External Hard Disk is a type of computer hard disk that is connected to the outside of a computer through a USB connection that is often used to backup computers. It is an output storage media of a computer. It is used to save the necessary data in the computer such as: documents, pictures, software in large size, etc. to view, correct, copy paste, print delete, etc. It is also known as a portable hard disk.

  •   The first external hard disk was developed by IBM Engineer Reynold B. Johnson in 1956.
  •   The popular size of external hard disk is 1TB and 2TB.
    For example, look at the External Hard disk in the below picture:

Fig: External Hard Disk