Arcade Boards

How arcade games are attributed to a hardware board, stored, and surfaced.

The ArcadeBoard type#

ArcadeBoard (in replay-control-core::arcade_board, wasm-safe core) is a Copy enum with one variant per tracked board (CPS-1/2/3, Neo Geo MVS, the Sega System / Model families, Taito F2/F3/Z, IGS PGM, Cave, Midway, Namco System, Konami, Data East, Irem, Jaleco). Selection is curated: a board earns a variant only when it groups several games — single-game drivers, and per-maker gambling / mahjong driver families, are deliberately left out so a board page surfaces a family of titles rather than a lone game. Each variant exposes:

• as_tag() — stable ASCII slug stored in the databases and used in /board/:tag URLs (e.g. cps2, neogeo_mvs).
• from_tag() — inverse, for deserializing the stored slug.
• display_name() — bare label (CPS-2), used as a recognizer search token.
• manufacturer() — board maker (Capcom).
• display_label() — "{display_name} ({manufacturer})" (CPS-2 (Capcom)), used at every UI surface. The bare display_name() stays manufacturer-free so it doesn’t pollute search tokens.

sourcefiles() — the single source of truth#

ArcadeBoard::sourcefiles() lists every emulator-driver sourcefile spelling that identifies a board, across all upstreams. from_sourcefile() is a scan over it. Adding a new upstream spelling is a one-line edit here. Each entry is one of:

• MAME-current canonical manufacturer/board.cpp (igs/pgm.cpp)
• FBNeo’s d_-stripped form, which often uses a different directory or basename (pgm/pgm.cpp, sega/sys16a.cpp, taito/taitoz.cpp, pre90s/namcos1.cpp)
• MAME 2003+ legacy bare board.c (pgm.c, system16.c)

Invariants are test-pinned: every spelling round-trips to its board, and no spelling is shared across two boards (which would make the unordered scan order-dependent).

Maintaining mappings on upstream updates. Driver sourcefile names change between MAME/FBNeo releases — MAME renamed taito/taitof3.cpp → taito/taito_f3.cpp, moved cave/cave.cpp → atlus/cave.cpp, and sega/atomiswave.cpp → sega/dc_atomiswave.cpp. When a spelling vanishes upstream, from_sourcefile() silently returns None and that board quietly empties — a board can drop to zero with no error. The round-trip tests only prove the list is self-consistent, not that it still matches the bundled data. So after refreshing data/upstream/ (scripts/download-arcade-data.sh), compare per-board game counts (Metadata → coverage, or library_report) before/after the bump and add any renamed spelling to sourcefiles(). There is no automated guard.

Catalog-build attribution#

tools/build-catalog resolves a board per arcade ROM per source and stores it in arcade_game.board. The four arcade sources differ in how they carry the driver:

board_tag_from_sourcefile() normalizes the one parser-shape quirk from_sourcefile() doesn’t model — normalize_sourcefile() strips the FBNeo d_ basename prefix — then defers to ArcadeBoard::from_sourcefile(). The legacy .c and canonical .cpp forms match verbatim against the sourcefiles() table. There is no separate legacy-to-canonical map; all spellings live on the enum.

Runtime merge — board has its own priority#

merge_for_system() (in replay-control-core-server::game::arcade_db) folds the per-source arcade_game rows for a ROM into one ArcadeGameInfo. Most fields follow the per-system metadata priority (arcade_source_priority), but board is resolved on its own fixed order, independent of it:

BOARD_PRIORITY = [Naomi, FBNeo, MAME 2003+, MAME]

A board is a physical property of the PCB — the same no matter which emulator’s metadata names it — so it should not follow, say, arcade_mame’s “MAME first” preference. FBNeo is preferred over MAME 2003+: FBNeo is Replay’s primary arcade core and carries the richest board coverage, while MAME 2003+ is legacy (enabled only on older Pis). MAME 0.285 sits last — its sourcefile (the extract keeps it) is used only when no higher-priority source carries the board, e.g. CoJag, which only MAME has. Naomi leads because its GD-ROM board hints live only in that source. An explicit sweep of any source not named in BOARD_PRIORITY follows, mirroring the metadata loop, so a newly added source still contributes a board rather than silently dropping.

Storage#

library.db’s game_library.board holds the resolved board slug (or empty), written at scan time from ArcadeGameInfo::board. A partial index idx_gl_board(system, board) WHERE board != '' backs the board queries. At read time the slug is deserialized back to ArcadeBoard via from_tag().

Because the board column is written during scan, changing the attribution or the merge order requires both a catalog rebuild and a library.db wipe/rescan for existing installs to pick it up.

Surfaces#

All board queries live on LibraryDb (no SQL in the app crate) and exclude clones / translations / hacks / specials so counts match the original release set.

• Board page (/board/:tag, pages/board.rs) mirrors the developer page. Server fns get_board_games / get_board_genres drive it via LibraryDb::board_systems, board_genre_groups, and search_game_library with SearchFilter::board set.
• Search uses replay-control-core-server::library::search_recognizer two ways: recognize() strips a leading/trailing board phrase into SearchFilter::board (the per-system ROM-list pill), and find_board_matches() token-scores every board against the query for the /search discovery block (search_by_board → top match + others, reusing games_by_board and board_game_counts).
• Recommendations (server_fns/recommendations.rs) add LibraryDb::top_boards as a Discover-pill candidate and as spotlight rotation type 6, both linking to /board/:tag and reusing the shared pill / GameSection rendering.

Notes#

• M84: Irem’s M84 hardware has no dedicated driver in any source — MAME and FBNeo both fold M84 games into the m72 driver — so it can’t be split from M72 without a per-ROM allowlist.
• The recognizer’s per-variant synonyms (board_tokens) and the sourcefiles() spellings are deliberately separate lists: one is human-typed search terms matched fuzzily, the other is machine driver filenames matched exactly. Both anchor on display_name() / as_tag() from the enum.