Abstract: In accordance with the present invention, a method of operating a magnetic tape drive, a magnetic tape drive and a servo control system are provided for obtaining and maintaining velocity control in a magnetic tape drive. In one embodiment, a method is provided for operating a magnetic tape drive. The tape drive includes a plurality of DC motors, and each DC motor has a plurality of Hall sensors. The DC motors are under the control of a servo system which is configured to read location information from the magnetic tape, and compute a primary tape velocity from the location information, and sense a secondary and tertiary velocity signal and compute a tape velocity based on one of the sensed secondary velocity signal and tertiary velocity. The method includes detecting if the primary velocity location information is available. In response to detecting that the primary velocity location information is available the primary velocity is employed to control the servo system.

Abstract: In accordance with the present invention, a method of operating a magnetic tape drive, a magnetic tape drive and a servo control system are provided for obtaining and maintaining velocity control in a magnetic tape drive. In one embodiment, a method is provided for operating a magnetic tape drive. The tape drive includes a plurality of DC motors, and each DC motor has a plurality of Hall sensors. The DC motors are under the control of a servo system which is configured to read location information from the magnetic tape, and compute a primary tape velocity from the location information, and sense a secondary and tertiary velocity signal and compute a tape velocity based on one of the sensed secondary velocity signal and tertiary velocity. The method includes detecting if the primary velocity location information is available. In response to detecting that the primary velocity location information is available the primary velocity is employed to control the servo system.

Abstract: A method and apparatus is presented to determine a lateral position of a read/write head relative to a sequential information storage medium having a servo signal encoded therein and moving adjacent to the read/write head, where the servo signal comprises a plurality of pulses. The method includes detecting the servo signal using the read/write head and calculating a timing interval between each of the pulses using a clock rate of a clock signal. The clock rate is then adjusted based upon the velocity of the sequential information storage medium.

Abstract: A method and apparatus is presented to determine a lateral position of a read/write head relative to a sequential information storage medium having a servo signal encoded therein and moving adjacent to the read/write head, where the servo signal comprises a plurality of pulses. The method includes detecting the servo signal using the read/write head and calculating a timing interval between each of the pulses using a clock rate of a clock signal. The clock rate is then adjusted based upon the velocity of the sequential information storage medium.

Abstract: In a tape drive during a transition to a stand-by mode, a tape is wound under control of a processor (e.g., CPU) until duration of a time interval between moments when rotational positions of the reels change decreases to a pre-determined threshold. Thereafter, in the stand-by mode, the processor switches control over the tape drive to a low-power logic circuit (e.g., PLC) and enters a power-save mode.

Abstract: Data reliability testing for a magnetic tape drive is conducted separately for the channels of a magnetic tape drive which write and read tracks of a multiple track magnetic tape. Memory stores testing data representing data separately written to tracks of a multiple track magnetic tape; each of a plurality of read channels reads data sensed by a tape head from a separate track of a magnetic tape; and error processing logic detects differences between data from each of a plurality of the read channels, and stored testing data of the memory representing data written to the same separate tracks.

Abstract: Disclosed are systems and methods for positioning a head. An exemplary system includes a light source; a detector configured to receive signals from the light source; a transducer that reads signals from a magnetic tape; a plurality of structures coupled to the transducer and configured to pass in opposition to the detector; a stepping motor; and circuitry configured to determine whether or not a light signal is received by the detector. If the light signal is received, the circuitry commands the stepping motor to move the transducer incrementally in a first direction. If the light signal is interrupted by moving the transducer within a first distance, the circuitry commands the stepping motor to move the transducer in a direction opposite the first direction until the light signal has been continuously received across more than the first distance.

Abstract: In a tape drive during a transition to a stand-by mode, a tape is wound under control of a processor (e.g., CPU) until duration of a time interval between moments when rotational positions of the reels change decreases to a pre-determined threshold. Thereafter, in the stand-by mode, the processor switches control over the tape drive to a low-power logic circuit (e.g., PLC) and enters a power-save mode.

Abstract: A system and method that directs a transducer to a home position while taking into account whether a light source, used to detect light interruption is inoperative. The method for the system including a light source, a detector configured to receive signals from the light source, a transducer that reads signals from a magnetic tape and a plurality of structures coupled to the transducer and configured to pass in opposition to the detector.

Abstract: Data reliability testing for a magnetic tape drive is conducted separately for the channels of a magnetic tape drive which write and read tracks of a multiple track magnetic tape. Memory stores testing data representing data separately written to tracks of a multiple track magnetic tape; each of a plurality of read channels reads data sensed by a tape head from a separate track of a magnetic tape; and error processing logic detects differences between data from each of a plurality of the read channels, and stored testing data of the memory representing data written to the same separate tracks.