how to clone a hard drive-Copy the entirety of one hard drive to another. It’s called cloning, and it’s an important process if you want to replace or upgrade the primary hard drive in your computer. Cloning isn’t the same as backing up. When a drive is cloned you have a perfect copy of everything that was on it – the operating system, the software and all of the files included. When you clone a hard drive you recreate its entire environment, partitions and all.