What is the full form of HDD?

HDD stands for hard disk drive and is often found in places where data is stored electronically. Such disks have several platters, which are really disks, each of which is spun so that information reading and writing activity can occur 'kind of like flipping pages in a book for hard disk drives'. They are actually non-volatile storage devices, meaning relatively - they do not need energy to keep one's data safe and accessible even if the computer is turned off.