A headcrash is a hard-disk failure that occurs when a read–write head of a hard disk drive makes contact with its rotating platter, slashing its surface
A disk read-and-write head is the small part of a disk drive which moves above the disk platter and transforms the platter's magnetic field into electric
situations. The most notorious cause of drive failure is a headcrash, where the internal read-and-write head of the device, usually just hovering above the surface