harddrive initalization on a mac?

i just finished installing a harddrive into my mpc and when i tried to connect to my computer i got a popup saying "cant read disk: initalize, ignore, eject"
i use a mac if that makes a difference
if anyone has had the same problem some help would be much appreciated

did you format it on the mpc first?

i woke up this morning with a clear more coherent thinking
and realized this question was dumb
i just forgot to change the disk i was accessing to compact flash
so that i could put on the jj os and format
a thousand apologies