CD-ROM Directory Structure

Root directory
A Crash Bandicoot game CD will have a root directory with contents similar to the following:
 * /BANJ - [Crash 2 and 3 NTSC-J only] Almost nothing is known for sure.
 * 1. - ???
 * 2. - ???
 * B0.DAT to B25.DAT - ???
 * BAN320.IKI - [Crash 2 and 3] ???
 * BAN320I.EXE - [Crash 2 only] Code for BAN320.IKI?
 * GOODIES.EXE - Blank space. Reserved?
 * MOVIE.EXE - Blank space. Reserved?
 * /BANJ_M - [Crash 3 NTSC-J only] Contains movie sequences from the Goodies menu in .IKI format.
 * /BANJ_P - [Crash 3 NTSC-J only] PocketStation stuff?
 * /DRAGON - [Crash 3 only] contains Spyro the Dragon demo files
 * /S0 -  contains NSD/NSF files in 00-0F range
 * /S1  -  contains NSD/NSF files in 10-1F range. Does not contain 1F in Crash 3.
 * /S2  -  contains NSD/NSF files in 20-2F range. Contains 1F in Crash 3.
 * /S3  -  contains NSD/NSF files in 30-3F range
 * ZBSPTREE.WAD -  [Crash 1 NTSC-U and PAL only] Dummy file to take space . Can be deleted freely.
 * ABSPTREE.WAD - [Crash 1 NTSC-J only] Same as ZBSPTREE.WAD?
 * ZTAIL.WAD - [Crash 1 NTSC-J only] Unknown. Not same as *BSPTREE.WAD.
 * SYSTEM.CNF   -  Disc boot information
 * SCUS_***.**  - [NTSC only] Crash Bandicoot binary executable
 * SCES_***.**  - [PAL only] Crash Bandicoot binary executable
 * SCPS_***.**  - [NTSC-J only] Crash Bandicoot binary executable
 * KDAT.DAT   - [Crash 1 and 3 PAL and NTSC-J and Crash 2 NTSC-J only] Unknown. Has no purpose? Located in S3 in Crash 1 and 2, but in S0 in Crash 3.
 * S0/WARPSC*S.BIN - [Crash 3 only] Another executable?

Binary executable
All executable code for the game is located in its binary executable. Depending on game episode and region, this may be one of the following:
 * SCUS_949.00 - Crash Bandicoot (NTSC)
 * SCES_003.44 - Crash Bandicoot (PAL)
 * SCPS_100.31 - クラッシュ・バンディクー
 * PSX.EXE - Crash Bandicoot (BETA 96/03/08)
 * SCUS_941.54 - Crash Bandicoot 2: Cortex Strikes Back (NTSC)
 * SCES_009.67 - Crash Bandicoot 2: Cortex Strikes Back (PAL)
 * SCPS_100.47 - クラッシュバンディクー　2:　コルテックスのぎゃくしゅう！
 * SCUS_942.44 - Crash Bandicoot: Warped (NTSC)
 * SCES_014.20 - Crash Bandicoot 3: Warped (PAL)
 * SCPS_100.73 - クラッシュ・バンディクー3 ブッとび!世界一周

Boot information
After powering on, the system searches the disc for the SYSTEM.CNF file. This file contains a list of directives that control the boot process. This includes the path of an initial binary executable (i.e. one of the binaries listed above) that will be loaded into memory for subsequent execution.

Game content
In the S0-S3 directories are .NSD/.NSF file pairs with the name S00000**.NSD/.NSF. Each pair corresponds to a specific level in the game, and these files contain the game data for that level.

An NSF file comprises most of the actual data for its associated level, which includes graphic models, music and sound data, executable object code, collision octrees, and level layout.

An NSD file is essentially an index for its paired NSF file, but also includes some additional information.