1000 networking, a standard VGA adapter and a static musl userspace.
| Init | rcl2, freestanding PID 1 |
|---|---|
| Bootloader | Limine, BIOS and UEFI |
| Shell and utilities | dash, minibox |
| C library | musl; gcompat 1.1.0 |
| Package manager | l2pm (.l2pm, .l2p) |
| Live root | read-only, 107 KB pivot initramfs |
| ISO image | 9,123,840 B (9.12 MB) |
|---|---|
| Installed payload | 7,082,129 B (7.08 MB) |
| Idle memory | 15.49 MiB installed 15.39 MiB live |
| Free at idle | ~520 KiB installed ~620 KiB live |
| Tested allocation | 16 MiB |
| Recommended launcher | 32 MiB BIOS 128 MiB UEFI |
Idle figures include the kernel and reserved memory. The kernel profile uses a single CPU and reduced hardening. The live image boots in BIOS and UEFI modes and includes a disk installer. Real-machine compatibility has not yet been verified; under 1 MiB remains available to applications at idle.
04 Architecture
One binary, two cores.
rcl2 is the init. It starts userspace as PID 1, supervises it, and remains the only resident process of its kind.
C core
Raw syscalls through syscall(2): fork and exec, wait and reap, signals, mounts, console and reboot(2). No libc is linked.
Rust core
A #![no_std] core with no external crates. It parses /etc/rcl2.conf, the kernel command line and /proc/self/statm.
Shared ABI
A pinned #[repr(C)] contract between both cores. Layout assertions are compiled into C and Rust and checked from both sides.
Drop-in init
Replaces the original script/init/init.c with the same mounts, console wording and L2# prompt. l2.rescue=1 opens a rescue shell.
The build path is deliberately non-GNU: clang, rustc, ld.lld and LLVM binutils.
05 Userspace
Everything present is used.
The installed payload is 7.08 MB. This is nearly the complete inventory.
__ _____
/_/\ /_____/\
\:\ \ \:::_:\ \
\:\ \ _\:\|
\:\ \____ /::_/__
\:\/___/\\:\____/\
\_____\/ \_____\/
OS L2 Linux Host l2 Kernel 7.2.11 Init rcl2 (PID 1) Session live media Uptime 3m Shell /bin/dash Terminal linux Memory 15.4 MiB / 16.0 MiB Disk / 5.2 MB / 64.0 MB CPU QEMU Virtual CPU
- dash
- POSIX shell, statically linked.
- minibox
- Core utilities in a single musl-static binary.
- l2pm
- Packages from
.l2pmrecipes into.l2parchives (newc-cpio + gzip); add, list and remove. - l2fetch
- System summary with an ASCII logo.
- mdev
- Device management in BusyBox daemon mode.
- udhcpc
- DHCP client, BusyBox applet.
- storage tools
- cfdisk, mke2fs and mkfs.vfat, statically linked.
- gcompat
- glibc compatibility with the musl loader for x86_64 binaries.
- console shells
- One resident shell at boot; a local VT starts on first key press.
06 Getting started
Boot it in a VM.
Run the launcher from the repository root. QEMU is the supported path; the BIOS profile needs 32 MiB and the UEFI profile 128 MiB.
bash script/run.sh bios windowL2#- Resident shell, serial when configured; the local VT starts on first key press.
poweroff- Accepted directly by rcl2.
l2.rescue=1- Kernel flag that opens a rescue shell.
l2pm help- Package manager usage.
07 FAQ
Questions
Does L2 run on real hardware?
L2 is designed for x86_64 PCs. The live image supports BIOS and UEFI boot and includes an installer for local disks. Hardware compatibility has not yet been tested; boot and installation results so far come from QEMU.
Why is there no glibc?
Native tooling is static musl. glibc-linked x86_64 binaries run through gcompat 1.1.0 with the musl loader; pthread, math and getpwuid usage are verified.
How are packages built and installed?
l2pm consumes .l2pm recipes and produces .l2p archives, which are newc-cpio images compressed with gzip. It can pack, add, list and remove packages.
How much memory should I allocate?
16 MiB is enough to boot and leaves under 1 MiB for applications. The recommended launcher allocations are 32 MiB for BIOS and 128 MiB for UEFI.
What happens if the system breaks?
Set l2.rescue=1 for a rescue shell. Offline and recovery boot paths are part of the verified checks.