# Disc identification — VERIFIED 2026-10-09

Your disc was identified while initialising this repository. It is the **best
case target**: the exact build that `OpenRAC/rac2-gc-decomp` pins.

## Result

| Field | Value |
|---|---|
| Title | Ratchet & Clank: Going Commando |
| Serial | `SCUS_972.68` |
| Version | **1.01** (Black Label) |
| Video mode | **NTSC** (60 Hz) |
| Region | USA |
| ISO 9660 volume | `RATCHETANDCLANK2` |
| Image size | 3,828,350,976 bytes |
| Publisher / Preparer | SONY / INSOMNIAC |

### Boot executable (`SCUS_972.68`)

| Property | Value |
|---|---|
| Size | 2,618,684 bytes |
| SHA-1 | `bacda860cbd6723142e86db56f197e47e728970f` |
| CRC-32 | `262705496` |
| Format | ELF32, little-endian, MIPS (EM_MIPS = 8) |
| Entry point | `0x00131AE8` |

The entry point `0x00131AE8` matches the value independently recorded by the
`rac2-gc-decomp` community reference for this target, which cross-confirms the
identification.

## Why this matters

**`VER = 1.01` + `VMODE = NTSC` is exactly what we want.**

- **v1.01 is the pinned target.** `rac2-gc-decomp` states plainly that
  *Greatest Hits v2.00 is a different target — do not point a build at it.*
  You have the Black Label original.
- **NTSC means 60 Hz.** This is the detail that decides the movement constants.
  PAL discs report `VMODE = PAL` and run the game at 50 Hz, which makes the
  chargeboots and other speed-sensitive movement run at 5/6 of their intended
  speed. Building against NTSC timing constants is correct for this disc.

There is no ambiguity to resolve, so no disc-conversion work is required.

## Not used for identification

Redump's catalogue records the **first track** hash for this disc as
`f2cfaf0eb12b3c0d8fd6db7aa49ce032e8a6020b` (CRC-32 `3828350976`). The values
computed above are the **boot executable's** hash, which is a different thing:
a single file rather than a track. Both are stable identifiers, but they must
not be compared against each other. We identify by serial + `VER` + `VMODE` +
boot-ELF SHA-1, which is unambiguous.

## Disc layout (observed)

R&C2 lists its assets in the ISO 9660 filesystem, unlike R&C1. Confirmed
entries at the disc root:

```
SYSTEM.CNF        60 bytes
RC2.HDR        408,444     <- the table of contents, as a named file
SCUS_972.68  2,618,684     <- the boot ELF
IOPRP255.IMG   264,449
Z6TAIL.DUP           0
G/...                    <- global WADs (LEVEL*, AUDIO*, SCENE*, MPEG*, HUD, …)
```

`RC2.HDR` being present as a real file is convenient: the extractor can read
the table of contents directly instead of hunting for it at a fixed sector as
with R&C1. The `G/` WADs are listed in the filesystem, so enumeration works
too.

### Observation on MPEG WADs

The three MPEG WADs are large — roughly 1.0 GB, 1.3 GB and 115 MB. That is a
substantial fraction of the 3.8 GB disc and will matter for the video phase
(R&C2 uses IPU/FMV streams, notably the title screen). Worth factoring into the
plan: video is a large *data* problem before it is a decoding problem.

## Reproducing this check

`tools/identify-disc.py` performs the same identification against any
R&C2 disc image and prints the table above. It reads only the ISO 9660
structures, `SYSTEM.CNF` and the boot ELF (a few MB of seeks), so it runs in
well under a second on a local image.