ps2 and mame

dear,

What is best 80' year game emulator for ps2?

next week my consolle will have dms4 modchip and i have some question.

It is possible run Ps2 mame from HD and not from cd?

there is a compatibility list of games?

why the limit is 30 roms.

Sorry for all my question

Thanks to all

Im trying to figure out how to run it from the HD.
Im getting flip top for PS2 soon. ALready have a 120GB mator HD on my PS2 with hd loader.