Abstract: A starting sequence is provided for a rotating disk data storage device by providing a low level sensing current to the spindle motor which is able to initiate rotation of the disk spindle assembly when, absent stiction between head and confronting disk surface, it is only necessary to overcome disk assembly inertia and head drag. A sensing device is provided to sense a back electromotive force (EMF) in the spindle motor windings which indicates the start of disk rotation when any stiction condition has been terminated. A sequence of alternating current pulse bursts are applied to the actuator motor to impart a dithering action to the heads which induces axial vibration of the disks to break the stiction between the heads and confronting disk surfaces.

Abstract: A method and apparatus for detecting peaks in a signal which comprises an alternating polarity waveform including a plurality of points. A selected point in the signal is designated. Thereafter, a threshold value for the selected point is established utilizing a prior threshold value associated set off with spaces with a point prior to the selected point as follows:(m(n)=t0*ax(n)+t1*m(n-1)wherein n is the point identifier, m(n) is the threshold value, t0 is a fixed positive constant less than one, t1 is a fixed positive constant less than one, ax(n) is the absolute value of the input signal, and m(n-1) is the prior threshold value for the prior point. In this manner the threshold value may be adjusted for fluctuations in amplitude of the signal. Next, the selected point is compared with the threshold value to determine whether or not the selected point is within a predetermined distance of the threshold.

Abstract: A recording film of a recording medium has tracks with a track pitch of 1.6 .mu.m. Each track has a land and a groove, and the width of each of the land and groove is about 0.8 .mu.m. The groove and land differ relatively in height by a degree corresponding to (2n-1)/4 (n: a natural number) times the wavelength of the irradiated beam. At the time of reproduction, reflected diffraction beam components reflected from the land and groove are provided with a phase difference .pi.. Thus, a peak of the diffraction beam is concentrated within the range of the NA of an objective lens, with high intensity. As a result, the presence/absence of pits located at a distance less than a diffraction limit, which have not been detected in the prior art, can be detected.

Abstract: An embedded servo system for a disk drive is disclosed. An asymmetrical position sub-field reduces the overhead of the disk position system. The sub-field includes at least two normal frame pairs and only one quadrature frame pair interleaved with one of the normal pairs to form the asymmetrical position sub-field. The prerecorded embedded servo information in each track of the disk includes a multiplicity of different length servo fields, i.e, each track includes at least two types of servo fields where the first type has a first length and the second type has a second length that is different from the first length. 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.

Abstract: The video-to-data converter buffers and converts the video data received from a camera or a conventional video tape drive into a data record format that is compatible with a computer data tape drive subsystem and its media, such as a 3480-type magnetic tape cartridge. In addition, a header is interposed between a leader portion of the magnetic tape and the remainder of the magnetic tape. This header segment contains two sections, a first of which is a data record directory that is used by the control unit to denote the location of each data record on the magnetic tape as well as administrative data associated with the data record. The second section of the header is an administrative information section that contains data relating to the magnetic tape itself.

Abstract: An optical pickup for all optical disk having multiple recording layers is provided to exactly control a focal position according to the thickness of optical disk, by separately controlling focal positions on each recording layer, wherein a Fresnel lens for diffracting an optical beam generated from an optical source and an objective lens for focusing the diffracted beam are separately located, and focus driving coils are included for separately driving the Fresnel lens and objective lens by using a signal detected by an optical detector. As the interval between the Fresnel lens and objective lens is varied, the interval between focal points formed on each recording layer is also varied. Thus, the focal positions formed on each recording layer can be exactly controlled according to the thickness of optical disk. Therefore, information can be clearly reproduced without interference by simultaneously scanning each recording layer while exactly controlling the focal positions.

Abstract: An optical head assembly for an optical information reading and reproducing apparatus including a laser for emitting a laser beam directed so as to impinge upon an information carrier disc. Rays of light reflected from the information carrier disc is separated into a reproduction signal detecting beam and two servo signal detecting beams by a path separator prism. The reproduction signal detecting beam enters a reproduction signal detector while the servo signal detecting beams enter an image sensor. The image sensor is so positioned as to cause images of the light beams to assume a substantially equal size. By selecting pixels effective to properly detect focusing and tracking errors, various servo signals can be obtained in dependence on outputs from those pixels selected.

