🗃 File system

roms/
- <AUTHOR_ID>/
  - <APP_ID>/
    - _bin: the main executable WASM binary of the app.
    - _meta: the app metadata.
    - _key: the app author’s public key.
    - _hash: the SHA256 hash of all files in the directory (both their content and their names) except _sig and _hash itself.
    - _sig: the PKCS 1 v1.5 signature signing the _hash with the author’s private key. Can be verified using _key.
    - May also contain any other files (game assets) that the app needs to run.
data/
- <AUTHOR_ID>/
  - <APP_ID>/
    - etc/: directory writable by the app. More precisely, the only directory in the whole FS where a non-sudo app can create, modify, list, or delete files. Empty by default. Usually, used to store game saves or assets produced using the app.
    - shots/: directory with app screenshots in PNG format.
    - stats
sys/
- priv/: directory with private keys.
  - <AUTHOR_ID>: the author’s private key. Used to sign apps when building with firefly_cli build. Private keys are only present on the emulator’s virtual file system but never on the device. Use firefly_cli key to manage keys.
- pub/: directory with public keys.
  - <AUTHOR_ID>: the author’s public key. Used to verify signatures of installed ROMs.
- launcher: short metadata of the launcher. This is the first app that is launched when device/emulator starts.
- new-app: short metadata of the latest installed app. If there is no launcher installed in the system, this is the app that will be launched first when device/emulator starts.
- name: the device name. By default, generated to be unique but users may change the device name. For multiplayer, we require all connected devices to have a unique name to avoid confusion. The name has the same validation rules as author and app IDs and can be at most 16 characters long.