Attribution

GenX-DOS bundles third-party emulators, libraries, system ROMs, and visual assets. This file is the canonical record of those components and the terms under which they are redistributed.

The live site, genx-dos.fun, carries all of it. This repository and the release zip carry no game ROMs, BIOS or firmware beyond what each emulator's own maintainer shipped with it. Rows below for files that are absent here describe the site's copy; ROMS.txt lists them.

It is maintained alongside CHANGELOG.md: whenever a new emulator, BIOS, ROM, bezel, font, or other asset is added or replaced, an entry is added here.

The summary list in README.md is a quick-reference; this file is the authoritative version.

Removal upon request

If you hold rights in anything bundled here, or legally represent someone who does, and you raise an identified copyright or intellectual-property concern, the material in question will be removed immediately. Not debated, not defended, not delayed pending a formal process.

This applies to everything on the site and in this repository, not only games: software titles, system ROMs and BIOS images, emulator code, artwork, fonts, sound, documentation, trade marks and names. Note that the games and the firmware we supplied are served by genx-dos.fun and are not in the repository at all — see ROMS.txt.

What a request must contain. Three things, so that nothing is pulled on an anonymous say-so:

1. Who you are — a name, and the company or firm if you act for one.
2. Your standing — that you hold the rights, or who you represent and in what capacity.
3. What and why — the specific title, file or asset, and the basis of the concern.

That is the whole bar. No notice format, no particular form of words, and no registration certificates, chain-of-title documents or legal citations — a few sentences covering those three points will be taken in good faith and acted on.

Where to send it - Email admin@genx-dos.fun — the shortest route, and it needs no account anywhere - Or open an issue, if you would rather it were public: https://github.com/Retro-Jack/GenX-DOS/issues (there is a "Content removal request" template, but a plain issue is fine)

The same procedure is published on its own page — REMOVAL.md — for anyone who would rather not read it inside an attribution file. It adds what we can and cannot reach: our site and repository, but not other people's copies or third-party archives.

Removal will happen as soon as such a request reaches me. GenX-DOS is a non-commercial preservation project run by one person; nothing here is worth anyone's legal costs, mine included, and no title in it matters more than a rights holder's wishes about their own work.

Site code

• DOS terminal, virtual filesystem, and 12×12 CP437 font sprite system — by Mike, who wrote it informally for LGR — Lazy Game Reviews (Clint Basinger, http://www.lazygamereviews.com). LGR's own site metadata credits Mike — <meta name="Generator" content="Mike"> and <meta name="Originator" content="Mike's brain -- thanks, Mike!">. The interactive prompt under prompt/, the fs.js virtual C: drive layout, the command dispatcher, and the CP437 sprite font and renderer originate from LGR-DOS (the "LGR-DOS Command Prompt"), LGR's in-browser DOS-prompt project. GenX-DOS extends that base.
• Both favicons — favicon.ico (32×32) and animated_favicon1.gif (16×16) — also LGR's, part of the same initial import. The .ico is the green C:\ prompt; the GIF is the same icon in six frames, which hold on C:\ for two seconds, cross-fade to LGR for two, and fade back. The tab icon has been crediting LGR the whole time. Both are served from the site root, from prompt/ and from systems/_shared/, and every copy is byte-identical to the original. (The favicon.ico under systems/bbcmicro/dist/ and systems/bbcmaster/dist/ is a different file, and comes from jsbeeb.)
• AMIBIOS POST animation, emulator integration wrappers, menu tree, and all bundled-emulator-specific code — © Retro-Jack. Original work added on top of the LGR terminal base.
• Retro-Jack's original work (above) is licensed CC BY-NC 4.0 — see LICENSE.TXT. The LGR terminal base is explicitly excluded from that licence and stays under LGR's own terms: source-available, with a clear credit to the LGR base required in any derivative work.

Emulators

Each bundle directory contains the upstream LICENSE or COPYING file where one was provided. Build recipes for self-compiled WASM bundles live with their bundle (systems/odyssey2/build.sh, systems/cpc/BUILDING-WASM.md); atari800's build-wasm.sh lives in the Retro-Jack/atari800 fork rather than the bundle.

