Game CD structure

It seems that the NeoGeo CD wants at least a PRG, FIX, SPR, Z80 and PCM loaded in IPL.TXT, or else it will simply reset after loading.

There must be no more than 512 files on the whole CD.

Recognized files
From table in System ROM dumps:
 * IPL file (no type)
 * PRG files (type 0)
 * FIX files (type 1)
 * SPR files (type 2)
 * Z80 files (type 3)
 * PCM files (type 4)
 * PAT files (type 5)
 * TXT files (no type)
 * OBJ files (type 7)
 * A** files, (type 8) ?
 * SYS files (type ?)
 * others ?