Abstract: The equivalent of D.C. erase in magnetic tape using a rotating head is accomplished by transmitting a time asymmetric square wave across a rotary transformer to the rotating head. The time asymmetry of the square wave in combination with passage of the square waveform across the rotary transformer creates in the rotating head an erase current asymmetric in amplitude about an average value. The short interval of the square wave has a large amplitude in one direction and the long interval portion of the square wave has a short amplitude in the opposite direction. This current signal in the head produces alternately a large flux bubble above the head and a small flux bubble above the head. By maintaining the relative head to tape speed such that the large flux bubble always overlaps the small flux bubble, the tape can be D.C. erased by an asymmetric waveform.

Abstract: A character generator for full page, raster scan printing is controlled to sequentially generate parts of different characters in a single scan. Further the character generation control independently stores for each row of text to be generated, the order position of a character or symbol being generated and the remaining number of raster scans required to complete generation of the symbol. Use of this control permits the sequential generation of parts of symbols even though the symbols have different relative widths and the full page raster scans are in a direction normal to the lines of text on the page. Use of the control also permits text assembly in a page memory to be generated in printed lines of text that extend either parallel or normal to the direction of light spot scanning by selecting predetermined alternative page memory access sequences.

Abstract: This invention provides techniques for producing unique cobalt-phosphorus (Co-P) particles. The Co-P particles produced by this technique are novel as to both size and morphology. Their size is uniformly less than about 300 A, with average sizes being about 150 A. This is substantially smaller than Co-P particles previously known or reported in the literature. Their morphology is unique, as shown by x-ray and electron diffraction, in that they are amorphous. All known prior art Co-P particles have been crystalline. In addition, these Co-P particles have the capability of being manufactured with selectively controlled magnetic coercivity.The new reaction system utilized to produce these unique materials provides a substantial departure from art known systems.

Abstract: A magnetic transducer exhibiting the magnetoresistive (MR) effect is made by depositing at least two thin film layers. An MR film placed in electrical contact with a higher resistivity layer is magnetically biased by a portion of the MR sense current shunted through the nonmagnetic layer.

Abstract: A head is moved toward and rotated against an abrasive while its resistance is monitored by a four-lead bridge. Prior to final manufacture, the head includes a highly conductive segment which surrounds the active head element on three sides and is electrically connected to it at one point. The segment is ground away during manufacture. Two leads from the head are connected to two slip rings, and each slip ring has two pairs of brushes, each wire from the bridge going to a different brush pair. Head movement toward the abrasive is terminated when a predetermined head resistance is detected by the bridge.

Abstract: A magnetoresistive (MR) layer is placed offcenter the distance between two shields to enhance self-biasing. Information is carried on a magnetizable medium as recorded magnetic areas. The shields are spaced apart by a distance on the order of and less than the shortest recorded wavelength for which the head is meant to be used. The MR element and the shields have their edges nearest the medium in a common plane perpendicular to the vertical component of a signal from the recorded area. An additional shunt bias layer may be provided immediately adjacent and coextensive the MR element, and the head may serve one or many tracks.