Abstract: A method and means is described wherein servo sectors written on a disk (or servo sections written on a tape) are equally spaced on a given track and read during seek, settle and track following operations. An algorithm is used to determine the allowable time separation between servo sectors (or sections) on a track and lengths of associated data sections, such as data sectors or variable length records, that may be accommodated on the disk or tape in such manner that each of the servo sectors (or sections) equally spaced on a given track is located within a data field of a data sector or within an identification region or immediately after an address indicating mark (such as address mark or index mark). The rate at which the servo sector (or section) is sampled is constant and independent of the number and lengths of the data sections.

Abstract: A seek command including a cylinder address and a head address is generated from a disk control unit. In a magnetic disk unit, an off-track amount is read out by the head address obtained by the reception of the seek command with reference to a correction table, and an off-track correcting state in which the off-track amount is eliminated from a position control signal is produced during the seeking operation until the start of the position control. A function to instruct the dependent magnetic disk unit to execute the measuring process of the off-track amount in accordance with a time schedule stored in a time table is provided for a higher-order magnetic disk control unit. The generation of a measuring command during the execution of a command chain is suppressed. When receiving the measuring command from the disk control unit, the magnetic disk unit measures the off-track amount of each data disk for a reference position of a servo disk and stores into the correction table.

Abstract: In a disk drive system having two actuators, each said actuator having a plurality of transducers, said system employing a transducer switching procedure for switching between a first presently selected transducer and a second to be selected transducer, an apparatus, associated with the nonpackwriting actuator, for controlling the sensing of an address mark by said second transducer, said apparatus comprising an address mark means for generating an address mark search signal to start an address mark search when an address mark is expected to be read by said first transducers; and an adjusting means connected to said address mark means for altering the time when said address mark means will generate said address mark search signal such that said second transducer will read the next address mark to occur on the track being read by said second transducer after said second transducer is selected.

Abstract: An optical tape is helically passed over a cylindrical outer surface of a drum at a first speed to effect a substantial circumferential wrap thereof. A first write/read head with a writing laser array generates light beams that are directed along a first path through an optical rotator, and then via an optical arrangement on the drum onto a portion of the optical tape at a wrapping location of the drum to effect helical scanning of that portion of the optical tape. The optical rotator and the optical arrangement are rotated parallel to the first path at second and third rotational speeds, respectively, where the third speed is twice the second speed. This results in a dynamic imaging of the light beams from the first write/read head in closely spaced and parallel tracks to write binary data on the portion of the optical tape at the wrapping location using a passive focusing control.

Abstract: A sector servo, zone bit recording disk drive includes a sector architecture in which the recording head locates and identifies data sectors without using data ID fields, but instead using information obtained from electronic storage and from servo sectors which need not be adjacent to the data sectors. The tracks contain servo information and data, but not data sector ID information. The tracks in each zone are circumferentially divided into segments. Included in each segment is a number of data regions separated from one another by servo sectors. The data regions may contain partial data sectors and complete data sectors. The format information provided to identify and locate data sectors, including ones whose region locations are not adjacent to servo sectors, includes an entry for each region in the section.

Abstract: A recording/reproducing apparatus includes recording medium transporter. A counter counts a number of pulses corresponding to a distance moved by the recording medium in a first fixed period that includes the instant at which the recording medium starts to be fed and a second fixed period that includes the instant at which the recording medium stopping operation is actuated. The count result is utilized by a timing control to control either the timing with which the recording medium starts to be transported or the timing with which the recording medium is stopped. The recording medium is thereby set at a desired position with respect to a recording/reproducing device when it is being fed or is at rest.