Corresponding source for the engine binaries

The GPL asks whoever distributes a binary to also make its source available, and the Artistic License asks the same of modified versions. The engines below ship here as compiled binaries, so this is where their source lives. None of it is fetched at runtime — these are links for anyone wanting to rebuild or inspect what we ship.

o2em is Artistic-2.0, not GPL (checked upstream 17/08/2026). This entry used to read GPL-2.0+, which looks to have been an assumption from most libretro cores being GPL. libretro/libretro-o2em carries a COPYING that is the Artistic License 2.0, our bundled copy is byte-identical to it, and no source file in the core carries a GPL header. The original O2EM was Artistic-licensed and the libretro port kept those terms.

How the cores are mirrored

EmulatorJS-flavoured libretro cores (FCEUmm, VICE family, gearcoleco, Stella, gambatte, handy, genesis_plus_gx, prosystem) are mirrored from cdn.emulatorjs.org/stable/ rather than rebuilt locally. The upstream CDN serves the same .data archives EmulatorJS itself loads from.

Exception — gambatte (Game Boy): the current stable build is broken — it renders a blank white panel (no ROM ever displays). Verified June 2026. We mirror the nightly build instead (cdn.emulatorjs.org/nightly/), which works. All other cores stay on stable. (vice_x128 was a second exception for the same reason until the C128 was dropped on 03/09/2026.)

Self-compiled WASM builds

• atari800 — built from atari800/atari800 v5.2.0 source via Retro-Jack/atari800 fork (adds build-wasm.sh + BUILDING-WASM.md on top of upstream). The pre-built .js + .wasm in this repo correspond to that build script. The fork also adds gx_state_* EMSCRIPTEN_KEEPALIVE wrappers around atari800's StateSav_*AtariState, run from a gx_state_poll() in the sdl/main.c frame loop so the file-based save/load is deferred onto the main-loop ASYNCIFY stack (a direct call would be a second concurrent asyncify op and corrupt the heap) — that's what drives the page's save/load buttons.
• cpc (tiny8bit) — rebuilt from floooh/chips-test via fibs (Deno + emsdk), recipe in systems/cpc/BUILDING-WASM.md. Beyond the overlay removal, examples/emus/cpc.c gains gx_state_* EMSCRIPTEN_KEEPALIVE wrappers around chips' cpc_save_snapshot/cpc_load_snapshot, with HEAPU8 added to EXPORTED_RUNTIME_METHODS in the fibs emscripten.ts. The chips snapshot is a self-contained struct copy (no emscripten_sleep), so unlike atari800 the adapter calls it straight from the button — no frame-loop deferral.
• jsbeeb (BBC Micro / Master) — built from the Retro-Jack/jsbeeb fork (a pure-JS Vite build; the pre-built dist/assets/ engine files in both bundles come from npm run build on the fork's main branch). Two local changes, both documented in the fork's GENX-CHANGES.md: (1) d-pad gamepad remap — four GP.D12–GP.D15 cases in src/gamepads.js so a launch URL can map the d-pad buttons to any BBC key (jsbeeb hardwires them to Z/X/:/? with no remap hook); this is a general improvement offered upstream on the fork's clean gamepad-dpad-remap branch. (2) monitor inset — src/main.js bottomReservedSize widened 68→120 for the sitewide-wallpaper breathing room (GenX-local, not upstreamed). The fork tracks upstream releases — currently rebased onto jsbeeb 1.14.0 (July 2026). Hats off to Matt Godbolt for being on the ball: 1.14.0 shipped the #704 workaround for a Chrome 150 V8 bug that had been wedging the emulator, within a day of it surfacing — rebasing this fork onto it cleared the BBC freeze on GenX-DOS with nothing more to do on our side.
• libretro-o2em — built from upstream libretro/libretro-o2em via systems/odyssey2/build.sh. Custom SDL2/emscripten frontend (frontend.c) statically linked with the libretro core; reproducible with emsdk. frontend.c also adds gx_state_* EMSCRIPTEN_KEEPALIVE wrappers around the core's retro_serialize/retro_unserialize to expose save/load state to the page (with HEAPU8 in EXPORTED_RUNTIME_METHODS).
• sdltrs (TRS-80 Model III) — built from jengun/sdltrs (gitlab.com/jengun/sdltrs) to WASM via emscripten (build-wasm.sh, -sASYNCIFY + -sUSE_SDL=2, -sMODULARIZE). Two #ifdef __EMSCRIPTEN__ patches swap sdltrs's blocking SDL_Delay throttle (trs_interrupt.c) and SDL_WaitEvent (trs_sdl_interface.c) for emscripten_sleep, so the continuous Z80 loop yields once per timer tick and the page stays responsive. The bundle runs as a Model III (-model 3), whose ROM is fetched by the page and written into MEMFS at boot rather than embedded, so the machine can change without an emscripten rebuild. The build still embeds a /level2.rom from its Model I days, but those 12 KB are zeroed in the shipped WASM, so it carries no Tandy firmware of its own. sdltrs ships a built-in save-state (trs_state_save/trs_state_load) that isn't wired to the page yet.
• VirtualT (Tandy TRS-80 Model 100) — Stephen Hurd & Ken Pettit's VirtualT (BSD, © 2004; sourceforge.net/projects/virtualt) is a full FLTK desktop emulator; this bundle is built from its core only. The FLTK-free 8085 CPU, memory, HD44102 LCD and keyboard-matrix sources are compiled to WASM with emscripten (-sASYNCIFY + -sUSE_SDL=2) behind a small headless SDL2 frontend (frontend_sdl.c) plus headless display / file / clock / stub units written for this project; the ~40 FLTK GUI/IDE/debugger files are dropped. Because so much of the original is stripped away this is an acknowledgement, not a fork — VirtualT's BSD licence and the original copyright are preserved in the retained sources. The 32 KB Model 100 ROM is embedded via --embed-file. The five headless units (frontend_sdl.c plus the display / file / clock / stub replacements), a reproducible build.sh, BUILDING-WASM.md and VirtualT's BSD licence are in systems/m100/src/.

