It has a harddrive.
8GB of flash ram
alone would cost around £500, never mind the phone. It would also be terribly terribly slow, and take up more physical room than a harddrive, and isn't too good on the power specs either.
Samsung, being a noteable manufacturer of harddrives including those in my PC, have undoubtedly built their own unit for this very application. The last I heard was that Toshiba had managed to get 4GB onto a 0.85" drive using PMR,
with plans to get it up to 10GB.
1 inch drives are already over the 12GB mark, so assuming this is a 1 inch drive then it isn't really bleeding edge technology. The other thing people forget is that the smaller the drive is (physical size), the less power is needed to spin it up, and it doesn't need to spin as fast either as the higher storage density of PMR reduces seek times.