Abstract: A method of adjusting the lateral position of writing on a magnetic tape. A magnetic tape recording is provided having a first track including alternate data and servo information wherein the data is written at a first azimuth angle and the servo information is written at a second azimuth angle, and having a second track including alternate data and servo information wherein the data is written at the second azimuth angle and the servo is written at the first azimuth angle. The first track is monitored during writing of the second track for the presence of servo blocks. Writing in the second track is interrupted upon the sensing of alternate servo blocks in the first track. Amplitudes of servo blocks received during writing are compared with amplitudes of alternate servo blocks received while writing is interrupted, and the lateral position of writing is adjusted in response.

Abstract: A head position detecting method and apparatus for detecting a phase difference from servo data on a recording medium to detect the position of a head. This head position detecting method and apparatus detect the phase differences between the read pulse of the servo data read by the head and reference clocks, and average the phase differences to detect the head position. A training area having a timing signal recorded therein is provided before the servo data on the recording medium. A phase-lock loop circuit for generating reference clocks is synchronized with the timing signal to accurately detect the phase differences. An integrator is used to average the phase differences. This design ensures accurate detection of the head position even under fast seek. Further, a phase difference signal around a target cylinder is obtained by selecting the phase of the reference clock in accordance with the position of the target cylinder.

Abstract: In recording and/or reproducing data into and from a disk record medium having a record medium in which a plurality of tracks are arranged radially, the record area is divided into a plurality of zones, and a clock frequency is assigned to each zone. The data recording and/or reproducing are performed according to the clock of the frequency assigned to the respective zone. Each zone is subdivided to include a plurality of tracks, and a clock having a different frequency is assigned to each zone. Each frequency is set in such a manner that the record capacity of the track gradually becomes larger as the zone is nearer to the outer zone.

Abstract: A head reads information from and/or records information to a disc. A head driving unit drives the head on a disc in substantially radial direction thereof, the moving being executed in either a first driving manner or a second driving manner different from the first driving manner and the moving of the head effecting seeking of a track formed on the disc. A disc loading detecting unit detects loading of a disc in said disc apparatus. A switching unit switches over a driving manner from one to another among the first and second driving manners, wherein the switching unit selects the first driving manner while a disc is loaded in the disc apparatus and the switching unit selects the second driving manner while a disc is not the in the disc apparatus.

Abstract: A data recording disk drive includes acceleration rate sensing for controlling or modifying one or more disk drive operations in response to external shock or vibration. An acceleration rate sensor is mounted on the disk drive housing and provides direct detection of acceleration rate of the disk drive when subjected to external shock or vibration. The sensor includes two spaced-apart piezoelectric transducers that operate in current mode. The transducers are connected to an interface circuit that generates two voltage signals that are directly proportional to the angular and linear acceleration rates, respectively, when the disk drive is subjected to an external force. The disk drive microcontroller uses the voltage signals to inhibit writing of data or modify the servo control signal to maintain the heads on track during track seeking or following.

Abstract: A magnetic tape drive in a helical scan system can shorten retry operation time. A data signal reproduced from magnetic tape through reproducing heads is supplied to a regenerative signal processing circuit. If an uncorrectable error is contained in the signal, the regenerative signal processing circuit outputs error information to a system controller. Then, the system controller sends a retry instruction to a movable head controller. When receiving the retry instruction, the movable head controller supplies movable head control signals to displacement elements which then displace the reproducing heads along a rotating shaft of a rotary drum for re-scanning an error occurrence data track. This retry operation is repeated until no error is detected. The magnetic tape is run at lower speed or is stopped as required during the repetitive retry operation.

Abstract: A protective reflex system for a portable computer hard disk initiates protective action before the hard disk suffers the shock of an impact in the event they fall from, for example, a user's lap. A three axis accelerometer is mounted in the portable computer. The output of the accelerometer is continuously monitored by a dedicated processor. In the event of an acceleration event within a preset range of values, the dedicated processor passes a high priority interrupt to the central processing unit of the portable computer and then proceeds to park the disk heads. Alternately, the interrupt routine of the central processing unit may also cause the park operation. In addition to park operation, a brake operation may be performed by either the dedicated processor or the central processing unit.