Abstract: A removable hard disc memory cartridge for use with a drive mechanism including a spindle located within a drive housing.The drive housing interior is provided with stationary position registration members which cooperate with mating side edge portions of the cartridge to provide positive positioning when the cartridge is inserted into the drive housing. A disc lock carried by the cartridge maintains the internally mounted cartridge disc in a secured locked position when the cartridge is not in use, the lock mechanism cooperating with release posts carried by the drive housing to free the disc for rotation just prior to engagement by the drive spindle.

Abstract: Apparatus for holding film strips of the type having a plurality of miniaturized film images carried thereon, wherein the apparatus is to be used with an optical system which illuminates and projects the images on an enlarged scale so that they can be viewed on a projection screen. The apparatus includes a rotary film holder or cassette having a number of concentric cylindrical segments defining a pair of coaxial cylinders, the segments being provided with grooves to permit insertion of a plurality of film strips in the cassette. The inner segments are longer than the outer segments so that portions of the radially outermost edges of the film strips are exposed and the outer edge of a selected film strip can be engaged by an edge drive wheel to permit the selected film strip to be moved partially out of and to be returned to the cassette.