So you are trying to format a drive you know is setup for PC or Windows. You keep getting an error stating Disk Erase failed, or /dev/rdisk1s1: partition size not a multiple of 4K. Its not so much an error, but rather a common oversight.
This essential tool allows you to make exact (bootable) clones/backups of your hard drives. Some of the key features include, block level disk to disk clones, scheduling, network based backups, bootable disks, and fast incremental backups.