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 current or, vice versa, transforms electric current into magnetic field. The heads have gone through a number of changes over the years.
A hard disk head and arm on a platter
Microphotograph of a hard disk head. The size of the front edge is about 0.3 * 1.2 mm. The functional part of the head is the round, orange structure in the middle. Also note the connection wires bonded to gold-plated pads.
Read–write head of a 3 TB hard disk drive manufactured in 2013. The dark rectangular component is the slider and is 1.25 mm long. The platter surface moves past the head from right to left.
Disk storage is a data storage mechanism based on a rotating disk. The recording employs various electronic, magnetic, optical, or mechanical changes to the disk's surface layer. A disk drive is a device implementing such a storage mechanism. Notable types are hard disk drives (HDD), containing one or more non-removable rigid platters; the floppy disk drive (FDD) and its removable floppy disk; and various optical disc drives (ODD) and associated optical disc media.
Six hard disk drives
Three floppy disk drives
A CD-ROM (optical) disc drive