The GameCube disc and its files

Sonic Adventure 2: Battle on GameCube is read here from a disc image of the USA release, game id GSNE8P. All data lives as files of the disc’s file system; there is no archive format layered over them, only compression and relocation of individual files (Stage modules). Observed

The figures are from a recorded census of that disc image; they cannot be re-checked now. Observed

Disc header and file system table

The header is big-endian: 0x000 game id, 0x01C magic C2339F3D, 0x020 title, 0x420 the offset of main.dol, 0x424 the FST offset, 0x428 the FST size. Sourced · YAGCD

The FST is a table of 12-byte entries followed by a string table; the root entry’s length is the entry count. Sourced · YAGCD

FST entry12 bytesSA2B0% known

Big-endian.

ProvenObservedSourcedInferredUnknownNot described

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x0

is directoryu8

name offsetu24

offsetu32

lengthu32

Offset	Size	Type	Field	Confidence	Notes
0x0	1	u8	is directory	Sourced	YAGCD
0x1	3	u24	name offset	Sourced	into the string table
0x4	4	u32	offset	Sourced	file: position in the image; directory: parent index
0x8	4	u32	length	Sourced	file: size; directory: one past the last child

On GSNE8P the FST is at 0x1FD100 with 2,821 entries (2,819 files; event/ is the only subdirectory). All files lie inside the image: the largest file end is 0x52597780, the image size 0x57058000. main.dol is at 0x1E700 and 1,960,448 bytes. Observed

File kinds on the disc

Kind	Files	Holds	Described in
stgNND.rel, boss_*D.rel, ChaoStg*.prs	stage modules	code and data of a stage: landtables, object lists, texture names	Stage modules
landtxNN.prs, bgtexNN.prs and other .prs	PRS-compressed GVM archives	the textures of a stage	Textures
setNNNN_s.bin, _u, _2P, _HD	object placement	the SET files	Object placement
stgNN_light.bin, stgNN_light_gc.bin, stgNN_fog*.bin	lighting	light slots and fog	Light and fog
main.dol	executable	start and end position tables	Object placement

All Observed except the SET file name pattern, which is Sourced · SA Tools (SALVL’s convention).

What do the event files hold?

The event/ directory is the only subdirectory of the disc and was not read.