Answer for Davie bout swapping disks
 

If you are using a cartridge then you can probably do the swap trick without any chip or external means of tomfoolery with your psx. I won't go through it again because it has been posted so many times before, try the search function after all thats what its ther for. But if you know the trick use that then save the game at the first chance you get.

I meant PS2 not PSX