Abstract: A floppy disk cartridge adapter having a removable coin shaped memory disk. The 3½ inch size cartridge adapter can fit into conventional personal computer disk drives. The small coin shaped magnetic disk has a diameter of approximately 1 inch, and can be easily snapped into and removed from the cartridge adapter. The coin disk fits on a spindle that is side by side to the floating drive plate used in regular 3½ inch floppy diskettes. The spindle can be attached by various drive systems to rotate simultaneously with the rotating drive plate. One version is belt driven, another has the coin disk snap onto a spindle supported wheel whose sides frictionally rub against the drive plate wheel, and a third version has the coin disk snap onto the spindle supported gear wheel whose sides contain teeth which mateably engage like side teeth on the drive plate wheel.