BIOS and system ROMs

Bundled for emulator-only use. These remain the property of their copyright holders.

Disk operating systems

The TRS-80 Model III has BASIC in ROM, but a diskless machine stops at the boot ROM's Diskette? prompt, so the menu's System disks entry boots one of two period disk operating systems instead.

Game ROMs

The live site bundles several hundred 8-bit-era game ROMs across all platforms, plus the hundred arcade romsets of the ARCADE section (the repo and release zip keep only those an emulator's maintainer shipped with it — see ROMS.txt). These remain the copyright of their original publishers and are included for historical preservation, emulator integration, and educational use.

Notable inclusions where the rights holder has explicitly released the software under permissive terms:

• Attack of the PETSCII Robots (David Murray, The 8-Bit Guy, 2021) — the free shareware release, on the C64 (systems/c64/games/petrobot.d64) and the PET (systems/pet/games/petrobot.d64). Its own start-up screen says the shareware version is free to distribute; the full game is sold at the8bitguy.com.
• Apple I cassette tapes — Integer BASIC era homebrew + Apple's own 30th Anniversary demo by Brian Wiser. Sourced from the Apple I Project archive.
• GCE Vectrex — the whole library, including the boot ROM. Jay Smith and Smith Engineering retain the rights; they are not public domain, contrary to a widespread claim. What Smith granted, from the mid-1990s, is standing permission to reproduce and distribute the software Smith Engineering published, on a non-commercial, non-profit basis. GenX-DOS is non-commercial by licence (CC BY-NC 4.0) as well as in fact, so the bundle sits inside that permission rather than relying on the preservation basis below. The permission covers the software; it is not a transfer of rights, and Removal upon request at the top of this file applies as it does everywhere else.
• The Atari bundles no longer use AltirraOS or Altirra BASIC. Avery Lee's clean-room reimplementations are still compiled into atari800.wasm by --enable-altirra_bios, but they are a fallback the emulator only reaches when no real ROM is supplied, and both bundles now supply genuine Atari ROMs at runtime via -osb_rom / -xlxe_rom / -basic_rom. Site policy is that firmware must be the manufacturer's own, not a reimplementation.

For every other commercial title, redistribution on the live site is on a preservation / personal-use basis, and will be withdrawn the moment a rights holder asks — see Removal upon request at the top of this file.

IBM PC (systems/dos/games/)

Ten DOS games, 1982–1990, and the operating system they ran on. Their standing differs entry by entry, and the differences matter more here than on most shelves:

Where a game states its own terms on screen or in its own documentation, those terms are what is recorded above rather than a third party's summary of them.

