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.

Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data storage. Recording may be accomplished with virtually any form of energy. Electronic data storage requires electrical power to store and retrieve data.