Abstract: An improved phase-locked loop control having DEAD TRACK acquisition wherein a separate oscillator generates a fixed frequency of digital pulses corresponding to the frequency of the data board in the storage media and, in the event of a DEAD TRACK in the storage media, the phase-locked loop control locks onto the fixed frequency output of the oscillator to insure lock during DEAD TRACK integral.

Abstract: An improved phase-locked loop control having a phase detector receptive of a data preamble of all "ones" from a storage sub-system for producing early and late signals to a voltage controlled oscillator in order for the frequency of the oscillator to be synchronized with the frequency of the data. A pattern detector senses the incoming preamble pulses and prevents the generation of the early and late signals when a preamble pulse is not present within a predetermined window of time.

Abstract: A method and apparatus for correcting the presence of non-zeros in the prefix and completion frames of a high density magnetic storage tape and for issuing a pointer identifying the track and frame that the non-zero error condition arose.

Abstract: A single diagonal syndrome generator receives first (forward reading) and second (reverse reading) sets of eight-bit data and a single vertical syndrome generator receives the first and second sets of eight-bit data from a progammable read only memory. The second set of data is reversed in bit order prior to delivery to the syndrome generators. The output of the two syndrome generators are delivered into an error processor and an error correction circuit for correcting errors in the first and second sets of eight-bit data. Upon error correction, the second set of eight-bit data is again reversed to put it in the same bit order as originally read.

Abstract: In a reel to reel tape transport system for determining the radii of the reel to reel tape by generating a series of forward and reverse pulses from a brushless DC motor driving the reel to reel tape, generating a forward series of pulses when said tape is turning in the forward direction and a reverse series of pulses when the tape is turning in the reverse direction, using a state machine to determine a forward or reverse revolution of the tape despite tape reversals before the completion of the revolution, and a counter and decoder for decoding the output of the state machine to provide an accurate determination of one revolution of the brushless DC motor.