I realize that a "Clone image" is used when changing out a HDD where you want to transfer all the data from an existing HDD and a "Backup image" is used for saving/restoring data from the same HDD. But what is essentially the difference between the two . . . i.e., why is it necessary to create a "Clone" of an existing drive rather than using a Backup image when installing a new HDD which will be configured to be the Master drive on the system? THANKS!!