Any hard drive can be used for backing up data. Some people prefer a external hard drive while other may want an internal one.
External Hard Drives: An external hard drive is any drive not inside the actual computer case. In most situations the external hard drive will be inside an enclosure case to protect the drive. The many advantage of having an external drive is ease of setup and portability if you ever need to take your files with you
Internal Hard Drives: An internal hard drive is used inside the computer case. In most cases the installer will need to ensure they get the right type of hard drive for the computer. Newer computers will use a SATA interface drive while older ones will use a IDE interface. Having an internal drive is a good idea for people who are concerned that a person may try to steal the external device. Most people will not have this problem.
