Internal disk drive
Hard drive is disk, optical, or tape drive that resides inside the computer is an internal hard drive is a Mostly all the computers come along with a internal hard drive.This internal hard drive stores pre-installed applications and the operating system.
some desktops also has many hard drive bays. Internal hard drives has 2 main connections - one connection for data and other for power. It also stores the personal files. When internal hard disk is damaged files in it cannot be recovered . Hence it is necessary to keep a back for it always .