SchOS
Copyright 2026 Nexoniarz

This product includes software developed as part of the SchOS project,
licensed under the Apache License, Version 2.0. See LICENSE.

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Third-party software
================================================================================

SchOS incorporates and redistributes software written by others. Their
licences apply to their code and are NOT superseded by the SchOS licence.
A built SchOS image contains binaries derived from all of the following.

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xv6-x86_64 / xv6                                                  MIT License
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Copyright (c) 2006-2019 Frans Kaashoek, Robert Morris, Russ Cox,
                        Massachusetts Institute of Technology CSAIL

The SchIFT kernel is a derivative work of xv6. Substantial portions of
kernel/ -- notably the process, trap, virtual memory, buffer cache and v1
filesystem code -- descend from it, however heavily rewritten. The MIT licence
requires that this notice be preserved in all copies; see LICENSE.MIT.

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musl libc 1.2.5                                                   MIT License
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Copyright (c) 2005-2020 Rich Felker and contributors

Built from ports/musl. Provides the C library every userland program links
against. See the extracted source's COPYRIGHT file for the full contributor
list, which the MIT terms require be carried along with binaries.

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toybox 0.8.12                                       Zero-Clause BSD (0BSD)
--------------------------------------------------------------------------------
Copyright (c) 2006-2024 Rob Landley and contributors

Built from ports/toybox. Supplies the standard command set in /bin. 0BSD
imposes no attribution requirement at all; this entry is courtesy, not
obligation.

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mksh R59c                                                     MirOS Licence
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Copyright (c) 2002-2023 Thorsten Glaser and contributors
Portions derived from the Public Domain Korn Shell (pdksh)

Built from ports/mksh. Supplies /bin/sh. The MirOS Licence is permissive and
requires the copyright notice be retained.

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Intel 8254x device identifiers                                BSD 3-Clause
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Copyright (c) 2001-2020, Intel Corporation
All rights reserved.

The PCI device IDs in include/e1000.h are transcribed from FreeBSD's
sys/dev/e1000/e1000_hw.h, which carries the Intel 3-clause BSD licence above
(verified: no advertising clause). Only the identifier constants are used --
data, not implementation. kernel/drivers/net/e1000/e1000.c is written from
Intel's public manual 317453 and contains no FreeBSD or Intel driver code.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the conditions of the 3-clause BSD
licence are met, including retention of this notice and the disclaimer, and
that neither the name of Intel Corporation nor the names of its contributors
are used to endorse or promote products derived from this software without
specific prior written permission.

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usb.ids -- USB vendor and product database          BSD 3-Clause (dual-licensed)
--------------------------------------------------------------------------------
Maintained by Stephen J. Gowdy <linux.usb.ids@gmail.com>
http://www.linux-usb.org/usb.ids

Distributed by its maintainer under the terms of *either* the GNU General
Public License version 2 or later, *or* the 3-clause BSD Licence. SchOS takes
the BSD option; the GPL option is not exercised and could not be, since
Apache-2.0 and GPL-2.0-only cannot be combined (see docs/licensing.md section
2).

Shipped verbatim as /usr/share/usb.ids. Cached in dist/ and refreshed with
`make usb-ids`, never automatically -- the version and date are in the file's
own header, so what shipped is always knowable.

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Roboto                                                        Apache-2.0
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Copyright the Roboto Project Authors (https://github.com/googlefonts/roboto)

Shipped as /usr/share/fonts/Roboto-Regular.ttf, from ports/Roboto. Licensed
under Apache-2.0 -- the same licence as SchOS itself, so it carries no
obligation beyond this notice. Intended for the desktop, window manager and
compositor.

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JetBrains Mono                                                SIL OFL 1.1
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Copyright 2020 The JetBrains Mono Project Authors
(https://github.com/JetBrains/JetBrainsMono)

Shipped as /usr/share/fonts/JetBrainsMono-Regular.ttf, from ports/JetBrains_Mono
(full licence text at ports/JetBrains_Mono/OFL.txt). Intended for the terminal
and TTY.

Under the SIL Open Font License 1.1 the font remains under OFL even inside this
Apache-2.0 system -- that does not reach any other part of SchOS -- and it may
not be sold on its own. Bundling it with an operating system is expressly
permitted. JetBrains Mono declares no Reserved Font Name, so a modified version
(a pre-rasterised bitmap, for instance) may keep the name.

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"New File System For XV6"                                     MIT License
--------------------------------------------------------------------------------
Copyright (c) Qi Ma, Leyi Pan, Ao Sun, Peiran Xu

kernel/fs/fs.c and parts of tools/mkfs.c derive from this project, which extends
xv6's file system with features SchOS still uses today:

  - the HTree hashed directory index (BKDRHash, HASHRANGE, the primary/overflow
    bucket layout), after Daniel Phillips, "A Directory Index for EXT2",
    5th Annual Linux Showcase & Conference, 2001
  - Ext4-style extents (T_EXTENT)
  - the inode bitmap
  - symbolic links, file permissions, lseek and append

Licensed under the MIT License, which permits this use and requires that the
copyright notice and permission notice be retained. This entry is that
retention; it was missing until 2026-08-09 and is recorded here regardless of
what happens to the code, because the obligation attaches to every copy already
made.

Distinct from xv6 itself (LICENSE.MIT), which this project in turn derives from.

================================================================================

The build downloads upstream tarballs into dist/ and applies the patches in
ports/<name>/patches/. Nothing in ports/ is SchOS code; do not add first-party
work there. See docs/layout.md.

Licence questions -- what may be copied in, what may never be, and how to check
a NetBSD file's clause before using it -- are worked through in
docs/licensing.md.
