Abstract: The present application discloses an electronic switching device in combination with a low noise, low input impedance preamplifier circuit. The resulting electronic preamp assembly is specifically configured so that it can be directly interchanged with existing mechanical relay/preamplifier assemblies such as those presently in use in recorder/reproducer apparatus having dual function record/playback heads, without disturbing the associated operating parameters of the record or playback channels. The electronic preamp assembly includes a balun transformer and a solid state switch coupled from a record amplifier to the record/playback head via a rotary transformer to define the record channel. The playback channel includes a diode bridge switch and a preamp circuit also coupled to the rotary transformer and head.

Abstract: A read/write magnetic head includes a step offset formed in the gap of the head which accordingly generates recorded transitions in a recording medium which also contain a step offset in each successively recorded transition along the length of a track. On subsequent playback of the track by the same or similar step gap head, fine transverse mistracking of the head as it follows the track results in a corresponding echo signal being generated along with the main readout signal. The amplitude of the echo signal is indicative of the degree of fine mistracking while the location of the echo signal relative to the main signal is indicative of the direction of mistracking. Fine mistracking correction is provided by circuits which detect the amount and direction of mistracking and supply an error signal to a tracking servo to correct the mistracking.

Abstract: A user configurable RAID system designed to provide RAID functions as well as mass storage functions in a non-RAID mode. Flexibility is built into the system to allow the user to configure the SCSI bus to which removable drive modules are connected into one or more channels to define some of the drive modules in a RAID set and others as stand-alone drives which are independently operated or logically grouped and operated in a non-RAID mode. Removable internal SCSI bridges allow the SCSI bus to be configured into one or more channels. In the RAID mode, the system is configured to prevent a wrong drive from being removed from the system in the event of a drive failure. The system automatically unlatches only the failed drive. The RAID system includes an intelligent control unit ("ICU"), a RAID controller and a modem. The ICU allows the system administrator to access the RAID system Monitor Utility so that the status of the system may be monitored and its configuration changed.

Abstract: A magnetic storage system includes a magnetic storage medium comprising a keeper layer of relatively low permeability soft magnetic material deposited upon a magnetic storage layer or between multiple magnetic storage layers. The low permeability keeper layer may be disposed either above or below the magnetic storage layer. In the unsaturated state, the keeper layer acts as a shunt path for flux emanating from recorded transitions on the magnetic storage layer, producing an image field of the recorded transitions in the keeper. This shunt path prevents signal flux emanating from the recorded transitions from reaching the head. To read data from a recorded transition on the magnetic storage layer; a bias current is applied to windings of the head, creating a bias flux which saturates a portion of the keeper layer. Once saturated, this portion of the keeper can no longer shunt flux emanating from the recorded transition, which is the region represented by the head reproduce transducer.

Abstract: Improved magnetic tip designs attain low spacing loss and enhance the channel output signal while extending head life. One embodiment includes a relatively flat tape contacting surface whose outer edges are modified to provide a tape contacting surface of dumbbell or bow-tie shape, that is, a shape which is narrower at its center near the magnetic gap and wider at its front and rear ends. The desired shape for the tape contacting surface is attained by shaving or beveling the edges of the tip at a relatively sharp angle to remove more material along the top of the curvature of the head near the gap than at the front and rear of the tape contacting surface. This allows air to bleed from under the tape as the head tip travels past the tape. In another embodiment the desired shape is attained by polishing and/or grinding the edges of the tip at a controlled angle as small as 1.0 degree to remove sufficient material to create the desired bow-tie shaped tape contacting surface.

Abstract: The invention provides techniques for changing the quantization used in multiple generations of selected complexity of data quantization such that the errors incurred in subsequent generations are substantially the same as the error incurred in a generation given the same complexity of data. To this end, in a preferred embodiment, quantizing factors are selected from a preselected finite non-degenerative set of quantizing factors provided in the form of arrays of a periodic series of individual quantizer values, wherein a special numerical relationship is maintained between corresponding quantizer values in successive arrays. A different quantizing factor may be selected for each generation of compression/decompression as required by changing data complexity as when performing a layering process during the generations.

