I know that I've posted this before, but one more time. Int13 extensions added 4 more bits to the addressing scheme for cylinder, head and sector. This new scheme took the limit from approx 8gig to 128gig. The problem you are having is that the new high capacity drives use lots of cylinders and not so many heads. Limited Cylinder mode gets around a Bios that can't handle the high cylinders but it reduces the overall capacity. Some drives have a jumper to remap the real heads.