Katana

Native macOS app for managing GDEMU SD cards (Dreamcast) with GDmenu, openMenu, and openMenu Extended.

Open a card root, browse numbered game folders, rename / reorder / delete with immediate on-card writes, inspect game metadata and covers, detect duplicates, hash content, and rebuild the slot-01 menu image so the console list matches the SD card.

• macOS 14+
• Xcode 16+ (to build from source)
• A GDEMU-formatted SD card mounted under /Volumes (or a local fixture folder with the same layout)

open Katana.xcodeproj
# or
xcodebuild -scheme Katana -configuration Debug -destination 'platform=macOS' build

Tests:

xcodebuild -scheme Katana -destination 'platform=macOS' test

Release builds are universal (arm64 + x86_64). Menu GDI bake is entirely native Swift — no nested helper binary, no .NET runtime, no brotli dylibs in the app.

# Once: notary credentials (Developer ID Application cert in keychain)
xcrun notarytool store-credentials "notarytool-password" \
  --apple-id "[email protected]" --team-id "YOUR_TEAM_ID" --password "app-specific-password"

Scripts/make-notarized-dmg.sh
# → build/export/Katana.app · build/Katana.dmg · dist/Katana.dmg

Pipeline: archive → Developer ID export → notarize/staple app → HFS-compressed stage into UDZO DMG → notarize/staple DMG → spctl verify.

• Menu bake lives under Katana/Services/MenuBake/ (MenuGDIBake, ISO 9660 Level 1 + multi-track GDI, LBA 45000, truncate/CDDA). Invoked only from MenuRebuildService.
• No runtime helper: rebuild is native Swift — no .NET process, no nested helper binary.
• Tools/MenuAssets/ — unpacked stock gdMenu / openMenu trees for unit tests (the app ships zipped copies under Katana/Resources/MenuAssets/).
• Tools/scripts/build-gamedb.py — regenerate the bundled serial→title map.
• Tools/licenses/ — third-party license texts (e.g. DiscUtils MIT).

name.txt → GameDB (serial / product) → IP.BIN product name → folder / image base name.

Update the bundled GameDB from upstream data:

python3 Tools/scripts/build-gamedb.py

Katana stands on the shoulders of the Dreamcast homebrew community.

Primary inspiration and reference implementation.

No GDMENUCardManager source code is used in Katana. Katana is an independent implementation written from scratch in Swift. What is shared is the on-disk format — the layout GDmenu and openMenu themselves define, which any manager must match for the console to boot:

• Numbered game folders and name.txt / serial.txt
• GDmenu LIST.INI and openMenu OPENMENU.INI
• Folder number width by magnitude
• Proper GDI menu image for slot 01 (MIL-CD–safe)
• IP.BIN field layout compatibility for menu entries

GDMENUCardManager is GNU GPL v3. Many thanks to sonik-br and contributors.

For Windows/Linux, archive import, GDI shrinking, or the original Avalonia UI, use GDMENUCardManager — it remains the multi-platform reference tool.

Menu GDI construction is a Swift port of the community GDI tooling lineage — the same multi-track path GDMENUCardManager also builds on, taken from its MIT-licensed upstream rather than from GDMENUCardManager:

• DiscUtils (Kenneth Bell) — MIT (see Tools/licenses/DiscUtils-LICENSE.txt)
• GdiBuilder (Sappharad) and related GDI / ISO tooling

As also credited by GDMENUCardManager:

• GDmenu by neuroacid
• openMenu by mrneo240
• openMenu Virtual Folder Bundle by Derek Pascarella (ateam) — bundled openMenu bake target (1.7.0-ateam)
• openMenu DAT resources: imagedb, metadb
• Special thanks to megavolt85 and the wider Dreamcast scene

• Aaru — IP.BIN / disc structure documentation
• Apple SwiftUI / AppKit

• Source: GameDB-Dreamcast (niemasd), derived from Redump (+ GameFAQs)
• License: GPL-3.0 (see upstream)
• Bundled: Katana/Resources/GameDB/dreamcast-titles.json

Katana itself is MIT © 2026 Matt Sephton.

• Menu GDI bake is a Swift port of the DiscUtils / GDromBuilder multi-track path (no Joliet, LBA 45000, truncated high-density tracks with CDDA).
• DiscUtils lineage is MIT (Kenneth Bell); license text in Tools/licenses/DiscUtils-LICENSE.txt.
• GDMENUCardManager is GPL-3.0. No GDMENUCardManager source code is used in Katana. Katana’s menu rebuild design and list formats are derived from that project’s publicly observable behaviour and the documented on-disk layouts — the file names, list syntax, and folder conventions that GDmenu and openMenu require — not from its implementation.
• Bundled GameDB-Dreamcast title data is GPL-3.0.
• Bundled GDmenu / openMenu binary assets are third-party menu images for rebuild; they are not original Katana content. Respect their original authors’ terms when redistributing.

If you are the author of code or assets included here and want clearer attribution or a license adjustment, please open an issue.

Issues and PRs welcome. Prefer small, focused changes; keep writes immediate and on-card (no deferred save model).