Abstract: A magnetic storage system is disclosed that includes a magnetic storage layer associated with a soft magnetic saturable keeper layer. A transducer is spaced from the storage layer and the keeper layer in flying relationship thereto, with an MR element contained therein to provide high sensitivity detection along with the reduced spacing loss available from the keepered storage layer.

Abstract: Servomechanisms (58 and 60) control a takeup reel (12) and a tension arm (16) in a cassette recorder. The servomechanisms receive control signals (54 and 56) generated in accordance with respective control functions, each of which includes a respective constituent function of the difference between a commanded tension-arm position and a measured tension-arm position. In a position of the tension arm that prevails at the beginning of tape threading the constituent of the tension-arm control function that depends on this arm-position error is a relatively large contribution and gradually decreases to zero as the tension arm moves to the position that it assumes for normal recording and playback. During the same time, the the constituent of the reel-control function that depends on arm-position error begins at zero and gradually increases. Such a gradual transfer of position-error-based control suppresses tape-tension transients that would otherwise result.

Abstract: A magnetic storage system includes a magnetic storage medium comprising a keeper layer of relatively low permeability soft magnetic material deposited upon a magnetic storage layer or between multiple magnetic storage layers. The low permeability keeper layer may be disposed either above or below the magnetic storage layer. In the unsaturated state, the keeper layer acts as a shunt path for flux emanating from recorded transitions on the magnetic storage layer, producing an image field of the recorded transitions in the keeper. This shunt path prevents signal flux emanating from the recorded transitions from reaching the head. To read data from a recorded transition on the magnetic storage layer, a bias current is applied to windings of the head, creating a bias flux which saturates a portion of the keeper layer. Once saturated, this portion of the keeper can no longer shunt flux emanating from the recorded transition, which is the region represented by the head reproduce transducer.

Abstract: A magnetic transducer is batch fabricated from a pair of confronting elongate composite block substrates each formed of a thin cap of non-magnetic material bonded to a much larger block of magnetic material, such as ferrite. An intermediate winding groove is formed in proximate relation to the non-magnetic material along the length of one or both composite block substrates. One (or both) of the substrates is provided with a plurality of parallel spaced V-shaped grooves oriented in a direction perpendicular to the winding groove, wherein adjacent grooves form therebetween track width defining lands. A core layer of high permeability magnetic material, such as Alfesil material, is deposited over the edges whereby magnetic poles are formed of the edges. A gap layer of insulating material is deposited on the edges over the high permeability magnetic material. Two of the composite block substrates are placed with the edges in aligned abutting relation and are assembled by glass bonding.

Abstract: A head having very low leakage flux loss since the head is constructed with a very small elongate magnetic intercore, having a winding window formed therein if desired, with the intercore being supported on either side by non-magnetic side support blocks. The side support blocks enable mounting of the head to the usual style of head block and provide the physical structure and size necessary for formation of a low wear head profile, if desired.

Abstract: A video special effects system and method includes at least one signal system operating in real time to transform one or more input video signals to generate an output video in response thereto, a work station, an operator control panel and a control system communicating with the signal systems, the work station and the control panel. Control surfaces defined by one or two control curves are developed at the work station and subsequent used by the control system to define a video effect in which portions of the input video images are selectively mapped to the control surfaces and subsequently manipulated to define an output video image. The control system operates to define each parameter controlling the output image at selected event times and to individually interpolate each given parameter between the event times at which the parameter is defined. The signal systems generate the output images in response to input images and the instantaneous values of control parameters defined by the control system.

Abstract: A video special effects system and method includes at least one signal system operating in real time to transform one or more input video signals to generate an output video in response thereto, a work station, an operator control panel and a control system communicating with the signal systems, the work station and the control panel. Control surfaces defined by one or two control curves are developed at the work station and subsequent used by the control system to define a video effect in which portions of the input video images are selectively mapped to the control surfaces and subsequently manipulated to define an output video image. The control system operates to define each parameter controlling the output image at selected event times and to individually interpolate each given parameter between the event times at which the parameter is defined. The signal systems generate the output images in response to input images and the instantaneous values of control parameters defined by the control system.

Abstract: An improved magnetic head obviates the need for separate read and write heads in a magnetic storage system by providing a head core having two physical gaps configured to generate a reproduce track width that is narrower than a record track width. The core of the head comprises a tapered center pole disposed between two generally symmetrical main poles to form physical record and reproduce gaps. A magnetically saturable, high permeability element is disposed within the core in a manner that bridges the rear of the record gap.

