Abstract: A generally square disk cartridge for a recording disk includes at least one air filter in a corner of the cartridge and a circular rib adjacent the disk and between the disk and the filter. The cartridge may also include a radial rib connected to the circular rib to enhance air flow to the filter. Air filters may be located in each of the corners of the cartridge with associated circular and radial ribs to induce air flow to each.

Abstract: A cartridge enclosing a disk-shaped magnetic recording medium is provided with a disk restraint disposed between the disk and the cartridge for sliding movement in the plane of the disk. A camming surface is provided on the cartridge which forces the restraint downwardly to restrain the disk when the cartridge is not in use. In use, the restraint is slid out of engagement with the camming surface to release the recording disk.

Abstract: Recording medium disk-hub combination wherein the hub has a central hole whose periphery is bounded at least partly by three flexure members which circumscribe a cylinder corresponding to a disk drive spindle. The three flexure members are arranged in a triangular configuration, and the parts of such flexure members that circumscribe the cylinder are coplanar, forming a flexure member plane of contact. The axial center line of the recording medium disk is spaced from the flexure member plane of contact by no more than three times the thickness of the disk itself. The combination is preferably designed with the ratio of the coefficient of thermal expansion of the hub to that of the recording medium disk being between 0.7 and 1.4. Hub is made magnetic, e.g., by attaching a magnetizable disk. The combination is especially useful for removable recording disks intended to cooperate with disk drives having circular motor spindles and magnetic hold down.

Abstract: A stretched surface recording disk includes an annular substrate to which are adhesively attached magnetic recording films covering each major surface of the substrate. The substrate has annular ridges adjacent its inner and outer diameters which support the film above and parallel to each major surface and film attachment surfaces adjacent the ridges which are radiused an amount sufficient to place the adhesive in compression, preferably about 0.030 inches (0.80 mm).