Abstract: A method and apparatus is disclosed which reduces tape stiction during tape acceleration and deceleration. Tape tension is adjusted to eliminate the effects of tape stiction when the tape is either accelerated from a stationary position to a steady state velocity, or decelerated from a steady state velocity to a stationary position. This method uses tape tension, tape velocity, and tension reference profiles stored in a microprocessor to dynamically adjust the tape tension during tape acceleration and deceleration. The tape tension is adjusted as a function of tape velocity by the use of both a current generated by the tension reference profile and a feedforward current. The feedforward current is determined by the sum of the tape velocity and tape tension profiles. This dynamic adjustment of tape tension essentially eliminates tape stiction in tape start and stop operations.

Abstract: The takeup reel positioning apparatus for the tape threading operation in a magnetic tape drive functions to precisely locate the takeup reel slot at the end of the tape threading path in order to enable the tape threading arm to load the leader block therein. This precise positioning is accomplished by the use of a disk that is fixedly attached to the takeup reel motor shaft. An interrupter is provided whose beam transverses the disk in the region of an annular ring thereon thereby indicating the presence of a transparent or opaque portion thereof. A selected boundary between the opaque and transparent portions of the annular ring is in the path of the beam of the interrupter at precisely the same time that the takeup reel slot is positioned at the end of the tape threading path. The interrupter is used to cause the takeup reel motor to oscillate around this predetermined position to automatically compensate for any mispositioning caused by inaccuracies in the appartus.