Abstract: A disk drive (30) for use with a magnetooptical disk cartridge (10) having a magnetooptical data storage disk (12) rotatably enclosed in a generally flat, boxlike housing (14), a sliding shutter (16) mounted astraddle one edge thereof for opening and closing a pair of disk access windows (22, 24) in opposite sides of the housing. The disk drive has a cartridge cardle (38, 138) for receiving the disk cartridge as the latter is inserted in an entrance slot (36) in the disk drive casing (32, 132). Pivotally mounted to the cartridge cradle a shutter opening lever (46) opens the cartridge shutter (16) well before the disk cartridge (10) is fully inserted through the entrance slot. The electromagnet assembly (68, 168) of the magnetooptical disk drive, by which a magnetic field is generated for biasing the disk during data transfer with an optical data transducer, is positioned sufficiently close to the loaded disk cartridge (10) to appeciably reduce the height or thickness dimension of the disk drive.

Abstract: An optical recording/reproducing system for optically recording and reproducing an information signal on and from an optical disc (31) to be recorded with a plurality of track turns includes a light source (52); an optical head (45b) carrying an objective lens (62) for directing a light beam from the light source (52) to one of the track turns, and a tracking servo actuator for displacing the light beam within a movable range to perform both track feed and tracking servo operations for one of the track turns; the optical head (45b) being stationary with respect to the optical disc (31) while performing the track feed and tracking save operations by displacing the light beam in a radial direction of the optical disc; and a recording area on the optical disc having a radial distance equal to or smaller than the movable range of the tracking servo actuator.

Abstract: A device which is compatible for selectively loading either a first disk cartridge in which a first disk is encased or a second disk cartridge in which a second disk is encased and wherein the radius of the first disk is different from the radius of the second disk, the first cartridge having a first width extending over substantially the whole length of the first cartridge in the intended direction of cartridge insertion, the second cartridge consisting of a front portion having a width equal to the first width and a rear portion having a width greater than the first width, the device including a chassis and a cartridge guiding and loading apparatus supported by the chassis for selectively loading either the first cartridge or the second cartridge, the cartridge guiding and loading apparatus including guides for guiding either the first or the second cartridge as the first or second cartridge is selectively loaded into the device, the guides being moveable between first and second positions such that when in