Abstract: An automatic scan tracking, helical tape type of data recorder is disclosed herein along with its method of operation. Data is written onto magnetic recording tape along with data retrieval information by means of a rotating scanner assembly forming part of the recorder as the recording tape moves at a given recording speed in cooperative engagement with the scanner assembly. Data is normally retrieved from the recording tape along with the data retrieval information by means of the rotating scanner assembly as the recording tape moves longitudinally at the same given recording speed. In operation, the rotating scanner assembly of the recorder retrieves data and data retrieval information from a segment of the recording tape while the latter is not moving, that is, during a period when the tape is stationary for enabling adjustment of the read head position relative to the track depending on the evaluation of the data resulting from the stationary tape read.

Abstract: Drivers (24, 26, and 28) in the controller for a motor (14) drive the motor in accordance with a pulse-width-modulation scheme in which each pulse-width-modulation cycle includes a positive interval and a negative interval so that the value of the filtered output is proportional to the difference in duration between the positive and negative intervals. The pulse-width-modulator cycle also includes dead times between the positive and negative intervals, and these dead times are varied so that a change in a positive interval's duration in a fixed-duration pulse-width-modulation cycle does not necessarily result in an opposite change in the negative interval's duration. Consequently, the value resolution for a system in which the pulse-width-modulation cycle is a given number of system clock periods can be finer than it would be if the dead-time interval's duration were fixed.

Abstract: An improved, shielded magnetic core structure is disclosed that is particularly well suited for use in magnetic read and write heads adapted for narrow track, short wavelength magnetic recording systems, and for transformers of high performance, wide band application. The improved magnetic cores use novel field confinement structures to reduce or eliminate leakage magnetic paths which normally do not link the head gap or do not link the transformer windings. This shielding arrangement substantially improves the performance of such devices, as compared to conventional, unshielded heads and transformers. Embodiments involving toroidal cores, thin film heads, and MR heads are disclosed, along with high performance, wide band transformer structures.

Abstract: In an azimuth recording format, the crosstalk of the A channel into the B channel is higher than the crosstalk of the B channel into the A channel because, at the ends of a magnetic recording where the switching contour of constant magnetic field strength is equal to the media magnetization switching field, the switching contour follows a curve. The resulting curvature at the ends of the magnetic recording vary accordingly the angle of azimuth rejection between the B to A azimuth relative to the A to B azimuth at the edges of the track. The use of a record head of a unique design wherein the trailing pole face of the head extends laterally beyond its leading pole face at the over-writing side of the head, removes the curvature at the ends of the transition recordings forming the recorded tracks.

Abstract: A flexural pantographic mount for use in a helical scan magnetic tape transport, the mount being a boxed leaf stiffened flexural pantograph mount, for holding and varying the position of a moveable head in a helical scan automatic scan tracking magnetic tape transport. The mount includes a moveable body such as a magnetic transducing head assembly coupled at one end of first and second generally parallel spaced apart elongated flexural pantographic leaves configured at the opposite free ends thereof for attachment to a fixed body. Each leaf includes first and second integrally formed and bent leaf edge extensions, which act as side stiffeners. A triangularly configured opening and a trapezoidally configured opening are formed in each leaf with each opening being configured to include tab projections for bending into the opening to provide transverse or lateral stiffening.

Abstract: A translatable capstan/tachometer assembly for use, for example, in transporting a magnetic media in a data record/reproduce apparatus, includes a capstan rotatably coupled to a tachometer unit. The assembly is supported for movement from an initial, unthreaded media position within a threading cavity of a data cassette, to a threaded or locked working position. The media path is arranged so that moving the capstan/tachometer assembly into the threaded position causes the media to wrap around the capstan with a substantial wrap angle. In play, record, jog or variable speed operational modes, movement is provided between a motor/disc assembly and the capstan/tachometer assembly to rotatably drive the capstan. In a high speed shuttle mode, the motor/disc assembly is disengaged but the capstan/tachometer assembly remains in contact with the media, thereby still providing tape speed information via the integral tachometer unit.