Abstract: A method is disclosed for specifying subsets and orders of processing of a set of target media elements utilized with a shared data transfer element in the backup of computer data to a data storage target device. Names assigned to selected target media configurations are used to designate logical groupings for storage and recall. In a described embodiment, a selected target configuration, chosen by name, is used to control the robotics of a tape cartridge backup system in coordination with the transfer of data to a tape drive read/write head, to automatically load tapes from user-designated slots of a tape magazine, in user-specified order, into the drive.

Abstract: A method for monitoring the performance of a DAT drive and a method for self-cleaning the tape heads of a DAT drive pursuant to the occurrence of an error that could not be corrected by re-reads or re-writes. The monitoring method includes the steps of (a) reading a tape, (b) determining for each of successive groups of frames respective A track and B track reference error counts representative of the A track and B track C1 error counts in each group of frames, each group having the same number of frames, and (c) providing a warning signal indicative of degraded performance if (i) either the A track reference counts for a predetermined number of consecutive frame groups exceed a predetermined threshold or the B track reference counts for a predetermined number of consecutive frame groups exceed a predetermined threshold, or (ii) if both the A track and B track reference counts for the predetermined number of consecutive frame groups exceed the predetermined threshold.

Abstract: A raw data reader for reading a magnetic medium computer storage device wherein data is stored as binary bits, including a data conditioner responsive to the computer storage device for providing serial binary data representative of the binary data read from the magnetic medium and corresponding thereto on a one-to-one basis, a serial to parallel converter for providing parallel data that includes formatting control information contained in the serial binary data, a decoder for decoding the parallel data, and control circuitry responsive to the serial binary data and the formatting control information for transferring selected decoded data to the host computer.

Abstract: Apparatus for fine positioning a tape head relative to a head carriage that is coarsely positionable by a lead screw. The fine positioning apparatus includes parallel first and second resilient support beams oriented generally parallel to the direction of tape travel and having their ends fixedly secured to the head carriage so as to be deflectable in a direction transverse to the direction of tape travel. The centers of the parallel first and second support beams have their centers secured to a tape head frame which contains the tape. A linear motor drives the tape head frame against the resilience of the first and second resilient support beams in response to a drive signal which, for example, is derived from tracking error information produced pursuant to reading of servo information on tape. Pursuant to the displacement of the tape head frame against the resilience of the support beams, the magnetic tape head is moved along a linear path transverse to the tape travel direction.

Abstract: A system and apparatus for startup and speed regulation of low-inertia capstan motors under circumstances where the capstan load during startup may vary widely. A stiction handler provides dynamic control of the motor drive voltage imposed to overcome stationary friction, minimizing the power consumption on startup independently of variations in drag load or motor inertia. A stepped speed-up signal is applied to the motor instead of a conventional constant current-limited signal or sawtooth ramp signal. Motor speed regulation is imposed at each step of a stepped speed-up drive signal. This invention is particularly useful, for example, in low-power magnetic tape drives that must efficiently adapt to variations in drag between one tape cassette or cartridge and another.

Abstract: A plurality of modules are removeably mounted in a rack. At least one of the modules is a drive module including a tape drive and at least one of the modules is a storage module including a carrousel for removeably receiving a plurality of magnetic tape cartridges. The storage module includes mechanisms for rotating the carrousel to present a selected cartridge to a withdrawal and replacement position. The drive and storage modules have track segments which are aligned in end-to-relation. A robot carries the selected cartridge between the carrousel and the tape drive. The robot includes a carriage mounted for traveling along the track segments and a gripper for gripping and releasing the selected cartridge. The system further comprises a control and sequencing circuit for rotating the carrousel, moving the carriage and operating the gripper.

Abstract: A write equalization circuit that includes a data encoder for producing a binary data signal wherein a 1 is represented by a transition at the start of a bit interval and a 0 is represented by no transition at the start of a bit interval, and a nominal pulse generating circuit for producing nominal equalization pulses respectively synchronized with predetermined 0's in the binary signal. Adjusting circuitry responsive to the binary data signal and the nominal equalization pulses produces a write data signal that includes equalization pulses having a width and location in bit intervals that remain substantially constant with changes in component delays due to changing temperature and voltage, wherein the constant width and location of the equalization pulses are selected to achieve a predetermined suppression characteristic.

