Abstract: A magnetic recording and/or reproducing apparatus is capable of recording or reproducing data at variable speeds. The value of the tape tension applied to a magnetic tape is set in accordance with the data rate of an input data signal received through an input data processing circuit and a recording signal processing circuit or the data rate of an output data signal output through a reproduction signal processing circuit. The data rate can be set to any one of 256, 128, 64, 32, 16 and 10 [Mbps]. The use of a tape tension value that is appropriate to the data rate, and to corresponding head drum rotation and tape advancement rates, allows the distance between a recording track TR and the control signal CTL corresponding to the recording track TR is kept substantially uniform, whereby the compatibility among different data rates is improved.

Abstract: A tape transport system control device for controlling a tape transport system in which a tape payed out from a supply-side reel driven by a supply-side reel motor travels through a predetermined path to be taken up on a takeup-side reel driven by a takeup-side reel motor, includes a tape speed control servoloop for the takeup-side reel motor, a tape tension control servoloop for the supply-side reel motor, a detecting part arranged to detect a difference between a tape tension obtained on the side of the supply-side reel and a tape tension obtained on the side of the takeup-side reel, and a loop arranged to feed the detected difference of tension forward to the supply-side reel motor.

Abstract: A magnetic data storage disk record carries a pattern of magnetic domains defining a plurality of concentric data tracks divided into data sectors by embedded servo sectors recorded at a predetermined constant frequency and containing head positioning information for positioning a data transducer head for reading the disk track. Each data sector is recorded at a data transfer rate selected in relation to displacement of the track from a center of the disk. Each data sector defines a plurality of variable length data segments which are combined to provide a fixed length user data block. In order to avoid a write-to-read transition and Barkhausen noise, each data sector begins with an ID header immediately following a servo sector. The ID header includes a plurality of count byte fields for providing a count of bytes of each one of the user data segments within the data sector, and a flag field for indicating whether the user data block begins at the first data block segment of the particular data sector.

Abstract: A method for effecting seeks of a transducer head across a data storage disk wherein the head is accelerated over a first sequence of time intervals and decelerated over a second sequence of time intervals. In each time interval of the first sequence, the head is accelerated in relation to the difference between the actual head velocity and a current demand velocity that is determined by incrementing the demand velocity for the previous interval by an amount that is a fraction of the difference between the previous demand velocity and a stored profile velocity selected in accordance with the current location of the head. In each time interval of the second sequence, the head is decelerated in relation to the difference between the actual head velocity and a stored profile velocity selected in accordance with the current location of the head.

Abstract: A servo head in a disk file data storage system includes two servo transducers which are connected so that noise induced by a nearby writing data head cancels. The first servo transducer, mounted on a slider, reads information stored on a servo disk. A second servo transducer, also located on the slider, is connected to the first servo transducer to produce an output signal so that noise signals induced in the first servo transducer by operation of the data transducer tend to be canceled by noise signals induced in the second servo transducer by operation of the data transducer. The two servo transducers are located such that they are closely spaced relative to the size of the servo transducers. The close proximity of the two servo transducers reduces the effect of unequal shielding from noise signals induced in the two servo transducers by the data head.

Abstract: A disk drive system for use in limited power applications is disclosed. The disk drive includes a spindle motor having two or more windings, along with a spindle motor driver which can drive the spindle motor in any of a unipolar, bipolar or tripolar mode. The bipolar or tripolar mode is used to start the disk drive and then the unipolar mode is used to operate the disk drive while data is being retrieved. By combining the three drive modes a large start current reduction and higher rotation velocities are achieved. Current consumption is further minimized by adaptively transitioning from bipolar to unipolar modes of operation. The disclosure also includes a general methodology for optimal motor K.sub.E and K.sub.M parameter selection.

Abstract: Disclosed is a magnetic picture recording and reproducing apparatus in which a magnetic tape is transported at a high speed in a fast-forwarding (or rewinding) playback mode so that a viewer can understand the details of records on the magnetic tape within a shortest possible time. In the magnetic picture recording and reproducing apparatus, the fact that the hub diameters of a pair of reels for supplying and taking up the magnetic tape are larger than capstan diameter is noted and a high-speed picture reproduction in the fast-forwarding playback mode has been attained within a controllable rotation speed range of a motor for driving the take-up reel turntable.

Abstract: A servo head in a disc file data storage system includes a servo transducer and a coil which are connected so that noise induced by a nearby writing data head cancels. The servo transducer, mounted on a slider, reads information stored on a servo disc. The coil, also mounted on the slider, is connected to the servo transducer to produce an output signal so that noise signals induced in the servo transducer by operation of the data head tend to be canceled by noise signals induced in the coil by operation of the data head.

Abstract: In an embedded servo system for a disk drive, prerecorded servo information in each track of the disk includes a multiplicity of different length servo fields. Each track includes at least two types of servo fields where the first type and the second type have different lengths. The length of a servo field refers to the number of prerecorded bytes in the servo field. The multiplicity of different length servo fields includes a first type having a full track address sub-field and a second type having a modulo track address sub-field in place of the full track address sub-field. One embodiment includes the first and second types of servo fields and a third type of servo field. The third type of servo field includes only track following information and no track address information. The servo fields of differing lengths are interleaved in each track of the disk. The servo fields are chosen to provide a high seek sampling rate in comparison to the required performance and a reduction in the servo overhead.

Abstract: Disclosed is a disk drive having at least one disk for storing data. The disk drive includes at least one transducer for reading or writing data to or from the disk. The transducer is attached to an actuator which positions the transducer with respect to the disk. The actuator includes a controllable motor which is used to move the actuator and the transducer attached thereto. The disk drive also includes a ramp for off loading the transducer or for parking the transducer off of the surface of the disk. Also disclosed is apparatus and methods for measuring and controlling the movement of the actuator and attached transducer while the transducer is coming from a position off of the ramp and onto the surface of the disk.

