High Quality Content by WIKIPEDIA articles! In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical disc drives, drum memory (historic), floppy disk drives (historic), punched tape (historic) and holographic memory (experimental). Mass storage includes devices with removable and non-removable media. It does not include random access memory (RAM), which is volatile in that it loses its contents after power loss.