An early magnetic card mass storage device from IBM. Used in the early 1960s and designed by Alan Shugart, who later engineered the hard disk and floppy disk, it was IBM's first direct access storage system. Each Data Cell cartridge contained 200 3x15" cards ("tape strips") for a total of 40MB, and each Data Cell could hold 10 cartridges. With up to eight units connected to one computer, the Data Cell had huge direct access storage potential. The card was extracted from the cartridge, wrapped around a rotating drum for reading and writing and returned. More than 100 Data Cell units were installed worldwide during the 1960s. Although being able to access a single card in half a second was a mechanical marvel, the magnetic tape cards were very susceptible to wear, and returning the card to its cartridge was problematic. All three magnetic card systems of that era (IBM Data Cell, NCR CRAM and RCA RACE) had a short lifespan because magnetic disks were becoming the norm by the end of the 1960s. See RACE and CRAM.