PSX ROM Notes

Ever see that Japanese ROM when you opened up your PSX disc of Final Fantasy Chronicles in your computer? Wonder what it was for? Well, thanks to halkun, we have the answer.


The ROM in the PSX CD is just a very unique way to hold game data; it's NEVER executed. The Chrono Trigger CD does not not contain an emulator, nor is the ROM emulated. Square wrote a whole new kernel for CT which simply opens the ROM to grab the game data, like maps, enemy data, and scripts but doesn't execute the RPOM itself.

If you look in the FF6 PSX CD and do a compare with the SNES ROM you will find that that CD contains the ROM too, but in FF6's case, the ROM has been "shattered" and split up into individual data sets. The executable data has been stripped. The CT ROM was actually there as a "secret bonus" for the Japanese market. It was put there on purpose.

However, the US version of Chrono Trigger has an exclusive distribution contract with Nintendo. If you run the US CT ROM in an SNES emulator it says "Licensed to Nintendo" in the US version. Because Nintendo has the rights, Square couldn't release the English version of the ROM in the US.

Well, why a ROM as a data set?

The sound chip in the PSX is actually *COMPATIBLE* with the SNES one. Sony made them both and one is just a big brother of the other, so the sound data can be directly "ripped" from the ROM. (That's why the PSX and SNES version sound exactly the same.) Not only that, Minoru Akao, the sound designer, was one of the original R&D guys who came up with Sony's sound system for the SNES. He was then hired by Square and not only did the original sound design for the Chrono Trigger ROM, but also did the remake. He knows the system forward and backwards. Not only that, but he's the sound designer for 98% of all Squaresoft games.

The PSX also uses the same high color colordepth format for displaying game sprites. That doesn't hurt either. However the display code is *WAY* different.

Swapping the ROM will break the game. It won't work. It's not an emulator.

This doesn't mean the ROM isn't used in the US Final Fantasy Chronicles, though. It still "rips" the graphics, sound, enemy data, and such in real time. They are exactly the same. However, the US version ROM is different than the Japanese one.

Due to the changes in the dialogue script, the English is external to the ROM now. (Actually is just a chunk of the US SNES ROM.) The kernel calls that as opposed to the original data inside the whole Japanese ROM.

From: Modification