why not check? do
Code:
dmesg |grep hd
that should give some info. and if you then do a check to see which disk has which files...
Code:
fdisk -l
might help some aswell, perhaps
Code:
mount
can give some further info. if you do these it should become clear which disk is which. if not. ask and i will try to answer.
btw, as long as dd gets input it SHOULD not crash, if the disk otoh has i/o issues... it might.