[spooky]

There is no boot disc required for the PSX SCHP-900x model, these were one of the last verions of the original PSX's that had a multi region bios!

If you are talking in relation to the DC boot disc then the PSX one is not to let the game boot without a mod chip, its purley for the PS 1 which does not have a multi region bios and therefor wont boot any imports you may have, the PSX boot disc lets you play you imports!