Abstract: A cartridge for a disk-shaped storage medium, wherein the cartridge has partition walls within the cartridge for separating the storage medium from other portions of the cartridge, thereby protecting the storage medium from damage due to debris particles. The partition walls are formed by ribs which protrude from the interior surfaces of each half of the cartridge. The ribs do not meet but rather define a small gap between them. The top of one rib has a V-shaped protrusion (taken perpendicular to the length of the rib) while the top of the other rib has a complementary V-shaped groove. Elongate debris particles are blocked from passage into the compartment containing the storage medium due to the tortuous path defined by the gap.

Abstract: An optical data storage disc comprising a disc-shaped substrate and a centrally-located magnetizable hub. The disc has a central bore configured to receive a drive pin from an optical disc drive. The substrate has a recessed annular portion adjacent its center bore. The hub is provided within the recessed portion of the substrate. The central bore of the disc may be defined by the central bore of the hub alone, so that the diameter of the hub's bore is less than that of the substrate. In the alternative, the central bore of the disc may be defined in part by the inner bores of both the substrate and the hub, in which case those inner bores are of equal diameter. In either case, the thickness of the disc when measured at its inner portion, i.e., in the area of the hub and recessed portion, is equal to the thickness of the substrate at the periphery thereof.

Abstract: A disk cartridge for a rotatable recording disk includes a slidable shutter for providing access to the recording disk through the disk cartridge. A unique mounting for a return spring for the shutter allows the return spring to be of a maximum length which allows increased control of the forces generated by the return spring. The disk cartridge is further provided with a locking mechanism for preventing movement of the recording disk within the disk cartridge during storage.