A floppy disk cartridge adapter having a removable coin shaped memory disk. The 3 & 1/2 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 3 & 1/2 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. The coin disk can alternatively be inserted into a separate casing having a spring loaded shutter so that the conventional disk drive being used can access the magnetic sides of the coin disk by sliding the shutter. When removed from the cartridge adapter, the disk can be inserted into a small clip retainer which has a paper clip edge allowing the coin shaped disk to be portably mounted on papers, cardboard, clipboards and the like.
A magnetic disk cartridge for use in a disk drive having both a slot and a guide portion. The magnetic disk cartridge comprises a generally disk-shaped housing in which a magnetic disk is rotatably housed, and protrusions. The protrusions are formed on the main surface of the housing and are used for positioning the magnetic disk cartridge in a direction capable of recording and reproduction in cooperation with the guide portion of the disk drive when the magnetic disk cartridge is loaded in the disk drive.
A magnetic disk cartridge capable of being loaded into a disk drive comprises a housing, and a magnetic disk, which is accommodated for rotation within the housing. The housing is provided with an opening, which allows a magnetic head of the disk drive to access a surface of the magnetic disk, and a shutter for opening and closing the opening. The housing has an outer peripheral shape composed of a circular arc, which is formed along a contour of the magnetic disk, and two straight lines, which are circumscribed with the circular arc formed along the contour of the magnetic disk and are normal to each other.