Abstract: An optical alignment system for aligning a multiple gap tape head assembly of a tape drive, including a cartridge plate insertable in a tape drive and having a first surface mirror that is parallel to a reference plane for the drive when the plate is inserted in the drive, a microscope objective imaging lens for providing images of the head gaps of the tape head assembly, a video camera and display for providing an operator viewable display of the output of the imaging lens, translation apparatus for moving the imaging lens, and an interferometer cooperating with the first surface mirror for maintaining the imaging lens at a constant distance relative to the first surface mirror as the translation apparatus moves the imaging lens from one head gap to another, such that the imaging lens moves in a plane parallel to the reference plane for the drive.

Abstract: A write equalization circuit that includes a data encoder for producing a binary data signal wherein a 1 is represented by a transition at the start of a bit interval and a 0 is represented by no transition at the start of a bit interval, an equalization timing generator for generating a start signal indicative of the initial edges of equalization pulses for predetermined 0's in the binary data signal, and a multiple stage delay delay circuit having logic gates implemented in an integrated circuit and responsive to the start signal and a control word for providing equalization pulses of a substantially constant width, wherein the number of stages employed for delay is determined by the control word.

Abstract: A method for monitoring the performance of a DAT drive and a method for self-cleaning the tape heads of a DAT drive pursuant to the occurrence of an error that could not be corrected by re-reads or re-writes. The monitoring method includes the steps of (a) reading a tape, (b) determining for each of successive groups of frames respective A track and B track reference error counts representative of the A track and B track C1 error counts in each group of frames, each group having the same number of frames, and (c) providing a warning signal indicative of degraded performance if (i) either the A track reference counts for a predetermined number of consecutive frame groups exceed a predetermined threshold or the B track reference counts for a predetermined number of consecutive frame groups exceed a predetermined threshold, or (ii) if both the A track and B track reference counts for the predetermined number of consecutive frame groups exceed the predetermined threshold.

Abstract: The present invention is an end loaded tape drive for an elongate tape cartridge having a door in one of its sides proximate one end of the cartridge. The tape drive includes an elongate table mounted at least partially within an elongate housing upon which the cartridge may rest. The table is movable in an x-y plane defined by an x axis and a y axis. The drive includes a magnetic head which is fixed against movement in an x-y plane. A cartridge door opening mechanism is provided for opening the access door of the cartridge sufficiently to provide access to the tape by the magnetic head. Movement of the table in the y direction actuates the door opening mechanism and movement of the table in the x direction positions the tape in a read/write position. A motor is further provided for moving the length of tape within the cartridge along the magnetic head when the tape is in the read/write position.

Abstract: A computer storage DAT drive which detects the form of a DAT tape and provides an audio signal output in response to an audio DAT tape. The drive rewinds the tape and then plays the tape at a speed that is about 5 to 15 times normal playback speed. During such playback, the tape length is determined and the subcode information is read to determine the format of the tape being played back. If the subcode tape format information reliably indicates the presence of an audio tape, the speed of playback is reduced to normal playback, and audio data interface circuitry is enabled for processing the audio data and providing an audio output signal to a front panel audio jack, for example. If the tape is not recognized as an audio tape within the playback of a predetermined length of tape, playback speed is reduced to normal playback speed and reading of the subcode information continues.

Abstract: A tape guide device adapted for a magnetic tape transport system is disclosed. A biasable flat spring, mounted on a barrel roller mechanism, frictionally engages the top edge of magnetic tape. The spring is mounted in order to allow simple adjustment of both the force applied to the top edge of the magnetic tape and the contact angle between the tape and the spring at the arc-radius of the barrel roller.