None of these files are in this repository or in the release zip, in keeping with the rule that the repo carries the emulators and not the games we added. ROMS.txt lists every filename and the folder it belongs in. Each game's dosbox.conf is here, because we wrote it. Sopwith and MS-DOS 4.00 are the two that could be — both are our own builds of released source, and we publish that source — but they are held out with the rest so the rule stays one rule rather than a rule with two exceptions.

Research and reference sources

Reference works — not bundled code — consulted to get the per-game gamedocs right (control schemes and in-game behaviour). The project leans on them and is glad to say so.

• Paul Farrow — ZX81 disassemblies (www.fruitcake.plus.com). Paul's meticulous, fully-commented disassembly of 3D Monster Maze (Malcolm Evans, New Generation Software, 1981) is the authority behind that ZX81 gamedoc — the verified in-game keys and menu details we would otherwise have had to guess at. Painstaking preservation work, freely shared decades on. Thank you.

• Mark Moxon — bbcelite.com (www.bbcelite.com). Mark's fully-commented, line-by-line disassembly of Elite (Ian Bell & David Braben, Acornsoft 1984) across its 8-bit versions is the authority behind our Elite gamedocs — the correct publisher and year, the real flight and chart keys, and which features each port actually has (no Thargoids or suns on the Electron, the Master's fractional scoring). A monumental preservation effort, freely shared. Thank you.

• David D. Busch — 25 Games for your TRS-80 Model 100 (TAB Books, 1984). The Model 100 bundle's games are hand-transcribed BASIC type-in listings from this book, and its per-game chapters are the authority behind those gamedocs — the controls, scoring and how-to-play. A lovely artefact of the type-in era, leaned on here with thanks. As with the other bundled game code, these listings are included on a preservation / personal-use basis; a rights holder who wants them removed can open an issue.

• Tandy — TRS-80 Model 100 Owner's Manual (Radio Shack, 1983; archive.org). The authority behind the Model 100 controls page — the exact TEXT / ADDRSS / SCHEDL usage and function-key labels (Find, Load, Save, Sel, Copy, Cut, Menu; and that ADDRSS and SCHEDL find records you enter in TEXT) come straight from it rather than memory.

• dplassgit — proposed the Tandy Model 100 as a GenX-DOS platform in discussion #2, "Tandy 100?" ("Based on the Intel 8085 CPU… it definitely has the 8-bit feel"). The whole platform exists because of that suggestion — and thanks to the above book, we were able to ship the usual amount of games, even when the primary source failed. Thanks for the nudge.

• jimbro1000 — pointed out that the Tandy CoCo needs composite artifact colour in its high-resolution modes, and named the option that provides it ("for the Tandy CoCo it really needs artifact emulation in hires black and white. For example Demon Attack should show black, white, red and blue"). Demon Attack had been rendering in stark monochrome. Four games now carry the setting, and testing the suggestion turned up two more that needed it and three it would have spoiled. Thanks for the correction.

Bezel artwork

systems/_shared/bezels/ holds the transparent PNG monitor/console frames used by the CRT-bezel overlays. Every platform is now wired to a bezel (the per-emulator integration pass is complete).

Per maintainer policy, bezel / wallpaper / texture artwork is not provenance-tracked — these are anonymous hardware shots or generic CRT frames sourced from public web archives where the original photographer is no longer reachable, then processed locally (alpha-keying, screen cutout) in GIMP. Source-code dependencies stay fully tracked (above). Wired bezels ship without credit comments.

Exception — Amstrad.png is properly source-cleared and carries a binding obligation: cropped from File:Amstrad_CPC464.jpg (Wikimedia Commons) by Bill Bertram (username Pixel8), 7 May 2005, CC-BY-SA 2.5. Modifications inherit share-alike; systems/cpc/play.html carries the author + licence as an attribution comment.

(Note: jsbeeb's CUB monitor frame lives inside systems/bbcmicro/dist/ and systems/bbcmaster/dist/ as part of the upstream build, not this shared set.)

Sound effects

Fonts

• systems/_shared/styles/VGA_font/f12.*.png — 12×12 CP437 bitmap font sprites. Generated locally by make_fonts.py from Unicode CP437 mappings; the rendered glyph shapes derive from public-domain VGA CP437 reference data.

