Abstract: A magnetic recording disk cartridge has a write control sensing aperture extending through the cartridge. A shutter is mounted within the cartridge for back and forth rotational movement between aperture blocking and aperture opening positions. The shutter is restrained against accidental movement or drift from these positions. The shutter can be assembled locked in a write protect position and must be reassembled to permit movement between the write protect and write enable positions.

Abstract: A feather-touch mode changer having low power requirements and being capable of selectively providing a plurality of modes of operation of a tape recording/reproducing apparatus, has two changing mechanisms which are each of the type that includes a rotatable changing gear with a toothless gap, a selectively actuable trigger for causing initial angular displacement of the changing gear from an inactive position in which the toothless gap faces a drive gear to an actuating position in which the changing gear engages the drive gear, and an actuating lever that moves in a response to the rotation of the changing gear by the drive gear. The two changing mechanisms are selectively actuable, and a single drive gear is positioned for engagement with both changing gears. Each of the two changing mechanisms has associated with it a selectively energizable electromagnetic device and a locking lever that moves into a locking position in response to movement of the respective actuating lever.