Abstract: Apparatus for orienting a magnetic tape head and a tape drive assembly has a frame with a support, and a shaft mounted for rotation around its axis on the support. The first end of the shaft is pivotally mounted on the support, while the second end, also mounted on the support, is movable relative thereof. A motor is provided for rotating the shaft. A head carriage assembly with a magnetic tape head is mounted on the shaft and positioned so that the head lies adjacent magnetic tape which is located in the tape drive assembly. The head carriage assembly moves up and down the shaft when the shaft rotates, and thereby causes upward and downward movement of the head. The apparatus includes an adjuster for adjusting the orientation of the shaft and head carriage assembly. Further, a laser source, reflectors and accurate measuring instruments are provided for accurately setting the tape head to facilitate accurate location of a track on a magnetic tape.

Abstract: Tape head positioning apparatus that includes a head carriage frame and a parallel beam positioning structure supported by the head carriage for supporting the magnetic tape head and for variably positioning the magnetic tape head relative to the carriage along a path generally transverse to the tape travel direction. The parallel beam positioning structure includes parallel support beams secured at their ends to the head carriage. The magnetic tape head is secured between the bender beam at a location generally between their ends. In a particular embodiment of the parallel beam positioning apparatus, the parallel support beams comprise first and second resilient reed beams having their ends secured to the head carriage and configured to be deflectable in a direction transverse to the tape travel direction. A voice coil linear motor deflects the reed beams pursuant to a control signal to move the magnetic tape head along the path transverse to the tape travel direction.

Abstract: The present invention provides an automated cartridge loader 10 of novel design for use with a cartridge drive 12. In accordance with one aspect of the present invention, there is provided a sequentially loading cartridge loader 10 which allows the unattended storage of gigabytes of data. The loaders are adapted to be attached to a cartridge drive 12. The novel loaders of the present invention may comprise three moving components: the magazine 30, the pusher 91, and the gripper 93. Each moving component has its own drive motor 80, 94, 146. The magazine 30 has a plurality of slots 40 for holding cartridges 38 which are loaded into a cartridge drive 12. The pusher 91 of the present invention is aligned with the cartridge drive 12 and pushes the cartridges 38 into the cartridge drive 12. The gripper 93 closes on a cartridge 38 after it is ejected from the cartridge drive 12 and holds the cartridge 38 as the pusher 91 moves back to pull the cartridge 38 back into its slot 40 in the magazine 30.

Abstract: An apparatus and a method for calibrating the write current applied to a write head (110, 114) in a tape drive (100) finds the peak value of the write current applied to the tape head (110, 114) (i.e., the write current value providing the maximum read voltage amplitude on a tape (104)) by indirectly measuring the voltage sensed by a read head (112, 115). The apparatus includes a digital write current control circuit (170, 160) that applies a write current having a magnitude responsive to a digital write current value. An amplifier (190) in a read circuit (180, 182, 184, 190, 196) has a gain responsive to a digital read gain value. The method includes the steps of sampling the output of a pattern detector (146) (e.g., a gap detector) as the digital read gain value is adjusted for each of a number of digital write current data values applied to the write current control circuit (170, 160).

Abstract: Apparatus and method for assembling data read from a data storage DAT tape into data groups. A tape data processing circuit responsive to the playback of DAT tape for provides for each frame a serial frame information output including a frame header and frame data, and an associated subcode information output, the subcode information output being available in advance of the associated frame information. A processor responsive to the subcode information checks the validity of the subcode information and determines the destination group memory locations of the associated frame data, such destination group memory locations being group frame locations specified pursuant to valid subcode information or temporary storage areas for frames having invalid subcode information. DMA circuitry transfers the frame data to the destination group memory locations.

Abstract: A changer method and apparatus for the loading and unloading of data storage modules from a module drive, such as a computer back-up tape drive, is described. To load the drive, the changer pulls a data storage module, such as a DAT cassette, from a magazine by its end, or face, farthest from the drive. To unload a module from the drive, the changer pushes the module by its end or face found furthest in the interior of the drive's module operative station.

Abstract: In a magnetic sensing head with reduced crossfeed interference circuitry, the winding of each half of a magnetic core of the head is wound in the same direction as the other about the core. Each winding is coupled to an individual differential amplifier and the output of each amplifier is fed to another differential amplifier which provides the head output substantially unaffected by interference signals picked up by the head. Both magnetically coupled and stray capacitive interference are compensated.