---
name: schunix-licensing
description: "Schunix is Apache-2.0, copyright Nexoniarz; BSD drivers yes, Linux no, and ports/ licences bind regardless"
metadata: 
  node_type: memory
  type: project
  originSessionId: a665e14b-86bd-4b41-a228-51377f3e9225
  modified: 2026-08-08T16:18:39.569Z
---

**`LICENSE` is Apache-2.0**, copyright *Nexoniarz* (not "Schunix Contributors" —
one author, and a fictional collective makes future re-licensing harder).
Chosen over MIT/BSD for the express patent grant.

**Settled, do not reopen:** the "Apache-2.0 but shared-source" question was
discussed at length in 2026-08 and **on 2026-08-08 Nexoniarz asked for it to be
dropped from the docs entirely** — `docs/licensing.md` is about licensing, not
about that debate. All references are gone from `docs/`, `LICENSE` and `NOTICE`;
don't reintroduce them. The substance that survives, in one line inside §1:
Apache-2.0 §2 is an irrevocable grant, so a restriction stated anywhere else
does not narrow it, and restricting distribution would be a licence change
(bespoke proprietary, or BUSL-1.1) rather than a wording change.

The decision that actually mattered to them is **when to publish**, not the
licence; the standing rule is still never ([[nexoniarz-sharing-preference]]).

**Binding regardless of what they pick:**
- The kernel derives from xv6 (MIT). `LICENSE.MIT` was *missing* — it was
  referenced as `bk/LICENSE.MIT` and lost in the `bk/` → `kernel/` migration.
  Recreated; must not be deleted.
- `ports/` is other people's code, redistributed in every image: musl (MIT),
  toybox (0BSD), mksh (MirOS). `NOTICE` carries the attribution musl and mksh
  require. Patches under `ports/*/patches/` inherit *their* licences.

New first-party files carry `// SPDX-License-Identifier: Apache-2.0`.

**Drivers: BSD yes, Linux no** (asked 2026-08-04, "for drivers we can try get
it from like Linux?"). Linux is GPL-2.0-**only**, and Apache-2.0's patent and
indemnity clauses are "further restrictions" under GPLv2 §6 — the two cannot
be combined and redistributed. Using a Linux driver means relicensing all of
Schunix to GPLv2 and dropping Apache-2.0; you cannot keep both. FreeBSD /
NetBSD / OpenBSD are BSD-2/3-clause and **are** compatible: keep the notice,
add to `NOTICE`, done. Reading Linux to understand hardware is fine;
translating a driver function-by-function produces a derivative work whatever
the identifiers say. Best source of all is the public specification — xHCI,
virtio, AHCI, NVMe, e1000 — which carries no licence on what you write from
it. Recorded in `docs/plan/roadmap.md` §1. See [[schunix-roadmap-and-projects]].


## fs.c is third-party, and was unattributed until 2026-08-09

`kernel/fs/fs.c` (and parts of `tools/mkfs.c`) derive from **"New File System
For XV6"** by Qi Ma, Leyi Pan, Ao Sun and Peiran Xu -- **MIT License**. Nexoniarz
mentioned the provenance in passing; the tree had **no attribution at all**,
only a comment crediting xv6. That was a live compliance gap, since MIT requires
the notice be retained in substantial portions.

Their work is what the HTree directory index (`BKDRHash`, `HASHRANGE`,
`OVERFLOW_DIR_START`), the Ext4-style extents (`T_EXTENT`), the inode bitmap and
`divesymlink` all are. Now credited in `NOTICE` and in fs.c's header.

**The obligation does not go away when fs.c does.** It attaches to every copy
already made, so the NOTICE entry stays even after the SchFS migration deletes
the file.

**The general lesson:** ask where code came from before assuming it is
first-party. "It is in our tree and looks like xv6" was wrong here, and the only
reason it surfaced was an offhand remark.