ISO & SFO

src/iso/ reads the disc container and the game metadata inside it.

File	Contents
iso9660.ts	parseIso, parseIsoFromFile, readFile, ISO 9660 reader
sfo.ts	parseSfo, extractGameInfo, the PARAM.SFO parser
iso-metadata.ts	disc metadata extraction

ISO9660

parseIso(buffer: ArrayBuffer): IsoVolume

Parse an ISO image into an IsoVolume ({ volumeId, root }): a directory tree of IsoFile entries (name, isDirectory, lba start sector, size, and children for directories).

parseIsoFromFile(file: File): Promise<IsoVolume>

The same, but reads from a browser File lazily instead of an in-memory buffer.

readFile(buffer: ArrayBuffer, file: IsoFile): Uint8Array

Read an entry's bytes from an in-memory ISO buffer.

readFileFromIso(file: File, entry: IsoFile): Promise<Uint8Array>

Read an entry's bytes straight from a browser File.

Path resolution is case-insensitive (PSP filesystems are).

When a game boots, the ISO's files are mounted into the kernel's in-memory filesystem (fileData) so sceIo* calls can read them.

PARAM.SFO

parseSfo(buffer) parses the System File Object into key/value pairs; extractGameInfo wraps the common fields:

Key	Meaning
TITLE	Game title
DISC_ID	Region + serial (e.g. ULUS12345)
APP_VER	Version string (what extractGameInfo reads for version)
CATEGORY	UG = UMD game, MG = memory-stick game, etc.
MEMSIZE	0 = 32 MB, 1 = 64 MB
SAVEDATA_*	Savedata title/detail/size

Two of these drive emulator behaviour:

• DISC_ID is the game id used to bind save states (falling back to a sanitized slug of the file name for homebrew with no disc id).
• MEMSIZE decides whether the game gets 32 MB or 64 MB of RAM. See the memory model.

The region is derived from the DISC_ID prefix (UCUS/ULUS = North America, UCES/ULES = Europe, UCJS/ULJS = Japan, …).