Ps2 backup cd questions...

I just have a few question I would like anwserd about back up copyies for ps2


Q:Where can I get a mode chip for a us virson playstion2?

Q:Is it true that you can use a gameshark to do a cd swap and if so. Does it work for all the ps2 games?

Q:Why do u need to pacth your ps2 burned cds and how do you pacth your burned ps2 cds?