Abstract: In a hard disk drive of a sector servo type, two low pass filters having different filter characteristics are used. One low pass filter has uniform group delay characteristics to accurately detect the peak positions of data read/written by a user without causing any peak shifts. The other low pass filter has attenuation characteristics representing a high degree of attenuation of signal components having frequencies higher than a predetermined frequency so as to accurately detect the amplitudes of burst data for positioning a magnetic head to the center of a destination cylinder by removing noise.

Abstract: A data access module adapted for use in hard disc drives for accessing information from rotational disc storage media which includes an arm assembly rotatably mounted on a support means adjacent a disc stack within the drive or cartridge for positioning a plurality of magnetic slider head assemblies over a desired data track location on the individual discs of the disc stack, a voice coil actuator means provided to the arm assembly and adapted to cooperate with magnetic actuator means in the drive for moving the arm assembly in response to electrical current flow in the voice coil actuator, electronic control means disposed mounted on the arm assembly, and a magnetoresistive position reticle indicating means for counting data tracks during track access operation.

Abstract: To position a magnetic head of a magnetic coding storage device relative to different tracks of a recording medium, a different and previously recorded track is used as the reference track in each case. The magnetic head contains an auxiliary read head which, with respect to the write head, is disposed at a predetermined distance at right angles to the direction of movement of the recording medium and follows the reference track during the movement of the recording medium. A control circuit in a control unit ensures that the auxiliary read head follows this track as accurately as possible. The reference track is a track whose changes in magnetization are recorded with different azimuth angles as instantaneously recorded adjacent tracks.

Abstract: An embodiment of the present invention is a disk drive comprising a rotating disk with a recording surface, a transducer in communication with the surface and swept radially over the surface by a servo-actuator, a variable gain read amplifier connected to the transducer, an analog-to-digital converter (ADC) attached to the variable gain amplifier, an erase frequency oscillator coupled to the transducer for erasing of the disk surface, a memory for storing digital outputs appearing at the ADC, and a controller for signaling the servo-actuator to move to such radial positions that result in transducer read amplitudes that are a percentage of previous read amplitudes represented in the digital memory.

Abstract: Two data-free tracks, a takeoff zone and a landing zone, are provided on a magnetic disc, in order to provide a place for the magnetic head to come in contact with the disc without risk of destruction of data. An actuator controller places the head on the takeoff zone at the start of the disc's rotation and on the landing zone at the finish of the disc's rotation. Wear caused by contact of the head with the disc is thereby distributed over two zones, which prolongs the life of the disc.

Abstract: A disk drive includes an on-board digital sampling analyzer. The drive has a data storage disk spinning at a predetermined velocity, a data transducer head for reading information recorded on a storage surface of the storage disk, an electromechanical actuator mechanism for positioning the data transducer head relative to the disk, a digital actuator controller means for controlling the actuator mechanism within a closed loop head positioner servo and having internal registers at addressable locations, a memory for storing information read from the disk and for storing at least one trace record, and a memory controller for controlling addressing of the memory. A trace taking process and structure reads at least one of the internal digital registers of the actuator controller during a sampling interval and records a resultant trace value within the trace record of the memory. An on-board analyzer process retrieves and processes the trace record into a correction.

Abstract: A disk drive that can read from and write to both standard floppy disks and high capacity floppy disks. The present invention provides a single slot disk drive that can accept both standard floppy disks and high capacity floppy disks. After a floppy disk is inserted, physical cues on the floppy disk are used to inform the disk drive as to the nature (standard or high capacity) of the inserted disk. The disk drive incorporates two interfaces, a standard floppy disk controller and an IDE interface for high capacity disks. The disk drive is configured so that both interfaces can communicate with a host computer at all times, regardless of what type of disk is inserted in the disk drive. This allows the host computer to operate as if it had two separate disk drives available.

Abstract: A magnetic tape has three evenly spaced-apart longitudinally-extending servo track areas. Four equal-sized longitudinally-extending data track areas are disposed between said servo track areas and between longitudinal edges of the tape and one of said longitudinally-extending data track areas. For track following, all servo track areas are simultaneously sensed for producing one head positioning signal. Data tracks are arranged into four groups of tracks, one-half of the data tracks in each group are concurrently accessed. The data tracks on the tape are arranged in clusters. Each cluster has one track from each of the groups of tracks. Two laterally-adjacent track clusters constitute four data track wraps for serpentine scanning of data tracks. The concurrent track accessing respectively occurs in first and second halves of a data track wrap (there is a number of wraps equal to one half the number of track clusters). Each servo area indicates two lateral positions of the tape to the head.

Abstract: A magnetic recording and reproducing apparatus, e.g., a video tape recorder for recording and reproducing digital video signals etc., is intended to reliably perform a tracking control even when recording tracks are formed with high density. A first pilot signal having a large azimuth loss and a second pilot signal without azimuth loss are recorded in a recording track, and a rough tracking control operation and a fine tracking control operation are executed on the basis of the second pilot signal and the first pilot signal respectively.

Abstract: A sensitivity correcting circuit offsets a data head outwardly from an ontrack position by a given quantity (X1), reads first and second servo information (A, B) to provide signals (V.sub.A, V.sub.B), and detects a difference (V1) between the peak values of the signals. Also, the system offsets the data head inwardly from the ontrack position by a given quantity (X2), reads the first and second servo information (A, B) to provide signals (V.sub.A, V.sub.B), and detects a difference (V2) between the peak values of the signals (V.sub.A, V.sub.B). The circuit then computes a proportional coefficient K according to the detected values (V1, V2), and according to the proportional coefficient, finds an offset specific to the data head.