• styles/fonts/web437-vga.woff — Web437 IBM VGA 9×16, from the Ultimate Oldschool PC Font Pack by VileR (https://int10h.org/oldschool-pc-fonts/), © 2016–2020 VileR. Licensed CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/). A genuine IBM VGA text-mode CP437 font; used on the home page (index.html) for the spec sheet and the "Enter the museum" button. Unmodified.

• styles/fonts/michroma-400.woff2 — Michroma by Vernon Adams. Licensed SIL Open Font License 1.1. Display face on the home page and the feature article (docs/article/index.html).

• styles/fonts/ibm-plex-mono-*.woff2 — IBM Plex Mono by Mike Abbink & Bold Monday for IBM. Licensed SIL Open Font License 1.1. The body and UI face everywhere: the landing page, the feature article, the wiki, the gamedocs and controls pages, and — declared separately in systems/_shared/styles/genx-controls-link.css so no play page has to pull in the whole design language — the two corner links on every emulator page. Subsetted to the Latin range.

CSS / JS dependencies bundled per-emulator

• systems/electron/jquery/jquery-1.9.1.js + jquery-ui-1.10.3.custom.min.js — jQuery 1.9.1 and jQuery UI 1.10.3 custom build, MIT — required by ElkJS upstream. Kept as-is to avoid divergence from the ElkJS source.

• systems/electron/ — ElkJS (© Darren Coles 2013) is locally patched from the upstream source: display.js row-doubling (removes upstream's baked-in scanlines), sound.js (adds the soundInit() AudioContext resume the upstream soundToggle() referenced but never defined, plus a 25% output mix), and elkjs.js (resumeAudio(), to start sound on a user gesture). The upstream duplicate jQuery 1.7.2 was removed. See CHANGELOG / wiki for the why.

• systems/js99er/lib/jquery-1.11.0.min.js — jQuery 1.11.0, MIT — required by js99er upstream. A second, separate copy from the ElkJS one above; the two bundles are independent and neither shares the other's build.

• systems/apple2/dist/39795c0b4513de014cf8.woff, b7bcc075b395c14ce8c2.woff2 — Bootstrap Icons (MIT), pulled in by the apple2js webpack build. The filenames are content hashes, so the font is only identifiable from its internal name table — recorded here so it is not lost the next time the bundle is refreshed.
• systems/_shared-ejs/ejs/data/emulator.min.js — bundles Font Awesome Free 6.5.1 (Fonticons, Inc.) for its UI icons: icons CC BY 4.0, fonts SIL OFL 1.1, code MIT. The upstream notice is retained in the minified file.

Other emulator bundles vendor their upstream dependencies; where a bundle's runtime is locally modified (e.g. ElkJS above, the atari800 / CPC / o2em WASM rebuilds) the change is recorded here or in the CHANGELOG.

On upstream licence files. Every GPL binary we ship now has the licence text beside it, which is what the GPL asks for:

apple1/ carries apple1js's MIT notice as systems/apple1/LICENSE, taken from the fork, and every pet2001 source file in systems/pet/pet2001/ carries Thomas Skibo's BSD notice in its header. The other permissively-licensed bundles — apple2/, msx1/, msx2/, cpc/ (MIT), trs80/ (BSD-2-Clause) — do not carry their notice files. Those licences do ask for the copyright notice to travel with the code, and the notice includes a per-project copyright line that cannot be reconstructed from here, so it has to come from upstream rather than be written locally. Until it does, the table above and its upstream links are the record. electron/ is a separate case: the ElkJS source carries a copyright line (© Darren Coles 2013) but no licence grant at all, so there is nothing to reproduce.

Do not read the absence of a licence file in a bundle as an unlicensed component — check the table first.

How to add a new attribution entry

When adding code or assets to the repo:

1. Identify the upstream source and licence. If the licence is unclear, ask before bundling.
2. Place the upstream LICENSE / COPYING file in the bundle directory alongside the binary or source it covers.
3. Add a row to the relevant table above.
4. Add a parallel entry in CHANGELOG.md under ## [Unreleased].
5. If the licence is one of the BY-SA family, note in the table that modifications inherit share-alike — this affects what we can do with derived work.