depending on what country you're in, it may not even be legal to make the backup of your disc period.
i see your location says singapore. I'm not an expert on laws there, but here in the US, it's technically legal to back up movies you own but illegal to circumvent copy protection to do so (therefore all backups are illegal in the US despite fair use laws)
This is a very international forum. off the top of my head I can't remember anyone from singapore, but maybe someone will come out of the woodwork with some more specific info for you.
and i agree...slonedvd2 is a great piece of software!