Abstract: A purge erase apparatus is presented to erase information stored on a magnetic disc. A multiplicity of coils are connected in parallel and are arranged around the disc to create a magnetic field having a region of maximum field intensity. When an erase signal is given, the information on the disc will be erased in one or two revolutions of the rotating magnetic disc through the region of maximum field intensity.

Abstract: A tape transport cartridge is presented having a pair of brakes for the drive belt, the brakes being positioned to increase the angle of separation of the drive belt from the magnetic tape. This increased angle of separation results in improved drive of the tape, and the dual brake arrangement also establishes a more nearly constant instantaneous velocity differential for the tape packs, resulting in a lower and more constant tape tension.

Abstract: Long and short term variations in the speed at which a magnetic tape is moved with respect to a read and/or write head are minimized by maintaining the product of the speed of the tape payout and take-up reels constant. In accordance with a preferred embodiment the rotational speed of the payout reel and the rotational speed of the take-up reel are sensed and effectively multiplied to derive a signal which is compared with a predetermined constant magnitude reference signal. The result of the comparison is an error voltage which is employed to energize and thus control the speed of the drive motor for the take-up reel.