Abstract: A method and apparatus is disclosed which minimizes the visual artifacts normally generated when images are compressed for transfer through very narrow band channels such as, for example, the Internet. To this end, the images are pre-filtered and then scaled down prior to compression using a two dimensional spatial impulse filter with good pulse fidelity rather than flat pass bands, rapid cutoff at high frequency and minimal impulse response width. The impulse filter preferably is operated at the 6 db point down about 0.6 to 0.9 of the output image spatial band edge, thereby removing visible aliases in the images while compromising between subjective sharpness and total picture entropy.

Abstract: An easily installed inter-row transfer unit is disclosed employing a movable cartridge bin assembly suspended via linkage from a pair of bearing blocks, wherein the resulting bin assembly carriage travels horizontally along a support housing extending between front-to-back arrangements of rows of library systems, to enable expansion of the library systems into very large mass storage systems. The pair of bearing blocks of the bin assembly carriage are spread or closed to respectively raise or lower the bin assembly from or into a respective library system. Thus, vertical as well as horizontal motions of the bearing blocks are controlled by a motor/cable drum drive device secured to the support housing. In a preferred embodiment, a trapdoor mechanism and a cooperating roller support mechanism are used to enable reversing the direction of horizontal translation of the bin assembly carriage with a single motor/cable drum drive device. Various other embodiments and modifications are illustrated.

Abstract: A relatively simple and easily installed transfer unit is disclosed employing a movable cartridge bin assembly which travels horizontally between two or more cabinets of respective tape cartridge library systems, to enable the expansion of individual library systems thereby increasing overall mass storage system capacity. The bin assembly is presented to a typical cartridge handling robot of respective library systems as if it were part of the stationary bin array housed within the cabinet, which allows the cartridge to be accessed and loaded in a constant orientation. A drive means provides the translation of the bin assembly and cartridge, and depots at preset stop locations include sensor means for indicating the location of the bin assembly and the presence of a cartridge in the bin assembly.

Abstract: A digital servo track pattern for a magnetic medium which can be recorded and reproduced by a recording and reproducing system. The servo track pattern has a plurality of digital mark patterns recorded thereon, each of said digital mark patterns having a leading identifier field of digital bits, a trailing identifier field of digital bits and a field of digital synchronizing data located between said leading and trailing identifier fields. The leading identifier field of digital bits is electrically equivalent during reproducing while the medium is moving in a first direction to the trailing identifier field of digital bits while the medium is moving in a direction opposite to said first direction.

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 tape system that uses a Kalman filter to produce both an estimate of the tape pack radius and an estimate of the associated estimation error variance. The Kalman filter produces the estimates based on current and prior angular estimation position measurements of the reel, capstan, and tension arm, and the prior estimates of both the tape pack radius and the estimation error variance. The filter gain is based on prior estimation error variance and a calculated measurement error variance, which is a function of the current and prior measurements. Preferably, the system uses two Kalman filters, one to produce the estimates for the supply reel and one to produce the estimates for the take-up reel.

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: There is described a tape format and a method for formatting a length of magnetic tape with a number of system zones. Each system zone contains an area for mechanical load/unload operations or threading operations and an area containing volume format information for the entire magnetic media.

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: A magnetic storage medium comprises a keeper layer of soft magnetic, saturable material disposed upon a magnetic storage layer. The keeper layer is disposed above the magnetic storage layer, and a non-magnetic "break" layer may be used between the keeper and the storage layer to reduce the exchange coupling between these layers. To increase the ability of the keeper layer to shunt flux from the magnetic storage layer, a longitudinal anisotropy is induced in the keeper layer. This establishes a desired magnetic orientation of the keeper which facilitates maintaining the regularity (i.e., relative uniformity) of the transitions, and reducing the magnetic interaction between transitions as the spacing between transitions is reduced to provide denser media. Specifically, the longitudinal anisotropy may be oriented either circumferentially or radially relative to the plane of rotation of the magnetic storage layer.

Abstract: The flexible, particulate magnetic storage medium includes a substrate and a magnetic storage layer of hard magnetic particles held within a binder. The flexible, particulate magnetic storage medium also includes a soft magnetic keeper layer. The soft magnetic keeper layer may be established by coating the individual hard magnetic particles of the magnetic storage layer with a layer of soft magnetic material to establish a "keeper layer" around each particle. A break layer of non-magnetic material may be provided between the hard and soft layers. The individual particles are coated by methods such as in situ precipitation. The soft magnetic layer may also be established by providing a separate layer of soft magnetic material within a binder of cross linkable resins. The resulting flexible, particulate magnetic storage medium is a laminate principally comprising a substrate, a first layer of hard magnetic particles within a binder, and a second layer of soft magnetic particles also within a binder.

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 servomechanism for controlling the position of a magnetic-tape playback head (16) with respect to a track (24) of digital data on a magnetic tape (22) positions the head by reference to an error signal that error-signal-generation circuitry (FIG. 10). generates. Sample-clock signals obtained from simultaneously read azimuth-recorded data tracks clock respective frequency dividers (52 and 54), and a phase detector 56 generates the error signal by comparing the frequency dividers' outputs.